Cardboard skin ...???

[TJinPgh]

Wow, that's pretty amazing.

I'd really like to see a write-up on that trailer beyond the little she did.

60 lbs for the shell? Sheesh!

[linuxmanxxx]

Yeah it's straight up fiberglass no insulation at all so that sucker is hot in summer and cold in the winter. Very gear oriented and not designed for sleep comfort at all but very neat and aero is very good.

[TJinPgh]

TJ I'll just use a 1x2 sandwich with 3/4" foam inside laid directly on my TSC 4x8 cross beams and bolted down and then use the same to do my side walls and overhangs light and ultra crazy strong.

Steve,
Certainly not questioning the overall strength of the structure. The only question I had was regarding the overhang.

In the discussions on that in the other thread, they were discussing a 6" overhang with the overhang attached to both a steel box and the inner wall liner.

Would I be correct in thinking that, without a steel outter box and what I'm guessing will be a 1' overhang that you'll be employing some sort of bracing system on the overhang?

It didn't really look like you employed one in your 5x9 setup.

[linuxmanxxx]

The full blown camper was 6 x 9 in size and I didn't have to support it because it rested on the rails and went all the way across and had 2 divider walls in the trailer to support the box in the center. A box once it is completely attached in all corners and surfaces develops it's own strength and rigidity and due to the fact I was only overlapping outside 6" I didn't need any bracing.

On the otherhand if I do this type build on the 4x8 I will have to employ corner braces at least 2 to 4 to a side and easiest would be place it where a 1x2 is embedded in the side and shelf sandwiches so that when you bolt through it won't pull through the wall or shelf floor. Just use some large L brackets you can find in the hardware section at lowes would be plenty strong enough because once the front and rear walls are up and attached you have your box structure intact and it will better support itself.

My first prototype which pics are only on facebook now was 6 ft wide on a TSC 4x8 and we hand built the whole lower storage area all the way out to the 6 ft semi enclosing the wheels and looked good but was a lot of work and not something I care to repeat and the storage inside is much easier to deal with building.

I was telling you about the 3/4" foam sandwich because it is cheap light and easy to build and very strong. You posted after the paper on foam sandwich so you can see why the thin sandwich works if you use the right glue which is the 30nf I have talked about on here many times and just 1x2 luan and foam and makes a 1" thick floor that you can literally walk on with little flex in it and is why you can bolt it directly to the trailer frame and not waste money building a subframe of wood to place the floor on.

[loaderman]

Yeah it's straight up fiberglass no insulation at all so that sucker is hot in summer and cold in the winter. Very gear oriented and not designed for sleep comfort at all but very neat and aero is very good.

Saya she used urathane and PVC foam.

[linuxmanxxx]

Yeah but zooming the pics to where I see the roof closer it looks like just standard fiberglass shell to me it's not a sandwich core roof construction that I can see at all. Hard to tell with the limited pics and information but if she did a sandwich no way it could come in that light not with 2 skins inside and outside the camper and she built it back in the days of fiberglass and standard resin way before epoxy came into the picture which makes a lot lighter structure than polyester resin does. She probably used the foam and stuff in the storage shelving but in the hull there is none of it there and that would be the only way she'd have the weight that low and she does state it as the hull weight not the whole box finished.

Its way cool no doubt and done by a champion fiberglass layer who has honed their skills making surfboards for many years. I tried doing some glass on my prototype and that cured me right away of ever wanting to do any glassing of anything. Was doing it outside and still the fumes are horrendous and its messy and a ton of work.

[TJinPgh]

Steve,
After I had made that last post, I was on your website and saw that you had a facebook page and looked through a lot of your construction photos.

Great stuff and very informative, btw.

I hadn't realized until I saw those that your production model was simply placed on top of the steel frame, so that obviously explained why you didn't need to support the overhang.

For what it's worth, I like the look of the production model (with the wheels not covered) compared to the prototype better.

As for the thought of building on a 4x8 frame. As I mentioned before, I'm not entirely sure that supports are needed in the front half of the trailer.

The bed platform is going to extend across the entire width of the trailer and will go back at least half way from front to rear (4'). If you bolt the overhang from underneath into the bed platform, you don't need to support it. It will be suspended, rather than supported.

So, at best, you'd just need it just need supports at the 6' and 8' points.

In truth, I'm not entirely sure that they are needed in the rear corners either, if you are doing a solid wall all the way across the back with only an opening for the door. The overhang would bolt into the rear wall, wouldn't it?

So, if you did a 5'x6' bed platform, there's only 3' not supported from either above or underneath. Not sure if that would be enough to worry about.

Sound logical?

[TJinPgh]

Out of curiosity, on the production model, is that one continuous skin on the front and top?

If so, where did you manage to find FRP that wide and long?

[linuxmanxxx]

Yeah I think you are right if anything just need it at the rear. I'd be inclined to take it the full 6 ft wide though and that might need bracing on the 4x8 since would be going out a whole foot to the sides. A full size is just over 4 ft wide so it would take up half the floor space and having a locking system for the bed where it can raise would add additional support while it is locked in the down position. Thinking raising so then you could easily build a sitting table configuration 2 people could sit and say play cards during rain or bad weather. Storage would be there basically during travel.

That isn't frp on production but aluminum from a trailer manufacturer in waco tx. it was on rolls 49" wide and we had them cut 10 ft pieces for my sides. For the prototype we did buy frp in 4x10 sheets but I'd urge to go aluminum if you skin it frp is crazy heavy.

[TJinPgh]

I guess, ultimately, it would depend on how you did the bed platform as to whether or not it would flex on the ends at the overhang. If the bed is going to be non-stationary, then, yeah, it would negate it's ability to support the overhangs as well.

