Foam Trailers (Foamies)

[GHCOE]

Yes, you heard me right. Trailers built with foam.



I am one of the pioneers of foamie construction which started in the early 2010 with just a handful of us. Below is my first build that I started in 2013 It came in at 510lbs.



Both of these trailers are built out of 2" XPS foam and have very little wood above the floor.



The foam is wrapped with canvas and is coated with what is poorly called Poor Mans Fiberglass (PMF).




PMF is basically canvas coated with Tight Bond II wood glue and then painted with latex paint. Makes for a super strong sock to keep the foam protected and together.



When we started to make these trailers, we were told they would blow apart on the highway. I aimed to prove them wrong. I was just getting back into overlanding so I though what better way to prove a foamies durability than towing it behind my overlanding rig. Well, that was 8 years ago and it is still going strong. Nearly all the multi day trips on my channel document what roads my foamie was pulled through. Believe me we don't just do forest roads. People who follow me have stated that they don't think a standard build off road trailer could go the places I go and hold up as well. You be the judge https://www.youtube.com/@swidahooverlanding2867.

This is a picture of the foamie shortly after it's first trip out. The original 12" tires were dogs off road and this was the first off road upgrade that the Harbor Freight #1195 trailer got, 13" wheels and tires.



It's original weight was 372lbs, but I have since moved up to a 15" trailer wheel and tire. I added a 2" tube spine front to rear, #3500 axle with soft ride shackled leaf springs, rear door for extra storage access and tongue rack for spare tire and extra fuel storage. Dry weight now is about 480lbs, loaded for a trip with fuel and 8 gallons of water is about 950lbs..



Here is a short video showing one of our most recent trips out. Both trailers are home built, but the other one is a traditional build.


Hope this gets some ideas flowing for you guys out there.

 

[DavidinPhx]

Very cool construction for lightweight overland!

I was familiar with foam construction from recumbent bike racing, where some folks (not me) built fairings or full streamliner bodies using foam, glue and I believe screen material or other fabric. The canvas seems like a much more substantial surface, yes? How does it hold up to mild impacts and scraping by vegetation?

I've thought about it for interior camper structure -- ie, non weight bearing cabinets, etc. based on seeing a bit about that in some van thing or another in the past. Haven't gone that route so far, just using open construction and Coroplast drawers for weight reduction.

For the curved front, I assume you scored/grooved the piece to get the bend? Also, what kind of internal joint reinforcement did you use? Having been a woodworker for a long time, I'm certainly aware of how strong and durable Titebond II/III glue is -- I guess a lot of folks might assume it's not. IME Titebond has a pretty quick tack time -- I'm wondering how that works with spreading a large surface? Maybe not an issue as you're not assembling complex time consuming joints. Are your joins made with Titebond too?

Anyway -- very interesting!

 

[GHCOE]

Very cool construction for lightweight overland!

I was familiar with foam construction from recumbent bike racing, where some folks (not me) built fairings or full streamliner bodies using foam, glue and I believe screen material or other fabric. The canvas seems like a much more substantial surface, yes? How does it hold up to mild impacts and scraping by vegetation?

There are some builds that people have tired different coverings such as bed sheets and plastic window screening and actual fiberglass (epoxy based). I find canvas really easy to work with and I don't like messing with fiber glassing materials, so I stick with canvas. I am quite familiar with how wood canvas canoes are built so I figured it would work for trailers as well.

Canvas has a lot of good qualities that work well with trailer builds. Not as substantial as fiber glass, but much easier to repair and work with in general and nothing that can sensitize you. I use 10oz. duck or drop cloth canvas. I glue it to the foam surface with Tight Bond II diluted to 50/50ish with water depending ambient temperatures that I am working in. Once I glue the canvas on the foam, I add another coat of Tight Bond II diluted 50/50 to the outside surface. You want to make sure that the canvas has all its weave penetrated with TBII so you don't get rot. Once the canvas is dry I add a coat of primer and then at least two coats of latex paint. Once you get this build up the canvas is pretty substantial.

Often mild impacts will pop back out. I get lots of gravel divots on the front wall going down gravel roads and they are often pushed back out in a day or two. Major impacts will as well. I had a full 5 gallon jerry can fall of my vehicle and hit the corner. I felt the impact inside the vehicle It pushed the front corner back about 3" and it had returned 95% to normal in a couple days. You can still see the impact area only because of the paint damage. The photo below is from a guy I sold a trailer to. He hit a buck at 65mph. You can tell from the rip in the canvas how far the wall pushed back. These pictures where taken the same day and the wall had already healed 90+%. He said he couldn't even tell on the inside that it had been hit. You can see hoof damage also farther back.



I don't often get into areas where I can scrape on vegetation, but when I do, I don't notice anything substantial. This trailer has been used for 8 years in the back country, and it still looks great once I clean it up.

I've thought about it for interior camper structure -- ie, non weight bearing cabinets, etc. based on seeing a bit about that in some van thing or another in the past. Haven't gone that route so far, just using open construction and Coroplast drawers for weight reduction.

I have seen some of that construction being used. I have watched a guy making cabinets in a old van with foam and window screen.

For the curved front, I assume you scored/grooved the piece to get the bend? Also, what kind of internal joint reinforcement did you use? Having been a woodworker for a long time, I'm certainly aware of how strong and durable Titebond II/III glue is -- I guess a lot of folks might assume it's not. IME Titebond has a pretty quick tack time -- I'm wondering how that works with spreading a large surface? Maybe not an issue as you're not assembling complex time consuming joints. Are your joins made with Titebond too?

Anyway -- very interesting!

There are two ways I have made bends. One way is kerfing, which works with smaller radius curves. I also have just bent 1" foam if the curves are not to tight.



The only internal joint support I have is what I call a frame rail. It runs along the bottom of the wall like a base board. All the other joints are just butt glued and held in place by the exterior canvas or if there is a shelf they will add strength to the joint as well.



Diluting TBII 50/50 slows the cure, and it allows it to flow into the canvas.



I assemble the panels with Gorilla Glue Construction Adhesive for the most part. I will use regular Gorilla Glue too since I can manipulate it to foam up and fill in gaps if needed. Usually if I am gluing panels on top of each others, like in the roof. Also, in dados that I slide the shelves into.