Monthly Archives: April 2019

Tips for Using Brushable Gelcoat

Brushable Gelcoat is a specially formulated product that is made to be applied like paint and eliminate the need for spray equipment. It has excellent leveling, Water/Osmosis resistance, UV light Stability, great Gloss Retention and a fantastic long-term durability and is available in a variety of colors. Here are some tips for successful brushable gelcoat application.

Applying Gelcoat by Brush or Roller – (Use a Brushable Gelcoat) When applying gelcoat by brush or roller, we recommend the Ultra Plus Brushable Gelcoat. (other Gelcoats are best applied by Spray) The Ultra Plus Brushable Gelcoat is designed to self-leveling and is much easier application. It allows for a much smoother finish and less time finishing the gelcoat. It is easy to use for the “do it your selfers’! Choose a good pure (natural) resin resistant bristle brush with tapered ends. Avoid brushes that are either too stiff or too soft. For most work, a 3″ or 4″ wide brush will suffice. If there is a trim color, you should have a narrow trim brush on hand. Our Brushable Gelcoat comes with MEKP hardener with every purchase, but you may need more which you can purchase as an option depending on the application, temperature and other environmental factors. Gelcoat needs to be applied evenly. We suggest a thickness of 18-20 mils to properly cure. The thickness of the matchbook cover is approximately 18 mils. If you’re not sure how thick it is, pick up a mil gauge. This is a simple, easy way to see the thickness of your gelcoat.

  1. Don’t add Patch Booster or Sanding Aid (wax). You don’t need to add sanding aid (wax) to Brushable gelcoat to have it dry tack free. The self-leveling technology added doesn’t require any additional products or additives.
  2. Proper gelcoat application requires you apply your coats about 15-20 mils thick. We offer mil gauge for purchase.
  3. Allow the gelcoat to cure overnight and then lightly sand it and buff it for an outstanding shine!
  4. Use Acetone for your cleanup. Just like other Polyester-based products, Acetone is the best cleanup material!
  5. The most important step: Adding the proper amount of Catalyst. We recommend 1.5%-2% Catalyst ratio. After adding the catalyst, you will want to mix for two minutes, preferably with a mechanical agitator (drill mixer). For your reference, here is the catalyst chart so you know exactly how much catalyst you need.

Tips
1 mL = 1 ccIf using wood mixing stick, place stick in resin before adding catalyst so wood doesn’t absorb catalystOnly catalyze slightly more than needed. Resin that cures still in the mixing pot is unusable.

Be sure to have a good strategy when applying your gelcoat. Once you mix and catalyze, you have about 15 minutes to apply the gelcoat before it starts getting hard or starts to “gel.” The actual working time depends on the amount of catalyst and how hot the working conditions are. Anything below 60 degrees, and your gelcoat will not cure, but as you get warmer and warmer, your working time will decrease rapidly. At 70 degrees, you get 15 minutes, but at 90 degrees, you only get 5 minutes. If you need more time to work, be sure to sit the can in some cold ice water to cool it down to 60 degrees to allow you a little more working time.

Here are some helpful tips on how to work with brushable gelcoat, especially during the warmer months.

  1. Cooling the gelcoat, by refrigerating the product to around 70 degrees, will give you up to 15 minutes of working time.
  2. Humidity can be another factor, so, make sure the mold and surrounding area is dry before applying your brushable gelcoat.
  3. Make small batches of gelcoat at a time and catalyze at 1 ½ % to avoid the material from getting hotter. When spraying the gelcoat, make sure you catalyze at 2 %. If you choose to use Duratec, please note, the product must be cool as well.
  4. If you seek to roll on the gelcoat, the product should be applied evenly at 14 mil thick.
  5. Do not apply gelcoat in direct sunlight.