Newbie jumping into building a foamie. Have several question

[Krusty]

First off: Greetings! I'm a southern California do-it-yourselfer who has recently become obsessed with building my own tiny trailer. Unfortunately, I also prefer small cars. As such, anything i build will be hauled around by my 2008 Mazda3 hatchback that has little towing capacity. For that reason, I'm attracted to the idea of building a foamie.

In particular, a pop-up style design has most interested me as it would allow my wife and I to get a little standing room as well. This is the one that has so far inspired me:
http://www.goldbrand.info/motorcykelhusvagn2.html


With that in mind, I have a plethora of questions.

I already picked up one of the middle weight harbor freight trailers http://www.harborfreight.com/1195-lb-capacity-48-inch-x-96-inch-heavy-duty-foldable-utility-trailer-with-12-inch-wheels-90154.html for about $220 after various discounts and coupons. I'm hoping that will be more than adequate for me.

I have read that the pink or blue foam is the preferred foam here. I checked out my local Home Depot and found that the only stuff they carry is the aluminum faced yellow polyisocyanurate foam. Is this still an acceptable foam to use? How thick is the minimum thickness? How thick is the recommended thickness? Will building a pop-up style affect this much since the bottom half will have no lid? I'm particularly intrigued by being stuck with the polyisocyanurate as I'm aiming to fiberglass it instead of use canvas and paint. By using the polyisocyanurate foam I should be able to make use of the much cheaper polyester resin as it won't eat this kind of foam.

What thickness of fiberglass should I use? Is two or more layers recommended on the outer shell?
Does anybody have any decent resources or advice they could refer me to for the mechanisms that would work best with building a pop-up style trailer?
If I built this in 4x8 or 5x8, how much do you think the whole thing would end up weighing, ignoring any water tanks or electrical?

What would you recommend for flooring material? I was thinking that it might be pretty strong and lightweight to use a sandwich (glued) method with 2 layers of 1/4" or 1/8" plywood with 1/2" foam in the middle, then wrapped in a couple layers of fiberglass. Think that would be any lighter or more durable than just using a single sheet of plywood?

And for perhaps my largest question, could you refer me to some decent (and, of course lowest priced) online resources for purchasing equipment? I already have:

etrailer.com: trailer equipment
harborfreight.com: trailer, solar cells, and other miscellaneous gear

I could use a good online source for foam, fiberglass, resin, and lightweight premade windows and doors.

Are there any other significant snags I should be watching out for as I plan this out?

[pchast]

IMHO fiberglass can add more weight than canvas and a thin layer of paint.

[atahoekid]

Greetings Krusty!!! Welcome to the world of Foamies. I'm a SoCal native who moved to Northern Nevada about 15 years ago. Wish I could give you some advice about that yellow foam, but I built mine with 2" thick pink foam. You mentioned wanting to build a standy... Here is Sharon's. This is an ingenious design that I think could work real well for you. She used standard building methods but it should be easy to do as a foamie. http://www.tnttt.com/viewtopic.php?f=50&t=27313. I saw it in person at the Falling Tears event about 2 weeks ago and it's pretty impressive. As far as building the bottom box rigid enough, just make sure you have bulkheads to provide support. That normally means cabinets or some inner structure. You shouldn't need structural members like studs or anything like that. I made the Road Foamie with fiberglass and I used a single layer of 6 oz glass. It is very structurally rigid. I did it mostly for aesthetic reasons to be honest but I did use canvas on trim pieces and to be honest, I like the look of the canvas a lot. If you're after a smooth looks and want to use canvas you could try block filler or other kinds of latex filler. Google canvas canoe filler and see what you find. For your floor, a composite of 1/2" foam sandwiched by thin plywood should work well. Good gluing will be critical to the strength of the panel. I used 1/2" plywood. Just make sure you waterproof well. You can use the mix or one of the asphalt types of roof coatings and that should keep things dry. I hope that helps... Keep asking, we're glad to share our knowledge. (There's also that mega thread to read... lots of info, some silliness and lots of things tried)

[Krusty]

Hi Pchast! I understand that fiberglass may weigh a bit more but it'll be more durable and more rigid. I like the idea of using paint and canvas but if it's only a couple hundred more bucks and doesn't add considerable weight then I think I'd prefer it. I like the smooth, glossy surface. I'm also assuming using fiberglass may enable me to use thinner foam. Think 1" foam is enough to keep everything together?

Hi atahoekid! Thanks for the advice. I was thinking 2 layers of 4oz glass on the outside and 1 layer of 4oz glass on the inside. Sounds like it doesn't take much to keep the thing nice and rigid so I'll probably start looking for whatever is the best bang for the buck as long as I can get at least 6oz on there somehow.

I hadn't thought too much of the bulkheads but you're absolutely right. I had aimed at some point to have a bed platform. It would be best to integrate that bed platform into the design to significantly boost the strength of the bottom half. I'm not so worried about the top half as it'l only be up when I'm inside of it.

Is there a post somewhere with the best online sources to buy a lot of this stuff?

