Thrifty Alternatives ..Building Foam Campers

[jim_manley]

Looks wonderful! And a late congrats for making it through the entire thread... it's a bit of a slog, but a fun one, and I love your self-awarded certificate. :-)

Those roof-raised designs that end up with essentially two full-length, modern-shaped windows have always looked so gorgeous to me, and I'm excited to see how it turns out in foam, executed by someone who has the skills and experience to pull it off in a home build without the tens of thousands of dollar price tag that those fetch in the wild... good luck!

Thanks for the kind words, Amanda! I hope to be able to live up to your level of excitement, in addition to my own. I have to agree that the prospect of taking in breathtaking views through those gorgeous windows sooner, rather than later, is strong motivation for me to maintain progress on this build. So far, my demonstrated expertise is in producing fanciful SketchUp drawings, writing various posts containing champagne wishes and caviar dreams, and buying miscellaneous construction materials

My progress at the moment is stalled, as I'm settling in to teach another academic year's worth of science, technology, engineering, and math (STEM) classes at a new-to-me school in a small, but very supportive, community. The student count is much lower (average about four per class) than what I've had to deal with until now (as many as 37 per class, which was a violation of state law - the school and district adminiweenies were not happy when I pointed that out). I hope to be able to resume construction within a few weeks, once I've got the administrivia (such as lesson and unit plans) buried in a convenient corner of one of the school's fields with a variety of other skeletons (I'm teaching six courses I haven't taught before, mostly math and one in computer science, this year). I'm also organizing after-school activities such as science, code, rocketry, astronomy, and robotics clubs, a Makerspace, a Civil Air Patrol squadron, etc.

In the meantime, we're choking back the smoky haze resulting from 35 fires started by lightning across Montana over the past few weeks, ranging up to 270,000+ acres in area for the largest one. It could be worse - I could be in Southeastern Texas ... God bless those there, including any TNTTT members.

[GPW]

Yes , it can always be worse … which is how all this got started in the first place .. Those who’ve read all this , will see and understand the Evolution of the foamie trailer , due to the brains and efforts of many people who believed there was a better , LIGHTER way …

And there was a lot of babble , but at the time we never knew what was going to happen ,or if the ideas discussed would be accepted or what … It was more “social” All started off as one innocent little thread in the general section… about waterproofing wood …

[eaglesdare]

I do remember the very first time I mentioned building a teardrop out of foam. The guy thought I was insane, but humored me anyway. LOL

[eaglesdare]

I do remember the very first time I mentioned building a teardrop out of foam. The guy thought I was insane, but humored me anyway. LOL

[jim_manley]

Hi Glen and Louella,

I suppose we need to crank up our marketing campaign about the benefits of foamies again, because it's pretty obvious that people from areas like Rockport, Port Aransas, and Aransas Pass (a college roommate of mine grew up there) are going to need temporary shelter for many months. It's becoming obvious that a lot of people in the greater Houston area and Harris County (where the total population is over five million people) are going to need affordable shelter at a level that may make Katrina look like a walk in the park on a showery Spring day, just in terms of numbers.

That's not meant to minimize at all the loss of life and mayhem after Katrina, but ironically, something like 150,000 people moved from New Orleans to the Houston area permanently in the wake of Katrina, just to find work and affordable permanent housing. The FEMA debacle cannot be allowed to be repeated, where formaldehyde-laden trailers were hastily built under government contract that wound up making people sick to the point where they probably wound up worse off than if they had somehow been able to stay in the New Orleans area. Over 133,000 were sold off in huge lots for an average of under $1,500 each - less than seven percent of what was paid to buy them. My understanding is that we're still paying storage fees through FEMA for some of those illness-causing contraptions.

It would warm the cockles of our hearts to no end if people forced out of their homes in the Houston area could live in foamies that we've developed over the years, based on the lessons we've learned. I hadn't intended it, but my modular Mod-u-Foamer Corto Series could readily be built for well under $1,000 even at the retail cost of materials for the 4 x 4 x 8 foot (H x W x L) minimal size. They could then be expanded up to the 6 x 8 x 16, 8 x 8 x 16 (or even larger), foot size for way under another $1,000 in materials at retail prices. Another $1,000 could buy a pretty nice basic set of bathroom and kitchen fixtures and appliances. Volume purchases of foam, FRP/PolyWall sheets (with UV protection built-in, or applied if/when needed), adhesives, fasteners, trailer kits, fixtures, appliances, etc., could drop those costs by 30%, or more.

