Epoxy 101


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Measuring & Mixing

  • How do I measure by volume vs by weight?

    Liquid products can easily be measured by volume; paste and solid products must be measured by weight. To measure by volume, the use of disposable cups with graduation marks on the side is adequate. Pour the Part A resin and the Part B hardener on top of each other, in the same container. For measurement by weight, a gram scale (for small batches), or a postal scale(for larger batches) is necessary.

  • How to use a 50mL cartridge.

    The 50mL cartridges are available with our 1:1 adhesives such as the T-88 and QuickCure 5 & 15 only.

  • Waxed paper cups.

    System Three's wax-lined paper cups are designed for measuring and mixing and not for storage. Most people will mix a volume as needed and apply it to the substrate well before it gets hot. Therefore, the wax coating is negligible. If a longer working time is needed, the contents should be poured into a wide containment such as a plastic paint tray. This will lengthen the pot life of the mixed epoxy and prevent it from getting too hot.  

  • How much epoxy do I need for my project?


    The tables below are a guide for estimating the amount of material recommended, depending on the end use.


    Coating Plywood/Hardwood

    Mixed resin/hardener coverage in square feet per gallon



     Seal Coat


     Build Coats





    400/4 mils





    400/4 mils

    Vertical Surface




    500/3 mils

    *Some soft wood materials will require 2 seal coats due to higher absorption.



    Mixed resin/hardener coverage in square feet per gallon





     Fill Coats

    4 oz. cloth





    6 oz. cloth





    10 oz. cloth





    24 oz. Biaxial Tape






    Adhesive Glue Lines








    Clamped Joints

    3-4 mils



    Vacuum Bagging

    8 mils



    Stapled Veneer

    20 mils







    Fillet Size

    1/4” X 1/4”

    1/2” X 1/2"

    3/4” X 3/4”

    1” x 1”

    Ounces Per Linear Foot









    Fairing Thickness



    1/4 “


    Ounces Per Square Foot








    U-TAH Cartridge*


    Bead Size

    1/8” x 1/8”

    1/4” x 1/4"

    3/8” x 3/8”









    Quick Cure 5 & 15




    *The units reflected are linear feet per cartridge.


    System Three® Resins, Inc.  P.O. Box 399, Auburn, WA 98071


    The information contained herein is based on the data available to us and is believed to be correct. However, System Three Resins, Inc. makes no warranty, expressed or implied, regarding the accuracy of these data or the results to be obtained from the use thereof. System Three assumes no responsibility for injury from the use of the product described herein.














  • Why did my epoxy heat up soon after I mixed it?

    Many of our clear epoxy adhesives, coatings, and laminating resins will heat up, or exotherm, if left in the mixing container too long because of the chemical reaction.

  • Epoxy got hot. What happened?

    Most of our liquid epoxy products need to be poured out soon after the two parts are mixed together to prevent premature curing, called "exotherm."



Product Compatibility

  • System Three Epoxy Products for Aquariums

    Q:  Can you make an aquarium out of System Three products?

    A:  Yes.  Here's a suggestion:

    Design and build the parts out of wood and/or fiberglass using Silvertip™ or General Purpose™ Resin systems.  Then bond the parts together with one of our adhesives like Gel Magic or T-88

    Finally, for finishing, because our products have not been tested for aquatic leaching potential, you cannot assume they will be safe for contact with your fish.  You'll need to apply a coating to the completed unit that has been tested for its safety with fish.

  • System Three Epoxy products and food contact.

    Q:  Can you make wooden goblets, cups or dishes out of System Three products?

    A:  Yes.  Here's a suggestion: Turn or carve them using the wood of your choice, then brush 2-3 coats of Silvertip™ or General Purpose™ Resin on the sanded surfaces. This will make them waterproof and even dishwasher safe.

    But for a final finish, because our products have not been tested for direct food contact, you must then apply a to the completed unit that has been tested safe for food contact.




  • Can I use TransTint dyes with System Three epoxies?

    While we have received positive feedback from customers who have used small amounts of TransTint liquid dyes, we have not tested it in our lab to guarantee it will work well. The majority of our epoxies are solvent free, 100% solids epoxies so care should be taken when introducing these solvent based colorants. The user should test the TransTint dye to ensure it cures to their satisfaction.

  • Can I use the hardener from one of your epoxy systems with the resin from another?

    No. Epoxy resin systems are two-part products where each part is designed to go with the other in the specified proportions.

  • Can I coat urethane (poly iso) foam with epoxy?

    Silvertip, General Purpose, or Cold Cure epoxy resin will coat the foam without attacking it.

