Epoxy Resin FAQs

Q: You have two different epoxy systems. Which should I use?
A: The 300/21 system is the most versatile. You can use it as an adhesive, coating, laminating, or casting resin. It is great for use with fiberglass or carbon fiber cloth. The 300/21 does not blush, which is a huge plus if you are laminating with cloth or coating. If you are using epoxy strictly as an adhesive, then the 300/11 is your best choice. It is thicker than 300/21 and it is a bit more flexible when cured.

Q: How critical is the mix ratio?
A: It's not critical at all with the 300/11. You can be 1/3 off on the mix and it will still work. However, try to be as close as conveniently possible. For the 300/21 system, you should try to be close- But we have done tests off ratio (like 3:1) and it performs well.

Q: What is the Double Mix and Pour Method for your 300/21 Epoxy Resin?
A: Mix 2 parts AeroMarine 300 Resin to 1 part AeroMarine 21 Hardener. Mix the two components together in a plastic container for 2 minutes, then transfer the mixture to another plastic container and mix them again for another 2 minutes. The theory is that the liquids clinging to the sides and bottom of the containers don’t get mixed well.  By transferring the mixture to another container, you are assured that everything is well mixed.

Q: How much epoxy do I need?
A: If laminating with cloth, it is a general rule to try to use an equal weight of mixed epoxy to the weight of the cloth. This gives us a 50/50 resin/cloth ratio, which is a desired ratio. Take the weight per yard of the cloth, then factor in the width of the cloth, and use the same weight of mixed epoxy.
If brushed or rolled onto a smooth surface, one mixed gallon of epoxy covers 1600 square feet at one mil (.001") thickness. One mil is not a practical thickness, but it gives a basis for calculating for your particular application. For instance, a ten mil layer of epoxy, which is a nice thin coating, would yield 160 square feet per gallon. A coating of 1/32" would yield 50 square feet per mixed gallon.
None of these calculations takes waste into account.

Q: How much heat can this epoxy take?
A: The 300/21 can take about 250F, which means that you can put hot cups of coffee or tea on it. Never put a hot pan or skillet from the stove directly onto the epoxy.

Q: Can I use a thinner to make the epoxy more 'flowable'?
A:The 300/21 system is very thin, so you should not have to thin it. If you really, really, want to, the answer is yes. The best thinners are lacquer thinner, acetone, MEK, Toluene, or xylene. DO NOT use regular paint thinner, also known as mineral spirits. Because the thinners are flammable and the epoxy generates heat while it's curing, it is best to add the thinner then spread immediately. This allows the thinner to evaporate. Use as little thinner as possible. Remember that any thinner needs to evaporate, so avoid using thinners in castings or laminates.

Q: How I remove "amine blush"?
A: AeroMarine 300/21 does not blush. Amine blush should be removed with a scotch-brite pad and a lot of water.

Q: What do I use for clean-up?
A: For hands,soap and water works fine as do most household cleaners such as Formula 409. All of the new citrus and orange oil based products do a good job, too. For routine cleaning, keep a spray can of carburetor cleaner around. For cleaning tools and spills, use solvents such as lacquer thinner, acetone, MEK, Toluene, or xylene.

Q: How can I speed up the cure?
A: Heat works best- Gradually raise the temperature and the epoxy will cure much more rapidly. Don't exceed 200°F. For every 20°F increase in temperature, the 300/21 cure time decreases by half.  For example, raising the temperature from 70°F to 90°F cuts the cure time from 24 hours to 12 hours.

Q: Does polyester gel coat adhere to your epoxy?
A: Yes, our customers have had many successful applications of gel coat over our 300/21 epoxy system. Abrading or roughing up the epoxy with sandpaper to give the polyester more 'bite' is a good idea.

Q: Will it bond to a painted surface?
A: Yes, but it is best to bond to the parent material. Make sure that the paint is well bonded to the substrate.

Q: Are there any surfaces AeroMarine epoxy won't bond to?
A: Yes, our epoxy does not bond to polypropolene, polyethylene, Teflon, Tedlar, EPDM or anodized aluminum.

Q: Is it UV resistant?
A: The 300/21 cycloaliphatic system has better UV resistance than any other epoxy, but it's not perfect. It should be painted or varnished with a UV resistant paint/varnish if used as a coating or laminating resin exposed to direct sunlight for a long time.

Q: What size batch can I mix?
A: Begin with a quart or so is the most, at least until you gain experience working with epoxies. Later, you might mix a half gallon or so. Never mix less than 3 ounces of our epoxy resin because it will not work.

Q: How do I change the color?
A: We stock colorants made specifically for epoxy in black, white, and grey. From those colors, you can create many other colors. We will pre-color the resin black, grey, or white before shipping. Just let us know when placing your order.

Q: How can I thicken the epoxy?
A: You can thicken this epoxy with the epoxy thickeners/fillers listed on the epoxy resin page. When mixed approximately 1:1 with the total mixed epoxy system, you will get about the same thickness as vaseline. You could use more or less epoxy thickener to get the desired thickness. You can use it to make a fairing or filleting compound that will build thickness on a vertical surface.  Do not use additional hardener to try to thicken this epoxy!

