Questions for the foamy guys

[Tigris99]

Started a build thread but foam was mentioned as something to consider and started doing research. Basic box with half of the front angled 45deg.

Foam for me sounds doable. Easier to deal with (not afraid of hot wire cutting, making a portable unit is easy enough). Definitely like the fact of major weight reduction.

Not sure on how cost saving it will be but water sealing is much easier.

Couple things I wanted to do though that I'm wondering about.

Is there any difference in using a 2" thick sheet versus gluing 2 1" sheets together allowing for more of a wooden frame work to be used. Also saw a pic (google) of 2 sheets together so there was an internal lip where a window was to be installed.

Reason I ask is because I have 2 major hard points I need. First is in the front. Need to be able to carry mountain bikes. My plan is to mount trays on the tongue frame and mount my forks (wheels removed) to a support that runs across the front near the top. Top half of front will be angled at 45 deg going back and putting a polycarbonate window on that area as well. Support for fork mounts would run out to the framework just inside the outer walls with vertical 2x4s and a plate to seal between the supports and the outer shell.

Second matter is the need for a bunk in the rear for our toddler which will be offset to one side allowing for something of a Galley (side access) on the opposite side. Thinking a flip out sink/stove. Was trying to get out of a galley but wife likes the idea .

The the rear, this is the interesting part. Going to create a soft sided "extension" where the rear hatch isn't the full width of the trailer. About that of the bunk. Hatch will open upwards. Then a second deck will fold down. Will create about a 5x3 sleeping space for my oldest boy.

Problems: Not sure how to mount a hinge with foam as the top there. Was thinking a 2x4 square frame (with support), t molding and regular hinges under that attaches to upper frame. Lower deck design is pretty straight forward, no foam involved there (too difficult to make fully load bearing)

Also I had aluminum L stock that I want to use on the front/upper corners. Mainly for looks and I'm tired of staring at $100 in aluminum in the top of my garage doing nothing.

Using dual layered 1" sheets would be easier if I'm not going to loose strength of the walls by doing so.

Final question, I haven't found how people are filling gaps before covering internal walls. Always gaps between wooden hard points and the foam. How is that filled?

Thanks.


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[KCStudly]

First advice is to stop thinking 2x4's. They really aren't needed. Yes they are cheap, but they have rounded edges, typically aren't straight, don't hold screws as well as other options (soft wood), are usually full of knots making them weak and resulting in poor yield when ripping down, and aren't very stable warpage-wise. If you have a good table saw and want to rip them down to 1x2's you might have better luck looking at 2x6's or 8's for better yield and less knots (although what passes for lumber at the big box stores these days is pretty poor IMO).

You can do everything you need to with 1x's.

For hatch hinge mounting consider using a harder wood that will take screws well, like oak 1x2 or 2x2 (depending on the weight of your hatch/swing down platform).

Same for the bike fork mounts. You could probably get away with a single 1x2 spar with a couple of 1x4x4 blocks pocket screwed (Kregg jig) to the spar; this would give you something sturdy enough to screw your fork mount hardware to; PMF skin right over, drill your pilot holes, seal the screws well with a dab of exterior grade paintable sealant (not silicone) at installation.

You can cut the foam very effectively using a straight edge and old steak knife; us long dragging strokes with the blade held at a shallow angle.

I don't recommend laminating multiple layers of thinner foam. I did it on my hatch and roof and it was not worth the extra time and glue to fit twice as many pieces. Just use the full thickness foam, especially for your simple flat/faceted profile. If you want to recess spars or blocking you can notch using a table saw, router or hot knife (I never seem to be able to get consistent results with a hot knife, so prefer the other methods... on my homemade setup it either gums up and drags or i have issues with the wire going slack and wandering).

I realize my build thread is long and arduous, but I have used a bunch of different foamie techniques, and experimented with many options so I am sure you would get something out of it (if not how to do something then how not to!).

[GPW]

We always Appreciate KC’s detailed comments and experimental testing ...

[Tigris99]

I'm guess the poet Creek build thread, holy crap that's a lot of info. I was digging through the main foamie thread and it's hard to keep track of because it bounces around a fair bit.

A lot of info from what works and doesn't work, trying to keep track of all the testing is headache inducing lol.

You guys do some amazing work with materials I had the conventional "no way in hell" mentality. Kind of blew my mind and realizing the methods that work best are few, ways that work but fail or don't work is a long list.

