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TR2/3/3A welding battery box

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sp53

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I went ahead and got the TRF battery box and what adifference. They are made just as original. Someone once suggested to get aspot welder from HF, but I think they were talking about welding the floors andsills with it. Would HF spot welder work somehow on the Battery box also?
My thoughts were to use that punch I got from HF and goaround the box and then weld in the holes. What have others done?
 
The battery box has tabs that overlap the firewall, creating lap joints. They are only accessible from one side, so a pinch welder (spot welder) won't do you much good. Punching those and plug welding the lapped joints works well and would be my choice for these welds. Consider adding a seam sealer for the joints after welding to seal up any small gaps.

Pat
 
If the shell of the car is off the frame it's easy to use the holes from drilling out the original spot welds. Just make sure the box is tight against the shell and weld in the holes starting from the center of the hole. It's unlikely you will burn through because the replacement box from TRF is a heavier gage steel than the shell of the car. No need to put any holes in the new box.
 
Steve, you're trying to get ahead of me...no fair!

A spot welder would be great, but I'm afraid they built the body at the factory from the center outward. For the battery box replacement there aren't any reasonably available spot welding arms to reach around and to the box. Plug welding is about the best you can do...
 
Yeh I kinda thought so, but why do the arms of a spot welder have to be stiff? Why not some kind of jumper cable deal with a clamp. If that works as an invention, I get a cut. Anyways I went ahead and used the complete box and did not cut the top of the box, like I did with the cheaper box. In doing so, I did have to drill out those top spot welds and will fill those from above, but on the ones I had access to I used a blunt rotary file that cut through the spot welds only and not the other side, so on the bottom and both sides I think I will weld straight down from the top with a punched out hole on the box. Like suggested the metal of the box is thicker, so this unexperienced welder will likely work the plug weld from the heavy metal back to the thin and try and not burn through. I guess if I do burn through, I can fill the hole with some putty. Oh, I have never used putty, so John you are way ahead.

Now I got thinking maybe I should turn the car over and punch or drill the car then weld to the heaver metal from underneath , or am I over thinking this. I just think the weld would be better thin to heavy metal. I mean I want the engine compartment to look nice because I plan on spending a lot of time under the hood.
 
I rolled my body shell on to it's side and welded from the bottom. It was harder to weld the plugs on the firewall but it can be done. Start the weld in the center of the hole, and then move in a circular motion. Each weld should take about 1 second and leave a nice flat weld on the bottom side without any distortion to the battery box. Make sure you remove all primer from both pieces before welding.
 
mallard said:
Start the weld in the center of the hole, and then move in a circular motion. Each weld should take about 1 second and leave a nice flat weld on the bottom side without any distortion to the battery box.
Click to expand...

I found that there is a bit of a learning curve with plug welds. Best to get pretty confident with then before actually welding the box. Practice on metal of the same gauges, tune in the feed speed, amperage and gas pressure to get those nice flat welds.
I use the mig when I have to for plug welds but prefer my ancient induction spot welder whenever possible. It's a powerful old thing and makes nice welds every time, even with the 18 inch arms I made for it.
Tom
 
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