View Full Version : Body: Help, Caulking between rear fender screws and body

Charlie D
06-06-2016, 01:55 PM
Ladies and Gentlemen:

At last I am going back together with my '55 President State Sedan. When the rear fenders were removed a few years ago there was some sort of calking/dope under the rear fender screws. Would you please give me a recommendation for a similar product that is available these days?

Thank you,
Charlie D.

06-06-2016, 01:59 PM
Usually just ordinary "Dumb Dumb", Body "Clay" sold in strips at Automotive Paint Stores was used for a non-hardening sealer under and around Screws.

In exposed, visible seams between major parts of the body and in the Roof Drip Rail, Seam Sealer was used.
The 3Ms modern Seam Sealer product is much better as it does not harden like a rock as the original did.

06-06-2016, 02:21 PM
I would recommend 3M 08578 strip caulk. The only difference between it and the original is that the original had a thread through the center to make it easier and more uniform to apply.


Also use this on the front edge of the rear fenders, where they join the "B" post.

06-06-2016, 02:36 PM
I used 3M seam sealer in a caulk gun style tube. The strip caulk would work fine as well. I went with the stuff in a tube because I already had it from when I applied the new seam sealer to all the "joints" in the body tub.


06-06-2016, 07:27 PM
I would also use the tube seam sealer but stay away from the two part epoxies. They are better but would make it a bear to ever remove down the road if you need to.

Charlie D
06-07-2016, 01:15 AM
I appreciate the suggestions. Any would work. I was doing some research tonight and found that butyl seal tape is used a lot for RVs, boat windows, etc. One of the sizes it comes in is 1/8”x ¾”x30’. It seems like I could cut 1 ½ inch or so pieces and apply them over the holes on the body and as I tighten the screws it would squish down to form a seal. Any excess squished material could be trimmed. The reviewers say it never hardens which appeals to me.

Thank you,
Charlie D.

Warren Webb
06-07-2016, 02:37 AM
Charlie, since Studebaker assembled the rear fenders while they were in untreated, bare metal, I would recommend painting those rusted areas with POR15 or even just a rust converter primer followed by any color from a rattle can. Then apply the sealer, install the fender & wipe away the excess sealer. I did this very thing recently on the 62 Cruiser's r/r fender. I preferred not to use the "dum-dum" or strip caulk due to my experience with paint not adhering that well to it. If you do use the butyl tape you mentioned then if you ever need to remove that part, good luck with that! You'll have to cut it off just like a glass company has to cut out windshields that are bonded to the body with the same material.