How to Apply Gelcoat – The End-all Guide

Gelcoat PhotoProperly applying gelcoat is the key to a good finish. Many of our customers are hesitant to use it, thinking it’s too complicated or they think they can’t end up with a good finish. So, we are here to provide a step-by-step guide on how to properly apply gelcoat. As with all our products, if you have any questions, we are here to help!

First thing you want to do is look at the surface you want to apply gelcoat to. If the surface is already covered with gelcoat, or if the surface is a fiberglass, or polyester resin, then applying gelcoat will be a snap. If the surface is paint, then the paint would have to be removed before applying the gelcoat.

gelcoat-sandingSo, you’ve decided the surface is gelcoat, so it’s time to begin. You want to sand the surface to create a mechanical bond with the gelcoat. Start by sanding the surface with 150 grit or lower sandpaper. Our technicians recommend using Dyekum Steel Blue to be very thorough. Steel Blue is a dye you wipe on. Once you don’t see the blue dye anymore, you know you have properly sanded everything. You can also use a pencil, but it’s harder to see and won’t guarantee complete coverage.

Next, you want to clean the surface. We recommend using Acetone, as it doesn’t leave a residue and evaporates quickly. Once the surface is clean, you want to get going pretty quickly; if the surface sits for any extended amount of time, you will want to re-clean the surface. Dust and dirt particles are your enemy here, so be thorough on the cleaning.

We are ready to gelcoat! First, decide if you need one or two coats of gelcoat. It will take a minimum of two coats of gelcoat if you are changing colors. If this is going over a patch, we recommend 2 coats at least, to get a nice, uniform surface. Otherwise, one coat will do.

Gelcoat needs to be applied relatively thin. We recommend 18 mils mil-gauge-2thick, to properly cure. 18 mils is approximately the thickness of a matchbook cover. If you aren’t sure how thick, pick up a mil gauge. It’s a quick, easy way to see the thickness of your gelcoat.

Gelcoat requires Methyl Ethyl Ketone Peroxide or MEK-P to activate the hardening process. The amount is very small. We recommend 1-1/4% to 1-1/2% by volume, which means 13-15cc’s per quart. Darker colors require a bit more catalyst for the same reaction, so you can catalyze up to 2%. Refer to the catalyst chart on the side of the can, or you can find one HERE.

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

Brushable gelFor applying your gelcoat, you can either roll the gelcoat on, like paint, or you can spray it on. We also sell a Brushable Gelcoat that can be applied with a brush. If you decide to roll on the gelcoat, be sure to use a solvent-resistant 1/8” or ¼” nap. Be sure not to use foam rollers, as they tend to leave bubbles. If you brush it on, be sure to use a solvent resistant brush. Your first coat will simply consist of the gelcoat and the MEK-P catalyst. Once applied, you want to wait about an hour and a half, for the gelcoat to set. It won’t be completely cured by then, but it should be hard and tacky.

Your second coat will consist of the same amount of Catalyst, but if you are doing one more coat, your next coat will include Sanding Aid, or ‘wax.’ You will mix in 1 oz per quart to the gelcoat, which will seal the surface from oxygen, causing the gelcoat to dry tack-free. If you roll or brush your seconding coating, be sure to go the opposite direction from the previous coat, allowing a uniform coating.

If you are using our standard Exterior gelcoat, you will be ready to sand and buff your freshly gelcoated surface. If you are using our brushable gelcoat, you will want to let it sit overnight to ensure it’s completely cured. To start sanding, begin with 320 grit sandpaper and sand the surface completely. From then on, start going up to 400, then 600, and finally 800 grit sandpaper.

At this point, you can use an 800 grit compound to compound the gelcoat. You want to use a buffer that turns at 1600-3000 RPM’s. The car polishers will not work, as they spin too slowly, so you want to check the spin speed. It’s best to do a 4’ by 4’ area and go from there. Every 10’ or so, you will want to clean your pad with a spur or with some air to ensure pieces don’t scratch your surface.

If you want a beautiful, glossy shine, use a machine glaze and then two coats of wax, and you will have a beautiful finish that any professional would be envious of.

5 Tips on how to use Brushable Gelcoat

Brushable gel

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. It comes in many different colors and can be bought online or in our stores! So, let’s talk about some tips on how to get the most out of the Brushable Gelcoat.

  1. Don’t add Patch Booster or Sanding Aid! You heard that right, you don’t need to add sanding aid 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,
    mil-gauge-2
    Mil Gauge

    using a mil gauge.

  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.

