. I thought that since this build will be read by many in the future that I should point out some things about this build/thread.
-First I would suggest reading through this entire build thread. Like I said, somethings worked, some not so great and some I had to start from the beginning again. Of course you won't know that unless you read the whole thing.
-Next I would like to add that the flashing is working as planned, but I think for future builds I will add the flashing to the outside of the canvas if needed. I have found with my second build that the corners are quite solid if you use liberal full strength TBII in the corner edging. By not adding flashing to the body before canvasing it saves time and effort by not having to fair in the flashing with spackle. If done right I think it will look just fine on the outside and can be used only in areas that many have a need for more protection.
-Expansion rate of foam needs to be addressed. Foam tends to have a high expansion rate compared to other materials in the build. In most cases in this build it is just cosmetic. The biggest problem I have is the drivers side door. I made my measurements for door size in the morning and allowed 1/4" clearance. I installed the door in the morning a few days later and all was good. Then I tried to open the door in the afternoon and the door was hitting the frame. Passenger side door is fine, but I remembered I made my measurements in the afternoon on that side when the foam had already heated up. This was my first indication of the expansion issue. I then noticed where I had to spliced the flashing on roof it was buckling and causing the canvas to buldge out when cold, it is fine when hot. Next was the front wall. Near the bottom, where the floor has another expansion rate, it tends to show the glue line between the side walls and the front wall. Since the side walls cant flex due to being glued to the floor the expansion and contraction of the front wall is noticeable along the front lower portion of the walls. This problem will probably be noticeable on most builds. To hide this on my second build I rapped the corners 2". This puts the corner cut line right on the foam to foam glue line and disguises any expansion issues.
-If you live in the Pacific North West I recommend the Bi-Mart utility trailer over the Harbor Freight Trailer. The biggest thing I like is that it is painted black. The hubs/bearings come pre-lubed with real grease, Bolts are SAE and it comes with a 2" hitch ball.
-First camping experience was great. Towed beautifully at 80mph. No bouncing, or swaying at all. I was running a tire pressure of 25psi to allow a bit better cushion on bumps, seemed to work just fine. I checked tire and hub temps at each stop.
-I have now built my second trailer, some details here viewtopic.php?f=55&t=65033. This is a much simpler design and I was able to put it together in 50 hours. Materials cost was $1200.00. I am building a DIY YouTube Channel where I plan to do step by step tutorials videos on how you can build your own foamie. I tried to keep this trailer as simple as possible so anybody could build one with simple tools. Yes it is a box, but it is simple to get you started. My long term plans with the channel is to show how to install accessories, design modifications (for more experienced builders), and building other trailer designs in the future. How much would you pay for trailer designs? Yes there are some free online designs and then I have seen some designs as much as $200.00. My YouTube Channel is free! https://www.youtube.com/watch?v=gTl7ZokgbuM . Please though consider supporting the channel through Patreon for as little as a $1 a video or a one time donation to PayPal, Links are in the video description. This will help me get things moving faster and show me that there are people watching and wanting more content. See you on the road, George.
Ok, so I have been wanting to build a TD for about 12 years now. I was looking at small manufacturing and even had a good friend that was interested to go in with me, even made some templates. Well things fell through and he moved farther away and life happened. I am still interested in building one to use behind my small car and if things work out maybe to sell a few.
As time has gone by my design ideas fell away from the TD and went more to the practical (at least in my own opinion) box type construction. It seems you just get more use out of the small foot print. Plus you get a more practical roof line to add a rack too for bikes, kayaks, and such. I really like the Grasshopper for these reasons. In my thinking I wanted to make it simple to build, just in case I would have a need to build more, and practical, so everyone would want one.
My biggest worry when thinking about a trailer build was water. I know how wicked water can be. When I saw these build ideas here I knew then that this was for me. I love foam, I have built a few foam RC planes and I loved working with it. I did own a motor home once that was built using a very similar construction and I remember then thinking what a great idea. I do not know why I did not put the two together to make a trailer. It's so simple...
I had to modify my plans some to make it work with foam. I know that there will be some unforeseen design problems, but that can be dealt with as they come up.
No surprises that way later on ... 