I need to get some more drawings done while awaiting my trailer to get finished. The wood work side of things I'm fine with (and doing my standard over engineering/over thinking of everything).

I'll check back in here as I hit points I'm having issues with and can't find my answers. A lot of info to dig through to find specifics, which are all covered, just taking time to find each one.

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[ghcoe]

My thread is a bit shorter. I did not use any wood, but I did use a hot wire quite a bit. Good luck. Link listed in the signature.

[GPW]

Guys , you must remember the Big thread was started way back in 2010 , and then although some foamie trailers had been built by a few, we basically didn’t know anything and all these ideas Evolved over time and much discussion and experimentation... Every bit of information discussed , tested , and finally applied to building ... and also it was more social then , not exactly on topic all the time ...
For those that want immediate direct answers to all their questions , best just ask than read through all those old pages ... Plenty of knowledgable Foamie builders here Now who can offer prompt assistance ...

[KCStudly]

Asking is great and always encouraged........ but on the other hand, sometimes we assume stuff and forge ahead w/o asking, and end up making preventable mistakes that have been well documented by many others that have come before us. Sometimes those mistakes are small in nature and/or are easily corrected; sometimes they are more fundamental and can be a major sticking point throughout the life (or early bailout) of a build (for example, installing side doors on both sides right from the beginning).

To this I say "research". If you are in this for the long haul and are building more than just a bare minimum shack on wheels, read the builds, read the construction techniques/secrets, read the trailer secrets, read the basic electrical threads.

If you think building one of these is fast and easy, so maybe you can't screw up that bad to begin with, I say regardless of the features you include or don't, these things are always a bigger project, they "always" end up costing more, and by the time you get close to being done you will have a whole new perspective on how big a project it was. From the simplest build to the most complicated, it is all relative.

One mentality just wants to jump in get started and "get 'er done". Another wants to do enough research to avoid the common pitfalls and "I should have's".

We are all going to ignore some good advice along the way, but at least we were informed.

[rruff]

Reason I ask is because I have 2 major hard points I need. First is in the front. Need to be able to carry mountain bikes. My plan is to mount trays on the tongue frame and mount my forks (wheels removed) to a support that runs across the front near the top. Top half of front will be angled at 45 deg going back and putting a polycarbonate window on that area as well. Support for fork mounts would run out to the framework just inside the outer walls with vertical 2x4s and a plate to seal between the supports and the outer shell.

Could you describe the "framework" in more detail or a diagram? For hard points carrying a significant load, I'd tend to have the wood go all the way through and use bolts rather than screws.

Like KC said, forget 2x4s. 1x boards are plenty.

[Tigris99]

Basically a standard skeletal frame inside since I'll need load bearing point on the front near the roof (150lbs capacity during towing), then the rear bunk to hold our toddler. Finally is just for the rear hatch (there is pictures of sketches in my build thread) as I'll be creating a sleeping area that's canvas sided for my 10 yr olds sleeping space when he's with us.

Though the idea of having him sleep in the back of the van is now being discussed. Plenty of room for even both boys, make a screen insert for the sunroof.

I know well what I'm getting into with wood, but making it out of foam has me intrigued because much less water issues to worry about and a respectable cost savings.

Length of time to do the build is only effected by costs. I have skills, equipment and extra hands (that are also skilled). But none of us have dealt with foam board outside of normal residential use.

I'm also rather resourceful. Junk yards are a great place to find door seals, scissor jacks etc. Rural type area means farm supply stores but northern part of the states means 2" foam is readily available at home Depot.

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[rruff]

Basically a standard skeletal frame inside since I'll need load bearing point on the front near the roof (150lbs capacity during towing), then the rear bunk to hold our toddler. Finally is just for the rear hatch (there is pictures of sketches in my build thread) as I'll be creating a sleeping area that's canvas sided for my 10 yr olds sleeping space when he's with us.

I'd probably make the front frame at least go all the way through (so it'd be 2" deep), but someone might have a better idea. Forces could be pretty high as you bounce down the road.

[Tigris99]

I was thinking just coming through the top. I hadn't decided if I was doing the top in foam or thin ply if I go the foamie route. Thin ply, pull spars and support structure in the front and rear. At least with ply being the material, I don't have 2 holes in the roof, just screw through the mounts, plywood and into spars/vertical supports

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