Nov 3 ' 04
Greetings All
I have been following the discussions initiated by the article by Mr. Mike Kojima regarding injection of 2 part, closed cell foam into chassis members.
I am restoring a '61 Austin-Healy 3000 that had the frame rust out from the inside, travel everywhere and ruin the car. When the frame repair is completed, I'm thinking of injecting foam into the interior chassis members so no water can ever again rot it out. The voids would all be filled so there are no holding spaces for water to settle.
Some questions I have are:
1. Which of the products are best for rust inhibition i.e. ITW Foam Seal, 3M automotive repair foam or Carbon Black 200 (is this even a product?). Stiffing is not my priority.
2. I'll need to do some welding on the frame. Will these products be likely to catch fire, expanding gases could create the potential for an explosion, give off toxic fumes, etc.
Any advice would be appreciated.
Hugo

I've used Great Stuff expanding foam for this before, mostly to fill the void in rocker panels. I would do all your welding first and then put your foam in once that's all done. I think most of these types of products are flammable. Also check out www.autobodypro.com They have a forum there and might be more knowledgeable about this.

Same, I did my 92 NX back in 94 with great stuff all over - A-pillars, roof, inside the body panels and anywhere I couldn't reach with the flashing product.

I have no rust at all in my A-pillars since water couldn't get in, the car is more solid and provided a nice degree of sound-deadening as well.

I'm going to be doing my rocker's here soon. The biggest trick is getting all the holes and pass throughs to other areas closed off so that the foam only goes where you want it to.

I have no rust at all in my A-pillars since water couldn't get in, the car is more solid and provided a nice degree of sound-deadening as well.

hehe I can imagine. Most cars, especially ours, tend to resonate like the body of a concert bass. Probably cleared up some squeaks and rattles too.

I just read kojima's article, and I have to comment I don't agree with him that it will form a gooey mess... mine cured. Maybe he tried the latex stuff. Then again, he never really said or showed WHERE he put it.

I don't know the structural strength of the hardware store stuff, it might be worth the money to get the professional strength for stiffening, but if you just want to prevent rust, the regular (non-latex) stuff should work fine.

I just read kojima's article, and I have to comment I don't agree with him that it will form a gooey mess... mine cured. Maybe he tried the latex stuff. Then again, he never really said or showed WHERE he put it.


OK R0b, since you mentioned it... can you share with us (say or show) where did you put it? :)

Seriously guys, for us B13ers this may be extremely valuable info...

So, where do we start?
What "areas" in the chassis actually need strengthening in our cars?
Which "areas" from those do you feel are the most important?
What holes do we use for pouring?
What holes do we "close" before proceeding?
What "areas" may contain cables, tubes or whatever and need to be avoided?
What type of chassis strngthening foam did you use?

Any chance of pictures to highlight the holes/process, etc. ?

Chris

I just read kojima's article, and I have to comment I don't agree with him that it will form a gooey mess... mine cured. Maybe he tried the latex stuff. Then again, he never really said or showed WHERE he put it.


Question is did the inside actually cure. Sure the outside will cure but once that seals up and the inside does not get any air will it still cure or will it just repuddle into a gooey mess. One way to find out is to fill a milk jug. Cut the hole a little bigger up top if you want but fill it and let is sit for a couple days. Then saw it in half. See if it cured or not.

don't ever weld if you use urethane foam - burning it releases cyanide gas. not to mention the heat will probably destroy the foam's adhesion to the substrate and render it useless

http://www.splparts.com/Parts/Z32/Suspension/Bracing/default.asp scroll to bottom...

too bad they don't have a price.

OK, I did the whole car head to toe... I used masking tape to cover the large holes in small sections, like the A-pillars, area above the windshield, between the T-tops, and side sections where the triangle glass is located.
I used some roof flashing as generic dynamat on the floors, doors, inside the doors, and inside the rear panels. I filled the rear panels with foam, and even foamed the area above the rear wheel wells.... there is like a little tunnel that goes around to the very back.. I filled in all that.

I used cardboard taped up to cover the big holes, like the rear quarter panels right behind the doors. I just sprayed it in and let it cure, then added more later. I think I used 9 cans, it was alot more than I thought.

What areas to avoid?? For sure, DON'T do the tunnel area above the rear wheel well on the driver's side. Why, you may ask? Because your GAS DOOR is located there. Fill that area in, and you'll have a blast trying to fill up your car next time... just ask me how I know. I had to chisel the door open and screwed up my paint by the gas door at the same time. Another thing to look out for is the seatbelt mechanism. the front mechanism has a nice little plastic liner to protect it, but the rears are fairly well exposed, so be careful not to let it expand into your seatbelt or you'll have a mess.

I just did a little bit of this on my new NX, the "super expanding" stuff works much better. I sprayed a layer on the outside wall and rear wheel hump inside the rear quarters, I'd guess it would still take 3 cans per side to fill in that huge hole.

I just read kojima's article, and I have to comment I don't agree with him that it will form a gooey mess... mine cured. Maybe he tried the latex stuff. Then again, he never really said or showed WHERE he put it.

I don't know the structural strength of the hardware store stuff, it might be worth the money to get the professional strength for stiffening, but if you just want to prevent rust, the regular (non-latex) stuff should work fine.


I agree. I've used it to fill many pairs of rockers on many cars, and I've also cut into it to later on to find that the foam was fully cured. The foam is exposed to air the second it leaves the can, that initial contact with air is what starts the curing process, not continuous exposure to air. It makes sense when you think about it, this stuff is meant to go into nooks and crannies where there's no air circulating, so it'd be no good for that if it didn't cure in a closed area with no air.

I remember an article a while back in 'Turbo Magazine' when they installed this structural foam into project SE-RIOUS. From what I remember, they said it added alot more rigidity to the frame.

Those single part cans rely on moisture from the air to cure, they will take a damn long time to cure in a long section, I would guess more than 6 months to cure, they are all poly-urethanes and WILL give off cyanide when burnt. The single part foams also decay easier when exposed to air/ozone etc.
My vote is to use two part if possible, but Its YOUR car, you use what you want.

Mike

What I did was for noise... I'd like to know what areas need to be done for structural rigidity. If anyone can tell what is needed for that, I'd be up for a little dual-part action!

It makes sense when you think about it, this stuff is meant to go into nooks and crannies where there's no air circulating, so it'd be no good for that if it didn't cure in a closed area with no air.

It's is not advertised to fill a cavity. It is advertised to seal cracks and stuff that is exposed on both sides. As long as you don't do too big of a area I would think it would cure just fine. I do wonder about long areas like rocker panels that only get air in a couple areas. Personally, I am going to do the 2 part stuff. I called foamseal before this thread even started but they have not called me back.

Reviving a year old thread here mainly because I have three boxes of 2-part laying around and I'd like to install it soon if possible.

Has anyone done it yet?

Where is the best place to put it for chassis-stiffening on a NX?

yes, 98sr20ve did it to his s13(14?) and posted his impressions on here - just search for threads he started relating to structural foam