2-Part Polyurethane Foam by the Gallon

[Buzz Nichols]

So...Maybe MEK would slow the reaction? Worth a small experiment, I suppose.

Sleddgracer, I've been thinking about your idea for using the old ceiling panels as molds for custom-formed foam insulation plugs. The more I consider it, the more I like it. I still think it may be feasible (with the addition, as Marc alluded to, of a bunch of steps I won't even think to consider until I'm up to my eyeballs in it) to pour AB foam behind forms in courses for the walls, but I don't see that method working on the ceiling. (Okay, I gave about .4 seconds' consideration to flipping the ceiling during the roof raise, putting the stuff in, and flipping it back over, but that idea doesn't even begin to pass the sniff test.)

I think a carefully designed mold involving an old ceiling panel, some sanded plywood, and a ton of painter's tape to make it release is probably a real sound idea.

Thanks so much for the ideas and insights. Keep 'em coming!

[family wagon]

It isn't what you asked for, but... maybe a few of us could have a bus insulating rally and invite a local spray foam contractor, or perhaps there's a quantity discount if we order a pallet of the Dow Froth-Pak 650 with several hoses and spray guns. I really hope this will finally be the summer that I get foam sprayed in my bus.

[o1marc]

So you want to go through this messy process to make what, rigid panels to go in the spaces? Don't they make rigid foam insulation? Slowing the reaction time gives what benefit, more time for it slough away from where you want it?
I have access to equipment to do my own spray foam, decided against it.

[Sleddgracer]

Originally Posted by o1marc

So you want to go through this messy process to make what, rigid panels to go in the spaces? Don't they make rigid foam insulation? Slowing the reaction time gives what benefit, more time for it slough away from where you want it?
I have access to equipment to do my own spray foam, decided against it.

finding out a bit more information about the product doesn't cost anything - perhaps by slowing the curing time a different process for application could be used, such as brush or roller like can be used for fiberglass, or perhaps applying one component by brush, then brush the 2nd component and mix as you're brushing - if that process was possible, you would have more control over thickness than by spraying - these are all just ideas - maybe not in the book, but who wants to be limited by whats in the book? - lol

[o1marc]

Originally Posted by Sleddgracer

finding out a bit more information about the product doesn't cost anything - perhaps by slowing the curing time a different process for application could be used, such as brush or roller like can be used for fiberglass, or perhaps applying one component by brush, then brush the 2nd component and mix as you're brushing - if that process was possible, you would have more control over thickness than by spraying - these are all just ideas - maybe not in the book, but who wants to be limited by whats in the book? - lol

They have already tried everything you have mentioned and they have perfected the system. It's called Spray foam. It mixes at the end of 2 hoses and sprays where you point it. At this point I'd like to see it go forward on the tests, I'm curious to the outcome.

Not limited to what's in the books, but common sense goes a long way. You're not going to reinvent the wheel.

[Sleddgracer]

Originally Posted by o1marc

They have already tried everything you have mentioned and they have perfected the system. It's called Spray foam. It mixes at the end of 2 hoses and sprays where you point it. At this point I'd like to see it go forward on the tests, I'm curious to the outcome.

Not limited to what's in the books, but common sense goes a long way. You're not going to reinvent the wheel.

I've always done well using my ingenuity - what someone might see as being wrong isn't always caused by what they're looking at - I've been involved in several fields and read and heard some 'experts', even with PHD by their name, and wondered how they came up with their conclusions - because someone has never seen something does not mean it doesn't exist or happen - just for the hell of it, I have a mind to try brushing a coat of each component, one over the top of the other - the first component won't start to set up until it's mixed with the 2nd component, and then it takes several seconds to react - more than enough time to brush out a fair sized area - I'm guessing the temperature also affects reaction time, so if it needs more time before it sets up when it's being brushed, do it in the cool of the morning - lol

[Buzz Nichols]

I sure can't say I've always done well using ingenuity, but I've always learned a little from effing stuff up, and the inexorable march of time has at least taught me to eff stuff up on a small scale before I go big.

...and from what I do actually know for sure about AB foam, it does go more slowly when it's cold, but it never expands as much as it's supposed to when it's cold, and doesn't have all the "fluff" that makes it a good insulator.

If I go this route (and at this point, I'm curious enough that I'll defilnitely at least do a small trial, if just for the advancement of pseudoscience), I don't think I would really benefit from slowing the reaction time, but that branch of the discussion is certainly interesting.

[Sleddgracer]

Originally Posted by Buzz Nichols

I sure can't say I've always done well using ingenuity, but I've always learned a little from effing stuff up, and the inexorable march of time has at least taught me to eff stuff up on a small scale before I go big.

...and from what I do actually know for sure about AB foam, it does go more slowly when it's cold, but it never expands as much as it's supposed to when it's cold, and doesn't have all the "fluff" that makes it a good insulator.

If I go this route (and at this point, I'm curious enough that I'll defilnitely at least do a small trial, if just for the advancement of pseudoscience), I don't think I would really benefit from slowing the reaction time, but that branch of the discussion is certainly interesting.

I too, have screwed up badly from time to time - lol - come up with some good things too

[Buzz Nichols]

So, maybe I should have started this thread with an open question:

What, if anything, is the advantage of spray foam insulation over EPS foam boards? Does it provide more insulation? The cons are obvious (high cost, inaccessibility of electrical conduits and whatever else you have inside your walls, mess, the hassle of trimming out an ddisposing of the excess), but the pros...less so.

