Teardrops n Tiny Travel Trailers

ai4kk wrote

I just used some of the roll roofing to patch part of my roof on my house... Way too heavy and not strong enough for camper use

Hummm, are we talking about the same thing here?? I went to
http://www.metacrylics.com/residential/ ... t_Data.htm
and
http://www.metacrylics.com/residential/specs/roof.html
which say the Stichbond Poly only weighs 3 oz per sq yard.
Can you specify exactly what "roll roofing" you used, it looks like it might be some other product

The second one is 108oz

I uses the stuff in the second link, it's basically like real heavy tar paper with mineral / gravel on one side to protect it against abrasion. This stuff here : http://www.homedepot.com/p/3-ft-x-36-ft ... 57&cj=true

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My tests showed that 8 or 10 oz canvas (I would have to look back at the moment to be sure... sucks getting older) and TB2 is almost the exact same weight as two plies of 6oz weave FG laminating cloth and epoxy. At this moment I forget if this included latex primer on the outside of the canvas sample but am pretty sure it was prior to any filler/sealer/paint work on the FG. Tested approx. 1 sq ft sections sized and prepared identically, and measured on a digital gram scale, check my build thread for more details.

Regarding FG bug screen material, I'm pretty sure that the fiber strands are all bonded at their intersections, so it will not conform over compound surfaces well at all; simple 2D profiles, yes; but 3D shapes, no. Linen and canvas do a lot better at this, but still have their limitations. Laminating types of FG cloth win the prize here (and maybe some of the other exotic weaves, to a degree) because the dry fibers slip and skew by each other very easily. Why does this matter? Because when we are talking strength we also have to consider how that strength is passed from segment to segment, or from joint to joint. If you have to pie cut and lap hundreds of darts, and/or overlap more and more cloth segments, that is going to add a significant amount of extra weight compared to something that is well planned out to minimize seams. Whereas the conformability of glass weave cloth allows you to strategically wrap compound edges, and to place, align and blend seams as desired (I think I did a pretty good job in this regard, reinforcing compound corner joints with laps and optimum sheet sizing).

Some might want to limit this conversation to FG bug screen, or other similar products, but why? The idea here is to share ideas and information, not stifle them. Just saying.

GPW is absolutely correct, regardless of the type of cloth used, there will be added expense, weight and man hours if you want it to be even close to 'slick' (I'm going for 'kind of nice and smooth', but definitely not even close to 'automotive show quality'). Part of the problem I found is that if you want to blend the laps, then you end up filling part of the weave; and if you fill part of the weave and not all of it you create an even more uneven appearance ( , yup). If you don't mind the texture of the weave, some exposed seam lines and a lot of "potato salad butt" surface waviness, you can get it done much faster, more thrifty and it will be lighter weight. (No offense intended to anyone, just admitting the facts to myself, we all have to decide what level of finish we like. Hello my name is KC and I have a body work image problem... )

Newbie here.... but a question about skinning foam. I understand that the 'cloth' is there to strengthen the foam, but how much does the 'adhesive/paint' have to do with it? My understanding is that part of the theory behind behind fiberglassing is the 'cloth' is as much for 'tensil' strength as soaking up resin and holding it in place while it cures. So is the 'cloth' as important as they glue? What glue/paint gives the best cost/practicality to strength ratio?

It all works Together !!! Every component is important to the rest …
To be totally honest , we never thought of a foamie as a "Beauty Queen" , but just a place to stay … a foam cave , a hard tent …. call it what you want it’s just a pragmatic camping /EVAC vehicle .

and the way things are looking , we may get a chance to try it soon ( hope not )

KC - do you believe that two layers of 6 ounce glass are required for the strength of one layer of 8 or 10 ounce canvas?

They're similar but not the same.