  • Painting and finishing System Three epoxies.

    We have found that most two-part or water-based paints will work well over System Three epoxies. This includes house paint. Solvent-based lacquers are also compatible.  One-part alkyd-based(aka oil-based) paints contain drier compounds that can be incompatible with epoxy hardeners, so the paint or varnish must be tested for compatibility before use. If the paint isn't dry in the time it states on the can, it's incompatible. 

    Surface Preparation: Allow the epoxy to reach full cure before priming or painting, then follow the manufacturer's instructions for surface preparation on the can.

See all 9 articles

Storage and Shelf Life

  • What is the shelf life of your epoxy resin products?

    Performance of our epoxy products is guaranteed for three years from the date of manufacture, printed on the bottom of the containers, provided they are stored properly. They will probably last much longer, but they should be tested first after the three-year period. The resin may crystallize or the hardener may darken but this does not affect its performance. Crystallized resins should be reheated in a water bath that is at least 125°F until the resin clears up prior to use on the project.


  • Will epoxy be damaged if stored in freezing or cold temperatures?

    Crystallization occurs when the product is exposed to low temperatures for prolonged periods of time; the presence of any impurities will then initiate the crystallization process. 
    System Three products are formulated to resist Crystallization, but it can still occur. 
    Heat will bring the resin back to a usable state, and the best way to heat the resin is to place the container in a water bath with water heated to 125°F. 

  • Shelf-life of System Three paints.

    System Three Silvertip Yacht Primer and WR-LPU Topcoat paints are guaranteed for 3 years from the date of manufacture. However, the shelf-life can be extended if stored well sealed above 50F. After 3 years, we recommend pre-testing a small sample prior to use. 


  • How to decipher the batch number or code.

    The batch number is a 6-digit code that is associated with the product's manufacture date and is typically located on the bottom of the container. 


    Example: A product with the batch code #806141 was manufactured on June 14th, 2018.


  • Avoiding Bubbles In Epoxy Applications

    Bubble formation in epoxy coatings is more times than not the result of air expanding within a porous substrate and releasing into the freshly applied epoxy.  To avoid this issue consider the following:

    1. Avoid applying epoxy on a surface that is being heated either by the sun or a conventional heater.  When possible, wait till the substrate has stabilized in temperature or is in the process of cooling before applying epoxy. 
    2. The first coat of epoxy applied on raw wood should be very thin.  Use a 1/8" foam roller and apply the epoxy at 1/2 fluid oz. per sq. ft.  Some ultra-porous substrates may require a second seal coat.  If a seal coat is applied too thick, persistent bubbles which are difficult to remove will result. 

    3. Bubbles can also be present over a fully sealed substrate.  These bubbles are the result of entrained air from mixing or the product from brushing or rolling.  Most of the time these bubbles will pop naturally.  Stubborn bubbles can be popped by lightly dragging a brush over the surface of the epoxy.  A propane torch can be used judiciously by holding the flame 6-8" from the surface while moving quickly back and forth.  Do not overwork the bubbles with the torch as scorching of the epoxy can occur.  
  • How do I clean up resin, hardener, and any uncured epoxy?

    Solvents such as lacquer thinner, denatured alcohol, and acetone may used for cleaning spilled resin and hardener. Lacquer thinner is the best choice for cleaning any mixed uncured epoxy. 

  • How to remove cured epoxy.

    Cured epoxy can be successfully removed from most substrates by using a quality paint and epoxy stripper.  However, care should be exercised as the stripper can damage other surfaces.  Carefully follow the manufactures instructions and recommendations.

  • How to fix orange peel in an epoxy coating.

    To help fix the appearance of orange peeling, please allow the existing epoxy to cure for about 48 hours or until hard enough for sanding. Block sand flat using 120-150 grit, vacuum sanding dust and wipe clean with denatured alcohol. You may then re-coat.

  • The Part B hardener has gotten darker over time. Can I still use it?

    Probably. Hardeners yellow and darken over time due to contact with air and sunlight. This does not affect their performance. If the batch date is older than 3 years, to satisfy yourself do a small test and make sure it cures properly.  Batch code: X(YEAR) XX(MONTH) XX(DAY) X (INTERNAL CODE).

  • Get rid of bubbles in an epoxy coating.

    Two methods can be used to rid of bubbles in an epoxy coating:

    1. Roll and Tip Method: Bubbles that persist in the coating can be broken with a disposable bristle brush by lightly dragging it across the surface after rolling the product out. 

