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Old 12-13-2006, 05:38 PM   #43
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I'm not a chemist, but the pourable urethane products I use on windsurfers from UScomposites.com is definitely exothermic. It gets hot enough to melt expanded polystyrene! It would do as Dan Clayton claims!
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Old 12-13-2006, 10:37 PM   #44
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I don't know how a spray in foam could not generate any type of heat. If I recall from my school days, any chemical that reacts, does one of two things, it either heats up or cools down. With the foam expanding and hardening my guess is that it would heat up, but it's been 30 years since I was science and a lot of things have changed, and if the MFG. says it does not heat up then, I guess you go with their word.
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Old 01-17-2007, 06:50 PM   #45
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I sprayed it today.

I work for a local building supply that has an installed insulation division. We install f/g, cellulose, and foam...both closed and open cell. Due to some turnover, I've been helping out one of the foam crews for a couple of weeks. We've been spraying open cell in new constructions. I'm by no means an expert, but here's my observations...
...the two chemicals are piped from a central pump/heater unit in 2 separate lines to a spray gun where they are mixed just before exiting the gun. The lines have integral heaters which are kept constant at 140 deg. for open cell. There are also primary heaters inside each side of the pump that are kept just lower.
...The chemicals are kept at just under 1100 psi in the pump. I witnessed TODAY the mess that can be made when one of those lines blow.
...There is definately heat generated as the foam expands, but it is cool to the touch in less than 5 seconds...also, the heat generated can't be very hot, because daily I have some drip onto my arms and it's very warm, but does not burn as it reacts.
...We trim any excess with either a small hand saw or an air saw with a long recip. saw blade on it. It scrapes off most materials very easily, metal being one of the easiest. Wood cleans up the hardest, especially any rough sawn wood that it can get into the grain.
...It does produce a very unpleasant and unhealthy vapor, so forced air respirators are a must for the primary sprayer, and at the least a good particulate respirator for anyone in the immediate spraying area. Dissipates almost immediately, but you still don't want that stuff in you.
...It's fairly easy to get a thin layer if you want it. As a matter of fact, the first layer actually goes on thin...It reacts to itself faster than to the base material. So it foams up less on the first layer.
...R-values and cost I'll check on and post them later. These statements are about open cell only. I have not done any closed cell yet.
Kevin
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Old 02-17-2007, 01:24 PM   #46
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I own a 1975 Argosy and a 1969 Ultra van. The Ulra van came with sprayed foam insulation from the factory that I would actualy like to remove. The sprayed insulation has apparently caused premature corrosion of the aluminum skin. This is attributed to chemicals in the foam causing the aluminum to corrode from the inside out. Wether or not this is the case is unknown, but earleir Ultras with the fiberglass bat insulation have not had these problems. In addition the foam adds weight. Maybe the chemicals in modern foams have changed, but I for one am seriously considering gutting the insides and removing the foam, a task that I am sure will not be pleasant.
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Old 02-20-2007, 07:39 AM   #47
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Thumbs up foam motorhome

Quote:
Originally Posted by vairynuts
...The sprayed insulation has apparently caused premature corrosion of the aluminum skin. This is attributed to chemicals in the foam causing the aluminum to corrode from the inside out....
It sounds like that old foam is trapping moisture in the wall and with the cold skin of course traps right next to the aluminum causing corrosion. It's been said before that the walls must be able to breath and release trapped moisture. The modern foams come in a variety of types...one is moisture proof. They can even spray it on the inside of stone basement walls. I'm guessing that a true chemical reaction would have distroyed the aluminum in faster than 38 years! Good luck removing it though. Peening with walnut shells at a relatively low pressure may work well for that, or just scrapping and wire brushing. I bet the foam almost falls off as you open the walls. Does that thing still have the Corvair motor? I don't think that Ralph Nader had any problems with that

Best wishes,

Steve
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Old 02-20-2007, 12:54 PM   #48
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Good general article, and an interesting article about foam as a vapor barrier.

Steve
Attached Files
File Type: pdf Construction Without A Vapor Barrier.pdf (57.0 KB, 132 views)
File Type: pdf JLC_SPF_Artcle.pdf (154.1 KB, 69 views)
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Old 03-05-2011, 04:17 PM   #49
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Foam insulation

Cool the outter shell with a sprinkler!
Quote:
Originally Posted by Dan Clayton View Post
Steve, The best product is the one that has the fastest curing time, and heat will be generated in any of the foams that are put out today. and oddly heat is a important factor in how well it will hold up over time. The foams in a box will not last, and cost 10 times as much as having installed by a foam business. I used a type that is well know in the RV business, can't recall the name, but it can generate heat up to and over 200*. There is no problem when using it on 16 gage metal or very thick fiberglass, but when your talking 0.32 gage metal that's a whole different story. I had to replace the sheet metal on the side walls because it was like a ocean wave. When the foam was first sprayed on I guess there was no issue, but as it cured and the heat generated then the warping started. I would just stay with the old type of insulation, or foil bubble. Sometimes it best just to stick with the old technology.
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Old 03-05-2011, 04:21 PM   #50
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Seal the interior of the skin and stringers with???