I was more curious about what you used for the front of the trailer, curving up onto the roof, which looks to be a solid 6' wide. Was curious as to whether that whole thing was one continuous piece going from the front end diamond plate all the way to the back of the roof.

In either case, you'd mentioned that you'd used aluminum so that probably answers my question regardless.

Aluminum is certainly nice, but probably a bit out of my price range. I wasn't aware of the weight for FRP panels.

Given that bit of information, I might be inclined to either seal and paint or to canvas it and paint.

I'm not overly concerned with having any kind of high gloss finish so it gives me a few options, I suppose.

The elastomeric roof coating you mentioned for your builders edition. When that stuff dries, what is the texture like? And, is it heavy?

Would be curious to see if one could paint the entire trailer with something like that... assuming it was skinned with luan first.

PS. I think we're threadjacking...

[linuxmanxxx]

Here's the scoop on what I've learned about frp aluminum laying it out and how to do it cheap. Find an enclosed trailer manufacturer close to you that you can call and ask about getting some aluminum skin from them and it will be way cheaper than any of the online vendors sell. It was about 400 to do the production build with aluminum and about the same for FRP which was noticeably heavier than the aluminum wound up being. We did the diamond plate so that it would take a 4 ft wide section up and over the front curve giving no seams in the front where all the wind and water would be while travelling. We did the roof in frp on the prototype 4 ft in center and a ft strip on each side of it. Huge mistake in how we laid it out and I didn't install the vent hood correctly either and when our drought broke and finally rained we learned we had a leak.

Production brought on a whole new design and idea with the aluminum. We laid the roof from rear to front overlapping the front sheet over the rear about 6 inches to a foot so we did the roof in 4ft cross segments of aluminum. I laid the rear siliconed the crap out of the lap and screwed down thru both aluminum sheets and into luan layer with sheet metal screws all the way across siliconed as well and then did the front section up and over the curve and overlapping the 2nd piece same screws and silicone.

So going down the road all wind and rain simply just pass over the overlaps and nothing is there to catch wind or water. We then put our trim up around the edges and rear and it has a sizable about 1/4" rise to it if not bigger. We used flat stock of the same flextrim across the roof seams and this is all glued down with PL Premium polyurethane glue and is glued solid with it. We then took the elastomeric white roof coating and went over the aluminum on top with it sealing the whole roof again. With the flat stock in place the roof actually catches and holds water when it rains and hindsight now won't put the flatstock on any other trailers BUT in spite of this it has downpoured and the roof has not leaked a single drop anywhere even with sitting water on it. Oh I forgot to mention the aluminum is glued with 30nf to the luan everywhere even the roof and then screws in the roof overlaps so it will not ever buckle in heat or leak because the glue is waterproof as well.

I really can't say enough how well the 30nf has performed and even if it is pricey it covers really well and kicks serious butt in he adhesion to foam dept and is NONTOXIC and very low odor.

I have a few gallons left and when I get this moving mess out of the way plan to play with doing some canvas layup with it and see how well that turns out. Do a mockup with luan interior and canvas 30nf exterior and see how strong it winds up being and how well the contact cement sticks the canvas to the foam.

I've built two now and can tell you number 2 incorporated all the stupid gotchas and flaws we learned on number 1 and 3 will be even better than 2. 2 with the exception of not understanding how to seal the silicone along the trim and it looking yucky in places otherwise has about 98% of the look of rolling off a production line.

Number 3 I'm going for lowest cost build and lighter build and keep my learning curve happening.

[GPW]

The skin makes it all possible ... The Foamie “sandwich" is the key to this method of construction ...

[kludge]

Just a thought ... NOT the corrugated stuff , but the kind that comes on the back or writing tablets ~ 1/16"

Hi All, been a couple years since I've posted, but a couple years ago I was thinking about foam for a shelter on my utility trailer in this post... viewtopic.php?f=27&t=34544 and now there is a section of the forum devoted to foam!

Anyway I've been reading this "new" forum section for a couple days now and I had some comments about this post by GPW that I wanted to share...

As for corrugated cardbard... why not? Layer it up and glue it up (no fancy glue needed) alternation the direction of the corrugation so it acts like plywood. Skip the foam insulation altogether... corrugated cardboard will insulate pretty well. It won't be as light as the foam, but I imagine you could just "paint" it with TB2 and get the water tight shell.

And my second thought...

Very strong, very light, easy to work with and glue things to it, but probably low insulation value... honeycomb core cardboard panels!

http://www.uline.com/BL_1856/Honeycomb- ... =Honeycomb



Because of the low insulating value it would also be possible to make panels of 1" honeycomb cardboard panels for the exterior walls and 1" foam board on the inside.

Probably the flat panel designs like the Weekender would be the best options, since kerfing the honeycomb cardboard panels is going to ruin it's structural soundness...

Anyway, those were just some thoughts...

As for my project... it doesn't look like the utility trailer will be going away, and I can't find a cheap 5x8 trailer, so I'm still wanting to enclose it somehow... and because of the small axle and tires, weight is the prime concern. I'm not terribly concerned with insulation value... I'm a 4-season tent camper.

[GPW]

Klu, although it’s entirely possible , it would be a “hard sell” around here ... It took over a year to get them to believe me about the Foam thing ... and still that’s not entirely settled in the minds of traditional plywood users ... as of yet

[atahoekid]

It took over a year to get them to believe me about the Foam thing ... and still that’s not entirely settled in the minds of traditional plywood users ... as of yet

GPW, It's tough being a pioneer!!! Comes with the territory We, as believers thank you for your creative thinking and for leading the way..

BTW, Kludge, I think corrugated panels should work real well. A thin inner skin for rigidity (I'm thinking 3 mm or 5mm lauan ply), a fabric skin outside and you've got a structural panel. Strong and Lightweight