Topic: Seam Sealers and Sound Deadeners - What worked for me

[J_Speegle]

PROJECT: Replacement or Repair of Factory Sound Deadener and Spray-on Sealer

TIME: Depends on the amount of surface and condition

SUPPLIES:

- Assorted rags for clean up
- Paint sticks and putty knife for applying and spreading
- Paint brushes 1" -4"
- Mixing bucket
- One gallon of Spectrum Sludge and activator (amount depends on the size of the task)
- Spray can or appropriate spray gun with paintable sound dead or undercoating (3M or Wurth)

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Years ago there were many good choices when it came to products for reproducing the original look and consistency of factory sound deadener and seam sealer (the sprayed on uses). Recently, choices have become limited as most products are difficult to build up as each coat dissolves the earlier ones. So many show cars have only a light coat of spray sound deadener, not very reflective of what originally was there.  During a recent restoration the shop ran across a product made for other purposes that showed promise. We purchase some and started playing with it to see if it would fit our needs.

The product is a two part water based goo (once mixed it has a consistency of peanut butter) that we could  built up to more than ¼” in thickness, dries to a fairly hard surface, but appears to remain somewhat flexible.  We quickly discovered that as usual, you need both a good product and the proper technique to produce the desired outcome.  This took a while, but once we had it down we could produce the irregular surface of the original sprayed-on product and could even get it to sag in the “curtains’ reminiscent of what we often find in the rear wheel wells of many Mustangs and Shelby’s.

NOTE: We have not tested this to see how well it holds up on a daily driven or even an occasionally driven car as of yet. Also not all plants and years used spray on seam sealer in the interior, trunk or front wheel well seams. There are other products and techniques for those applications.


Before I go further I guess I should mention the product by name. It’s referred to as “Sludge” and is produced by Spectrum.






Doing a 69 Dearborn car we found the product useful in areas where the seams were originally sprayed – producing the look of waves, splatters and heavy applications approx 4-6” wide.  These seams (on this project) included the seams found in the trunk area, interior seams, and front wheel well, at the firewall, seams.

We also used it where the factory applied spray sound deadener, in the rear wheel wells where, originally, it was typical to find heavy applications of sound deadener and overspray onto the rear frame rails while thinning at the upper surfaces of the wheel tub. We found another excellent application was reproducing or repairing the pattern of sound deadener that was applied to the inside surface of the rear quarter panels in the trunk interior.



Step 1- Once mixed the first step is to apply the Sludge to the panel. Of course you should consider what your final look will be. “Extra heavy there, a little thinner there?”  “If it’s thick to the edge of the wheel well, then I’ll need some “overspray” on the frame rail below and behind that point.”  Basically lay out a plan in your mind before you start. Not that you cannot adjust if need be, but go at it with a plan.


The plan should be formed after researching what workers did at that car’s particular plant at that time and date. Examining original cars can tell you how many passes they took with the application wand and even where they stopped and started each pass. All important if you’re going to make this  look right.


While I think of it, I should offer that too much of the product should not be mixed at one time. It normally has a pretty decent pot life but you can add additional product if you run out and it’s not fun to have a hardened lump in your mixing bucket. NOTE: The Sludge mixes up and takes on a deep purple color which changes into a dark gray/black when dry.


The makers of the produce suggest that it can be sprayed. Figured that was going to be a mess and not provide me with the control I wanted, so I relied on a more basic technique, slap it on anyway I could find.


After a while I found that a combination of paint stick and trowel would allow me to get the Sludge out of the bucket, on to the panel and get the thickness I was looking for.






Step 2-  So the material has been applied to the surfaces as planned. Next a texture must be produced in the surface to reproduce the sprayed on look. Originally the look of small peaks that fall over into the product is somewhat similar to butter cream frosting on a cake. I found that by using a brush dipped into the surface, then removed straight up, then towards my next dipping point (every ¼” or less) I could produce the look similar to the original. I did this over and over again in the direction that I wanted to reproduce the direction of travel the worker would have made with the spray wand. This is going to take some time.















Step 3- Once dry, areas can be repaired, expanded, or corrected as you see fit. Since the edges are rough and very unlike a sprayed on product, the final application, once dry, must be over coated with a good spray on sound deadener or undercoating that will dry to a firm surface and is paintable when dry.

Many will have 3M or Wurth products left from prior attempts at reproducing the original sealers, these will serve our purpose well. Simply spray over the complete surface of the Sludge application, extending the edges and continuing the overspray to the logical destinations.













Step 4- After all is dry the surfaces are ready to be over coated with primers, body color and/or black out spray, depending on year and plant practices you are imitating.