What about sealing or painting the interior before applying the foam??What paint works best on aluminum?


Quote:
Originally Posted by vairynuts View Post
I own a 1975 Argosy and a 1969 Ultra van. The Ulra van came with sprayed foam insulation from the factory that I would actualy like to remove. The sprayed insulation has apparently caused premature corrosion of the aluminum skin. This is attributed to chemicals in the foam causing the aluminum to corrode from the inside out. Wether or not this is the case is unknown, but earleir Ultras with the fiberglass bat insulation have not had these problems. In addition the foam adds weight. Maybe the chemicals in modern foams have changed, but I for one am seriously considering gutting the insides and removing the foam, a task that I am sure will not be pleasant.
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Old 03-05-2011, 04:39 PM   #51
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Warping of panels

Could this have been caused by the foam expanding and not the heat??? So the foam expands against the stringer and pushes out the panel?

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Originally Posted by filterman View Post
Cool the outter shell with a sprinkler!
Quote:
Originally Posted by Dan Clayton View Post
Steve, DONOT USE SPRAY FOAM INSULATION!!!! Im telling you is sounds like a great idea, and does do all the things you say, but the heat thats generated by the reaction of the curing of the foam will warp the sides and the corners of the trailer, I speak from experence!!! and as a result I had to replace all of the side panels, 4 sheets and a lot of time. It was bad enought to have too do it the first time, it took me serveral months because of my work. but to have to do it again was almost too much. I ended up keeping the foam on the roof, end and front panels, and some on the corners, other then that it's all gone.
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Old 03-19-2011, 04:42 AM   #52
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R Paint

Insuladd.com :: Radiant Barrier Testing Overview
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Old 03-19-2011, 06:39 AM   #53
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Quote:
Originally Posted by sfixx View Post
I'm not shot down that easily...recall this is for the cause of science. Also, I bet the technology has changed maybe a tad in the last 40 years. I remember that old foam would turn to dust with age even without abuse. I plan to set up some tests when I order the product next summer.

Steve
Hi Steve;
Have you found a flexible foam of good R value? In my book RIDGID Uretane Foam Is RIDGID. Airstram is NOT, it flexes. "Boatdoc"
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Old 03-19-2011, 10:19 AM   #54
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Why not put the 1/4" bubble foil, or something like it against outter skin, then spray an inch of foam?
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Old 03-20-2011, 02:14 PM   #55
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Foam

You would want to use closed cell foam as it absorbs less water.
Quote:
Originally Posted by farmsc View Post
I work for a local building supply that has an installed insulation division. We install f/g, cellulose, and foam...both closed and open cell. Due to some turnover, I've been helping out one of the foam crews for a couple of weeks. We've been spraying open cell in new constructions. I'm by no means an expert, but here's my observations...
...the two chemicals are piped from a central pump/heater unit in 2 separate lines to a spray gun where they are mixed just before exiting the gun. The lines have integral heaters which are kept constant at 140 deg. for open cell. There are also primary heaters inside each side of the pump that are kept just lower.
...The chemicals are kept at just under 1100 psi in the pump. I witnessed TODAY the mess that can be made when one of those lines blow.
...There is definately heat generated as the foam expands, but it is cool to the touch in less than 5 seconds...also, the heat generated can't be very hot, because daily I have some drip onto my arms and it's very warm, but does not burn as it reacts.
...We trim any excess with either a small hand saw or an air saw with a long recip. saw blade on it. It scrapes off most materials very easily, metal being one of the easiest. Wood cleans up the hardest, especially any rough sawn wood that it can get into the grain.
...It does produce a very unpleasant and unhealthy vapor, so forced air respirators are a must for the primary sprayer, and at the least a good particulate respirator for anyone in the immediate spraying area. Dissipates almost immediately, but you still don't want that stuff in you.
...It's fairly easy to get a thin layer if you want it. As a matter of fact, the first layer actually goes on thin...It reacts to itself faster than to the base material. So it foams up less on the first layer.
...R-values and cost I'll check on and post them later. These statements are about open cell only. I have not done any closed cell yet.
Kevin
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Old 03-20-2011, 02:15 PM   #56
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Foam

Foaming over the bubble wrap would not give you good adhesion to the shell. You would be better to use foam sheeting I think , in this case.
Quote:
Originally Posted by lahrfarm View Post
Why not put the 1/4" bubble foil, or something like it against outter skin, then spray an inch of foam?
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