    2. Propane Torch: Quickly and lightly fan 6-8 inches above the uncured surface with a propane torch to accomplish bubble popping with greater speed. Avoid overheating an area as this could cause the epoxy film to pull away from the surface creating craters.

    NOTE: When coating a porous surface like concrete or wood, overheating to pop bubbles with a torch can cause the expansion of any air in the pores of the substrate and can make the bubble situation worse.

See all 8 articles

Product Safety


  • System Three products and aquariums

    Q:  Can you make an aquarium out of System Three products?

    A:  Yes.  You can build it out of wood and fiberglass using Silvertip™ or General Purpose™ Resin systems.  And then you can bond the parts together with one of our adhesives like Gel Magic or T-88.  But because our products have not been tested for aquatic leaching potential, you must then apply a finish to the completed unit that has been tested for its safety to fish.

  • Do I need to wear a mask when working with your materials?

    Wearing an organic vapor respirator is necessary in the following situations:

    Spraying Silvertip Yacht Primer,

    Spraying WR-LPU

    Spraying, brushing, or rolling S-1 Penetrating Sealer

    Most of our products do not contain hazardous volatile materials, so wearing a vapor respirator is not necessary.  However, when sanding any of our products when cured, it is highly recommended you wear a dust mask or respirator, as any airborne dust particles can be irritating.

  • Are your products REACH Certified?

    Yes.  If you need documentation, please contact Technical Support, support@systemthree.com, and reference the specific product.

  • Are your products compliant for RoHS?

    Yes.  If you require documentation, please contact Technical Support, support@systemthree.com, and reference the specific product.



Surface Preparation


  • What is the minimum application temperature for epoxy?

    Different products have different minimum tolerable application temperatures. Please see the individual product pages on the website or the Technical Data Sheets for the product.

  • Painting over worn non-skid.

    Applying a fresh coat of paint over existing non-skid can be done, but.....  The main principles behind good paint adhesion are first, the substrate must be clean and secondly, it must be sanded.  Due to its rough surface, non-skid is difficult to both clean and sand. 

    Clean the surface with TSP in warm water with a heavy duty bristle brush.  Go over the surface a few times from different directions to ensure surface contact with the bristles.  Rinse the surface well with fresh water and allow to dry.

    Since the non-skid particles will prevent standard sandpaper from deglossing the surface, use an abrasive pad. Again go over the surface a few times from different direction to ensure that the entire surface is deglossed.  

    Rinse the surface well and allow to fully dry before painting.

  • Painting over System Three Epoxies / Adhesives

    System Three epoxies/adhesives offer a very good substrate for most interior and exterior paints.  The epoxy/adhesive should be cured 2-3 days prior to painting.  Before painting, wash the surface with warm soapy water.  Once dry, sand the epoxy with 150-220 grit sandpaper.  Clean the substrate and you're good to go.  

    Priming is typically not necessary unless specified by the manufacturer.  Priming is beneficial when painting with colors that have poor hiding characteristics (red, orange and yellow).

  • Can I use stearated sandpaper in preparation of System Three epoxies or varnish?

    Avoid using sandpaper that contains stearates.  Stearated sandpaper can cause coating defects such as fisheyes.  Most of the well known manufacturers such as 3m and Norton make abrasives that are safe for epoxy, paint and other coatings.

  • How to prep surface of aluminum before bonding with epoxy.

    Method One (Recommended)

    1. Degrease with denatured alcohol or acetone.

    2. Apply an aluminum pre-treatment primer or solution such as Alumiprep-33.

    3. Rinse the metal thoroughly in cold running tap water followed by distilled or deionized water rinse.

    4. Bond within 1 hour.

    Method Two

    1. Degrease with denatured alcohol or acetone.

    2. Sand to 80-100 grit.

    3. Clean sanding dust.

    4. Bond within 3 hours.



  • Sanding guidelines for applying multiple coats of product.


    • Recoating or applying multiple coats of one of our 2:1 epoxy products (General Purpose, SilverTip, Clear Coat, MirrorCoat, etc.) can be done without sanding if done within 72 hours of the previous coat. Beyond 72 hours, sand the previous coat with no higher than 120 grit sand paper to ensure the next coat adheres or properly levels out. 
    • For S-1 Sealer and Cold Cure products, the recoat window is 24 hours. 
    • For all System Three adhesives (Quick Cure, T-88, Gel Magic, MetlWeld, etc.) sand in between coats for best adhesion if a second application is desired. Please follow all instructions on substrate surface preparation prior to applying System Three adhesives.
    • For fairing compounds, putty, and pastes, please allow to fully cure then abrade or sand if additional product is to be applied.


