Epoxy User Guide & FAQ
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Epoxy FAQ

1. What type of epoxy do you sell?
2.
Why do you refer to the epoxy as a system?
3.
Which hardener to you recommend?
4.
What is pot life?
5.
Do you manufacture your own epoxies?
6.
How can you sell your epoxy for so much less than your competitors?
7.
What are the advantages of epoxy over polyester resins?
8.
What system do you recommend to use with carbon fiber?
9.
Do you sell high-temperature epoxy?
10.
How do I protect my epoxy from UV deterioration?
11.
What is blush?
12.
Do your epoxies blush?
13.
How do I clean/remove the blush?
14.
Are your pigments compatible with your epoxy systems?
15.
Do I need to buy pumps?
16.
How do the pumps work?
17.
Can I leave the pumps on the bottles?
18.
Do I need a respirator when working with epoxy?
19.
What safety measures should be taken when working with epoxy?
20.
Is there a hazardous fee for shipping?
21.
How do you package your epoxy systems?
22.
Do you have local distributors?
23.
What is the shelf life of your epoxy systems?
24.
What if the epoxy freezes?
25.
How do I make glue with your epoxy?
26.
Do you sell any fillers I can use to make the epoxy easier to sand?
27.
I'm building a canoe/kayak and want to see the wood through it, which epoxy do I use?
28.
Can I put polyester gelcoat or polyester resin over epoxy?
29.
How much epoxy do I need for saturating my fiberglass?
30.
What is the coverage of your epoxy when sealing plywood?
31.
Do you sell epoxy floor paint?
32.
Do you have casting epoxy?
33.
What can I use to clean my tools while the epoxy is still wet?
34.
Can I put in more hardener to speed up the dry time?
35.
Can I work with the epoxy in cold weather?
36.
I need an epoxy to build a thermonuclear support valve. What do I buy?

Troubleshooting FAQ
1.
My epoxy is taking forever to dry. What went wrong?
2.
I mixed up a quart of epoxy and before I could get it out of the cup it started smoking and cured immediately. What happened?
3.
I applied epoxy outside under a covered awning but it rained last night and now the surface is cloudy and sticky. What do I do?
4.
I made a part and it is too flexible. Why?

1. What type of epoxy do you sell?

This FAQ is dedicated to our 635 Thin Epoxy System, our most popular and versatile epoxy. The 635 Epoxy is used extensively in composites due to its low viscosity(like motor oil) which allows easy saturation of all types of fiberglass, Kevlar and carbon fiber cloths. It can also be mixed with our selection of fillers to make many types of putties and sanding fillers. For full descriptions on our other epoxies please follow these links. 150 Thick System, Klear Kote table top epoxy, The West System Epoxy, and our Epoxy Adhesives.

2. Why do you refer to the epoxy as a system?

All of our epoxies are two part systems consisting of a resin side and a hardener side. Unlike some of our competitors who sell them separately, we sell them together as a kit. More specifically the type of system is defined by your selection of hardener.

3. Which hardener do you recommend?

When choosing a hardener many variables must be considered including working temperature, desired cure time, working time, pot life and your desired post production properties.

We have three hardener systems to choose from.
The (2:1)#556 slow hardener is meant for tropical conditions(above 80 degrees). This hardener also cures as the most flexible laminate.

The 3:1 Medium hardener is our best all-purpose hardener. You can use it in temperatures down to approximately 55 degrees and still get a 24 hour dry time. This is our most user-friendly hardener for most applications.

The 4:1 Fast hardener is also an excellent hardener. You can use this hardener down to 45 degrees. Caution should be taken when working with large batches.

4. What is pot life?

Pot life refers to the amount of time you have before the system kicks(begins to gel) in the container(pot) being used to mix the two parts. Depending on your method of application this can be a critical factor in reducing waste. Working time refers to how long you have after the product is out of the container.

5. Do you manufacture your own epoxies?

No. All of our private label products are produced by our manufacturing partners and meet the highest industry's standards for quality and performance.