[ghcoe]

Remember that if you glass over foam you will have to use epoxy resin not polyester resin fiberglass. Polyester will melt the foam. I hate working with fiberglass and the safety precautions that come with it.

If you want the smooth look at the wood canvas canoes and it you do not think paint over canvas is tough, think about what a canoe goes through. I will be using a product the wood canvas builders/restorers are using to experiment with smoothing out my build. I am curious to how well it will work.

[GPW]

Krus’ , have you read the "Big thread" yet ? That might answer a lot of your questions ...

[Krusty]

Hi Gchoe. I did read that I'll need epoxy resin for the blue or pink foam, but I'm currently looking at using the yellow polyisocyanurate foam as that's the only foam readily available at my local home depot. I'd like to know if anyone has built a foamie with that foam yet though as it does seem a bit more inclined to break apart.

GPW, I'm about halfway through the thread now. Made it to about page 150. Gotta digest it in pieces.

[GPW]

It is a bit of a read eh ! ...

Personally , I’d look around at other places for the Blu or Pink foam ... I believe the foam you mention is more brittle than the usual foams ...

[Krusty]

Hmm...after reading about a cardboard and fiberglass trailer, I'm thinking I can easily get away with some thinner foam.

http://tnttt.com/viewtopic.php?f=50&t=38781

Going with 1" foam should cut down on weight and cost a bit and it's still way better insulation than being in a tent.

[KCStudly]

I used cedar for my minimal wall frame work (around door and along wall sill) with 1x pine for let in blocking everywhere else. My foam is 1-1/2 thk with 5mm marine ply inner skin.

One of the things that I did, that I have never regretted, was gluing 2x2 cedar sills all along the bottom of the walls. This did several key things; it gave me a solid edge to stiffen and protect the walls during construction; it gave me a place to screw into up thru the floor assembly to mechanically fasten the walls to the floor during glue up; it gave me a straight solid reference point for all of my vertical measurements; and it acts as a low profile tie member under the door (otherwise the narrow areas of foam above and below the door opening would be extremely fragile).

After handling my walls many times during the course of construction, I would be reluctant to go any thinner than 1-1/2 inch on 9 ft plus length wall. Maybe it would work; maybe I just like the solid sense that the 1-1/2 inch thickness provides; that the door latches do not need to be surface mounted; and that I will be able to use a decent length screw to attach things like my draw latches for the hatch without worrying about stripping out the relatively soft wood (I realize that this could be dealt with by adding local blocking).

With epoxy/glass inner and outer skins I think it would be plenty strong, but with just canvas I don't know. Be sure to integrate cabinet "bulkheads" and keep spans of big open areas down. My biggest concern would be fragility during construction.

[Krusty]

Good info to know, thanks.

I'm still reading through the big thread and my confidence is slowly increasing.

I just read a post where someone recommended getting 13" tires and cutting down on the weight by getting some torsion axles. Anyone have opinions on the overall quality of the 1195lb harbor freight chassis and tires? Is upgrading the tires and axles something I should be concerned about?

[ghcoe]

I just read a post where someone recommended getting 13" tires and cutting down on the weight by getting some torsion axles. Anyone have opinions on the overall quality of the 1195lb harbor freight chassis and tires? Is upgrading the tires and axles something I should be concerned about?

I do not think that torsion axles will reduce any weight. The only things a torsion axle does is to allow the trailer floor to be closer to the ground or more ground clearance, depending on what you are trying to do. The harbor freight trailer is a great 4x8 trailer. Hard to beat the value you get by time you add all the materials separately.

[Mary C]

Krusty, There are lots of opinions of the building of Foamies, keep in mind that the gang here has given opinions and guesses about the building of Foamies the original Idea I think was to build thrifty and light. Many experiments have come about some came about because of lack of funds, some came with new products and some with all the historically acquired knowledge by the boat building and plane building people. The ideas of using some of the ingredients has come about because of need and just plain fun. Some people on here make less than a comfortable living and others have disposable income and some fixed income. considering this and the needs of the tow vehicles lead to exponentiation on the group . so if you want to get the td low to the ground then put a torsion axle on if you want a cheap new trailer use HF if you want a light aluminum trailer , cheap and with some work then you will need to go to an area where they are available. we say read because these and more stuff is on the big thrifty thread. We know it is long and there is a lot of opinions and trials and stuff that is not necessary but you will get the idea if read closely that all those questions and ideas running thru your head has been discussed in one form or another including what to feed frogs, teeter totters,Formica, epoxy and fiberglass, and the material used in sails and how to get a glue to hold. you will note that by reading some of the builds that temperature and moisture will affect glue, how to bend (school is still in session on that one) how to work in the snow cold rain and heat, and you will learn how we all did things differently but how great it all seems to work. Good Luck!!!

Mary C.

[KCStudly]

Well said Mary!

[GPW]

So aptly put Mary !!!
... and you get to read about the people who said a foamie‘ would never work .... proven WRONG !!!! I always find that amusing ...