fast, cheap, fiberglass/ foam stressed skin panels

[saywhatthat]

There a trailer being built off you book ( Building a Teardrop Trailer: Plans and Methods for Crafting an Heirloom Camper )

I think you skipped over the plywood part.

Tony

you did such a great design could be built from anything

[saywhatthat]

Door if you buy premade one they can at least get you a nice motel room and a box of chocolates and dinner.
The most important part is the door jamb and seal.
By the way those drop down horse trailer windows the most sell as doors they're $175 each on a skid of 60
The pod I'm building will probably last well over two hundred years and most door companies we'll be long gone
The door jam that I'm doing you just need two pieces of angle and some type of seal.
Made fiberglass angle that will expand with the pod.
install the outside angle then trim to the inside
on the inside angle trim down one side for your bulb seal to set on and door to reset on.
I like a big deeper channel that way I can put in dust brush & bulb seal

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IMG_20220129_164311.jpg (38.21 KiB) Viewed 1639 times

[MickinOz]

Saywhatthat, who are you?
I've skimmed back to your very first posts, I still haven't figured you out.
I have formed the impression that you work for a company maintaining hire trailers, but your build is at home, and your first language is French?

[saywhatthat]

mostly French moved around a lot when I was a kid dad was an oil man. Born in Louisiana. Activate angel investor ( which means I give someone a lot of money to work for free ) have invested in ballistic panel manufacturers and trucking companies several RV repair places and it's just nice for customers to have a trailer while you work on theirs. the one's I'm showing made at father n law home. I just wanted to be out there that you can build a cheap trailer that can last forever and you don't need a big workspace on the cheap.

[MickinOz]

I just wanted to be out there that you can build a cheap trailer that can last forever and you don't need a big workspace on the cheap.

It may be the case that its cheap to do it this way in the US, but let me tell ya, creating DIY composite panels like this in OZ is expensive.
1.5mm fibreglass sheet = $38 per square metre, add freight on top. (Which will double the cost for me as I am about 3000 km from the factory)
30mm thick XPS foam = 21.60 per square metre
So if you DIY your own panels like the guy in the video that you link to in your first post, with 30mm foam in the middle and 1.5mm fibreglass sheet each side, you are looking at $98 per square metre, not counting the cost of freight and whatever adhesive you use.

THE most expensive 3/4 inch ply wood I have found was imported 19mm hardwood marine ply, $175 for a 4 x 8 sheet.
That's $59 per square meter for Roll Royce grade timber. Yes, you have to seal it, but at $68/gallon for premium polyurethane here in Oz, I am really struggling to figure the advantage of the homemade composite panels.

[saywhatthat]

What makes this cheapest you do your own skin you start with a bucket of resin and fiberglass material and anything flat.
The foam averages $ 22 US for a 1-inch piece. when you make your own skin you can add woven which makes them extremely strong.
YOU drill angle holes all the way through the foam locking it from any movement.
If you let the resin drizzle through it will try both skins together so the foam density means nothing . you don't have to fill the holes with resin just let it drizzle where hole gets a real small lining tying the Skins together. you have all these little tubes of resin in the foam on a 4 to 6 in grid.
t
The video just give you an idea of the process but you are making your own skin you don't have to use high density foam. Jess is great at making videos to me is so easy ten words would explain it.

By making an interior and exterior Bond beam fiberglass you're not paying that high price for aluminum, corners and you have made a fiberglass skeleton. everything .
pretty much expands the same.
the strength from the structural panel is the distance between the two skins.
You will be making your own skins mat is the bulk and the woven makes it extremely strong. .if you want to use a different type of foam then you can make your own skin because the store-bought ones are all polyester .then bond with epoxy . Also the door jamb will be adding quite a bit of strength
you are the factory for the skin and it has insulation where plywood would not

This way of building when the first start seems extremely flimsy but its strength is in the sum of all its parts.
you are making your own skin the density of the foam does not mean anything.
By making your own panels This Way you put an actual bowl shaped into the panel . so everything is under load it makes it extremely strong.

as that interior Bond beam pulled in just a little bit and when you revit and glue it together it is actually pulling the roof down onto the walls


.

[MickinOz]

The numbers aren't much better if one does one's own fibreglass layup.
Leaving out the provision of a flat surface to layup on, and things like plastic sheet to lay it on, measuring cups, gloves, cleaning solvents, all the consumables, etc, let's look at Australian costs.

I costed it out at well over $200 to make a 4 x 8 sheet using box store 30mm XPS foam and 600 gsm (2 oz) chopped strand mat and epoxy resin.
I did type it out item by item, but decided not to bore everyone to death.
Much cheaper to buy polyester resin, but then you can't use the polystyrene foams. 10mm boat building foam here is about $40 per square yard, so you could, with polyester resin, get down to about $170 or so per 4 x 8 sheet, at about 12mm thick.
I got 12mm marine grade hardwood plywood at $105 per sheet.

It is just plain expensive to do this method of construction here in Australia.
Which is why I'm saying what I'm saying.
I've noticed that new builders tend to look for less conventional approaches.
I'd hate for an Aussie newbie to fall into this trap - "Hey, this looks cool. Let's go high tech." Here in Oz, they'd get burned financially in my opinion.
It would, at least, be no cheaper. And if you didn't live in a capital city, absolutely everything would be order in. Nothing off the shelf at the local hardware store except the rivets.

