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ivantruckman

expanding foam bodywork, you know you've done it

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spray foam bodywork, it fills holes in the fenders causing dust to get in the cabin, you can sand it and shape it with a surform blade, than all you have to do is prime it with a latex exterior house paint, after that you can spray undercoat, and you cant even tell its there, sound deadening too, a true miracle product. pictures to follow. as soon as i can find the camera. arrggg..

please share your spray foam pics

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Done it to many cars but don't have pics. If you really take your time and do a nice job it comes out looking pretty good (I only did that once).

I see it a lot around here on various rusty cars.

Andy

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I admit I've considered the sound deadening applications, but I think I'm also a bit frightened by the prospect of structural metal being replaced by foam.

 

be scared, be very a-scared

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I admit I've considered the sound deadening applications, but I think I'm also a bit frightened by the prospect of structural metal being replaced by foam.

 

be scared, be very a-scared

 

What worries me is trapped moisture.

 

nipper

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I suppose just like paint if there's the slightest rust it will just keep it trapped and eat it out in pockets. :dead: that would be no good.

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SCC did new car (I think it was a 350 Z) with some industrial strength stuff a few years back.

Sprayed it in all the cavity areas of the unibody.

Guess the hardcore stuff adds rigidity without adding much weight.

Never tried it myself though.

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if it was done new at the factory it wouldn't necessarily trap moisture and worsen rust issues like nipper was talking about, it could seal it out and improve longevity. but for the likes of trying to do it with 10 to 20 year old cars...

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if it was done new at the factory it wouldn't necessarily trap moisture and worsen rust issues like nipper was talking about, it could seal it out and improve longevity. but for the likes of trying to do it with 10 to 20 year old cars...

 

Exactly.

It was for the magazine but the car was right off the lot. (They had a body shop do it I believe)

 

If I did that to my GL.

It would proly rot faster unless I had the shell acid dipped and preped first.

And I'm not tearing down my entire car just for that.

I'll save that for a full on race car project that I can't afford. :lol:

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What worries me is trapped moisture.

 

nipper

Amen. Give Me Duct Tape or Give Me Death!

 

I suppose just like paint if there's the slightest rust it will just keep it trapped and eat it out in pockets. :dead: that would be no good.

No; its not like paint at all. Its more like a sponge; if any of this foam is open to the atmosphere it will wick moisture up into the crevasses in question.

 

No way comparing work like this on a new vehicle to work like this on a rusty soob is apples to apples.. one hasn't had a chance to even get dirty, the other is already rusting out.

 

Unless EVERY ASPECT of this repair area is dried out (mojave dry) and sealed up (space shuttle sealed) this will lead to major rust. Will it happen quickly? No telling; but living in a swamp it is the LAST thing *I* would do; I would sooner ignore the rust and let it get worse of its own accord, at its own rate. Is it worth it to anyone else? that is for them to decide based on atmospheric and road conditions, value of the car, and how well they think they can seal the foam off from the water in the rest of the world.

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Who the heck cares, if you've got that much rust your just putting off the inevitable. Here's my tip of the week........ Get some of the nylon window screen and put it on the inside of were you are spraying the foam. It will get encapsulated and add some strentgh to your foam. Spray foam FTW:headbang: :headbang: :headbang: . Tim

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I did the rockers on my mom's taurus front to rear... Skimcoat with bondo, spray white paint. Got it past inspection for another year... that's all that counted. It even held up when the car was hit in the rear quarter, the plastic window held in with wood screws and caulking didn't though.

 

If if hadn't been hit again and the state hadn't come down on us for not having a salvage inspection from the first rear end hit, I coulda milked another year out of it.

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If you use the automotive grade stuff, it's waterproof and doesn't trap moisture like the house stuff does (but it's more expensive)

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be yee warned!!!!

 

i have used the exspanding foam. great for short term fix. take it from me and my dad. for we used on his f100 under the dash to stop air from getting in. let me just say that the rust was so bad it made the cab deform. if you open the door you had to football tackle the door closed. again short term great, long term well lets just say if you would like to watch rust grow like grass grows go for it:rolleyes:. just my 2 cents! worth about half that:cool: .

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If you just spray it on the rust, it will continue to rot.

The one car I did a "nice" job on (I say "nice" in quotes because it was still spray foam, after all) held up at least until I sold it a couple years later. I ground the rust as best I could, treated it with "rust converter" (the stuff that turns black), let it dry out for a week in a heated garage, then foamed it. After trimming the foam, I sealed it on the outside with brush on bedliner. I followed the panel line (this was on a Toyota 4Runner) and it came out looking really good. In the end it was probably just as much work as doing it with Bondo and fiberglass, but the foam is faster and I've never been much good with shaping Bondo.