6. How can you sell your epoxy for so much less than your competitors?

We are able to keep our prices so low because we buy direct from the manufacturer and sell directly to you. All of our epoxy systems are of the highest quality and are all proudly Made in the USA.

7. What are the advantages of epoxy over polyester resins?

There are many advantages including being non-flammable, not exhibiting a strong odor and being up to 25% stronger than their polyester counterparts. In marine applications, epoxies are far superior in resisting water absorption and are less likely to blister. Epoxies are more flexible and adhere better to all surfaces.

8. What system do you recommend to use with carbon fiber?

If you are using carbon fiber to make a structural(non-cosmetic) part we recommend using our 635 Thin Resin with our 3:1 or 4:1 hardener which will provide the most strength and stiffness. Our 2:1(556) hardener should only be used with a core material that will provide stiffness or if extended working time is needed.

For a clear, cosmetic carbon fiber part we recommend the Silmar 249 Clear Polyester Resin instead of the epoxy. This polyester resin has UV protection that will last longer out in the sun than any epoxy. The Silmar 249 can be polished and if necessary top coated with a clear coat automotive urethane.

If you must make your clear part with epoxy we definitely suggest cleaning, sanding and top coating the epoxy with a clear coat automotive urethane.

9. Do you sell high-temperature epoxy?

No. Our marine and commercial use epoxy systems can only withstand temperatures from 150 to 195 degrees. Most high-temperature epoxies on the market will require autoclave or oven cure cycles.

10. How do I protect my epoxy from UV deterioration?

As none of our epoxies offer UV protection a top coat is required. The best protection is to use a quality paint. If your project calls for a clear finish we recommend a marine varnish or a clear urethane. Careful attention should be paid to watch for oxidation of the epoxy. Fresh coats of the varnish/urethane should be applied as a preventative measure to keep UV protection effective. The epoxy must be completely cured and free of blush, which we will discuss next.

11. What is blush?

Blush occurs when the discharge of carbon dioxide reacts to moisture in the air during curing. It presents itself as a greasy film and is easily removed by washing the part with warm water and a clean rag. More specifically, blush is an amine carbonate residue produced by the reaction just described. This residue must be removed before top coating or if fully cured, before re-coating with additional epoxy. Blushing is more commonly seen in stiffer, faster curing epoxy hardeners and more pronounced in cool, high humidity conditions.

12. Do your epoxies blush?

The 3:1 and 4:1 systems do. The 2:1 system is completely non-blushing.

13. How do I clean/remove the blush?

If your epoxy has blushed it must be cleaned before applying additional epoxy or a top coat finish. Follow the below steps.

1. Wash the surface of the epoxy with warm water. Using a clean rag, scrub the surface until the greasy/waxy feeling is removed.

2. Lightly sand the epoxy with 220 grit(or similar) sandpaper. This creates an etched surface that will allow for the maximum mechanical bond possible between additional layers of epoxy or between the epoxy and primer/paint top coat.


3. Wipe down the surface with Acetone or Denatured Alcohol. Again, use a clean rag to do this. Cleaning with a solvent will remove surface contaminants and slightly tack-up the surface for better bonding.

14. Are your pigments compatible with your epoxy systems?

Yes. Our pigments can be used with both epoxy and polyester resins. We recommend not exceeding a one ounce pigment to one quart resin ratio.

15. Do I need to buy pumps?

No, they are not required. Our pumps are ideal for measuring smaller amounts. Generally, larger batches are easier to measure and mix using graduated measuring cups. We have a wide assortment.

16. How do the pumps work?

We sell identical pumps for the resin and hardener which, when properly primed, will dispense one ounce per stroke. The pumps will fit securely on all of the plastic bottles we send you. You will have to trim the straw to fit the smaller bottles.

To prime each pump push down approximately three times which should expel the air. During this process it is advisable to have something to catch the liquid that comes out with air still in it. This can easily be returned to the bottle by unscrewing the pump. This should not result in losing the prime.