[saywhatthat]

with building anything you have to use your due diligence always great to read about perspectives from different parts of the world
you don't use epoxy The foam is cheap big box store insulation foam isocyanate. one of the businesses I am involved they use quite a bit of foam but it's $400 a sheet.
I figured out here in the US by buying off-the-shelf not wholesale . with increased cost. 4,5 by 9 foot 1 in foam about $120 a panel . you have insulation something that won't rot can take an impact light make with under 100 bucks in tools . it would be nice if you wax it once or twice a year and maybe every five to 10 years spray clear coat over it. if you have any damage you go to Walmart.

Has Prudential to last hundreds of years with little maintenance. Wood not so much. you could put a hole in it the size of a basketball and a few years you might have to think about fixing it cuz there's nothing to rot.
A s with any project you have to figure out the pros and cons. upfront cost yearly maintenance, cost of Towing. a big one storage if you have to pay the storage that's time
12.
All I can go by is cost here in the US.
From the repair shops that I am invested in and from trade manuals they say about from 55% to 70% of all manufactured RVs are going to need major repair within the next 10 years.
So it's no surprise that labor rates are high—they average between $150 and $170 an hour nationally. A price like that makes even simple, commonplace repairs expensive. Many RV repairs occur at dealerships, which may be even more expensive.. Most go by book rate Which is higher than the actual hour you work.
Even the most uncoordinated never built a thing would Excel.
$11 piece of hardboard works great for a flat surface

[saywhatthat]

much cheaper to buy polyester resin, but then you can't use the polystyrene foams.. RIGHT foam cheap isocyanate insulation foam
sadly that has become one of the web's biggest lies from people that read bulshit on the web and don't do research. From what I've seen it used to be the ones that sell epoxy or maybe built a trailer from epoxy and are pissed and want everybody else to waste money there the one that spread the lie at first
now it's I read it on the web I've never done it but I'm an expert.
boats are made from polyester resin all the Skins you buy are made from polyester resin
https://www.homedepot.com/p/Thermasheath-Rmax-3-1-in-x-4-ft-x-8-ft-R-6-Polyisocyanurate-Rigid-Foam-Insulation-Board-787264/100549260

[MickinOz]

This makes me sadder every time I check in on this thread.
isocyanurate foam at $24 for 8 x 4 x 1" - you are spoiled over there

I spent a very long time searching and could not find even XPS in 8 x 4.

Box store extruded polystyrene would cost $60 for 4 sheets measuring 4 x 2.

They do have 20mm foil board which is expanded polystyrene, and has aluminium foil on both sides.

Nope, the more I look, the more I'm convinced your method is simply not viable in Australia.
Styromax premade panel is readily available, of course. They'll even cut and ship your profile.
You just have to have enough money.

[saywhatthat]

I guess that's the cost for living in a country that has lower crime rate. stable government fantastic scenery except for the bugs that keep trying to kill you and snakes .
What is the exchange rate for your dollar to our dollar ?

[John61CT]

Aussie homes rarely get built with thick insulation.

Huge differences stateside too, Michigan vs Florida.

Then the low population less competition, plus huge shipping distances.

Then comes taxes.

But the more comfortable wages & benefits, PTO health care more than make up for it

[MickinOz]

I guess that's the cost for living in a country that has lower crime rate. stable government fantastic scenery except for the bugs that keep trying to kill you and snakes .

Snakes? We don't got no freaking snakes!
I only have to look out for eastern brown snakes, western brown snakes, king brown/mulga snakes (really black snakes), red belly black snakes, inland taipans, tigers, copper heads, death adders, and dugites.
Bugger all, really.
I mean, they can all kill ya, but ya just about have to dare 'em to do so.
Almost all of them will go the other way if you give them enough space.
Apparently, the inland taipan is the most venomous snake in the world. But, given its "placid" disposition and its preference for living out bush many miles away from people, it is not considered anywhere near the most dangerous.

King browns are a bit scarey, I saw one that was at least 8 feet long. At least, without exaggeration.
(With exaggeration, he was 10 feet long. )
I was riding a motorcycle at the time, it was a challenge to avoid running him over.
Those buggers have been known to keep chewing when they bite you, but they are not the most venomous snake around. There hasn't been a recorded king brown death since 1969.

An acquaintance got bitten by a death adder. It got him in the webbing between his thumb and index finger. The fangs went right through. He held the snake with his other hand and watched its venom squirt harmlessly onto the floor, not attempting to disengage the beast until the venom flow stopped.

[saywhatthat]

sounds safer to drive through Oakland California at midnight with a gold watch hanging on your arm out your window. at 8 Kilometers per Hour.

[MickinOz]

Nah, they are venomous, and they are here.
But almost all of them will move away if they feel/hear you coming. They don't have ears but can "feel" sound through their skulls, apparently.
The exception to moving away is the death adder, he'll stay put. But, unless you step directly on him, he chooses not to waste his venom on something too big to eat.

A friend had an open faced hay shed where a brown snake took up residence. Watching that beast hunting for mice amongst the loose hay spillage was well worth the time.
Just had to be careful and stomp your feet good when you went to get hay for the horses.

I don't get that worried, even out bush. You just seldom get near them. Which is just as well, cause the buggers make my skin crawl when I'm up close.