  • Sanding guidelines for applying one System Three product over another
    • Recoating or applying one product on top of another for most of our 2:1 epoxies (General Purpose, SilverTip, Clear Coat, MirrorCoat, RotFix, etc.) can be done without sanding if done within 72 hours of the previous coat or product. Beyond that, sand the previous coat or product with 120-150 grit sandpaper to ensure the next layer adheres to the previous one. 

    • For S-1 Sealer and Cold Cure products, sanding must be done after 24 hours. 

    • For all System Three adhesives (Quick Cure, T-88, Gel Magic, MetlWeld, etc.) allow an overnight cure, sand the surface and apply more product.

    • For QuikFair, allow to harden 4-6 hours then sand with 120-150 grit paper and apply more QuickFair.

    • For SculpWood Putty allow to harden 4-6 hours then sand with 120-150 grit paper.  Apply RotFix Epoxy then while wet, add more SculpWood Putty.

    • For SculpWood Paste allow to harden 6-8 hours then sand with 120-150 grit paper and apply more SculpWood Paste.

Product Application


  • How much clamping pressure do I use for an epoxy glue joint?

    Epoxy adhesives, being gap-filling glues, need only enough clamping to close the joint. Unlike other glues, epoxy requires low pressure and a proper film thickness of resin to make a proper glue joint. 

  • System Three Adhesives And Knife Making

    System Three manufacturers a number of adhesives for the knife maker.  We offer both 5 and 15-minute fast setting materials.  Quick Cure-5 and Quick Cure 15 are used to glue wood and composite materials (G10 and Micarta) with decent performance.  For high performance applications, T-88 offers superior heat and impact resistance, while having a 30 minute working time.  When working with oily, tropical woods, our G-2 adhesive excels.  It too has very good heat and impact resistance with an exceptionally long working time of 1.5 hours.  Both T-88 and G-2 bond well to nearly all materials used for crafting knife handles.

    Epoxy adhesives perform best by ensuring that both surfaces are clean and sanded.  Apply the adhesive to both surfaces and apply only enough pressure to close the joint.  Over clamping will result in a starved joint and poor bond strength.  

  • How soon can another coat of Quick Cure 5 or 15 adhesives be applied?

    QuickCure 5 or 15 can be reapplied over the top of an initial coat as soon as the adhesive gels.

  • What is the maximum moisture content allowable for gluing wood?

    For an epoxy adhesive or solvent-free coating to bond well to a wood surface, the moisture content of the wood should be 12% or below.  To give you some choices, here's a link to the adhesives page on our website.

  • Can I glue wet wood with one of your products?

    For an epoxy adhesive or solvent-free coating to bond well to a wood surface, the moisture content of the wood should be 12% or below.  To give you some choices, here's a link to the adhesives page on our website.

  • Which product do you recommend for gluing oily woods such as teak and rosewood?

    We recommend the G-2 Adhesive for oily woods. Surfaces to be bonded should be free of oils for optimal adhesion. With a clean cotton rag liberally moistened with lacquer thinner, vigorously wipe area to be bonded. While surface is still moist with solvent, wipe with a dry rag and allow to dry completely. If necessary, repeat wiping until surface dries to a whitish color indicating extraction of surface oil. Once dry, sand using 120 grit to open up the grain. Bond within eight hours of cleaning.

See all 9 articles

EndRot Kit

Flotation Foam

General Purpose Epoxy

  • How to incorporate thickener and fillers into General Purpose Epoxy

    If you prefer to mix your own putties, pastes, or thickened epoxy concoctions, here a couple of guidelines:

    The correct sequence for making your own recipes:

    1. Correctly measure and mix General Purpose resin/hardener. 
    2. Add fibrous fillers like milled or chopped glass, or mini-fibers and mix well.
    3. Add bulking agents, like microspheres and mix well.
    4. Add thixotropic agent like fumed silica, or wood flour and mix well.

    Please see The Epoxy Book Section VII C - Modifying Epoxy with Fillers for more information. 

Marine Spar Varnish

  • Recoating Varnish

    Marine Spar Varnish can be recoated in 10-12 hours at the recommended coverage rate.  The varnish can be recoated without sanding up to 24 hours.  Beyond 24 hours, sanding is required.  Use 220-320 grit paper for brushing applications.  Use 400-600 grit for spray applications.

  • Buff and polish Marine Spar Varnish

    Marine Spar Varnish can be buffed out to remove dust and minor surface scratches.  The video below details how to buff and polish our popular MirrorCoat bartop coating.  The same process can be applied to buffing and polishing the Marine Spar Varnish.  See the MirrorCoat Buffing & Polishing Procedure below for detailed instructions.