17. Can I leave the pumps on the bottles?

Yes, the pump keeps the container air tight. However, after the bottles have sat unused for several weeks you may have to follow the priming procedure again.

18. Do I need a respirator when working with epoxy?

Should you be working in a poorly ventilated area and the fumes become noticeable we would recommend using one of our high quality charcoal/chemical masks you can view here. We also sell replacement cartridges and filters which will considerably lengthen the lifetime of your mask. Proper eye and skin protection should always be used.

19. What safety measures should be taken when working with epoxy?

Skin and eye protection should always be worn when working with epoxy. Epoxy can cause severe skin irritation and also sensitization to the skin and eyes. Never breath the dust or mist. Contact us for more information or the MSDS relating to the product you are using.

20. Is there a hazardous fee for shipping?

No. All of our epoxy systems are classified as nonhazardous and can be shipped by UPS Ground or UPS Air. There is no additional hazardous shipping fee for these liquids.

21. How do you package your epoxy systems?

Our resins and hardeners are packaged in plastic jugs up to one gallon in size. Multiple gallon kits are still shipped in gallon increments, four gallons per box. We take great pride in our packing methods which are painstakingly followed for every box we ship. This means your shipment virtually always arrives intact and damage free.

22. Do you have local distributors?

No. All of our products are shipped directly from our Florida location.

23. What is the shelf life of your epoxy systems?

We recommend using our epoxies within one year of purchase. Epoxies should never be stored in direct sunlight and should not be kept in freezing temperatures. Storage in temperature above 90 degrees should also be avoided.

You will find that your epoxy can last much longer than a year if they're kept in a dark storage container(cardboard box) with temperatures between 60 and 80 degrees.

If you sometimes have to wait a couple months in-between uses we recommend shaking up the hardener bottle for about 45 seconds to re-agitate any settling that may occur. This is not necessary for the resin.

24. What if the epoxy freezes?

Our testing has shown that epoxy freezing for a short period of time is not harmful to the product and will cure with full physical properties. We strongly recommend not storing the epoxy anywhere that could result in freezing for more than a few days.

25. How do I make glue with your epoxy?

We offer a complete line of fillers that when added to the epoxy will thicken the liquid to your desired consistency and application without compromising the structural properties of the epoxy.

For thickening, we recommend our Aerosil/Cabosil. To achieve a mayonnaise like consistency follow these guidelines.

1 Gallon mixed epoxy to 1 Gallon of Aerosil-Cabosil
To make a consistency like peanut butter
1 Gallon mixed epoxy to 2 Gallon of Aerosil-Cabosil

Note: adding 1 gallon of Aerosil-Cabosil to 1 gallon of epoxy will not yield 2 gallons of putty. The filler will only add about 5% volume to the mixed epoxy.

26. Do you sell any fillers I can use to make the epoxy easier to sand?

Both our phenolic microballoons and our 3M Glass Bubbles are excellent choices for this purpose.
Slightly less easy to sand but much better as a thickener, if our
fairing compound.

To make a consistency similar to mayonnaise
1 gallon mixed epoxy to 1 gallon of filler

To make a consistency like peanut butter
1 gallon mixed epoxy to 2 gallons of filler

Note: adding 1 gallon of microballoons/fairing compound to 1 gallon of epoxy will not yield 2 gallons of putty. The filler will only add about 5% volume to the mixed epoxy.

27. I'm building a canoe/kayak and want to see the wood through it, which epoxy do I use?

Our 635 Thin Epoxy Resin with our 3:1 Hardener has proven to be the most popular System for this application. Our 4 and 6oz cloths will wet out completely transparent when applied properly. You may have noticed an amber tint to our hardeners. When mixed with the resin and applied in thin coats over wood they will dry clear.

For better long-term performance of the epoxy follow our cleaning steps(see answer #13) and then apply a topcoat of UV protected marine varnish.

28. Can I put polyester gelcoat or polyester resin over epoxy?

There are conflicting opinions on this subject. We DO NOT recommend applying a polyester gelcoat over epoxy. The polyester based resins/gelcoats do not offer great bonding strength to the epoxy. Instead of gelcoat or polyester we recommend using an epoxy or urethane based primer and paint to finish your epoxy made part. Some industry leaders for these type of finishes include Interlux, Pettit and AwlGrip.

