Is this patch on the right track, or can be fixed?

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PostPosted: Thu Aug 31, 2017 10:27 pm
I have a 1996 Dodge Neon that has developed rust along the top of the door sill. I had to cut out a section, got a donor door from a salvage yard and cut out a replacement piece.

Well, I cut as best I could but nobody's perfect. There was some overlap and as a result I have a lip of about 7/100ths of an inch at the bottom and left side. Will body filler manage to cover this, or am I asking too much? If so, how far should I spread the filler from the overlap? I've done a couple of small patch repairs in the past but they've always been on flat surfaces.

How would you proceed on this? I don't mind spending some time on it for practice, but if what I'm doing is a total lost cause I can hear that too.

Here is a link to some images http://imgur.com/a/RGYEP showing what's what. Before anyone asks, I haven't finished welding by any means, I need to get some more shielding gas for the mig welder.



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PostPosted: Mon Sep 04, 2017 7:32 am
Its true none of us is perfect-----but your patch panels need to be, or at least close to it. Sorry for the bad news, but to be honest its better to have a gap than to overlap. Its possible that there could even be a problem with trim, if there is any.

I suspect you had trouble holding the patch in to get it cut right, and also trouble holding it to weld. You can get some small magnets to hold it, just don't try to weld too close to the magnets. It looks like you could probably do some grinding on the spot welds and reuse that patch after trimming, but you need to do some practice welding first.

Aviation snips are good for trimming patch panels, but make sure to use the right or left cut, not the straight cut.

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PostPosted: Mon Sep 04, 2017 8:36 am
:goodpost: :goodpost:
I agree, lightly grind the welds down and trim your patch to fit as perfect as possible.
Your welds are not penetrating properly and my guess is you have the heat too low.
Do as stated above and practice on some scrap metal pieces the same thickness as your patch panel. When the you get the welder adjusted right the whole process goes much better.
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PostPosted: Mon Sep 04, 2017 11:17 am
Looks like the door skin itself wasn't sanded clean and free of all paint before welding took place. its important for both sides of the metal to be clean and free of all contaminants before welding takes place the metal needs to be super clean on both sides of the metal before any welding.
The door panel and the patch panel on BOTH sides cant stress that enough.

Good job at not blowing holes in it or getting a bunch of weld splatter on the glass.

I am not a fan of using a Mig welder for this kind of work but it does look like you have a good handle on the idea of how to do it correctly although your beads do look a Tad on the cold side and lack good penetration a trade off seen in almost everyone's mig welded sheet metal projects I have ever seen, except a few.
Some machines are easier to control heat settings than others if you could bump the heat up a Tad bit it could help with penetration but you may blow through too so you have to juggle that.
After your done welding grind the beads down as flat as you can without grinding through them and cover both sides with Fiberglass filler. Probably the best your gonna get with Mig welding.

Your Mig welds Look better than Mine on thin sheet metal so Kudos to you!
I gave up and went to the Dark side and taught myself how to Gas weld and Tig weld sheet metal instead I am much happier with my results now.
Mig welding is good for many things welding thin sheet metal isn't one of them in MY opinion.
Dennis B.
A&P Mechanic, FCC General radio Telephone Operator
Line Maintenance A&P Mechanic and MOC Tech specialist.

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