  • How do I thin down or lower the viscosity of the Marine Spar Varnish?

    The Marine Spar Varnish can be thinned with mineral spirits at up to 10-15% by weight.

  • Marine Spar Varnish Over Sanding Sealers

    System Three® Marine Spar Varnish can be used over some sanding sealers but it will depend on the formulation of the sealer. Most lacquer-based sanding sealers are not recommended because the sanding aids are wax-related. We recommend testing the varnish over any other sealers in a small section to ensure you get good adhesion between the two coatings.  Also, for future reference, the Spar Varnish does not require sanding in between coats if applied within 12-24 hours of the initial coat. 



  • What are the causes for fish-eyes or craters in Mirror Coat?


    From our experience, cratering or fish eyeing almost certainly indicate that one of three things occurred during your application:

    1. Insufficient drying and/or incompatibility with a stain or oil: Pre-testing is always recommended when using products from another manufacturer.

    2. Sanding too smooth can cause the epoxy to draw away from the surface. For example, sanding higher than 220 grit will make it difficult for the Mirror Coat to overcome the surface tension of the substrate. 

    3. Lack of coverage: We specify pouring the MirrorCoat at 4 oz/sq ft to allow enough coverage on the substrate. Any less will result in a lack of adequate coverage.


  • Thickness of MirrorCoat

    A seal coat plus a flood coat per System Three recommendations yields approximately 70 mils of thickness or a fat 1/16".  This thickness can vary slightly depending on substrate porosity. 

  • How much Mirror Coat do I need for my project?

    Mirror Coat requires a total of 4.5 ounces per square foot (1/2 ounce for the seal coat and 4 ounce for the flood coat) of mixed resin and hardener. Therefore, you can multiply the square foot area of your project by 4.5 to calculate an estimate coverage. 

  • How to apply MirrorCoat over previously varnished wood.

    For best results, the varnish film must be intact, and not flaking or peeling.  Then Mirrorcoat can be applied and present a uniform appearance.  Ensure the film is sufficiently cured, clean, and sanded with 80-120 grit untreated sandpaper.

  • Can fine scratches or defects be buffed or sanded out of your products?

    Yes.  System Three® offers a sanding and buffing kit for sale on the website.  Contents are shown below.  The video shows its use with Mirrorcoat®, but it also works well on WR-LPU and coating epoxies like Silvertip™.  Click on the image for detailed information and to purchase.



    A white paper literature piece can also be downloaded from the website here:

    Guide to Buffing and Polishing

  • Can fine scratches be buffed or sanded out of Mirrorcoat?

    Yes.  System Three offers a sanding and buffing kit for sale on the website.  Contents are shown below.  The video shows its use.


    A white paper literature piece can also be downloaded from the website here:

    Guide to Buffing and Polishing

See all 10 articles


  • Can QuickFair be applied over SilverTip Yacht Primer?

    Often, once the primer is applied, you will notice some sort of defect (pinholes or a low spot) that was not addressed before priming.  Such defects can be filled with QuickFair.  Lightly sand the primer with 150 grit sandpaper and clean well.  Apply the QuickFair with a flexible spatula.  Once sufficiently cured, sand and feather out the edges.  Clean the area well and then apply the SilverTip Yacht Primer.  If full hide is achieved, then no additional coats of Yacht Primer are necessary.  

  • Sealing Quikfair before priming with paint.

    Quikfair is slightly porous when sanded so we recommend sealing it with a thin coat of epoxy before priming and painting. Sealing will help to keep your primer coats consistent throughout. We recommend using a 2K epoxy such as our Silvertip Laminating Epoxy or General Purpose Epoxy for this, followed by the Silvertip Yacht Primer

  • Can Quikfair be stained?

    Quikfair will not accept stain.  For a surface to accept stain, or be "stainable," it must have a certain amount of porosity, for colored stains must sink into a surface.  Quikfair is highly-filled, but the rest of the formula is an epoxy resin blend, which will seal the surface too well for it to accept stain once the Quikfair has cured.


  • Rotfix on damp wood.

    RotFix is chemically formulated to cure over damp substrates. Best results are achieved by removing the wet, punky wood from the repair area.  If the wood is visibly wet after removing the punky material, use a hair dryer or heat gun to further dry the substrate.





  • RotFix Epoxy Coverage Rate

    RotFix Epoxy soaks deeply into porous wood materials.  Because of the varying porosity of rotting wood, the coverage rate can only be estimated within a range.  RotFix is available in 4 different kit sizes.  The kits are listed below with the approximate coverage per kit.

