Foam inside wheel arches
- Dave Summers
- Posts: 179
- Joined: 9th May 2007 - 8:10pm
- Location: Culloden, Inverness
Foam inside wheel arches
I've been cutting rust out of the rear wheel arch on my 412, and the cavity is filled with some yellow foam stuff which I presume is meant to inhibit rust as well as absorb sound or vibration. I've dug it away from the immediate area (just a few mm so far) but I'm wondering how flammable it is - I don't want to find out the hard way when welding! Also if I remove a lot of it, what would folks recommend as a good rustproofer to inject into the space once the repair is done? Waxoyl is obvious but if I'm right in thinking the foam is also meant to absorb vibration, there may be something more suitable.
So far I'm on the forward part of the wheel arch, but there's another hole in the inner wing where lots more of the yellow stuff is visible.
So far I'm on the forward part of the wheel arch, but there's another hole in the inner wing where lots more of the yellow stuff is visible.
Dave
412 Variant
411 2-door saloon
412 Variant
411 2-door saloon
Re: Foam inside wheel arches
Very incredibly exceptionally flammable. Waxoyl is useless these days. You're better off with dinitrol, it has rust inhibitors in which waxoyl doesn't seem to have anymore. Sound proofing wise, use some dynamat on thr cabin side of that cavity. It will kill the noise very effectively with out the need to fill the cavity
The sultan of swing
Re: Foam inside wheel arches
Another vote for Dinitrol, waxoyl is old hat these days, rust prevention has moved on somewhat in the last 50years I've been using a lot of dinitrol recently on another project, ML(if going into existing metal with possible rust present) or 3125HS (if going into fresh metal)for cavities, aerosol with the extra long hose they sell. There are some of the treatments which claim to offer noise absorption, I think Dinitrol 4941 does. It's an underbody black treatment applied by aerosol, much easier to use than traditional treatments and leaves a nice level coating, it's what a lot of manufacturers use in the factory now on underbodies and arches etc. As for other methods, Broady is spot on with Dynamat, great stuff if a bit of a faff to apply.
- richtbiscuits
- Posts: 145
- Joined: 28th February 2015 - 11:25pm
Re: Foam inside wheel arches
I recently cut the quarter panel skin from a 411 variant. That foam extends right round the wheel arch at 2-3 inches thick. I presumed it was sound deadening but it also sticks to the metal pretty well. It's also found it in the cavities at the top of the posts next to the rear hatch at the roof line on variants. I found my rear screen heater wiring stuck fast in it! Perhaps this foam holding water next to metal is the reason the rear arches and roof gutters rot from the inside out!
'72 412 LE Variant
'73 412 LE Variant
'83 1200 Beetle
'73 412 LE Variant
'83 1200 Beetle
- 937carrera
- Posts: 1190
- Joined: 7th June 2013 - 11:54pm
- Location: North Yorkshire
Re: Foam inside wheel arches
I did a small sill repair to my 412LS. I was very careful to pull the trim and carpet away from the inside. The foam tends to smoulder rather than burst into flames,but I was very very cautious with the MIG and water on hand.
Good to see you still drop in from time to time Chino, though you have been away so long I have managed to catch up on your post count
Good to see you still drop in from time to time Chino, though you have been away so long I have managed to catch up on your post count
David
1974 412LS Variant
1973 412LE 4 door Fastback / Saloon
1974 412LS Variant
1973 412LE 4 door Fastback / Saloon
Re: Foam inside wheel arches
It’s what brought me back, I’d heard the rumours937carrera wrote: ↑1st September 2020 - 9:06pmGood to see you still drop in from time to time Chino, though you have been away so long I have managed to catch up on your post count
You never know, might find myself with another type 3 at some point.
- Aaronslimvw
- Posts: 180
- Joined: 10th August 2018 - 7:49pm
Re: Foam inside wheel arches
Roof flashing makes great soundproofing, and a damn sight cheaper than dynamat. Used it on a couple of mini projects in the past and it works a treat.
Re: Foam inside wheel arches
And me, as long as you heat it gently and use a roller.Aaronslimvw wrote: ↑4th September 2020 - 7:39pmRoof flashing makes great soundproofing, and a damn sight cheaper than dynamat. Used it on a couple of mini projects in the past and it works a treat.