Seam sealer or bondo?

[shawge]

Hi all,
I am working on a 1970 Challenger. Just finished the exterior body work and put down two coats of Endura Prime expoy primer. I have some questions on what to seal the seams with:
- For the exposed seams of the trunk and sail panel/rear window area, should I use seam sealer or bondo?
- Is two coats of epoxy primer enough for the seams? Should I lay down or brush on more primer before sealing the seams?

I tried attaching a picture of the area I am talking about (hope it works :o )

Thanks for any and all replies,
Jerry

[wes292]

funny thing is i have just completed a resto on a rotissorie of a 72 challenger and i will tell you from the factory they used seam sealer in these locations.the rear valance area is tricky to get looking right but i wouldn't smooth it.i have my choices of sealers but len will set you straight on what to get.

[Len]

On horizontal seams that need to be pretty, like the one between the rear window and the trunk, I'd use a Self-Leveling Seam Sealer. This type of sealer is applied out of the tube then it flows into a smooth surface ready to paint.

On seams that are located in less visible locations I recommend a good urethane sealer like the Fusor 800 or 803 pictured below. This can be applied with a caulk gun then be brushed in order to level it and push it into and over the seams.


http://autobodystore.net/Merchant2/graphics/00000001/fusor800.jpg

Seam Sealer Link (http://autobodystore.net/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=JASS)

[Darrell48]

Len,

I am confused about filling seams. I have read some articles where "lead" was used to make factory body seams dissapear. On a 56 Ford F-100 cab, this involves several seams where the roof connectes to the sides of the cab, seams where the dash hooks to the window posts, and seams where the front cowling hooks to the firewall. First, is it possible to fill these seams with a metal filling product (the metal to metal you sell) and if so, will it remain free from cracking or flaws if properly filled? Second, what preperation is necessary to get a good finish. In some of these seems, there seems to be some sort of "sealer" that was applied at the factory.

I would think there would be potential for enough flexing at these seams from the factory to be impossible to achieve good results. While they may finish nice, ultimately, I would suspect they may fail and end up with a crack in the seam if filled and finished.

Darrell

[Len]

Len,

I am confused about filling seams. I have read some articles where "lead" was used to make factory body seams dissapear. On a 56 Ford F-100 cab, this involves several seams where the roof connectes to the sides of the cab, seams where the dash hooks to the window posts, and seams where the front cowling hooks to the firewall. First, is it possible to fill these seams with a metal filling product (the metal to metal you sell) and if so, will it remain free from cracking or flaws if properly filled? Second, what preperation is necessary to get a good finish. In some of these seems, there seems to be some sort of "sealer" that was applied at the factory.

I would think there would be potential for enough flexing at these seams from the factory to be impossible to achieve good results. While they may finish nice, ultimately, I would suspect they may fail and end up with a crack in the seam if filled and finished.

Darrell

Seam Sealer is applied to seams that don't need to disappear. Seams like the trunk floor or under the car should use a "good" sealer like the Fusor 800 series product while seams that show but you want to look good can use a self-leveling seam sealer. Most of these sealers don't need any prep for primer or paint to stick to them but if they get real hard I usually scuff them with a scuff pad before coating.

In order to fill a seam and make it disappear you should make the seam so that it doesn't flex then fill and level it with filler. The type of filler to use over seams is usually one that is moisture resistant so that the filler won't blister if moisture comes through the seam and contacts the filler. Metal to Metal, All Metal or fiberglass fillers can be used to seal the seam then regular body filler used to level the surface. If the seam is unstable and flexes then any filler will tend to crack.

[55chevrolet]

Please keep in mind that the High qualify Polyester Fillers we now have was not available back when the Factory used Lead. Many Customers have ask me to use Lead thinking that it was for reasons of Quality. I answer them by asking if they also want we to use the Antiquated Paints that were put on at the time too.