Teardrops n Tiny Travel Trailers

So I've gone ahead and took the plunge
Here's the story and background.

After spending most of 2018 researching, thinking, planning, hoping, worrying etc... I've decided to build out a foamie on a van cab and chassis that I bought. See my other threads for pics on rig and proposed style.
Having built things before, a small 6*10 steel stud and wall camper on a harbor freight 4*8, sort of kind of have some experience. And built other things. I use the term build very loosely for my craftsmanship skills. I only have portable battery powered tools and no carpentry or cabinetry 101 training. None.
But where there's a will there's a way I say.
Decided that a full foamie, minimal framing and PMF was light, cheap and durable enough. Could I pull it off was the question having had zero experience with them.

So the idea of unconventional and light weight appeals to me as does low cost and light weight. Ideally.
The low cost is always debatable at the start of a project and not necessarily what you end up with.
As all projects end up over budget.

This was my main concern, the cost factor. If one can build it for much less than conventional materials or comparable vehicles, can justify the weak points of structural and outer skin limitations of foam and PMF builds. But if it costs you the same, you've spent all that time and money on something that is inferior. Worthwhile is the question as well as value for time and money spent.

Have no concerns on the feasibility and benefits, only cost, overall value to a comparable box truck. I looked at ambulance boxes but they were heavy, not spacious and lacked headroom for the ones that I saw. Not ideal but could be had in my area for $1500.
Found a fiberglass box made exactly for my chassis for which they wanted$1500 also. It was a little rough and not negotiable on price. So I sat on that as a fallback. The fiberglass was thin, not super strong, but enough to do the job with heavy wood flooring. It was as light as could be had for a commercial unit. It also had the huge garage door at the back which I would have to gut and build.

So I was constantly looking on craigslist for materials for bargains and deals. Was flip flopping between a conventional wood and ply build, aluminum foam core or PMF foam build with minimal framing for Max light weight. Even considered drywall metal studs which I had used before which were light and strong but costly compared to wood studs. On a small project the extra cost wasn't significant but on a bigger build it added up quickly. Wouldn't hesitate if I had the budget, maybe on another build.
So on Craiglist, the stars aligned and three things came available at the same time at low cost.

1. The foam. Polyiso 2" in my area is going for $40 a sheet, much more than elsewhere. Big cost, if I could reduce this, would be great and make the project worthwhile. If not, should just buy the box and bolt it on.
For a build on something for which I was inexperienced, didn't make sense to take the risk for something that I wasnt sure I could build strong enough on a vehicle. Unless I could do it really cheaply than the failure could be easily written off. Spend serious money and have it fail or need to be redone, well, might as well just light money on fire. The structural strength and requirements for the size I wanted to build 6-7*12-14', couldn't find a pre-existing model to copy from and was a proven design.
I was boldly going where no man has gone before.

So I managed to locate a seller who had 4*8 sheets of used 4" Polystyrene for $14. That was worth learning, taking a chance and not losing too much in the worst case scenario. Fear and the unknown play a huge part when we make decisions. Understandably.

2. Glue. Everyone builds with TB2 but the water resistance only aspect was a concern, even if in the Southwest. To me TB3 is the way to go but it is much more expensive. And with a much larger surface area planned than a 4*8 teardrop, was going to take a lot more. 3x more I figured, hundreds of dollars worth. If I could get it cheaper than $28/ gallon. Hmmmm.
Found I could. HD lists a 2 * 1gallon pack for $42 online. That's $21/ gallon or just a bit more than the $18/ gallon of TB2. It's a go, sort of. HD doesn't stock TB3 in my area or state. But some Lowe's did. Thank you price matching and overworked managers who approved the price reduction. 10 gallons btw.

Two out of three, not bad so far.
3. Now paint. Mistints are okay at $9/ gallon but how many gallons did I need for approx 400ft2? Had no clue but if I could go cheaper would be great.
Once again, on Craig's, found a large paint contractor who was selling is leftovers for $2/ gallon. Great. Picked up everything that he had. 27 gallons. I was making sure that I had enough paint and wouldn't run out. At $2/ gallon, bought it all, cost me $50. I had paint and was good to go.

