Hi,
This question might need to go to the bodywork forum, but it deals specifically with the bumpside and I hope someone here has an idea on how to fix it.

I am doing the body prep on a '70 Highboy. I have a little rust along the top seam of the bump on the bumpside along the outside of the bed. I noticed on a friends bumpside that there is some type of filler like DAP in that seam that is original to his truck (67). I plan to sand/grind the rust out. Once that is done I want to prep that seam.

Does anyone know what to use to fill/smooth the seam or what Ford used? Should I use a body filler like Bondo?
Thanks

 

I would'nt use bondo. Sombody at some point did that to the truck I bought, and it is chipping and cracking.....and I don't think that there is any good way to get it back out. I think that it is just a paintable body seam sealer that ford originally used...that is what I would put back in there.

 

Thanks Project

 

I've heard of people welding them up too and grinding them smooth afterward. at any rate, if you decide not to fill it, make sure you prep it well, i had mine prepped and painted at a local body shop and everywhere theres a seem on mine it is cracked and has cancer bubbles and for $5000 it should not have cracks and bubbles. i'd take it back but it started cracking and bubbling about 2 years after paint

 

Weld the seam first, then some Metal to Metal (Evercoat product) and the usual filler procedure. Bondo is a brand name, a good quality filler will work fine after it is welded. I've been using all Evercoat products the last few years, I use their Rage Gold for a filler, works great....

 

Dave, please detail your welding process. Are you welding (MIG?) the seam from the outside? I presume this works because the polyester filler cracks when the seam flexes around the internal spot-welds and the welding stabilizes things. I am trading an earlier bed for a bumpside bed, so while I may have to deal with this. Maybe I am old-fashioned, but I would think of braze-welding up the seam and then leading it in. (Don't mind me, I live in the past a lot of the time . . .) thanks

 

Mig would work fine, used the tig on mine. Before I did any welding, I thouroughly cleaned the seam and sandblasted it....

 

I actually have a TIG unit and not a MIG, so no problem.

Did you just stitch it or did you weld up the whole seam?

 

I stitched, about 1" weld, skip 2". Did the seams and the filler probably 10 years ago, still no cracks anywhere. I do use an Evercoat product called "Metal to Metal" over all my welds prior to the filler. It's an EPA legal version of the old Alumi-Lead that I used for many years. It's totally moisture proof with a catalyst for a hardener, filler is not water proof so I prefer using Metal to Metal over all my welds and bare metal.... Kitty hair (fiberglass impregnated filler) that Evercoat makes is waterproof, too.

 

Gonna have to deal with this same problem on mine and looking at it brought up a question or two: Is the back of that seam accessible from the bottom of the bed? I know it's not from in the bed itself. I wonder if you could not remove the bed, flip it over and attack the seam from the back side (There has to be a gap back there somewhere where the two pieces meet) to stop moisture from damaging it from the inside out. I'd bet money Ford did nothing to protect it. Most of these seams rust from the inside out and I can't help but think that it's from moisture leeching in from the back. Thoughts?



spots

 

Yup, with the bed upside down you can reach it. Covered mine with 3M seam sealer, then some rust inhibitor paint.

 

I have had the same problem w my '69. It seems that the junk they spray on the roads these days eats classic metal for lunch. Even ate the spiffy paint from Eastwood off of my frame. Maybe powder coating is the way to go there.

Back on the subject, I tried to fill my seems w a body sealer and the moisture seemed to push it out after the first winter. I have often wondered about welding it up and smoothing it off. I just got a '68 to redo, maybe I will do it on that one and see how it works.

 

Scott,

If moisture (+ salt) is coming through the seam I think that sealing the seam is necessary, so there are two problems: sealing and stabilizing.

I am in the process of acquiring a bed, so I do not have one to look at. I currently have a stake-bed installed on my '68, so I might have an incorrect assumption, but it would seem that the best way to seal the seam would be something like POR poured in the seam groove with the bed on its side. This would allow the POR to flow through where-ever there was a gap. If the stitch-welding was done with short stitches, the seam could be stabilized mechanically (welded) before the sealing. Then the filling could be done.

My old-fashioned approach combined with Dave's might be to do some stitches with a TIG process, then grind the welds, and finish filling the grove with solder, which would be easy with the bed on its side. (The obvious argument for polyester filler is that it can be done with the bed mounted.) (I agree that only a purist would use "lead" these days, but . . . )