I thought that the government wasted an average of $18,000+ per trailer on those disaster-upon-disaster crappy post-Katrina trailers, for a total expenditure of 2.7 billion of our hard-earned tax dollars . Then, I found this story from last year's flood of Baton Rouge:

http://www.theadvocate.com/louisiana_flood_2016/article_533d1b20-bd98-11e6-affd-338dd8bab188.html

It said that FEMA spent $75,000 to $84,000 each to purchase and install minimal-sized mobile homes at group sites after Katrina, but worse, FEMA has been spending upwards of $170,000 for the same minimal mobile homes placed in group sites around Baton Rouge as of 2016 - and they still had thousands of people on waiting lists! Mobile home vendors said that the local market purchase costs of such trailers are less than $22,000 each in bulk purchases, and transportation, siting on a concrete pad, and maintenance costs would add well under $10,000 to the price - they would even buy them back for all but $4,000 each after a year of use, and still be able to make a tidy profit in any case

Imagine what a foamie could be with $170,000+ of materials and labor put into it!

[jim_manley]

Another thought prompted by Harvey-associated flooding - it's time to dredge up the wise content in the bug-out posts. Even if it is too late for the prior preparations, there's good info in them about techniques and plans to make long-term coping a bit easier, albeit not easy. Education is all about advancing civilization (you call this "civilization"?) by not making the same mistakes made by others - there will be plenty of time for our own mistakes to be made, too!

[GPW]

"The FEMA debacle cannot be allowed to be repeated, where formaldehyde-laden trailers were hastily built under government contract that wound up making people sick to the point where they probably wound up worse off than if they had somehow been able to stay in the New Orleans area.”

Jim we saw many of these trailers and they were made as CHEAPLY as possible with absolutely the WORST materials … Which IMHO taught trailer manufacturers how to make trailers quick and cheap in their retail market too … after a few months they literally started falling apart . Now it seems commercial retail trailers suffer the same problems after Katrina …

[jkviper]

I'm slowly collecting materials to build a foamie as well but one of my biggest concerns is that the racking from sides to side will bumping down the road toward my destination will kinda self destruct the poor thing. I plan to use a fair amount of wood framing in order to attach the dividing wall between galley and sleeping compartment. (Not a single, monolithic, straight wall of course. More like a "Z".) Will that bulkhead, alone provide sufficient sway-bracing?


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[GPW]

JK, although that's a concern that was expressed years ago , it has NEVER happened in many builds and many thousands of miles in Foamie travels .. Build as heavy as you want , but remember to protect any wood , or you negate the Best effect of a foamie … No ROT !!!  

[KCStudly]

Will that bulkhead, alone provide sufficient sway-bracing?

Between that, the front wall, any cabinet face frames (even if just cubby holes and not full blown cabinets) and the roof, you will be impressed with how rigid it becomes.

The only thing you might want to consider is the 'wing' walls of your galley. The original foamies were relatively small and had a small or no galley hatch at all. This meant that they were naturally stiffer. Larger builds may have a harder time keeping free standing galley walls stiff enough to not feel somewhat flexible, especially if going with a Benroy style profile where a good "lobe" of the galley wall sticks up and back, being relatively unsupported by the imaginary straight line between where the roof ends (hatch hinge) and the floor or lower rear galley bulkhead begins (in the case where the hatch does not go all the way to the floor).

Even on TPCE with 5mm ply inner skins, 2x2-ish nominal laminated wooden "rib" hard edges at the profile, epoxy/FG outer skin, and with my galley counter support and upper shelf face frame dry fit, I can still move the upper rear parts of my galley walls just a little bit and with a decent amount of force. Just a little. (The rest is rock solid.) I know this isn't an apples to apples comparison, but on a basic foamie with a lot less wood, a large-ish rear hatch and a canned ham or Benroy profile it might be something to consider, IMO. I'm satisfied with how my walls turned out and that it will take more than just casual force to see any deflection, but it took a lot of things working together to build up this strength. (I have always said that it is the sum of the parts and their assembled geometry that make up the strength, not any one single part.)

What would I do if that were the case and I was going with a more basic foamie approach? I would probably just leave a little more room between the first (outer) hatch ribs and the galley wall, so that they can't rub on each other. Another option would be to use a surface mount type of hatch where the roof skin comes all the way around the side of the galley to the bumper and you leave a 6 or 8 inch flange all the way around the galley opening (like Woodbutcher is doing on his Standrop, and others have done on various builds). This would stiffen the galley walls significantly w/o losing any significant storage space (canned goods and spice racks inside the side walls), and might even make sealing the hatch up easier with a wider overlap.

[jim_manley]

There are a few factors that people without engineering backgrounds may not be aware of that are non-intuitive.