4. Oh, there was another major cost, glue. Which type and how much. This was the critical component for success, structural ridgity, and making it all possible. Many where using gorilla glue but at $8 a small tube and a large project, didn't seem economical and would quickly kill a budget. For this size of project, going to need allot of glue and $8 is expensive for a little tube. So I wondered if PLP 3 which came in the construction size tubes which is 3x larger but at the same $8 cost would be strong enough. That was the cheapest potentially strong enough glue that would do the job that I could source locally. Did a test with a piece of wood buttered with glue to a block of 4" Polystyrene and waited a day for it too dry. It wasn't coming off without disintegrating from the foam. I was sold and everything was go at that point.

So I said to myself, I could pull this off as cheaply as possible with all of the main costs, I could do this on a budget and reasonable cost. Why not?
Fear, the unknown and no experience with these materials. Regardless of what anyone says on here, these builds and materials are not as durable as conventional. That's a serious downside but if it's a small fraction of the cost, then worthwhile. But they are good enough for the cost. And don't consider the cost or time of your labor.

So at this point, I said f*kit and made an executive decision, ordered the foam from the seller delivered.
There was no going back at this point when he arrived with the foam.

To be continued.

I would also like to thank George Coe for answering my many questions and endless pestering for information. He was totally kind, helpful and patient for which I appreciate tremendously. Thank you George for your help and assistance in sharing your experience and knowledge for, and with those who wish to follow in your footsteps. A great fellow human being.
We should all applaud him.
Let's take a moment and give him a standing ovation.

...

hear here

A mighty lite load.
Wonder how much of my 1 ton capacity is left at this stage?
Let the madness commence.

“ May the Foam be with you !!! “

So I'm all in at this stage and there was no going back.
We were going to learn how to build a foamie hands on with only online help for reference. Oh boy, am I in trouble. And with only a set of new battery powered hand tools, built in someone's yard in one to two weeks.
Right, well that's what I told her to let me build it on her yard. Six weeks later, I pulled out of the yard for good with a completed, empty box and hit the road. The interior could be built out on the road in HD, Lowe's and Walmarts parking lot. I full time so the cost and insulation are the main selling points. The less you spend, the longer and farther one can travel. And the lighter the rig, the better the mpg.
As I told friends what I was doing, they had no reference or comprehension of building with foam and PMF. I had one suggestion to strap it down upon my first highway test run just in case so it doesn't fly away.
If anything were to go wrong and I did leave a wake of styrofoam going 75 miles down the hwy, tie down straps were not going to hold an avalanche of disintegrated styrofoam beads.
I can happily say that after 6 hours of driving on highways at 55 to 75 mph, so far so good. And withstood 30+ mph wind and gusts. And dry as a weathered, sun dried bone in the desert from a day with 2"+ rain accumulation.
So far...
Currently in the life cycle testing phase, to be determined.
Let's see how this works out

Ok, Legos. Just like assembling Lego blocks, or arts and craft class, gluing a project together right?
How hard can it be? It can't possibly take very long.
There was a van gathering in two weeks and meeting a friend in Vegas in three, should be no problem to make those rendezvous. Right? Like it's 13, 4*8 sheets glued together and then covered in glue and canvas, then painted with a couple coats of water based paint.
Easy peasy.
Not so fast Mr Naive. Didn't make either appointment with a completed box that I felt was capable of making a 6 hour road trip.
Oh, you want to know about the build?
Back to the nitty gritty details.
Foam, the building block, had 18 sheets, a few extra just in case. You know, the 10% safety margin cushion.
So before I bought this foam, had to inspect and determine suitability and strength. I was sold on polyiso, not so much on Polystyrene. But the price was attractive and the seller claimed he himself had built one that I could see. Off I set to check it out. Well it was a sorry, neglected slide in camper, flaking in the sun, cracked body filler peeling off of the seams. But it was solid enough and the massive four inch thickness was reassuring. This must be the stuff Foamstream was built with. Could be done and should be adequate. However, didn't recall Foamstream ever making it out of the yard. And I would be building on a van frame, another level of challenge. What could go wrong?
So off I went to get bucket loads of paint, rolls and rolls off cloth, tubes and tubes plus jugs and jugs of glue. I was ready to start on assembling a box with 400ft2 of surface area. Kind of on the big side for a tnttt build.