    3 oz. / 3-5 sq. ft.

    1.5 Pint / 24-26 sq. ft.

    1.5 Quart / 48-50 sq. ft.

    1.5 Gallon / 192-195 sq. ft.

  • Can you use RotFix with other wood preservatives?

    While we haven't done extensive testing with wood preservatives besides System Three EndRot™ Borate Powder(sodium borate), we know that copper and zinc naphthenate are compatible with RotFix, when the preservatives are given at least 7 days to penetrate and dry.


  • What finishes are compatible over RotFix?

    We know that System Three® finishes, WR-LPU and Marine Spar Varnish 
    are compatible with RotFix™.  Nitrocellulose lacquer, waterborne finishes, and 2-part polyurethanes will work as well.  As far as oil and 1-part polyurethanes, you will need to test for compatibility.

  • RotFix as a paint primer

    RotFix Sealer is a great product for consolidating or hardening soft or rotted wood.  It's also useful as a general purpose wood sealer.  If you have wood to paint, and it's a little soft, but not rotted away to require a full repair,  Rot Fix epoxy sealer will act as a primer for paint.


S-1 Sealer

Sculpwood Putty & Paste

  • Can you re-coat SculpWood after it has dried?

    If the Sculpwood Putty has cured to a hard state, you can apply more SculpWood Putty.  First, apply RotFix Epoxy to the SculpWood Putty.  Allow the RotFix to reach a tacky state, then apply SculpWood Putty over the RotFix.

    If working with SculpWood Paste, simply sand and apply more SculpWood Paste.

  • Paint over Sculpwood.

    Once the Sculpwood putty/paste is hard enough to sand, both are capable of accepting any latex or water-based primers and paints. Oil based primers and paints can sometimes have drying issues so spot testing is recommended. 

  • Sculpwood Putty Coverage

    The amount of Sculpwood required for a given project varies widely because it is difficult to estimate the volume of an irregular void.

    You will need to estimate the cubic inches of the void by measuring the average length X width x depth.  The sum of this calculation is the total cubic inches.  SculpWood Putty comes in 4 kit sizes.  The kits are listed below with the number of cubic inches per unit.

    8 oz. / 14.4cubic inches

    1 Quart / 58 cubic inches

    2 Quart / 116 cubic inches

    2 Gallon / 462 cubic inches


  • Can Sculpwood Putty or Paste be colored?

    Yes.  There are a few options:

    1)  Dry pigments can be added into the mixed products in any proportion. 

     2)  Liquid dyes or paint colorants can be added into the mixed at up to 2% by weight.

     3)  System Three® Epoxy Paste Pigments can mixed into the Part A at up to 10% by weight and then mixed 1:1 with the Part B.


  • Can you stain over Sculpwood Putty or Paste?

    Unfortunately, no.  The resin content of the products is high enough to effectively have them function somewhat as sealers, and the stain will not penetrate like it will into the bare wood.

    The suggested workaround is to mix dry pigments or house paint colorants into the paste or putty as you combine the Part A and B.  This can approximate the color of the stained wood around it.

  • How soon can SculpWood Putty be applied over the RotFix Epoxy?

    SculpWood Putty can be applied over the RotFix immediately after application.

Silvertip Yacht Primer


  • Using Non-Skid With WR-LPU

    Non-skid polycarbonate crystals can be utilized in one of two ways.  They can be added directly to the paint within the can, or broadcast into the freshly applied WR-LPU.  

    If adding directly to the paint, it's best to experiment some on scrap material.  You'll want to first determine how much of the non-skid to add for your liking.  Once this is determined, you may want to practice some on your application technique. Apply the non-skid / WR-LPU mixture as the final coat.

    The second approach to using non-skid is to broadcast the polycarbonate crystals into freshly applied WR-LPU. Since the WR-LPU set fairly rapidly, the non-skid should be broadcast immediately after application.  In some cases, a helper may be necessary.  After 4-6 hours (do not go beyond 24 hours) an additional coat of WR-LPU should be applied over the textured surface.  This additional coat locks in the non-skid particles for maximum durability.

  • Recoating WR-LPU

    WR-LPU can be recoated without sanding within 24 hours.  After 24 hours, sand with 220-320 grit paper.  

    When rolling and tipping, best results are achieved by applying no more than 2 coats per day.  Allow minimally, 4-6 hours of dry time before recoating.  This timeframe allows the WR-LPU to develop water and chemical resistance.  When the next coat is applied, much better flow and level occur. You will also see an improvement in wet edge extension (more open time).

