Thrifty Alternatives ..Building Foam Campers

[GPW]

QUOTE: “ they will come up with cheaper and less toxic epoxy or other polymer kind for foam home builders” ... Actually they have ... Titebond 2

This all goes back to how far you want to take (and invest) in your Foamie .... and how much you really need .... I’m quite Happy with my little TB2/canvas covered foamie trailer ... some want to go further , but as you can see , the more you want , the more complicated it gets exponentially ... Just sayin’ ...

[Wobbly Wheels]

That's a good point Tony - I stand corrected.

I now agree that precoating with epoxy and then doingpolyester FG is not a good idea.
Then you mentioned:

Personally, I think using epoxy over XPS is a false economy.

- So, for trailers too, and if yes could you elaborate why you think so? That is what I am doing (XPS with epoxy) and some other people did before me. I never had experience with PVC foam core and have no idea of prices, but I thought that using PVC core for the trailer will be too expensive, or I am wrong? Rutan planes are built using epoxy over XPS...

When I say a false economy, it's from knowing that I was using XPS as a way to save a bit of money. In Canada, a gallon kit (1-1/4 mixed gallons) of Epiglass (comparable to West 105/205) retails around $250 (my cost is around $180). If I were using a single gallon on a small job, it might make more sense to use XPS that runs about $18 for a 2X8 sheet of 1". After 4 gallons came and went on my build, I had to re-evaluate my build budget given that I was only about a third done. Had I used PVC foam, I would have continued the project as time allowed but, combined with the failures I had already seen in the XPS core, it felt like I was throwing good money after bad. I just looked up a US price for PVC foam: 5lb Divinycell 1/4" X 4 X 8 at Jamestown is $135. If I'm already spending the money on epoxy, it just makes sense (to me) to go the extra step and lay it up onto a decent quality core. I haven't done the math, but I'll bet that a polyester resin/PVC layup would end up costing less than epoxy/XPS with the result being thinner, stiffer panels.

Sounds like some testing is in order !

Don't get me wrong - others have indeed done nice work with epoxy and XPS: look up Mel's (atahoekid) Road Foamie for one. I think Micheal (Atomic77) used XPS for his Astroliner build as well but I'm not sure on that one.

As to Rutan's use of XPS wing cores: he's a pretty smart guy and obviously I wouldn't second guess his designs. It would be interesting to see how he mitigates the comparatively low shear strength of XPS over more traditional coring foams that are already proven. I would guess that the skins are laid up to carry the loading with the core serving as little more than a mold to allow the builder to align and bond the skins together.

I don't want to dissuade you from your build. I just wanted to share the 'buyer's remorse' I had after investing so much in applying resin over a foam that wasn't all it could be. I have long since made back what I spent on epoxy but it still stings when I think about it.

Live and learn....and share what you've learned

[OP827]

I hear what you are saying, WW.

Did you have this kind of cracks in XPS foam in a trailer build or a boat build, why do you think the XPS foam cracks happened, over bending stress? I have never experienced XPS foam cracks in my build.

BTW, in my area the retail price for East system epoxy 3.7l with hardener 0.8l is 140CAD$ total. I actually like East system better not only for the price, but also that it is somewhat thinner than West, it impregnates fiberglass quickly. I already used 20l package and now going with smaller 3.7l packs to finish the parts, only few are left to laminate. PVC core is much more expensive as I suspected. I built 1.5" thick XPS foam walls, it would cost a lot to do out of PVC core for a trailer build.

[Wobbly Wheels]

I hear what you are saying, WW.

Did you have this kind of cracks in XPS foam in a trailer build or a boat build, why do you think the XPS foam cracks happened, over bending stress?

This was on large panels on a trailer - I wouldn't feel comfortable using it for a boat. As I recall, the cracks were mostly near corners - not actually in the corners but running parallel to them several inches away. I suspect it was from the panels flexing as they were moved around, despite bracing them where appropriate. Going with 1.5" foam instead of the 1" I used may eliminate that.

Right now I'm working on a 4X8 Benroy and to do that in PVC foam would be a sheet of 3/8" for each wall and probably a sheet and a half of 1/4" for the roof. Compared to the whole cost of the build, I don't think the cost would be a huge hurdle but those are decisions we all make for ourselves.
It's certainly not 'thrifty' by any stretch so I hope GPW doesn't give us heck for going off topic

[GPW]

No troubles ... we all have our methods , and some are just more costly ... Some are just a lot more money and labor that we are willing to commit to for a simple camper trailer ..

[GPW]

Speaking of Costly foam trailers , I’d still like to be able to afford an EPP (expanded polypropylene) trailer build ... Flexes instead of breaking ... Very strong ( the foam they make new car bumpers out of ) ... Very Expensive ... Being moldable , it could be just be molded into the exact trailer shape and wouldn’t even require skins ... ( possible only , if I win the Lottery )

[GoTurtleGo]

Hi Gang,

I haven't been on this thread in awhile. Looks like you guys have been busy yakking so I caught up.

tpstorey and Bruce Schneider - Congratulations on finishing the read! It's a great feeling isn't it? I have a notebook full of notes from the read. tpstorey - I live in Saint Louie too. Pretty close to that arch, actually.

This Winter I hope to get my build journal up and going. I've finished the trailer and am building the floor. Yes, there are even photos. I just need to organize them and resize them.

Glad to see the foamie family is growing.

Cheers,

Kathleen

[GPW]

Yes , please send pictures !!!

[GoTurtleGo]

You're making me laugh. I will. I promise. I am just sloooooowwww.

Kathleen

[GPW]

No worries , everything is slow this time of year ... or Frozen ...

[Wolffarmer]

Cold here at least -10 F at my place. Going to have to get ready for work much earlier today. Put on more clothing. Put on winter boots ( that is a struggle ) See if vehicle starts. If it does let it warm up a few minutes before venturing out to see how many snow drifts I need to bust through.

Idaho in the winter.

[GPW]

Wolf , although the thermometer says 74F inside , I’m still sitting here in my camo hoodie' and with the little heater on ... Winter in New Orleans , sorta’ , ish’ ...

[Ned B]

It was a balmy 63* here today...

ImageUploadedByTapatalk1448674813.735171.jpg (39.22 KiB) Viewed 1628 times

so we fixed our driveway. Added a lane making it three cars wide. 6 cars, 5 drivers and winter is coming...

[GPW]

6 cars !!! That’s not a driveway , it’s a Dealership ..... hahahaha

[Mary C]

my new design for my standie, I am wondering how high? or rather how tall inside? I am 5'3" . Should I go 5, 6, 7 inches over my height. Any suggestions?