Like original – only a little cleaner

Redone wheelwell



Samples of original rear wheelwells for comparison



Has been black out by prior owner

[thefordshow]

 I've been playing around with the wurth sprayable seam sealer gun and pretty happy with the results. With some practice,..distance from the surface your spraying, air pressure, volume of material setting it can look very convincing. The down side is that the gun is not cheap and you can go through alot of tubes because of the amount of material being sprayed. The up side is is paintable and won't bleed and its a lttle flexable, so if you bump it ,it won't chip off the paint. [pic's are from my 67 shelby]

[thefordshow]

67 shelby trunk

[J_Speegle]

67 shelby trunk

Interesting - the application looks more like IMHO Dearborn application rather than San Jose at the rear bumper supports but there is a range

Looks like it would work well around the base of the rear wheel tub to floor.

Did this car originally have the panel (vertical back of the interior panels) to the wheel tub covered?? Haven't seen San Jose fastbacks (65-68) sealed there that I recall 

Had some stuff we use to use, , unfortunately he stopped making it. It did bleed a bit and would even change the tone of the paint shot over it - as the original stuff did. Was a nice IMHO by produce especially on a white car (5S431) we used it on.

[thefordshow]

Wow, pop quiz already! um,..I'm sure I've got some photographs when I first got it back in the late 70's, but something tells me the car had black rust proofing back there?  Shipped to Canada and driven in the snow [it had 60 series snows on it when I got it].    The sound deadener seem to hold up better for not bleeding , in fact I don't recall any bleeding vs the seam sealer around the tubs.    Chris

[J_Speegle]

Wow, pop quiz already! um,..I'm sure I've got some photographs when I first got it back in the late 70's, but something tells me the car had black rust proofing back there?  Shipped to Canada and driven in the snow [it had 60 series snows on it when I got it].    The sound deadener seem to hold up better for not bleeding , in fact I don't recall any bleeding vs the seam sealer around the tubs.    Chris

For bleed through I should have included I was looking for it for the sound deadener especially that applied to the inside surfaces of the quarter panel and on 69-up seam sealers at those same locations.

Would agree that the seam sealer used where you illustrated on 64-68's didn't bleed through.


Good to see you here.

[thefordshow]

Thanks for havin' me,..and if I get a little out of control, just pop a chunk of cheese in my mouth, [from the 3 stooges for some of you younger folks].   Chris

[buckeyeresto]

Great Work Jeff.   to make it easier next time this is the tool to use.  It get that oem look everyone is looking for

http://www.autobodytoolmart.com/3m-sprayable-seam-sealer-applicator-gun-08400-pc-15901-513.aspx

[J_Speegle]

Great Work Jeff.   to make it easier next time this is the tool to use.  It get that oem look everyone is looking for

http://www.autobodytoolmart.com/3m-sprayable-seam-sealer-applicator-gun-08400-pc-15901-513.aspx

Thanks - did try it and was not happy with the results as much as the more time consuming way we edged up with. Maybe with more time and playing with it.  Of course others will have different opinions and experiences 

While we're discussing the 3M product and gun. How many cartridges would it take to equal a gallon of finished product? I can see where the cost of the applicator and the product could be outside of anyone but a shop doing these sorts of restorations on a regular basis.


Unfortunately neither bleeds through like the original

Thanks for mentioning another option

Might fill a need when I need to do a set of front wheelwells - since they are much different from the other applications. Luckily this was a 69 Shelby so no need to apply sound deadener to the front wheelwells

[Skyway65]

Jeff-  How did this Sludge work out for you?  Would you use it again?  Any other problems that came up later?  Other comments...

[J_Speegle]

Jeff-  How did this Sludge work out for you?  Would you use it again?  Any other problems that came up later?  Other comments...

Been on the car for a couple of years - no cracking, peeling or coming off. Stuff is hard but seems to flex well with the temp changes.

Others have reported that they have had success at spraying the product but I've not yet tried it.

See where others have found some products they have also had success with in other post. Though I would try other new products for my uses I would not hesitate to use the Sludge again at this point

[Skyway65]

Thanks for that.  I have a small repair to make and this stuff seems like it might be perfect without having to spray it, making a mess of everything!

[69 black r code]

I used it in my trunk & wheelwells. Was very happy with the results. Was considering using for my floor pans, with a different application method of course.

[J_Speegle]

I used it in my trunk & wheelwells. Was very happy with the results. Was considering using for my floor pans, with a different application method of course.

Is your car a Mach I?

[69 black r code]

Is your car a Mach I? Yes, had sound deadner from just behind where floor shifter mounts back to about shock mount area covering floor pans , trans tunnel ect.