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Foam and fiberglass and paneling glue???

PostPosted: Thu Sep 24, 2009 12:00 am
by Minicamper42
I would like to know if using that stiff lightweight foam insulating material at the home improvement store would be ok to use for my mini camper construction?

The sides will be tilted outward slightly and the front will be pointed about 30 degrees to make a point...I was going to taper the edges to square them up and glue the joints with epoxy...then use a fine fiberglass tape and epoxy over the joints inside and out, then glass the whole outside for strength and seal it up weather tight...then on the inside after the rough wiring and other stuff is done, epoxy some 1/8" paneling to the inside walls to finish it off and then build my cabinets and such...I believe this type of construction would yield both a very rigid structure and keep the weight to a minimum as the interior walls would act as shoring as well...the foam board is very rigid and will insulate the trailer at the same time, saving a whole nother process...wiring will be ran mostly through the floor at the walls and a trench cut out for the wire, then use some dense spray foam in a can to fill it back up and sand back down flush before installing the paneling...mainly for light wires and speaker wires.

I could also cut out enough foam at the joints before glassing the joints on the inside so I would be able to epoxy a nail strip so I could just glass the whole inside first and then attach my finish paneling with nails and just enough glue to avoid moisture buckle on the thin panel.

So, has anyone here done a similar process?...any suggestions or other similar ideals would be helpful in my build plan

Thanks, and great smiles you guys have! :thumbsup:

PostPosted: Thu Sep 24, 2009 12:19 am
by doug hodder
I'd think, based on your description, that maybe a "stitch and glue" technique as used on smaller boats would be a viable alternative. It would provide more puncture resistance on the exterior and is quite light weight. I'd think that 1/4" thick ply would work quite well in this application. It would cut out a fair amount of exterior glass and epoxy work as well as dollars, Just my 2 cents on it though. Sorta depends on what you mean by "glass the outside" though. Doug

PostPosted: Thu Sep 24, 2009 5:01 am
by Steve_Cox
I'll call your two cents and raise you a nickle. 8)

I've been thinking about a method for building flat fiberglass - foam board - 1/8" plywood sandwich panels. It would consist of a build table as large as the biggest panel you would want to build that was coated with mold release wax. Roll on gel coat, then epoxy, add a light weight fiberglass cloth, wet out the cloth. place a lightweight wood frame for the perimeter edges, windows and doors, fill in with foamboard insulation, run the wiring, roll on more epoxy then top with the 1/8" plywood and vacuum bag the whole thing. Use a router on the edges and openings. All the components would be pre-made to speed up the assembly time.

PostPosted: Thu Sep 24, 2009 7:07 am
by WesGrimes
Make sure your foam and epoxy are compatible. Polyurethane foam will not react, but polystyrene will melt when layed up with some resins. I have only worked polyester resin, and I know it melts it. I think epoxy is styrerne free, but check it out first...

PostPosted: Thu Sep 24, 2009 1:06 pm
by Steve_Cox
WesGrimes wrote:Make sure your foam and epoxy are compatible. Polyurethane foam will not react, but polystyrene will melt when layed up with some resins. I have only worked polyester resin, and I know it melts it. I think epoxy is styrerne free, but check it out first...



Wes,

Could you imagine anyone, foam roller in hand applying mass quantities of epoxy resin on foamboard as it turns into a big puddle of goo? :lol:

Since you haven't tried epoxy resin yet, please give it a try, it'll make you forget how to spell polyester. 8)

PostPosted: Thu Sep 24, 2009 6:37 pm
by Minicamper42
doug hodder wrote:I'd think, based on your description, that maybe a "stitch and glue" technique as used on smaller boats would be a viable alternative. It would provide more puncture resistance on the exterior and is quite light weight. I'd think that 1/4" thick ply would work quite well in this application. It would cut out a fair amount of exterior glass and epoxy work as well as dollars, Just my 2 cents on it though. Sorta depends on what you mean by "glass the outside" though. Doug


When I mean glass the outside I was meaning that fine mesh they use on canoes after the stitch and tape process...the stuff that turns transparent when you lay down the resin over it...I want to do this so the 1/4" ply won't splinter...I will still paint my trailer white when it is finished, but think a good sealing first would be in order...I will download one of your free CAD programs and tinker around with a design and show you all what it might look like when completed...I figure at least 6 months or so in design work and layout before cutting anything...this way I can get your all's opinion before moving forward.

ISO board

PostPosted: Sat Sep 26, 2009 5:39 am
by TomsTwin
Hi... I recently began a similar type build using foam. The type I chose is ISO Board. It was used as a florring for our new roof at work. It is very strong and both sides are covered with paper which soaks up the epoxy nicely.

Here is the thread which follows my progress.

http://www.tnttt.com/viewtopic.php?t=31714

my gallery: http://www.mikenchell.com/forums/album_personal.php?user_id=8732

I am epoxying the walls each separaqtely. Firstly, because of the time needed to accomplish just one side. And Secondly, because I realliy need them to be flat to perform the task.

I got my epoxy from http://www.raka.com/. A 5 to 1 mix was recommended to me. The inside wall surface will have 2 to 3 coats. The outside surfaces will have 3 coats... 1 to soak the paper, 1 to lay in the glass fabric and another 1 (maybe 2) to smooth it all over.

Of course, I have no idea if this will all work or if the whole shabang will blow apart on the highway... :x

Hope this helps... Tommy

PostPosted: Sat Sep 26, 2009 12:36 pm
by Minicamper42
Thanks Tom...I did see your brave build...my only question wold be is the softness of the insulation, that stuff seems to dent easily...with the process you describe on the layers of resin and glass you should be fine...I would be willing to bet that you will be able to stand on it when finished, maybe :thinking:

Thanks for the tips and good luck with your build Tom

ISO board

PostPosted: Sat Sep 26, 2009 1:54 pm
by TomsTwin
Hi...

Actually, the ISO board soes not dent easily with the paper intact. They use it as a base for the rubber roofing sheets. Even without epoxy, I can walk on it and not leave a dent. Without the paper, it is brittle. However, I am using 2" thick pieces for my walls. I just finished glassing both sides of the first wall. Seems strong. The only problem is that the ISO board doesn't have a completely flat surface. If you care about a glass smooth finish, consider some leveling.

Otherwise, it supports walking without leaving marks.