    Recoating in the 1-3 hour window is not advised because WR-LPU has not developed sufficient water and chemical resistance.  Poor application characteristics such as reduced flow and level as well as decreased open time will result.






  • WR-LPU as pool paint?

    The WR-LPU is intended for short-term immersion only. It is not designed to be used below the waterline.

  • Sheen Variations In The Topcoat

    Sheen variations and dull spots in high-gloss topcoats usually result from one of the following:

    1. The topcoat has been applied unevenly.
    2. Sandpaper used before application of the topcoat was too coarse.
    3. The topcoat was applied in conditions which cause it to set up prematurely.  These include a substrate which is heated from the sun or where wind or ventilation is excessive.

    You can avoid sheen variations by coating in an environment where the substrate is protected from the sun and wind.  Additionally, sanding the substrate to 320 will provide sufficient tooth and a scratch pattern which promotes a uniform final appearance. 

    Dipping the brush or wetting out the roller with the topcoat charges (fills) each applicator with a given volume.  This volume of topcoat has an optimal area in which to be applied.  In the case of the brush, it will glide smoothly.  Once it begins to drag, the volume of topcoat within the brush is depleting. Avoid further brushing.  Recharge the brush, overlap into the previously applied material and dispense the topcoat. 

    A freshly charged roller will apply topcoat smoothly and with little noise coming from the substrate.  Once the roller begins to make some surface noise, you know it's time to recharge with topcoat.  Again, slightly overlap with the previously applied material. Be consistent in charging and dispensing and you will get a much more uniform sheen over the surface.




  • WR-LPU for pool paint or use below the waterline in general

    WR-LPU is a topside paint intended primarily for above the waterline applications.  It can be used below the waterline for day use watercraft only.  Like with most highly-weatherable polyurethane paints, too long an exposure underwater will allow blisters to form in the film.

  • How long before I can apply the WR-LPU over epoxy?

    Allow epoxy to cure at least 7 days at 70°F or above before applying WR-LPU. Please see the Technical Data Sheet and the Paint Literature for more information on application. 

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Project Recommendations

Wood Repair

  • Which product do you recommend for wooden support beam repair?

    Repairs in a wooden support beam that has lost its structural integrity are beyond the capabilities of epoxy filler putties and adhesives alone.  Additional materials, methods, and expertise must be accessed to complete a successful and safe beam repair of this type.

    For cosmetic repairs please watch our beam repair video and/or print the article below it.



Bar Top


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  • Will UV light affect System Three epoxies?

    Products based on room-temperature curing epoxy resins have poor resistance to UV or sunlight.  Depending on the severity of exposure, the surface will become dull, then cloudy, finally chalking breaking down sometimes in less than a year's time.

    We recommend overcoating with System Three Marine Spar Varnish or WR-LPU, both thin-film coatings which contain UV absorbers to protect the epoxy and the surface underneath from the sun.

    Please see the attached white paper on Clear Finishing Outdoor Wood for more information on recommended products as well as instructions on application. 

  • What is your best product for gap-filling?

    Use our product Mirrorcast, a 2-part epoxy casting resin developed for just this purpose.  Watch the video, then click on the box below for complete and detailed descriptions and instructions.



  • Do Epoxy Coating Resins And Adhesives Shrink?

    Most epoxy systems will shrink in a range of 1-5% in volume once fully cured.  You will find that in most applications, this shrinkage is virtually undetectable. Where it can be noticed is when epoxy is used to fill voids such as large knots and cracks in wood slabs.  The best way to minimize the shrinkage is to slightly overfill these voids.  Additionally, allow the overfilled void to fully cure (4-6 days) before block sanding flush with the substrate.  

  • Coating Raw Wood with Epoxy

    System Three Coating Epoxies offer tremendous benefits in protecting and stabilizing wood components.  Not only do they offer exceptional protection from moisture, they also bring out a high degree of depth and beauty to wood. Coating epoxies can be used as the sole finish, or they can be implemented as a high-build protective sealer.  Most waterborne or solvent-based top coats can be applied over System Three Epoxies.  Exterior applications require a UV protective topcoat such as System Three Marine Spar Varnish or System Three WR-LPU.  Always test if not using a System Three topcoat.

    Stain can be used with System Three Coating Epoxies.  However extended dry time of the stain is necessary before coating can begin.  Traditional oil base stains work best, but need 5-7 days at room temperature to fully dry.  Waterborne and gel stains are not recommended.  As always, test your stain color with the epoxy before proceeding to your project. 