The first is the concept of toughness - the ability of materials and structures to withstand stresses despite what may seem like excessive flexing. If you think a foamie bouncing down the road is a disaster waiting to happen, then consider that the tops of typical very tall modern skyscrapers move upwards of tens of feet horizontally in winds even below hurricane/typhoon speeds. If they didn't do that, they would fracture and collapse. Now, that's not to say that a poorly-designed and/or constructed foamie won't become "Dust in the Wind", as the rock group Kansas sang, but the same is true for a poorly planned and/or executed woodie, fiberglass, or even metal trailer build.

Foamies, done right, do flex, but no more than they need to as they redistribute stresses, and when foam is skinned properly, it is strong in ways that are superior to other materials, especially over the long term because rot and cyclic stress are generally not issues. Old woodies, fiberglass trailers, and metal builds have the potential to become the proverbial "Dust in the WInd" due to rot, UV exposure, brittle fracture, and other effects unique to each of their materials. Cyclic stress (repeated increased/decreased stress - think of bending a paper clip repeatedly) results in failures where plastic deformation occurs, which is permanent dislocation of atoms/molecules at that level, often resulting in "necking-down" of material cross-sections, and that results in a cycle of increased stress, further cross-section reduction, etc.

The second concept is that of brittle failure - the sudden release of energy when bonds or materials completely separate due to cyclic stress, crack development and propagation, or splintering at adhesive/fastener/wood bonds. These are particular "features" of metal and wood structures and, ironically, can occur due to overbuilding because, as the mass of structural components increases, the stresses on bonds and materials goes up as the fourth power of the distances of outside edges from the geometric centers of their cross-sections. Most materials have uniform properties across their cross-sections, so the larger the cross section, the more mass there is.

The distribution of the mass is also important, especially at the outer edges of the structure, as it affects structural integrity, towing handling, and longevity where cyclic stress can lead to failure. This became obvious when larger catamaran ships were built and failures began occurring, especially in metal structures where cyclic stress occurs along outer edges (corrosion due to salt water made a bad situation worse, too, and trailers can suffer from corrosion due to road anti-freeze agents). As catamarans become wider, the accelerations increase exponentially in amplitude and frequency, increased amplitude and higher frequency means more powerful cycles in the same amount of time, and so failure occurs earlier than it would otherwise. Trailers are simply land catamarans because of the wide stance of the tires relative to the supported trailer structures.

Finally, wood and metal construction tends to rely on point-concentration of stresses at fasteners/welds. Even if glue is used in wood joints, stresses are still concentrated in limited sites where cuts/holes penetrate wood surfaces (e.g., biscuits and through-hole metal fasteners). When metal fasteners are buried in wooden structures, corrosion is often hidden, and cyclic stresses frequently enlarge holes where metal contacts and penetrates wood.

Properly-built foamies feature rot-and-corrosion-proof materials, much lighter components, significantly lower rotational moments about the longitudinal (fore-and-aft) axis (and hence lower amplitude and frequency accelerations), stresses distributed across entire joints and surfaces of the trailers, lower cost of construction, and faster, simpler construction requiring more straightforward tools and materials. Their vastly reduced masses greatly improve tow vehicle fuel economy, reduce braking equipment requirements, and increase the longevity of everything. There's a reason why aircraft construction has been steadily moving to composites, on top of monocoque (single-shell) construction that's been in use ever since pretty close to the beginning of aviation.

[KCStudly]

The readers digest version is basically what I have been saying all along; the strength comes from the outer fibers; if you build it lighter it does not need to be as strong; and by spreading the loads across larger areas with good joinery and structural geometry, you can build lighter.

With a little bit of design theory, or just the ability to copy proven designs and techniques, there is nothing to worry about. But when in doubt, test and decide for yourself.

[jim_manley]

The readers digest version is basically what I have been saying all along; the strength comes from the outer fibers; if you build it lighter it does not need to be as strong; and by spreading the loads across larger areas with good joinery and structural geometry, you can build lighter.

With a little bit of design theory, or just the ability to copy proven designs and techniques, there is nothing to worry about. But when in doubt, test and decide for yourself.

Hey KC The Studmeister! Many here have tried to keep things short, thinking that it would foster understanding. However, lots of readers have yet to get the message, let alone believe it, basically because they've been given no reason to do so. So, I figured that supporting details were long overdue - both kinds of posts are needed.

It should be obvious that I consider 140-character cyber-grunts to be worthless, and few ever follow embedded links in them, so why bother (especially tiny URLs that contain no content, let alone context)? The trend toward just emitting video grunts with no way to search/copy/archive corresponding text is even further down the road to Oblivion

"A capacity, and taste, for reading gives access to whatever has already been discovered by others." -- Abraham Lincoln

[GPW]

As someone so aptly said …” a hard tent” ..

[KCStudly]

Hmm.

Did I just get "told" by the newbie?