Q: Can I apply this epoxy directly to Styrofoam or EPS (expanded polystyrene)?
A: Yes, our epoxies have no effect on Styrofoam. They bond to it very well.

Q: How do I determine the relative amounts of resin to cloth?
A: Under ideal conditions, you will use just a bit more resin than cloth by weight. The higher the ratio of cloth to resin the better. Aircraft manufacturers try to get a 1:1 ratio of cloth to resin, but they use expensive autoclaves and platens. Most of us working under more average conditions are lucky to get below a 2:1 ratio of resin to cloth.

Q: How many layers of cloth do I need?
A: It depends on what you are trying to accomplish. The hull of an ocean going vessel may contain a few dozen layers of cloth, while a wood kayak might have only one layer of cloth. It is generally better to use multiple layers of light weight cloth than fewer layers of heavy cloth.

Q: How do I fiberglass the hull of my boat?
A: Start by cutting the cloth in to slightly larger sections than you will be needing. Mix a small batch of epoxy and brush it into a few areas that will tack the cloth to the wood. Then stretch the cloth to fit the area you are working on and apply more mixed epoxy over the cloth. Squeegee or roll the excess resin out of the cloth. When the cloth changes color from white to clear you know that the cloth has been saturated with enough epoxy. Squeegee off most of the excess because excess epoxy will just result in unnecessary weight. If you need to apply more layers of cloth, it can be done immediately. The sooner the additional layers are applied, the more of a chemical bond you will attain. With a non blushing epoxy you can add further layers, even weeks after the previous layer, however it is preferred to sand lightly to help key the old layer to the old layer.

FAQ's about Epoxy Countertops

Q: I'd like to embed bottlecaps, baseball cards, photographs or posters in my countertop. Is this possible?
A: Yes people do that all the time. Don't put anything irreplaceable in epoxy because you will never be able to remove that item. Also, it's also impossible to test every possible product that someone may want to encase in epoxy. We have never had a customer tell us about any kind of incompatibility, but making a small test is certainly a good idea.

Q: How thick should I make a countertop?
A: We generally recommend 1/8 of an inch. That is typical of what you will see in a restaurant such as Hooters or Outback Steakhouse. Keep in mind that doubling the thickness will double the cost of your project. The maximum thickness that we recommend is 3/8". This is because the epoxy generates heat in order to cure- the thicker the pour the greater the heat- It's called exotherm.

Q: How big a batch should I mix at one time?
A: The first few batches should be small so that you learn how to use the epoxy, maybe a quart or two. After you get the hang of using the epoxy, then you might mix a gallon or two at a time.

Q: Can I pour additional layers over a cured layer?
A: Yes, generally there is no prep required between coats. Be certain that the first batch has begun to cool before pouring the next coat.

Q: How do I handle the edges?
A: This can be tricky, depending on what effect you are trying to accomplish. In order to avoid trapping air bubbles, an epoxy coating needs to be quite thin. Otherwise, any air trapped in the mix will not rise and escape to the surface- So if you need to pour a thick countertop then you may need to build a dam around the top, then remove the dam. Most pros use formica to create the dam, and use vaseline as a release agent. Alternately, a wood strip can be used as the dam and left in place. A third method is just to brush, roll, or pour several layers onto the countertop and let the excess run off- but this can take several coats if you are trying to build up a lot of thickness.

Q: Is this epoxy UV (sunlight) resistant?
A: This epoxy is more UV resistant than most because it is a cylcoaliphatic system, but it still is not totally UV resistant and should not be used for table tops kept in direct sunlight.

Q: I've read on other sites that you should use a torch or a heat gun to break air bubbles. What do you recommend?
A: We primarily recommend in a well-ventilated area breathing onto the epoxy to break any air bubbles. A heat gun or propane torch can be used, but be careful.  The speed of the air from a heat gun may cause waves in the surface. The same holds true for propane torches- the propane is under a lot of pressure and leaves the torch at a high speed, often causing waves in the countertop. Plus it is tempting to use too much heat. In this case, "if a little is good, then a lot is better" doesn't apply here.

Q: Do you have any other tips?
A: It is important to keep the dust down for the first 12 hours after the pour. It's a good idea to just close off the room for the day to prevent dust from settling on the countertop.

General business questions:

Q: Why is your epoxy so cheap?
A: We buy highest quality epoxy resins and hardeners from major manufacturers. We keep prices low by keeping our overhead costs down.

Q: Do you take credit cards?
A: Yes, by telephone. If you use the website shopping cart, the order will be processed by PayPal, which is very safe and easy.

Shipping FAQ's

Q: Do you ship outside the US?
A: Yes, if it makes sense. The Post office is usually the best carrier, but they don't like to take large containers of chemicals such as 5 gallon pails. UPS will take just about anything anywhere, but shipping can get expensive.

Q: How about shipping to Alaska or Hawaii?
A: It can be difficult with large orders. The Post Office doesn't like to take liquids, especially in buckets. UPS doesn't mind liquids or buckets, but the cost can be high. Our shipping charges in the shopping cart reflect shipment to the contiguous 48 states. In most cases, the shipping is higher to AK or HI.