Questions For Foami Builders

[Jwh92020]

After seeing a Tusca Hitchiker camper, I'm toying with the idea of building a 5x8 foamie. I have a few questions:
Best adhesive for foam to foam "glueing"?
Best way to attach wood framing where necessary (door & window openings)
Best way to run 12v wiring for interior lights & fan?
Any issues when towing due to the trailer being so light?
Any & all advice will be appreciated

 

[Grummy-TNT]

Disclaimer.... I have not built an entire foamie, but I did some testing for a foamie project I have planned for spring. Regarding your questions:

1. Best thing I have found is a "collapsing Polyurethane foam" adhesive. It's a general construction adhesive, but works very well on foam tests I did. Great Stuff makes some, but you need a special gun to use it. I have used Tremco, because you do not need any special gun. https://tinyurl.com/2csdd82m

2. Same Adhesive as above.

3. Use a trim router to cut organized grooves only to the depth you need them. Fill with an expanding foam and saw off the excess. But plan ahead if you do not want that one wire you forgot to be exposed. Run the router along a guide for nice straight lines.

4. Over the years of reading, I have heard of people having their trailers blown sideways in side winds, even flipped over. That said, I followed a fellow for 7 miles in a snow storm who was towing a regular 6 x 12 single axle cargo trailer in a snow storm with high side winds. The trailer was sliding 90 degrees along side of him the whole way on the slippery road. CRAZY to watch, but there was nothing he could do. I'd like to think the thing was empty, but it shows that anything with a large side exposure can be a problem with side winds.

The good news is that because you have such a light trailer, you can carry a lot of water and gear to make up for the difference ! Kind of defeats the purpose, but seriously, there are obvious some tradeoffs with being really "light".

 

[Jwh92020]

Disclaimer.... I have not built an entire foamie, but I did some testing for a foamie project I have planned for spring. Regarding your questions:

1. Best thing I have found is a "collapsing Polyurethane foam" adhesive. It's a general construction adhesive, but works very well on foam tests I did. Great Stuff makes some, but you need a special gun to use it. I have used Tremco, because you do not need any special gun. https://tinyurl.com/2csdd82m

2. Same Adhesive as above.

3. Use a trim router to cut organized grooves only to the depth you need them. Fill with an expanding foam and saw off the excess. But plan ahead if you do not want that one wire you forgot to be exposed. Run the router along a guide for nice straight lines.

4. Over the years of reading, I have heard of people having their trailers blown sideways in side winds, even flipped over. That said, I followed a fellow for 7 miles in a snow storm who was towing a regular 6 x 12 single axle cargo trailer in a snow storm with high side winds. The trailer was sliding 90 degrees along side of him the whole way on the slippery road. CRAZY to watch, but there was nothing he could do. I'd like to think the thing was empty, but it shows that anything with a large side exposure can be a problem with side winds.

The good news is that because you have such a light trailer, you can carry a lot of water and gear to make up for the difference ! Kind of defeats the purpose, but seriously, there are obvious some tradeoffs with being really "light".

Thank you for the input. What foam board are you using? I'm thinking of 2" Foamular XPS, but I'm not sure about the film - does it have to be removed? I'll be covering it with PMF. (Tusca uses a spray on bedliner interipr in & out) Not sure about the interior. I had a built out 7x14 cargo trailer I was towing try to pass me on the driver side when I got caught in a nadty thunderstorm between Wichita and OKC. I pulled off the highway and parked with my truck pointed into the wind and waited for the storm to pass.

 

[Grummy-TNT]

For PMF, Yes, Pink foam... foamular. Polyurethane foam if I need to fiberglass with conventional resin. I'm leaning toward traditional glass for what I have planned, but time will tell.

I always peel off any film when a sheet has it. Some have it, some don't. Not sure why, but it comes off easily, which means if you try to adhere to it, it will just pop off the foam anyhow.

Some of the urethane shelling products being used on foam is pretty tough and wonderful if you have someone in the area who sprays it and you can afford it. I think the guys spraying directly onto foam are using more than just a bedliner product. Similar, but not the same.

 

[TimC-TNT]

...
Best adhesive for foam to foam "glueing"?

I've had good success with PL Premium for foam to foam and foam to wood. It's a polyurethane based product.

Best way to attach wood framing where necessary (door & window openings)

Create a pocket using a hot wire cutter/knife for adding 1X lumber in the edges/faces of the foam. At doors and windows I inserted quality 3/4" plywood surrounding the opening so I could screw the door or window frame securely. Glue them in with your preferred adhesive (I used PL Premium and finished up with spackle on exposed wall anchors). For misc. attachment points I created pockets for 1X lumber for hooks, shelving, light anchoring points, whatever. When you are done adding anchoring points stand back and think about anything else you can add.

And a biggie... buy a cheap, clear painting drop "cloth". I used .7 mil plastic drop cloth. Tape the drop cloth on any walls/ceiling that have important anchor points or wire runs. Use a permanent marker and trace the cabin profile, door openings, etc. Label that drop cloth with descriptions (port side, starboard side, interior, exterior, etc. You'll have a reference for when you start locating and drilling. I store my folded drawings below the mattress since it doesn't take up any room and I always know where it is.

