Authenticity: 356A sound deadening

[Carrera_The_Kid]

Guys,

I am trying to gain some insight in the sound deadening used on the A cars. It appears as though color and texture might have changed somewhat over the years. I'd love to see pictures of known original sound deadening. Also curious to learn if the color and texture might be different in the front compartment versus the back compartment.

Last question, are there people out there who might have some scrap pieces of original material. They do not have to be large. Just big enough to use to match patterns.

TIA,

Joris

[JTR70]

Joris,

Here are a few shots of original sound mat from a '58 coupe.

I took these so I'd remember how it overlaid if I ever decided to reproduce it.



Certainly nothing high tech. Just tar soaked paper board pressed together in various thickness. I'm thinking the highly sought-after Waffle/corrugated pattern was made during the process of bonding each layer. BTW the kick panels in this photo were better than double the thickness of the rest of sections. I've got a line on good heavy paper board so I was thinking about a 5-gallon bucket of tar with a mesh or roller type die to make my own. Not like I have enough to do already but I'd like to give it a go some day.
Justin

[Carrera_The_Kid]

HI Justin,

Thanks for posting. Wow, I never noted the thicker material on the sills. is the material really thicker or just two layers?

I have attached some pictures of original cars with clean padding. I have found that the dimples changed and might also be different on the same car engine versus luggage compartment. The other thing I have found is that some of the material has a brown hue over it. I have especially seen this on earlier cars.









I'd be curious to learn about the material you have found. I would like to find some material which is closer to original than the current available stuff.

[Carrera_The_Kid]

Forgot, would you happen to have some scrap pieces?

[JTR70]

Not thicker on the door sills

But very thick here at the rear seat pan wall.
As for the new paper board I'll have to round a piece up and see how it reacts and looks once soaked in tar. All the different pattern impressions you show just tells me it they went through different press dies or rollers but the basic material looks the same. I'll see if I can round up a loose original sample for you.
Justin

[S.J.Szabo]

Mr.Rio:

I've had occasion to study this issue up close and my conclusion was that material-wise, I would suggest you take a look at 30# roofing felt (there are other weights to consider as well). One could also layer up with roofing asphalt as the binder as well as an applied adhesive.

I believe the key technique is to apply the material warm (just short of melting out the asphalt). This is the method I used with success to re-attach a couple sections in my T1 A's engine room (including the very tricky horizontal piece between the lid hinges), but one must apply the heat judiciously. I ended up using a fan-tipped propane torch, but a pricey heat gun might work as well.

After considering the way that Rueter, et al worked, I have come to believe that these guys were not brewing up this material on their own. I think it more likely that they would have found some existing material to adapt to the purpose and long-standing roofing felt (tar paper) would fit the bill, easy-peasy.

For the early cars, the texture is the tricky part.

It is possible that the early texture may well have been a common configuration of roofing felts in post-war Europe. Certainly the smooth face on later cars looks very like contemporary felts. I think there is also a corresponding difference in the tar content of the succeeding generations (less in later).

Generally, all the T1 As I have seen use the same material throughout the body. Also, any changes in coloration are more likely attributable to deposits on the surface. I have seen that cleaning with soap and water often restores the color. My personal choice is to follow up with some semi-gloss black (that mostly soaks in) to give the material a little "skin" that is more durable and easier to clean.

My $.02 worth.

[roy mawbey]

Good comments from SJ I attach below a photo of my original factory sound deadening under the front hood.

I have never replaced this although the cut out around my chassis number was not exactly a neat job by that fitter.

I also painted the parts that show over 40 years ago so it was as DJ said easier to clean. I have often thought a coat of satin would look better than gloss.

I don't have any samples though never removed any.






Roy

[bbspdstr]

http://www.societe.com/societe/adroplast-331503300.html

This link is less understandable than when I researched the Adroplast sound deadening years ago. I have some German, no French. That was my mother's fluency.

The company existed and made sound deadening about 10 years ago.

"Back in the day" we scrapped rusted 356s. I was disposing of a completely stripped '60 B Coupe shell in the later '70s and Dick Koenig (known for Carrera articles and old-timer interviews in the 356 Registry over the years) asked if he could scrape the tar paper out that shell before it went to the crusher. He spent many days, patiently removing each section intact. Cold. By hand. I supposed it was for one of his own "show cars."

An advertiser of restoration services in the Registry, Dennis Frick, used to have rolls he had a machinist modify to reproduce a close approximation of the pattern of the original type, "waffle". I vaguely remember 60# or 90# felt roofing paper was used. That process changed dramatically over the 356 models in appearance, materials and coverage. It's been a restorer's enigma to reproduce. Enough of a detail dilemma that I want every serious 356 restoration to be a GT clone!

Bruce

[S.J.Szabo]

Right you are Mr.Baker. 90lb. felt sounds just about right; pardon my typo error.

[JTR70]

Fantastic info guys! Okay, roofing felt, noted and will be looking into that product. Beats the hell out of my original plan.
Thanks for the tip.
Justin

[Drew.s]

Hi Guys
Heavy duty roofing felt is the way to go.
I did the Con D that way.

Here was my method:
To get the desired 'dimpled' effect I used square weave wire mesh, polythene sheet, white spirit and a couple of ammo boxes filled with metal scrap.

1. Lay out some polythene sheet on the flat garage floor make a thin frame around the perimeter so you have a sort of shallow flat bath.
2. Lay your heavy duty felt on top.
3. Pour on the white spirit, just enough to get it wet, see why you made the bath as this gets pretty messy.
4. Don't smoke a cigarette as this point as is's quite combustable.
5. Lay your wire mesh over the soaked felt.
6. Lay a piece of 1/2 inch ply (or similar non flexible wood panel) over the wire mesh.
7. Find lots of heavy stuff (I used 2 large metal ammo boxes filled with all sots of old metal).
8. Place heavy stuff on top of ply wood so that there is an even pressure across the area.
9. Crack open a beer/ bottle of wine and if you need a cigarette go outside, leave for 24/48 hours.
10. Remove heavy stuff, ply wood and mesh and marvel at your concours sound deadening material.
11. Leave to dry in the sun.
12. Cut to size noting that sometimes the pattern goes in a diagonal direction.

I just used tar to attach to the body just like the factory, just head it up in a pot and brush it liberally on both surfaces and push.

A couple of things to watch out for. The tricky part is finding the wire mesh that is as close as you can get to the original pattern from memory it's about 10mm to 11mm.
And this is best done in the summer months when everything is nice and warm.

Good luck
Drew