Andy

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If you just spray it on the rust, it will continue to rot.

The one car I did a "nice" job on (I say "nice" in quotes because it was still spray foam, after all) held up at least until I sold it a couple years later. I ground the rust as best I could, treated it with "rust converter" (the stuff that turns black), let it dry out for a week in a heated garage, then foamed it. After trimming the foam, I sealed it on the outside with brush on bedliner. I followed the panel line (this was on a Toyota 4Runner) and it came out looking really good. In the end it was probably just as much work as doing it with Bondo and fiberglass, but the foam is faster and I've never been much good with shaping Bondo.

Andy

I'm sure in the end it works acceptably, and done well you will get good results.. It simply IS the sort of thing that can be done.. poorly.. and in that case, you wind up with poor to disastrous possibilities. That was all I had to say; After all, I cast MY vote for Duct Tape :rolleyes:

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i'm confused. spray body foam? like it replaced the metal body panels? that sounds bizarre, i'd like to see pictures of that. i can't picture it looking right and if it does it seems like it would be loads of work to get it to that point. isn't it easier to just buy one that doesn't need that much work? here is a better use of my own time that might work for others: go find a cheap soob that needs work, bad trans, blown headgasket...etc, fix it, sell it, make a few thousand and go buy a whole herd of EA82 vehicles without as many issues.

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I heard this stuff is highly flammable. Someone should put a flame on a dry chunk of it, and report back.

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its only bad when its wet

 

i have tried to burn the stuff out from around a mechanisim and all it did was turn black and smell, couldnt burn it for the life of me!

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be yee warned!!!!

 

i have used the exspanding foam. great for short term fix. take it from me and my dad. for we used on his f100 under the dash to stop air from getting in. let me just say that the rust was so bad it made the cab deform. if you open the door you had to football tackle the door closed. again short term great, long term well lets just say if you would like to watch rust grow like grass grows go for it:rolleyes:. just my 2 cents! worth about half that:cool: .

 

ABOVE is the coolest ************rep I ve read this week!

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I think Popular Mechanics ran an article this past summer about "bonding" in rust repair panels.

 

I know adhesives are getting MUCH better (liquid nails, etc) .....but I just cant get past "gluing" your car together:confused:

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I read about it on a Porsche 914 forum... Seems a lot of progress has been made in the world of adhesives, I guess it works reasonably well, haven't seen too many complaints about it. I'd sure consider it in a non-structural location like the rear wheel wells on my Brat since I don't have access to a welder right now...

I agree though, seems kinda strange to "glue" your car together, then again, a lot of planes are "glued" together and they deal with a LOT more stresses than a car does (in regular service)

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I'd sure consider it in a non-structural location like the rear wheel wells on my Brat since I don't have access to a welder right now...

 

I *think* you will find that your rear wheel wells are "structure", unless you are doing something else for mounting your rear shock/strut (depending on year), the wheel well flexing in "normal" suspension operation is likely what caused the necessity of replacement/fix.

 

Anybody out there using this stuff?

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What worries me is trapped moisture.

 

nipper

See, if you're doing this right you should be encapsulating the foam with fiberglass. Then it's as simple as a little bondo, sandpaper and paint and you've got a body-shop quality repair. I'm a surfboard shaper and I fix surfboards so if there's one thing I know it's foam and fiberglass. 

 

The best way to do it is to use the expanding foam to fill your gap. Make sure you've prepped and sanded the area around the repair, otherwise it won't stick. Sand down the foam to just below the level you want it, then mix up some epoxy and apply the fiberglass. The best technique is to use a brush to paint a small amount of epoxy where the glass will go, then stick the glass to it - the epoxy will help keep the cloth from falling off. then, lightly paint epoxy onto the fabric, just enough that it turns transparent. If you do this properly you will still be able to see the texture of the woven fiberglass. If you use too much it will drip or pool and you'll have the biggest pain in the rump roast ever sanding - less is more. Once it's cured lightly prep it with some 80-120 grit and then apply the bondo, sand, reapply as needed, prime, paint, polish... you get it. Super easy and that's how the pros do it. It's way easier than you think, the tricky part is just learning those mistakes the pros already know like not laying down epoxy too thick, avoiding brushing the edges of the cloth so it doesn't fray, etc... The same technique is used for boat repair, surfboard repair, body repair, model making... pretty much anything you can think of. 

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