Welds....

[thejunkman]

So i'm in the middle of replacing the floor and cab mounts on my 67. Let me start out by saying, I'm no welder, no body man, and way out of my element. I am however up for the challenge. So after picking the brains of professional body guys, hot rodders, fabricators, old timers, and anyone else I can find... there seems to be some disagreement about what type of weld is the best route for the floor. I'm talking about butt welds vs. lap welds (using a flange and punch tool, and plug welding.) Now, I don't think it's much of a contest, I think butt welding is the best, however I have no welding skills yet, and this will never be a show truck or complete resto kind of truck. So as far as ease, I think that properly done lap welds and plug welds, with a lot of properly placed seam sealer is good enough. What do you guys think? I know this is how a lot of pro body shops do it. Also, this truck will never see road salt or much weather at all as long as I own it. I know how I'm going to do it I think, but I wanted to get opinions from those who have done it on these trucks.

[sargentrs]

So as far as ease, I think that properly done lap welds and plug welds, with a lot of properly placed seam sealer is good enough.

That's what I did. Lap weld in the cab then wire brush and 2 coats Rust Encapsulator on the bottom. Then went around the bottom seam with black silicone and covered it all with 3 coats of rattle can textured bed liner on the whole bottom of the cab.

[daveford72]

Yeah I use lap on mine cus everytime I butweld I burn thru.I have replaced Good Many floorboardsand cab mounts on many of my trucks over the years.Weld or bolted them in.Yes seam seal it and put on some good protection.

[HIO Silver]

I am a butt-weld kind of guy... seal the seams with 3M brushable seam sealer. NEVER SILICONE.

[thejunkman]

Looks good Sarge! I wish I had welding skills, but I have a feeling this truck is going to give me PLENTY of practice. I'm going to lap weld the floor pans for sure, but then I'm going to try butt welding some patches I have to put in the seat pedestal area. This way I can get some experience with both.

[sargentrs]

Thanks, junkman! Fortunately the technique is more multiple tacking that actually running a weld bead. I do OK at that and can weld thicker metal fairly well but I would destroy this light gauge sheet metal. A good welder and a lot of practice and I'd get the hang of it though. I'm sure you will too!

[jimmy828]

Find you some scrap so you can get some practice before starting on truck. I also recommend a die grinder (if you have compressor) with some ro-loc sanding disc to help pretty up those welds. You Tube some welding info. Good luck on your venture.

[HIO Silver]

Just some background on handy tools. I'm sure others will chime in....

Electric grinders. Get two - a good one like a $50 DeWalt or Milwaukee and a cheaper one like a Harbor Freight ($10). Arm the good one with flap wheels and the cheap HF with cut-off wheels. The HF's bearings are cheap and don't like to be side-loaded.

• Magnets
  Hole punch
  Step drills
  Punch
  Scribe, carbide tipped
  Sharpies, black and silver
  Metal rule
  Body hammers & dollies
  C-clamps and locking pliers
  Metal brushes. Get the wooden handled ones.. the plastic ones will break.
  Aviation snips

[thejunkman]

Just some background on handy tools. I'm sure others will chime in....

Electric grinders. Get two - a good one like a $50 DeWalt or Milwaukee and a cheaper one like a Harbor Freight ($10). Arm the good one with flap wheels and the cheap HF with cut-off wheels. The HF's bearings are cheap and don't like to be side-loaded.

• Magnets
  Hole punch
  Step drills
  Punch
  Scribe, carbide tipped
  Sharpies, black and silver
  Metal rule
  Body hammers & dollies
  C-clamps and locking pliers
  Metal brushes. Get the wooden handled ones.. the plastic ones will break.
  Aviation snips

Luckily I've acquired all this over the years. Nothing worse than having to buy a whole mess of specialty tools all at once. $$$

[leo]

I'm an apprentice for Motor Vehicle Body Repair and Refinish and finished my first level of technical training a few months back. Instructor taught us to do a lap with everything except on panel edges. For example, if someone were to be welding in box side patch, they would want to but up on the wheel well flange but on the panel itself you would want to overlap approximately a 1/2". It minimizes the amount of warpage and is overall a much stronger bond given that the weld has proper penetration. Also a good idea to round the corners of a patch. Just be sure to clean the metal you'll be overlapping very thoroughly and apply a good weld-thru primer. As well as cleaning up the backside of the patch after the welding, brush on an epoxy primer to the corrosion protection and apply a high quality seam sealer to the resulting seam on the back of the patch, 3M brushable seamsealer works well from my experience. Patience is key when welding, and keep heat down, weld about a 1/2" to 1" at a time.

[thejunkman]

I ended up going with butt welds. Not because I think a lap weld is bad if done right, but more because I couldnt seem to do them right. I had no confidence in the joint. I then tried butt welds, and it seems to be what works best for me. I took (and am still taking, since I'm not yet done) tons of time cutting, prepping and fitting my panels perfectly with as good of gaps as I could get. Taking my time tacking, spreading the heat and keeping her cool. The finished product is nothing I'd brag about or post pictures for all the world to see, but I'm confident it's strong and should resist corrosion. I've heard lots of arguments both ways, and I have a buddy who is 100 times the body man I am that lap welded some panels a few years back before he could butt weld. He recently cut the welds apart to do something different and he discovered lots of corrosion in the joint. Both sides were welded and seam sealed with 3m brushable. His attention to detail is far beyond most I've seen. He said he would not lap weld on that car again. But like I said, I think in most situations lap welds are more than suitable. I just suck at them either way. But all that being said... a tip for anyone who finds themselves being a novice welder like myself doing butt welds. I work in robotics and we use the strongest rare earth magnets on the planet for our servo motors, and as it turns out, the scrap magnets make really nice clamps for butt welding. Just put the panels together and slap a magnet over the joint to hold it while you tack. Kinda tough peeling the magnets back off though haha.

[hillcountryflt]

wish I could find some good magnets.
I was looking at those clamps Eastwood sells that supposedly puts a 1/8 inch space between the pieces for good spacing.