BONUS TIP: In the hot Florida weather, working time is tough for any gelcoat. So our FGCI Pro Tip is to chill the gelcoat down to 70 degrees before mixing. This way you can get a bit longer working time.

 

DID YOU KNOW: That FGCI Colormatches gelcoat? We can make as little as a gallon to nearly any sample you have. Call us for details!

  1. catalyst-chart-copy

FGCI Product Spotlight: Tuff Coat

ftl-demo-boat-5Every once in awhile, we get really excited about a product or product line we bring in. To say we were giddy with our latest product line would be an understatement. With that, let’s talk about Tuff Coat!

So, you may be wondering ‘what is Tuff Coat?’ Tuff Coat is a rubberized non-skid coating you can apply to many different surfaces from concrete to fiberglass, even aluminum. Instead of the other non-skids that wear off quickly, or are really hard on your feet, this product is extremely durable, and the rubber makes walking on it very easy.

Now that you are thinking that it sounds like fun, it’s time to talk about the application. Applying Tuff Coat is actually very easy!

 

Step 1: Surface prep. You will want to scrub your surface with soap and water to remove and dirt and grease. The folks at Tuff Coat say the product is only as good as the surface it adheres to, so make sure it’s cleaned. If you are applying to concrete, use a concrete cleaner like ZEP or Simple Green. Make sure you don’t use a solvent, as that can leave a residue.

Step 2: Primer Application. Tuff Coat offers two kinds of primers. The first is the CP-10, which is a 1:1 epoxy primer. This is mixed in equal volumes with a drill mixer and mixed for 2-3 minutes. It is recommended you roll it on with a 3/8″ nap roller or paint brush. You have a pot time of 90 minutes, so make sure you only make what you can spread. This product will be ready to go in 6 to 48 hours, depending on how hot it is and how humid it is.

The other primer is the MP-10 Water based Metal Primer. This is good for any metal application and is a single-stage mix. Again, you will want to stir with a drill mixer and apply the same way. This product is ready to go in 1-4 hours depending on the temperature and humidity.

Step 3: Apply your Tuff Coat. Once you choose which color you want (they have quite a few) it’s time to apply the Tuff Coat. You need to mix with a drill mixer in a bucket, slowly moving down from the top. You may need to mix several times to keep the rubber suspended in the material. When it’s time to apply the product, apply with a Tuff Coat specific roller (it’s the only way to properly distribute the rubber coating) and apply with 2-3 coats, applying at right angles with each coat to ensure a proper covering. The product can also be sprayed with certain sprayers for larger applications.

It’s that easy! Below we have some pictures of a demo boat we did, and I also included a great how-to video that shows how it’s done. And with all of our products, if you have any questions, please don’t hesitate to e-mail us, Facebook us, send us a Tweet, or give us a call at 1-800-272-7890 and we will be happy to answer your questions.

 

tuff-coat-4

Tech Question: “Can I Gelcoat or Epoxy in the Cold?”

cold

I woke up this morning to the outside being much colder than my warm bed. It hurt to get out of bed and touch the tile floor. When I got going, I threw an extra jacket on and bundled up my daughter before heading out the door. It’s December, and this kind of weather is expected, and even welcomed in Florida. As hard as it is to get up and going, it can be even harder to go and gelcoat or work with Epoxy.

Businesses don’t stop just because it gets cold, and that is even truer in Florida. So, we get a lot of calls from people looking to make a gelcoat repair, apply a layer of epoxy or even laminate a pool or boat in the cold. “Will this work in the cold?”

With Epoxies, they are very sensitive to temperature. Anything 50 degrees and below will not work. You will also notice them very thick and very slow to cure out. It is problematic for Clear Casting and Table Top because the material is so thick, those bubbles can work their way to the surface.

 

drum-heater
Our Drum Heaters.

Gelcoat has the same magic number; 50 degrees. Anything below 50 degrees and the gelcoat will not cure. The farther away you get from 70 degrees, the longer it takes to cure; meaning at 55 degrees, you could be looking at days before it gets hard.

 

So, what do you do? The only answer is you need to add heat. Everyone has tips and tricks they’ve picked up on how to work through the cold. Our techs recommend setting the epoxy in a bucket of warm water for a half hour. We also sell drum and pail heaters that will keep your material warm. For small spaces, you will want to apply heat through a heat gun as well. I’ve also seen pool and boat manufacturers put a heater behind the plug to ensure the part is toasty warm before working.

Whatever the technique, you will need some heat, because like me on an early, cold December morning, gelcoats don’t like the cold.