Dum dum equivalent?

[dpledger]

After 4 years and 5 4x8 foot sheets of 18 gauge the metal work on my 53 is done, and time for finishing. I note that the mastic material applied in the trunk and doors and floors is referred to in the manuals as "dum dum." Seems to be somewhat different from undercoating products available today. Does anyone have a handle on a modern day equivalent, or something that would work as well?

[Kenn Evans II]

Have you looked into the rino-liner epoxy paints? They might be good for your application. Just make sure the drains are still open to drain out or you will get water damage to the interior panels. I know its not original but for preservation it works well and parts are becomming harder to locate in junkyards.

[Gordie]

I thought that you could still get dum dum.  Try the auto paint supply stores.  It is sold in rolls.

[darrin145]

Good morning - You mention "mastic". Are you looking for glue, seam sealer or a finish material?? If it's glue, there are many brands of spray or brush on adhesives available. If it's seam sealer, there is a product from 3M, #08578, which is called "strip-calk" (with no "u"). It comes in 1 foot lengths about 1/4" diameter, very easy to work with, and will fill minor gaps, etc. Also, brushable seam sealer is a good choice for areas that will be covered, as by a trunk mat. You might also try  seam sealer available in a caulking gun style tube, this can be "tooled" with a damp finger for a nice finish look and painted over when dry. I hope I didn't confuse anyone!

Gary (darrin145)

[Terry T]

I believe that the dum dum used was a damping material.  Typically on relatively flat surfaces, you want to add a material to keep the panels from "drumming".  In production, a somewhat dense material was sprayed onto the panels in a thick layer. There are several types of heavey stickey-backed materials that accomplish that same purpose. I haven't used them since I retired from the auto industry,  but I bet that 3M has some.