Get a move on, got two weeks to cut, glue together, lay more glue on the sides, wrap with cloth and then slap on coats of paint. I was working on borrowed time on borrowed property. I hustled but the short winter days and chilly mornings limited my time.
And I built it all singlehanded.
Luckily, I am massively strong and capable to manhandle 20lb sheets of styrofoam.

So here was the plan from many nights of pondering, researching, and on the fly assessment since I switched to Polystyrene at the last minute. The walls and roof would be 3.5 sheets long. As with any build, the corners and seams are weak points. Like drywall, they will need to be set, bonded and filled, seams which are prime to cracking and coming apart from any stresses or loads. And that's for a stationary house. I was adding much more flex and movement with a vehicle going 75 mph down the highway. Who again said that this could be done so that I could blame them in the case of catastrophy? George, right. I had his number just in case.
Better overengineer just in case so as not to leave an avalanche of Polystyrene in my wake going down the highway. But at least I know it wouldn't hurt anyone. Tiny beads of Polystyrene, sounds like a song.
Ok how to reinforce the seams for added strength. The roof and edges were my main concern as that will be holding the box together, bear the brunt of the flex and movement, be subject to the most stresses goin down the road, over bumpy rock strewn dirt roads, through the occasional ditch and gouged road.

The roof joint was going to get the flex from the chassis and sidewall flex and it was going to be levered, enhancing the flex and movement. Here's the solution that I developed. God, I hope it would be enough.

I would countersink 1*4 boards flush into every side interior seam for extra strength, ridgity and increased bonding area for the joint. Doubling the bonding area in essence.
The corners as well would get extra wood for strength and extra bonding surface. Would notch out the sidewall roof joint for it to sit properly, tight and once again give increased bonding area for extra strength at that weak point.
For a long time I thought about wood vs metal framing. Wanted to go metal to eliminate the rotting wood issue. But the increased cost, increased assembly time, bonding issues negated the benefits. I had 4" of barrier to any wood which would be used only in the interior and it was cost favorable, flexed, bonded well, was ready to work with and readily available. It wasn't impressive like metal, but durable for the application and good enough for interior use. But the challenge was then, how thick and what sizes to use? The whole purpose was to build light yet had to be strong enough. I decided against a traditional ply and frame build for weight reasons. How to make a strong and light frame to increase the strength of the foam sheet for this application? And with only hand tools?
Don't know but here's what I did.
Some use a router to make a channel to glue in their wood board. Didn't have or want a router. Messy and long routing out channel. George uses the hot wire method on polyiso. Too long and slow a process, I had deadlines. Would it work on Polystyrene? I determined from trials that I could quickly cut my sheets with a circular saw in a maelstrom of Polystyrene beads. Static cling anyone? And that I could channel out the edges of two adjoining sheets, insert a 1*4 board to stiffen the joint, give increased bonding area and increase the load bearing capacity. Sounds good but will it work?
Chose 1*4 as not to costly, give two inch overlap on each sheet, double the glue bonding area and reinforce the seams, seemed about the right width. Of course wider would be better, possibly six inch wide 3/4" plywood or wider? Time will tell. Ideally I wanted to go every 24" but I could cut a channel out of the edges easily. A channel down the middle would require a router and I decided against that. Figured that if I needed to, could surface mount if required later in the build.

Then for the corners, could add a 2*2 to screw the insert boards together at that joint. Glue and screwed, shouldn't come apart, right? Right?
Where's an engineering neighbor when you need one? I was in cowboy country with horse ranches, I was on my own. The only assistance that I got was from a neighbor encouraging me to finish quickly lest be reported to the local authorities for my activities. He gave me a one week deadline, great inspiration. Nice guy huh?

Ok, assembly plan decided upon. I would overcome obstacles as I reached them, there was no blueprint or design that I could copy. A simple basic box was the plan. It should be basic, easy to build with basic hand tools and quickly assembled. The details I developed as I went along, God help me.

Now the walls were going to be 6'6"*12' panels. The roof 7'*12', rather large. Reinforced with 1*4 at every seam and joint. The seller told me that a sheet weighed 20 lbs, so about 100lbs per panel. Not too heavy but cumbersome. So I could assemble a 4' side wall, roof panel and side wall, and mount on the van, then continue to add another section. Assemble the box and then PMF the entire exterior which is what George does. But my sides and height would be 7 feet and that is longer than me armspan. That's a problem. I could assemble one section, PMF the 4' wide section, assemble another section, PMF that and keep going but was concerned about overlap, the finish smoothness and strength by doing PMF in sections over a couple days.