Yes the cotton canvas is the tensile element of the composite, but it and the set glue remain more flexible than the FG/epoxy. In fact I was able to bend my single sided PMF sample over to a surprising bend radius with no apparent adverse affect to the foam; unlike an unsupported piece of foam, the 3/4 thick sample with PMF bent right around in a 'U'-shape and, more or less came right back. Whereas an unsupported piece of foam would have snapped. The single ply of 6oz FG also could take a surprising amount of bend, it did not shatter or crack as some would have you believe (even after curing for a long time and retesting multiple times).

The PMF sample had the most give to it under point load (trying to indent with thumb pressure). The FG sample with just one 6oz ply was better. With two plies of 6oz I was happy with the point load and impact resistance. It still has a very slight amount of give under a heavy finger press point load but does not tend to indent locally, and the sample was much stiffer. Sure, the PMF has shown in many cases to heal itself from dents over time, but the 2-ply FG doesn't readily dent in the first place... this is not to say that the PMF dents easily, it is impressive, it just has a softer feel and will take a dent more readily without springing back instantly.

For me, with moderate off road plans, it was a very difficult choice, but I wanted the extra "armor". Like GPW says, the benefits of PMF are actually quite remarkable. It is surprisingly close to FG in many ways and has some great benefits that you can't get with epoxy/glass. It is hard to argue with a durable, flexible, self healing, and easy to repair material. After a few simple tests I still had a very hard time deciding which way to go. Cost and time were not necessarily my biggest concerns, and I have learned to deal with the PPE issues surrounding the use of epoxy (religious use of proper respirator, proper cleaning and storage of said respirator, disposable gloves and Tyvek style arm sleeves... while applying, sanding and cleaning up afterwards, including servicing the shop vac). These things are not small issues of time, effort and cost, and should all add into the decision. A big part of the decision, for me, came down to perceived quality; when I showed the unfinished samples to my learned friends, very few believed that the PMF could be finished to the same level of quality, or would maintain the perceived value standard that I had been striving to achieve on the rest of my build (not perfection, but a certain level of material quality, attention to detail, fit and finish that I had been working on for a very long time). This later part is very subjective and they had not done the same degree of "research" (essentially, reading this forum and doing personal tests) as I, so I admit that it is very subjective input. There are some very well finished PMF foamies out there, I'm not saying it cannot be done. However, most of the people that I presented the samples to were hands on fabricators and craftsmen in their own right, so I still valued their input and advice very much.

This is why we always say, "test". It is far better to invest a relatively small amount of your time and money to determine what are the best materials and methods for your own build. We all have different resources, skills, budgets, goals (time, creative, and otherwise) and planned end uses.

As stated above^, the engineering process is always a juggling act between intended function, cost, durability, and ergonomics (...and other factors).

"You can have it GOOD/FAST/CHEAP; pick two." - author unknown.

One of my thoughts with my current trailer I'm working on is to start with PMF and then if I eventually convert it to off-road use, put another layer of fiberglass itself over it

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Gene , I think once you discover how durable the PMF is , you’ll realize you don’t need the fiberglass …

That may very well be the case

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Hi- In a parallel universe, I have been building a fiberglass screen covered foam standy trailer...very little wood, very light weight. I wanted a standy that could be pulled by anything and not rot! I am posting on foamies, "A Foam Project". I am beyond theoretical into " this Has to work, because I am already doing it"...Nodrog

Wish they had a like button because I loved your last line or two.
My last few trips out that way have had me all up around the Puget Sound, Olympics, Hoh rainforest, playing to hit Portland on my next trip out... Would love to see what you're playing with their

Hey ai4kk, glad to hear back from you....maybe a viewing could be arranged, I also refer you to my topic " a foam project". I will really want to post mostly there, sooon will be pics!! I am slooow, because I am pretty old!! Thanks all for replies, views, praise or criticism!! Yours truly....Nodrog

I'll keep an eye on it and let you know when I'm in the area. There's a good chance I'll have my trailer built by then though LOL
I've actually found some other interesting uses for this, dressing up my car and a fuel Bowser for a southern version of Wasteland Weekend to be held in Alabama in November. To be honest, if I thought I could finish my camper before then I would take that instead of the fuel Bowser

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