Gudgeon

Member

Registered: 23 Feb 2012

Posts: 13

Mottled Surface on Epoxy

I have just had a look at the epoxy coating I did late last night and the surface is mottled.  The temperature was about 7 dgrees when I put on the second coat and it did not look uneven at the time.

Richard

Member

From: East Sussex

Registered: 7 Jun 2011

Posts: 75

Re: Mottled Surface on Epoxy

sounds like the epoxy might be a little cold.

What are  you making?

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Canoe & Kayak Owner

Gudgeon

Member

Registered: 23 Feb 2012

Posts: 13

Re: Mottled Surface on Epoxy

I am making an Elterwater.

I think I have mislead everyone - the temperature was 7 but I kept the epoxy at about 16.

Paul

Employee

From: Gatebeck Cumbria

Registered: 4 Aug 2011

Posts: 131

Re: Mottled Surface on Epoxy

Don't panic there will be nothing wrong with the boat but you will have a little extra sanding to do.

It is unusual to get this effect but by coincidence you are the second to ask this week which means that I am ready with the answer.  You have not mentioned how you applied the second coat but I suspect that you used a sponge roller or sponge brush because the temperature of the epoxy is sufficient to make it run well.

If you look at this link FAQ PEC there is a full answer but in essence the problem is with the sponge roller which was not evenly coated.  It puts thick patches down in some places and then misses other areas or, worse, drags epoxy off the surface.  It is not easy to get the sponge to take up the epoxy uniformly even if the temperature of the epoxy is above 16 degrees: I certainly cannot manage it.  I have found that it is easiest to apply the second coat with a squeegee.  You simply spread the epoxy and any lines formed by the edge of the squeegee usually disappear.

By the way, if you are painting the boat you can fill the weave of the fabric using epoxy that has been slightly thickened with silica.  This flows beautifully and is thicker and lighter than unthickened epoxy.

To solve your problem wait until the epoxy has cured and you cannot dig your fingernail into it and sand the area smooth.  We always wash the wood with warm water containing a little washing up liquid before sanding because it removes any stickiness that will clog the sandpaper.

Gudgeon

Member

Registered: 23 Feb 2012

Posts: 13

Re: Mottled Surface on Epoxy

Thanks for the replies and the speed of them!

Sanded a test area last night and it came smooth.  I was goingto do it all but I am not sure that the epoxy was cured fully. I assume that I can cover any areas that do not come smooth. I have a horrible feeling that I have wasted a lot of epoxy.