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it's finally time to get some paint on the mule. when the guy at the body shop noticed the cracked caulk in the seams he said it would look good if just dug all the caulk out and left it out. i'm considering it but don't know what i will look like. any opinions or pics ( if anyone else has done this ) would be appreciated
I would recommend replacing the seam sealant, these have improved in 40 yrs. They way these trucks are assembled at the factory you need some type of sealant to make them not leak. All of the joints I have found on my 68 are spot welds. Some uses have welded the seams up. Others used body filler. Some did both. Weld to keep the joint from moving, body filler to smooth it out. To each his own, its your decision.
I would use some type of seam sealer or weld the seams up. If you leave the ones on the side of the bed open it is a good place to catch dust and it will eventually rust out. Welding them up is time consuming but gives a good look. Don't just slap body filler in the seams it will crack out.
The first time I painted my truck I ground out all the caulk and did not replace it - BIG MISTAKE!!! It lasted one winter (I live in Nebraska) and the paint started to buble due to rust. I had to take off my box and redo it. Todays caulking is much better and much more flexible so you wont have the cracking that the old stuff did. When you do this, I would suggest you take off your box - Turn it over and seal the bottom side of the seam on your box (Inside your wheel well) This is where the problems always start on these trucks. You can use the same sealer on the under side that you do on the outside. I sealed mine then sprayed a lot of rubber undercoating along the seam and underside of the box. You probably wont have the same problems with rust in NC as we do in Nebraska. If you want to know what I used e-mail me and I will send you the brand and part number.
Not to hijack this thread but I am within weeks of starting on my bed. Can the seems be cleaned and braised? I know that braising was used in the manufacturing process. Are the bed seems too wide or long for this method of filling to be used?
You put than much heat, it will warp on you. You can mig weld the seams, but you must jump around, and no longer that 1" at a time to keep the heat down. The processed used in assembly of most beds are spot welds. I know of no place that used brazing on body panels. In the early days body panels were filled with solder (before bondo) , which is < 500F. Brazing is ~1600F. Then the seams were sealed with sealer. Sealers to day are a lot better than they were 40 yrs ago. I would just chip the old sealer out and reseal them.
My understanding is probably incorrect but I have always associated Lead with soldier and Brass with brazing. I have seen the brass in the seems on several cars being media blasted. Even our Bumpside truck roofs have brass in rear corners above the rear pillar seam. Besides, isn't brazing done with less heat than welding?
Brazing heats up a larger area than welding, due to heat transfer properties of steel. A Oxy/Ace torch is ~6000, where an electric arc is ~10,000F. Steel melts in the ~2400F, brazing is ~1600F. A wire feed welder actually will have a smaller heat effect zone than brazing. Since brazing uses a torch, you end up heating a larger area that with a mig welder. Now there are some new process that use electric current to heat up the zone being brazed which is more locallized and better heat control than a torch. In this case brazing has a smaller heated area. Anytime you heat up steel past 550F you start changing its properties. Brazing will actually soften the metal around it. Where welding has a smaller heat effected zone do to the speed and time you stay in one spot. A weld is actually stronger than a braze. If the brazing joint is design properly it will be stronger than the base metal. A tig torch gives you the greatest amount of heat control and a better weld quality. But like mig if you stay to long in one spot you will get warpage.
i guess i was so up in the air of what to do i just left clean. no weld no seam sealer. i was concerned it would look like this again after a few years
so i left clean and painted. now im second guessing i used rust mort it was primed for about 3 years and thats not rust its just the pitting showing through and the was the paint laid down. you jave to get up close to see this as this is a close up picture. stand back it looks fine
