what densitiy is best?,.. if you use the 15 lbs per cubic foot stuff isnt that going to add a significant amount of weight?

 

I simply meant that the standard home depot expanding foam is better than nothing.

I however used the structural foam made for the application/use in cars.

 

I remember that thread earlier this year about how you had the doors stuck or somthing like that. I knew that you used the proper foam as well. I suppose I was surprised that you suggested using the canned expanding foam from a DIY store. I am not arguing at all that it won't work. The piont I was making is that it shrinks over time. BTW I didn't realize how old this thread is. Also, Have you done this to any coupes? If so, what amount of improvement did it make?

 

Ok, now I'm confused. Does the proper foam shrink over time, or just the crappy foam? Even if it shrinks, is it still worth it or does it become a hindrance?

And... where would I pump it into the frame at?

 

#1 this thread is at least a couple years old, resurrected by a newbie

#2 I have never ever ever seen generic home use designed expanding foam ever shrink, and suggest that perhaps we are talking about something else.

#3 I have used generic exapnding foam to fill body cavities on dozens and dozens or cars, for sound deading purposes. These cars have seen years and years of daily driver use with no shrinking or rattling of the foam.

#4 since this thread was originally posted and replied to a couple of years back (03-01-02), I have since switched to using structural foam, for the added stiffness benifits, rather than sound deadening alone.

 

I think they men't that the crapy foam shrinks over time.

I plan to do thisn in the future, but with the proper foam..

 

I didn't mean to crap in your Cheerios . If you read what I said, I remember another thread this year where you used the structural foam in your vert. I realized at the end that this thread was brought back from the dead. I HAVE seen the crappy foam shrink before. It's in my truck right now. It has been there for about three-and-a-half years. This foam I believe wsa branded "Great Stuff" and was triple expanding home insulating foam. I don't understand why you seem to be getting so defensive. I was making a simple point, which was to make sure that people use the proper structural foam. I hate to see people get the wrong idea and go hack somthing up. BTW I am done with this thread. Back to the dead it will go.

 

http://www.sportcompactcarweb.com/pr...scc_proj300zx/

There is the article by SCC about using foamseal on their project 300ZX car. They used stuff from a company called FoamSeal. You'll have to do your own search on where to buy it. I'm trying to find it, but it is 5:30AM here and I have to get to class.

 

This is a _very_ good thread.

I am posting here so I can find it later.

 

Jason, "tofuball" I guess I can order some of this stuff and we can try it on my vert one of these nights at your garage.
Sean

 

What about tig or tac welding the frame. I've heard it mentioned in a couple SCC mags before also. J/w so any info would be great.

 

Sounds like you are talking about seam welding. Normally panels on mass produced cars are spot welded together. This is great 99% of the time because it is cost effective, quick, and should a panel have to be replaced as a whole, drilling out the spotwelds is not a huge deal.

However some (anyone's guess how much) structural rigidity can be gained by seam welding the seams where the panels that are spotwelded overlap. There are some drawbacks:

- Makes panel replacement from accident damage very hard to do if you have to replace the whole panel.
- Adds weight. A spool of welding wire is pretty heavy
- In a serious accident can change the dynamics of the structure
- Possibility of warping the panels you are trying to strengthen. Also burning through if you are inexperienced.
- Takes a LONG time.

The positives are it's cheap, does have a positive effect in rigidity, and can be fun (for the first hour..).

Really should be a new thread so people who have done seam welding can put their input in.