Our colored pigments are ideal for colored parts. A ratio of one ounce pigment to one quart resin is recommended. However, for a more brilliant , sharper finish and far superior UV protection, we would recommend finishing your part using a quality paint.

29. How much epoxy do do I need for saturating my fiberglass?

This is a very common and complex question. Each type of fiberglass saturates resin at different ratios. Below is a brief summary of the saturation rates for different reinforcements.

Chopped Strand Mat: Approx. 2 pounds of resin for 1 pound of mat
Fiberglass Woven Cloth: Approx. 1 pound of resin for 1 pound of cloth
Biaxial (1708,1208,1808): Approx. 1-1/2 pounds of resin for 1 pound of biaxial
Carbon Fiber and Kevlar Cloths: Approx. 1 pound of resin for 1 pound of cloth

Your technique for application and experience will determine the exact amount needed but the ratios shown above provide a good starting point. For reference, 1 gallon of epoxy weighs about 9 pounds.

30. What is the coverage of your epoxy when sealing plywood?

There will be slight variations depending on how heavy it is applied. Generally speaking, a gallon of epoxy will yield 250 square feet. Therefore a typical 4'x8' sheet of plywood would require about one quart(32oz) to seal both sides.

31. Do you sell epoxy floor paint?

No, we do not sell epoxy floor paints/coatings

32. Do you have casting epoxy?

We do not have any epoxies considered castable. Our epoxies are considered laminating epoxies, meant for applications no greater than 1/4 inch in thickness. If you are interested in attempting to cast with our epoxies the primary concern is the heat generated when the product is curing in a large mass. Testing can be done by using our 635 thin epoxy resin system along with purchasing a filler called Alumina Trihydrate. You would mix the epoxy at a ratio of 1 pint of mixed epoxy to 1 pound of Alumina Trihydrate. Buying a slower curing hardener with the 635 epoxy system will generate less heat exotherm and allow slightly larger castings. We strongly recommend buying the smallest kit possible for testing purposes when using our products for other than proscribed uses.

33. What can I use to clean my tools while the epoxy is still wet?

Any of the following solvents will work for cleaning wet epoxy from your tools.
Acetone, Denatured Alcohol, Lacquer Thinner, MEK Solvent.

We always recommend using disposable brushes and rollers so that you don't need to spend the time cleaning them. Epoxy is very sticky and and it will cost more in solvents to do the cleaning than you would pay for a new brush or roller cover.

34. Can I put in more hardener to speed up the dry time?

No, our epoxy systems are formulated to react at certain ratios of resin and hardener. Deviation of only a few percent in your mixing ratio can result in uncured epoxy.

35. Can I work with the epoxy in cold weather?

Yes. Our 4:1 ratio Fast Hardener can be used down to 45 degree, and the 3:1 Medium hardener down to 55 degrees. Please be aware however that the drying times will be significantly longer at these lower temperatures. Also, epoxy gets thicker as your temperature gets colder and it can make the saturating of fiberglass more difficult. Lastly, you should always be careful of using the epoxy outdoors in cool conditions when you are expecting rain. Despite working under cover, if it rains overnight and the epoxy is still wet you can get moisture contamination on the surface of the epoxy and the surface will never properly cure.

36. I need an epoxy to build a thermonuclear support valve which is subject to temperatures above 1000F and come into contact with hydrochloric acid and aromatic hydrocarbons.

Are you the guy who called last week? We are certainly happy to hear about your idea and attempt to make a recommendation. While we are very familiar with the epoxies that we sell, there are still many untried uses and developmental projects that we are not able to solve. Many of these projects require testing by our customers of several different products which is why we package our epoxies in small quantity kits for purchase.



Troubleshooting FAQ

1. My epoxy is taking forever to dry. What went wrong?

The reasons listed here cover 99.9% of possible scenarios. One or more of them should ring true to your situation.

