Patch Panel Question

[glovemeister]

I have been doing some work with patch panels. Thus far I have made sure my welder is setup for 1 thickness more than what I am welding. I've been doing a tack every few inches, planishing as it cools. Then letting it sit for a few minutes, grinding tack down and coming back, and hitting it again 1/2 distance between tacks.

At the stage when the tacks are approximately 1/2 to 1/4 of an inch apart. Should I stitch weld from the top/edge of one tack to the next tack, to ensure good penetration and no pinholes? Or simply keep tacking until the entire thing is taken care of? Thus far haven't warped/distorted a panel very much yet, knock on wood haha.

[glovemeister]

 Kept up my tacking and planishing routine until I had the tacks 1/8 or so apart. I then decided to stitch weld from 1/2 of first tack, over second to start of flat. I think this may be the best routine as it ensures good penetration and I think the risk of warping will be minimal. We shall see.

[734406pk]

Basically a series of connecting tack welds. Hammer straight and keep going. Are you using the butt weld method with a spacer or the flange method? In either case, contolling warpage in these thin sections is key. My best advice is to go slow and let the panel cool before continuing. Use the hammer frequently to keep the panel in shape. It is easy to overun with welding, but after it's a problem to straighten out.

[Finoke]

Basically a series of connecting tack welds. Hammer straight and keep going. Are you using the butt weld method with a spacer or the flange method? In either case, contolling warpage in these thin sections is key. My best advice is to go slow and let the panel cool before continuing. Use the hammer frequently to keep the panel in shape. It is easy to overun with welding, but after it's a problem to straighten out.

Well said and Good advice. 

Any personal preference between butt weld and flanged technique?

[glovemeister]

Well said and Good advice. 

Any personal preference between butt weld and flanged technique?

Appreciate the advice everyone. When I fire up a patch panel it takes me hours to get it done. I supposed a little long, but I've got time and can jump between 2-3 at once. It is so much easier to avoid warping than to fix it later.

My concern with the million tacks method. It seems like it gets good penetration, but the welds are more uniform, less pinholes etc. if I use my stitch method for 1/4 of an inch, encompassing the tacks. 

The only patch panels I will do is a butt weld, if that was a question to me. In the event, the seam is a factory part with a lap or flanged joint then I will use weld through primer and replicate that.

[734406pk]

Well said and Good advice. 

Any personal preference between butt weld and flanged technique?

I find the patch area comes out better with the butt weld spacer technique, but you need to have easy access to the weld area or burn through happens. If I'm welding in an area with limited visibly etc. I would use the flange meathod. It's more forgiving on burn through. A copper backing bar is very helpful.