What I decided upon was to assemble each wall with 3.5 panels, using the flat bed of the van as my working table, assembling and gluing on the large flat horizontal surface. Build one wall, then the other, then the roof, PMF each separately while flat on the horizontal would be easiest, assemble the three walls, finish the joints from PMF overlap. Sounded good to me. Remember, developing the method on the fly, in the moment.

It worked out actually rather well. Couldn't see applying PMF on a vertical wall alone, that was 12' long and 10' up in the air the way George does it on his teardrops. Just too large and I'm not a big guy so limited reach. Place a sheet on the bed, notch out the channel, do the same with a second, add glue and board, repeat for the next sheet. Compress with straps to the front of the bed and allow to set overnight. Repeat with other wall and for roof.
Voila, three panels complete.

Pictures? Oh you want pictures.
Luckily for you i took a few.

The stuff I'm working with. Edging out side channel.

The roof. The roof.
My biggest concern structurally. It was going to get the most of the flex and be the most important part of the structure, holding the sides together, withstand the flex, it's own weight, be resistant to hail and falling meteorites, and if all went right, support solar panels. I must be crazy right? I am, I'm building a foamie on a perfectly good van chassis. Who does that? Nobody I know.

I worried and stressed over roof stresses and what would be strong enough to do it without massive heavy trusses to support. One of the first things was a test with homemade T trusses. After talking with George, he shot down my idea of using metal T fence posts. Light enough cheap and strong but narrow. Was contemplating using just that of under a board to spread the weight and support. But they came in 6 ft lengths, too short as I was 7 feet wide. What if I made one out of wood.
So I took a 1*4 and glued one with a 2"2, another with a 1*2, allowed to dry overnight and verified the next day.
Surprisingly, the 1*2 T was just as strong if not more so than the 2*2. Think that the wood type was the issue, pine vs spruce.
I had also played with and tested 3" steel drywall studs. A single would flex but if I doubled them, one nested inside the other, I could stand on it and wouldn't flex. Torsion box strong. I was sold, but the cost. Double that of wood. Went with wood. Cost overruns will kill a budget quickly.
I decided to go every 4 ft at the seam and could add more later once assembled if required to every 2'.

I decided upon the style of my build would be simple, easy to build since it was going to be built with simple hand tools only and with limited time. I liked the overland expedition style so gave it the back notch out to prevent the tail from grounding going through deep ditches. Have no plan to do so but like the look regardless.
I call my rig overland lite.
So I built a slanted front over the roof for reduced aerodynamic drag. Great for storage. Someone mentioned round and teardrop style as a suggestion. In my research, if you're going to be doing lots of highway travel, the aerodynamics become significant and worth the extra effort to design and build. If you're parked mostly in the driveway and only the occasional couple hour drive, didn't seem important or worth the trouble beyond a slanted front imho. Have no plans to cross continents at high speed. So I built just a slant over the cab which was an extension of the windshield rake to take the airflow up and over smoothly. Ideally. Hopefully. Maybe. It better.

And I built that section totally out of plywood.
What, do you think I'm crazy and build that out of Polystyrene taking the total brunt of g and wind force going down the highway setting foamie land speed records? I do have the LS4 big 6l V8 engine in Terra6, the one they put in the Camaro, GTO, etc... It'll scoot. And why the 6 and Terra6. Plus I had the stickers of the 6. There's method to the madness. Maybe.

So the nose cone is plywood because I may be crazy, but I'm not that crazy.

The fancy schmanzty high tech design plan I developed after hours of design work and CAD design.
Fyi, done completely on Graphtech software version 6.9 using Fujichrome Technicolor paper.
For the tech heads out there.

I would like to take this moment and thank Mr Insomnia for his assistance in allowing me to post this morning.
I am actually in TERRA6 at the moment being gently rocked by 20+ mph winds which woke me up at 4 am this morning. And it seemed like a great time to post. Been having major problems posting and pics but it seems to be working this morning. Yay.
The ridiculousness and entertainment will continue.

In a whirlwind of Polystyrene beads, notching out the roof and wall joint for a better press fit and increased bonding area to strengthen what is probably the weakest link.
At least I hope so.