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PMF and epoxy resin

PostPosted: Tue Mar 19, 2019 12:18 pm
by FBJcreation
Can you do PMF over epoxy resin for skinning? Thinking of doing an epoxy base on bare wood like a “mix” as it would strength and waterproof the wood. Then do PMF on top. Thanks.

Re: PMF and epoxy resin

PostPosted: Tue Mar 19, 2019 12:24 pm
by Sparksalot
Why not go ahead and do the fiberglass too? The cloth is the inexpensive part compared to the epoxy.

Re: PMF and epoxy resin

PostPosted: Tue Mar 19, 2019 1:09 pm
by Pmullen503
Sparksalot wrote:Why not go ahead and do the fiberglass too? The cloth is the inexpensive part compared to the epoxy.


Ditto. Epoxy resin only over wood is a waste. It will eventually crack from expansion and contraction of the wood. Use glass cloth if you are going to use epoxy.

PMF is a good way to protect wood. Boats have used it forever in a very harsh environment.

Re: PMF and epoxy resin

PostPosted: Tue Mar 19, 2019 2:22 pm
by tony.latham
I agree on the fiberglass. You're toying with a dissimilar materials issue. Fiberglassing works and isn't an artisan operation. I've always felt that poor in PMF is a bit of an exaggeration since it doesn't save much money.

Epoxy resin only over wood is a waste. It will eventually crack from expansion and contraction of the wood.


I use Raka's thin epoxy resin for areas such as the galley floor and it soaks into the wood about 1/16" deep. I've been going this route for years without any cracking. In a sense, it becomes a wood/epoxy matrix.

:thinking:

Tony

Re: PMF and epoxy resin

PostPosted: Wed Mar 11, 2020 9:10 am
by Westley
It's my understanding that plywood, like marine plywood, is much more stable than lumber, in regard to expansion and contractions.

Also, there are so-called flexible epoxies available for use on wood boats. Total Boat and West System sell it, and probably others. There is also two-part marine varnish with UV protection.

Re: PMF and epoxy resin

PostPosted: Wed Mar 11, 2020 2:02 pm
by RJ Howell
The game with PMF is getting a great bond between material and subsurface (as is the same for FG"in..). I really wonder why the mix of the two different systems.. :thinking:
Then of course... the benefit.. :NC

Are you thinking using canvas cloth vs. FG cloth??

Re: PMF and epoxy resin

PostPosted: Wed Mar 11, 2020 5:38 pm
by tony.latham
Are you thinking using canvas cloth vs. FG cloth??


He was on the forum for about a month last year and I don't think he has been back. :thinking:

T

Re: PMF and epoxy resin

PostPosted: Thu Mar 12, 2020 11:13 am
by rjgimp
tony.latham wrote: I've always felt that poor in PMF is a bit of an exaggeration since it doesn't save much money.

Tony


Perhaps now that is more the case, particularly in this forum where the latest and greatest inventions in the paint and adhesive worlds are being experimented with and applied over new unblemished canvas with no seams. The costs for doing so might actually exceed that of a traditional fiberglass layup. Back in the old days when the process and the name for the process were invented I suspect there were many more cases of builders using whatever scraps of cloth and leftover dribbles of paint that could be scrounged out of the depths of the cellar or garage. In that case, such skinning could effectively be "free" as it brought zero additional cost to the budget for whatever project was being undertaken.