Wax residue on epoxy coat

I searched and found many threads on the use of wax paper with epoxy. One in particular, from Lazlo indicates the "possibility of wax melting into the epoxy if the curing process goes exothermic."

I have coated all sides of the parts that make the seat and foot braces of my Chester Yawl. I thought I would use wax paper on the bottom and above. The result looks great with a smooth surface on both sides. Only, now I am supposed to put a second coat and the first coat feels "waxy."

Do you all suggest I sand the layer and re-epoxy without wax paper OR is there something I can clean it with (alcohol or else) prior to the second epoxy coat?

Thank you in advance!

Eric


7 replies:

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RE: Wax residue on epoxy coat

Eric,

I tried wax paper after laying down a coat of epoxy in the rear compartment and it left a very smooth surface with zero orange peel.  I found out, however,  the residual wax left behind runs the risk of not bonding well to the next coat, I stopped using it.  I was advised to use (I believe.....need to hear this from someone that knows for sure) lacquer thinner on the cured epoxy to remove any residual wax.  The test (I was told) to know if you have removed all the residual wax is to drop  water on the surface, and if it creates bubbles and runs right off, there is still wax to remove... I found it took a few wipe downs with the lacquer thinner before the water dropped on the surface ran off in sheets, not drips that stood up like on a waxed car...again let's wait to hear from someone to confirm this, but that was my experience...right after this I ordered a bunch of Peel Ply which has other benefits anyway.

Curt  830/997-8120 [email protected]

   

RE: Wax residue on epoxy coat

Eric,  Forgot one point...I was also told NOT to sand the surface where the wax paper was applied...it will just smear the wax around...needs to be cleaned first...but we do need to hear from someone else whether or not it was lacquer thinner to remove the wax.   

RE: Wax residue on epoxy coat

I am glad I waited and did not sand the surface to get rid of the wax. Thank you, Curt for the suggestion to use lacquer thinner. I am traveling and will work on the boat next week, so I am happy to wait and see if someone can confirm the correct product to use for removal of wax on cured epoxy.

Cheers,

Eric

RE: Wax residue on epoxy coat

   More than likely the waxy film is what is called amine blush. I have never heard of putting wax paper anywhere but to keep from sticking to anything. DO NOT use lacquer thinner as a cleaner it will soften the epoxy. If your going to wipe it down acetone is the answer but I find that acetone makes the epoxy really sticky. I have just scuffed and put another coat of epoxy on it with the chance of a delamination but that has never happened. In a boat shop we used primarily a mixture of epoxy the old man worked out and if it was a lot of humidity in the air we would get this blush. He always just mixed up West System and coated with that one coat. That is all he used West for. I'm not a big fan of West System but it sure worked in this situation. If you allow epoxy to fully dry then it needs to be sanded to recoat of wait till it becomes tacky but does not come off to the touch and your ready to recoat. Use a dry brush or roller to leave no orange peel.

Bruce

RE: Wax residue on epoxy coat

FYI..the potential .waxy film is not amine blush if you used MAX epoxy, it is residue from the wax paper.

RE: Wax residue on epoxy coat

   So if you get the waxy film from the wax paper then use plastic you should get the same result. MAS does claim to be amine blush free along with many others but I have always been taught that all polyesters, vinylester, and epoxy have to have a wee bit of blush in order to cure. Even RAKA claims to be amine blush free but if the humidity is just right or it is cold out and the epoxy is in a very slow cure you will get a slimy coat over the epoxy which is the blush. I have been pretty loyal to RAKA over the years and I know that there has been many improvements to products that I have not kept up on mostly because 99.9% of the time I have no problem and never had any delamination problems with RAKA.

My thought about covering uncured epoxy and not letting it gas off in the curing process it would develop this waxey slimy build up. I am no chemist but have experimented with many different epoxies in various boat shops. I dont mean to sound as if I getting sideways with anyone and if it is the wax from the paper then denatured alcohol should do the trick to dissolve the wax. Through the years I have used wax paper to seperate pieces from sticking to each other and have never experienced any waxy surface on the epoxy from the wax paper.

Bruce

RE: Wax residue on epoxy coat

   Thanks Curt and Bruce for the really helpful replies! I ended up using alcohol on the fully cured MAS epoxy that had residue wax after I used waxed paper in lieu of ... Peel ply. Isopropyl Alcohol cleaned the surface nicely but did nothing to the wax. I did not have acetone or lacquer thinner handy and did not want to sand wax into epoxy as you had mentioned, Curt ... So I used the tungsten carbide pull scraper, which in a few passes peeled the wax and epoxy right off to bear wood. A quick pass with the orbital sander and it is ready for epoxy.

I am glad I learnt from that experience and the only pieces I coated that way were the four flat pieces that make the seat and the four flat pieces that make the foot brace .... All fairly small surfaces.

by the way that carbide blade pull scraper has been one of the most helpful tool in assembling this boat. Thank you guys for the kind input and whoever provided the sku# for Home Depot for that pull scraper. The blades last incredibly long ... Just don't get any wet/tacky epoxy on them or the blade will loose efficiency, even after thorough cleaning.

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