    Substrate Preparation:

    Wood must be clean and verifiably dry before coating can begin.  High moisture content can be problematic and should be avoided until moisture levels drop to 12% or less. 

    Sharp edges and outside corners are difficult to coat and more times than not, inadequate film build occurs, resulting in poor protection from moisture.  To prevent potential failure of the epoxy, edges and outside corners should be slightly rounded over.  You can round over or break the edge with sandpaper or using a router and a small radius round over bit.  Sand with 180-220 grit sandpaper.  Remove sanding dust from the wood substrate with clean shop air, or a vacuum.

     Measuring and Mixing:

    Most System Three Epoxies are mixed at an easy 2 Parts Resin to 1 Part Hardener.  Once epoxies are mixed, they have a limited pot life.  Because of this, it’s best to start with small 3 - 6 ounce batches to prevent loss of material. In a disposable graduated cup pour in 2 Parts Resin and then follow by adding 1 Part Hardener.  Mix with a flat stir stick, by scraping the sides, stirring from the bottom up.  Pour contents into paint tray or disposable pie tin.  Spreading out the epoxy prevents heat buildup and therefore increases your pot life.


    For interior applications, apply at least 2 coats of epoxy.  Exterior applications require 3 or more coats for good outdoor durability. 

    System Three Coating Epoxies are best applied with a 1/8” nap foam roller and disposable natural bristle brush.  Use the natural bristle brush to reach areas the roller cannot.  Optimal results are attained when the wood substrate is sealed with a very thin layer of System Three Epoxy at ½ fluid ounce per sq. ft.  Some porous woods may need an additional thin seal coat, applied at ½ fluid ounce per sq. ft.  Once the wood is sealed, additional coats can be applied.  Aim for 1-2 fluid ounces per sq. ft.  Vertical surfaces require thin coats to prevent runs or sags.

     Note:  Sanding between coats is generally not advised.  The sanding dust produced is very persistence and difficult to remove from porous grain.  If not completely removed, fine white specks will show on the next coat.  If sanding is necessary use 150-grit sandpaper.  Fine sanding dust can be removed with careful use of clean shop air or a good quality vacuum.  Wipe the surface with denatured alcohol. 

    Unlike other finishes, you can apply System Three Epoxy over itself, even when the prior coat is still tacky.  System Three Epoxies have a 72-hour window during which sanding is not necessary between coats.   

     Top Coats:

    When the epoxy has cured to a sandable state (24-36 hours) most topcoats can be applied.  Some spar varnishes are not compatible with epoxy.  Be sure to test ahead of time to determine compatibility.

    Sand the System Three Epoxy with the finest grit that efficiently levels the surface.  Best results are achieved by using a hard backed sanding block or electric sander with a dense rubber pad.  Care should be taken when using electric sanders, as too much of the epoxy surface can be removed.

    When sanding, be sure to maintain the proper grit sequence.  Failure to maintain grit sequence can end in scratches showing through the top coat.  Finishing with 320-grit sand paper is recommended for gloss finishes.  Satin finishes can be sanded up to 220-grit.

    Exterior application need at least three coats of a UV protective top coat for prolonged durability.  UV protective topcoats will periodically need recoating.  When the UV protective coating begins losing it luster, you should plan on recoating soon.








  • Best product for river rock tables.

    River tables are very popular in 2018.  System Three has developed a two-part epoxy casting resin called MirrorCast which is perfectly suited for pouring river rock tables.



    The product is brand new and has passed field tests with flying colors.  Complete product description and usage instructions are in the document below.

    acrobatpdf.jpg Mirrorcast™ Void and Crack Filler



  • Clear Coat vs. S-1 Sealer

    We carry two epoxy sealers, both of which will perform equally as a sealer. The differences are found in application and physical properties. 

    1) Clear Coat is a low-viscosity, 100% solids, solvent-free epoxy sealer that cures to a clear gloss finish. It has a 2:1 (resin:hardener) mix ratio by volume and is best applied by the roll and tip method.

    2) S-1 Sealer is a great alternative for a penetrating epoxy sealer. It is a 50% solids, solvent-based epoxy system that can be applied by brush, roller, or spray. This sealer has a 1:1 (resin:hardener) mix ratio by volume and offers a long pot life of 24 hours at 70°F. 

    The mode of application, porosity, and material of the substrate may be a good deciding factor in choosing the best sealer for your project. If the substrate is very porous, you might consider using the Clear Coat for its higher solids and faster film build. The S-1 Sealer may not be ideal for materials that are not compatible with strong solvents (e.g. EPS foam, thermoplastics). However, if you prefer to spray, S-1 Sealer is the product to use. 

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