Best way to run 12v wiring for interior lights & fan?
See above, hot knife/cutter for wire runs. Run what you can through the roof or floor. You might find that there are not many wiring runs needed in side walls. Mine are just the porch light switches but I could have installed them somewhere else. My porch lights are on the chassis frame just below the doors. I used license plate LED lights. I found in my other TDs that a light up high blinded me as I approached a door. The lights down low illuminate perfectly and no longer blind me.

Any issues when towing due to the trailer being so light?

Thousands of miles with a 750lb 4x8 Benroy foamie design. No problems with wind but then I use that big block above my shoulders and get off the road if there are storms or high winds. That my friend is the biggest thing you can do to avoid weather related accidents. The example Grummy noted with the guy driving through a snow storm ..."but there was nothing he could do"... is dead wrong! I hope I don't have to explain why. I have had no problems with trucks blowing me sideways as they pass by.

Any & all advice will be appreciated

Build walls flat on their sides. Add attachment hard points, wiring runs and wire, and "final" finish while on their sides on saw horses. Make a drop cloth template as described above. Do as much finishing you can before raising the walls. Obviously the windows and doors can wait for final assembly.

 

[Grummy-TNT]

>>> ..."but there was nothing he could do"... is dead wrong!

Well, I know what your saying, but with more story, on the Interstate, he had no where to get off until the next exit, which in this case was about 7 miles. Had he pulled off to the shoulder, the trailer would have stayed out in the lane of traffic unless he went into the snow filled ditch which makes no sense either. Visibility was practically zero. I followed him with 4 ways on mid lanes (not that we could see the centerline). That 7 miles took us over a half hour. A half hour prior to that, it was pretty nice out.

So, your right, there was more he could do, but it wasn't for 7 more miles. Frankly, nobody's 750lb trailer would have done any better.

 

[Jwh92020]

Tim - Thank you for all the input. The more I look into it, the more I want to build one. I just need to sell the 5x8 I just finished to fund it (so my CFO says).

 

[TimC-TNT]

>>> ..."but there was nothing he could do"... is dead wrong!

Well, I know what your saying, but with more story, on the Interstate, he had no where to get off until the next exit, which in this case was about 7 miles. Had he pulled off to the shoulder, the trailer would have stayed out in the lane of traffic unless he went into the snow filled ditch which makes no sense either. Visibility was practically zero. I followed him with 4 ways on mid lanes (not that we could see the centerline). That 7 miles took us over a half hour. A half hour prior to that, it was pretty nice out.

So, your right, there was more he could do, but it wasn't for 7 more miles. Frankly, nobody's 750lb trailer would have done any better.

Good clarification. There's always more than one side of the story. I probably should have asked for clarification instead of jumping to conclusions.

 

[fr3dcat]

After seeing a Tusca Hitchiker camper, I'm toying with the idea of building a 5x8 foamie. I have a few questions:
Best adhesive for foam to foam "glueing"?
Best way to attach wood framing where necessary (door & window openings)
Best way to run 12v wiring for interior lights & fan?
Any issues when towing due to the trailer being so light?
Any & all advice will be appreciated

I finished my first foamie in September and I have camped in it about 5 weeks. I built a small 3 hoop truss out of 2x4 and used 2 inch pink foam (don't use the foam with scribe cuts).
Based on reading here and youtube videos I did the Bugout design on youtube and all foam glueing with Great Stuff.

The walls were sawtooth joints and I was a bit sloppy and my walls are not plumb and square. I used a hot knife, hand saw and a drill for the lumber. Also used poor man's fiberglass.

I have to say that it is very strong despite my rough work. It works great. When travel I throw all my heavy stuff in the foamie (tool box, clothes, TV fridge jack stands bikes etc. and I haven't had a problem (yet). I haven't been in high winds or snow yet.

I am amazed at the joint strength using a sawtooth pattern and Great Stuff!

This is not rocket science. The foamie can be built in minimal space with minimal tools and come out pretty nice even if for folks that aren't that mechanical IF you follow what others have done and don't try to become an engineer.

That's my experience.

 

[Jwh92020]

I finished my first foamie in September and I have camped in it about 5 weeks. I built a small 3 hoop truss out of 2x4 and used 2 inch pink foam (don't use the foam with scribe cuts).
Based on reading here and youtube videos I did the Bugout design on youtube and all foam glueing with Great Stuff.

The walls were sawtooth joints and I was a bit sloppy and my walls are not plumb and square. I used a hot knife, hand saw and a drill for the lumber. Also used poor man's fiberglass.

I have to say that it is very strong despite my rough work. It works great. When travel I throw all my heavy stuff in the foamie (tool box, clothes, TV fridge jack stands bikes etc. and I haven't had a problem (yet). I haven't been in high winds or snow yet.

I am amazed at the joint strength using a sawtooth pattern and Great Stuff!

This is not rocket science. The foamie can be built in minimal space with minimal tools and come out pretty nice even if for folks that aren't that mechanical IF you follow what others have done and don't try to become an engineer.

That's my experience.

Thanks for sharing your experience. As soon as I sell my 5x8, I'm going to dive in to the foamie pool head first