  • The ratio for resin to hardener was not correct. This is most commonly a function of poor or imprecise measuring. Eyeballing the epoxy for your ratio is not good enough. A graduated cup should always be used for measuring.
  • Improper usage of the pumps. If you did not prime the pumps properly it can throw off the ratio. An indication of an improperly primed pump would be when small amounts of air are expelled when dispensing. It may also be a result of losing count of the number of pump strokes.
  • The resin and hardener ratio was reversed. Odd as this may sound, we've heard about this happening many times. If your hardener is a 3:1 ratio, this mean 3 parts of resin to 1 part of hardener.
  • The batch was too small. Often when customers are testing epoxy for the first time they will only mix a few teaspoons of epoxy. We encourage testing but when done in such small batches a slight deviation in ratio is greatly magnified. We therefore recommend that your test batches be at least a few ounces, be accurately measured and be thoroughly mixed.
  • The resin was applied too thin. Very thin applications take longer to cure especially when applied without fiberglass. In these cases patience is required. If the epoxy still does not cure refer to the other scenarios listed in this section.
  • Something was mixed into the batch. We have heard of people mixing strange things into their epoxy, with water being the strangest. Always use uncontaminated containers and clean stir sticks when mixing the product.
  • It just wasn't mixed thoroughly. This is more likely to occur if your epoxy is cold. Ideal mixing temperature is about 75 to 80 degrees. If you can't meet these temperatures just be certain your are getting a complete mix.
  • Low air temperature increases dry time. Temperature plays the biggest factor in the speed of drying. Even when you are using our fastest hardener low temperature always increases dry time. If the resin can be kept between 75 and 80 degrees, i.e. indoors, before mixing, a lower working temperature is not a problem. But again patience is required.
  • The hardener may need to be shaken. If your hardener has not been used for a month or more, we recommend shaking it at least 45 seconds to agitate any settling that may have occurred. This is not necessary for the resin.
  • Epoxies cure slower than polyesters. If you are used to working with polyester resins, epoxy cure times will seem to be dramatically longer. They are! And unlike polyesters, there is nothing you can do to speed up the process. Epoxy ratios must be accurate and consistent.

2. I mixed up a quart of epoxy and before I could get it out of the cup it started smoking and cured immediately. What happened?

The amount of time you have before your resin begins to kick in the container is referred to as Pot Life. {link to pot life Q&A ). When determining the size of each batch three factors should be considered. First, the larger the mixture the shorter the pot life. Second, the method of application can play a significant role. Ideally, after the epoxy is mixed you can pour it out of the container and then begin to apply it. Once out of the pot you will have a greater amount of time, referred to as working time, before the epoxy begins to cure. If this method is not possible, smaller, multiple batches should be used. Third, air temperature can effect pot life. A 10 degree difference from one day to the next will affect your pot life. Reduce your batch size to accommodate the higher temperatures.

3. I applied epoxy outside under a covered awning but it rained last night and now the surface is cloudy and sticky. What do I do?

Caution must be taken when using epoxy in cool, humid conditions. Despite working under cover, if it rains while the epoxy is still wet, moisture contamination can occur and the epoxy may never cure properly. If this happens it will have to be removed by mechanical means, either scraping and/or sanding away the contaminated epoxy.

4. I made a part and it is too flexible. Why?

Epoxies are flexible by nature. If you are accustomed to working with polyester resins you will definitely notice that epoxy is more flexible. Cured epoxy will become stiffer after a few days. If a fully cured part is still too flexible it is most likely that additional layers of reinforcements are necessary. Generally, two layers are more than twice as strong as one, etc. Only you can determine your strength and performance requirements and this can only be done by experimentation and testing. Finally, the stiffness of a part can be a function of the system(hardener) chosen. Our 2:1 hardener is our most flexible post-cure system. Our 4:1 hardener is our most rigid system which is still flexible enough to not be brittle. Our most popular system, the 3:1 hardener combines the properties of the 2:1 and the 4:1 systems.

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