MAS Epoxy coating application

I am building the Tenderly.  I coated the sanded seats with the MAS epoxy, using a foam roller.  When cured, it looks and feels like very coarse sandpaper.  A lot of power sanding makes it smooth, but seems to take off all the epoxy.  Bubbles?

How do you apply the epoxy coating?  Roller?  Brush?  Roll and "tip" with a foam brush?  What I have done is not working, and I am afraid to start the epoxy coat on the bare wood of the hull, non-horizontal curved surface and all.

Thanks for any help with this.


5 replies:

« Previous Post       List of Posts       Next Post »

RE: MAS Epoxy coating application


Anytime you apply epoxy with a roller, you need to then tip it out. The roller always leaves behind air bubbles, exactly as you've seen. Just pass the tip of a dry brush across the newly-epoxied surface. A disposable foam brush is fine for this. You need to just barely touch the surface, just enough to eliminate the bubbles, with a very light touch.

You also need to do it immediately after rolling on the epoxy. You can't wait until you complete the entire surface. Roll on a couple of square feet of epoxy and immediately tip it out, then do it again with the next bit. I usually end up with the roller in my right hand and the brush in my left so that I can get it done as quickly as possible.

You can also use a squeegee to basically spread a puddle of epoxy around on the wood. A lot of people have good results and prefer that. It should keep any bubbles from forming. The main reason I prefer rolling and tipping is because is because it applies thinner coats. Thinner coats means less chance of sagging and dripping and less need for sanding.

Good luck,



RE: MAS Epoxy coating application

Be sure when you begin coating bare wood / plywood that the surfaces being coated have acclimated to room temps first.

Where uncoated, porous materials aren't temp-stabilized to the working environment, if room temp is increasing or other means of localized warming of the now-coated materials planned, outgassing will inevitably result in bubbles forming that may go unnoticed until it's too late to do anything but sand them off before recoating.

I ran across a couple of videos awhile ago suggesting epoxy can be 'tipped out' immediately after application by means of rapid passes with a propane torch flame.

Bear in mind the caveat that I have NOT tried this particular technique myself - yet - and whether it has applications for our kind of projects, rather than the thickish, deep clear-coat stuff being used for coating things like bar tops, needs to be addressed. The video showed quick passes at distances that ought to avoid any localized heating, making me wonder whether an industrial-type heat gun might also be employed in a similar but perhaps safer application?

RE: MAS Epoxy coating application

Heat will make it cure faster, which will interfere with self-leveling.



RE: MAS Epoxy coating application

   spclark has it right.  I've done a lot of restoration work with epoxy over ply and hardwoods.  Don't do your seal coats (especially the initial coat) when the temperature in your shop is rising or the material you're coating is rising to room temperature.  You'll experience outgassing of the wood which is what a lot of those little bubbles are.  For years I've used a Milwaukee Variable Temperature Heat Gun to smooth out a seal coat.  I use System Three general purpose resin which is not as thick as West.  I can't speak to the torch technique as I've never done that.  As for heat making the film cure faster - That's generally true but remember you're heating a thin film of resin just long enough to pop the bubbles.  I've never had a seal coat kick off while I was using a heat gun on it.




RE: MAS Epoxy coating application

   Go with the roll and tip, especially for all non-horizontal surfaces.  Keep that film thin because if not, it will all look good, you'll turn your back and the sags will start when you aren't looking.  That was quite frustrating for me.  There will always be some place it will sag, you just want to keep the really large ones from happening because that's just extra sanding you'll have to do later, and sanding epoxy is my #1 least favorite pasttime.  I'll sand wood or even varnish but hate the epoxy.  I did get a HEPA filter for my shop-vac which helps and wound up hand sanding with the sandpaper/block in one hand and the vacuum hose in the other. Hearing protection, gloves and respirator.  I reserved the orbital sander for big flat surfaces, of which there are few on these boats. That epoxy dust still cakes in the vacuum.  Shop-vac sells a washable HEPA cartridge for most of their vacuums. Get it.

« Previous Post     List of Posts     Next Post »

Please login or register to post a reply.