It occurred to me, for instance, after spitballing sleddgracer's ceiling insulation mold idea, that it would probably be a lot easier instead to make a couple of jigs to cut form-fitting blanks out of EPS foam board.

So, in short: what makes the spray foam worth it?

(I did try a couple of keyword searches before writing this. Apologies in advance if this subject has already been covered at length.)

[dan-fox]

I'd be interested in seeing some numbers - seeing someone pencil out the various approaches. IIRC people have said that they got their buses sprayed for $800-1200, with them doing the prep first. The ones on the low end have prepped their bus then driven it to the insulator's current job site and had it done "at the end of the day" while they are already set up for some other customer.



Unless it's your idea of fun, setting up molds and jigs to premake insertable panels sounds like waaay more work than it's worth. Also, unless somebody comes up with a video, I'm going to have a hard time believing that they can mix this in some vessel, let it expand, and then trowel on some sort of pliable dough. That doesn't line up with my limited exposure to using this stuff. My memory is that it's like 15 minutes from when you have the idea to when it sets up hard.



I think others have determined that it's a wash money-wise between having it sprayed by a pro and buying enough DIY kits. Some have complained that the pros skimped; one of us complained that it went on waay to heavy and that he had to grow a new bicep in order to do the work of cutting it flat again.



When it comes time for me I'm going to look long and hard at kerfing flat pieces of foam, gluing them up, and then filling the cracks and crevices with either one small DIY kit or a handful of spray cans of Loctite foam which is advertised as closed cell.

[gclarkv]

My bus will have interior wood wall and ceiling paneling, which I will apply aprox two vertical feet at a time. Into the open spaces behind this paneling, I will pour two part foam. The ceiling will get similar treatment. I will inject the foam there. I used two-part pour foam in a past life and, with very little experience, became quite proficient at estimating the liquid volume necessary to fill a given space with expanded foam.

As a money-saving measure, one could insert rigid foam board into the wall space and pour liquid foam on both sides of it.

The pour in place foam will fill voids, cracks and crevices better than even spray foam. It can be installed with very little waste and almost no mess. Most important to me: It forms a powerful bond between inner and outer wall and ceiling skins, resulting in the strongest, most rigid and quietest structure.

The only noteworthy caution to be observed is to not try to fill too large a space at one time. The expanding foam is capable of building a surprising amount of pressure and, if the containing structure is not sufficiently strong, in can bow or even break through.

Obviously, all utility infrastructure will need to be in place before starting, and it makes sense to run wiring in conduit.

[Doktari]

I’ve saved a lot of money on spray foam by salvaging lots of scraps of rigid foam, duct taping or wedging them in place, then sprayfoaming around and over them. I’ve gone to several construction sites and picked up truckloads of random chunks of rigid foam.
I bought two of the $600 spay foam kits and did two very dificult to insulate and drafty walls. The spray foam sealed it up tight. Expensive but it worked.

[o1marc]

None of the product I see says how much foam it actually makes. $40 for 2 quart cans, how many cubic ft is it? It calls for 15second mixing and a 30 second work time. You best be ready to pour all you've mixed quickly. IMHO not the best choice though it may have some minor benefits.

[Elliot Naess]

I have used X-30 from TAP Plastics. (It expands 30 times the liquid volume.)
But mostly I have used it for flotation (buoyancy) in water.

I did use it one time in Millicent, and it did get the job done.
I used it to fill the empty space above the windshield and make that solid, so the two-foot tall "forehead" skin would not buckle inward from wind, bird strikes, and tree-branch strikes.

But the stuff expand so fast... you have only second from the point when the two liquids appear fully mixed... before the stuff "explodes" out of the jar or bucket. Ask me how I know.

[Native]

Originally Posted by Elliot Naess

I

That's an Elliot Maess! (Sorry, I could not resist!)

[milkmania]

Originally Posted by Native

That's an Elliot Maess! (Sorry, I could not resist!)

I can just hear Mrs. Naess in the back of the bus now.....
"ELLIOTTTTTT! WHAT THE HELL HAVE YOU DONE NOW?!?!?!"

[ol trunt]

Lots of ways to skin a cat. Here is another "out of the box" idea. Perhaps we could start a skoolie Go Fund Me and raise enough money to buy a big auto rotisserie like this

https://www.youtube.com/watch?v=yNWwt3wRW0U

and a spray foam system that we all could share--------------------
Jack

[Buzz Nichols]

Hmm...That would make it easier to pour foam into the roof panels....

[Buzz Nichols]

Originally Posted by o1marc

None of the product I see says how much foam it actually makes. $40 for 2 quart cans, how many cubic ft is it? It calls for 15second mixing and a 30 second work time. You best be ready to pour all you've mixed quickly. IMHO not the best choice though it may have some minor benefits.

My understanding is, the pound notation (2#, 4#, etc.) denotes how many pounds of the liquid it takes to make one cubic foot. Thus, if your 2 quart can kit is 2# foam, it'll produce about 2 1/4 cubic feet, beause the components are a little heavier than water, weighing in at around 9# to the gallon.

[o1marc]

Originally Posted by Buzz Nichols

Hmm...That would make it easier to pour foam into the roof panels....

If you're doing a roof raise , cut the roof off, turn it over, pour you foam and then reinstall the roof.