Technical BODY, patchin panels with a mig welder (tech)

....now for some completely unprevoked tech. nothin too complicated here, just some basic MIG welder/sheetmetal tech. i'm no Cole Foster but i don't have a TIG either .

first you cut out the bad area. make sure to get all the rust holes and very thin metal out but don't make the patch any larger than you have to. next get the patch piece cut to size (the closer the better) then get it positioned as precisely as possible. use magnets if you need to. i tack welded a thin strip of sheet metal to the patch to use as a handle when positioning. then i cut it off when it's tacked in place. the better you get the piece pisitioned the better it will turn out in the end and the less finish work will be needed.



after it is tacked in position start your way around tacking every so often, take time to let the welds cool. i blast the area with air from the compressor every 2 or 3 tacks. TAKE YOUR TIME here. i try to keep the panel cool to the touch at all times. do several patches at a time to avoid bordom and overheating. continue till it's completely welded solid. pretty, huh?



next i grind the welds carefully with a stone on the 4 1/2" angle grinder. just grind the weld NOT the sheet metal. stop before you grind it all the way down. care must also be taken when grinding so as not to overheat the panel. it's just as easy to warp the panel from grinder heat as from welding heat. once the tops are knocked off make sure you don't have any gaps. if you do tack em up now then repeat.



next i switch to the 60 grit flap wheel on the angle grinder OR an 80 grit twist-lock wheel on the die grinder (the second one is slower but easier to control). take the welds right down till they are gone, being carefull to only grind on the weld and not the sheet metal and WATCH THE HEAT. i will also use the air to cool when grinding. take your time.



it aint perfect but it'll work. VERY little filler will be needed and a few heavy coats of a high build primer would prolly do the trick by itself.

if your real anal, like me, a pass with a light grit ona DA will make it look kinda like this...



the main things to remember are:

1) good fit of patch. i like to leave about the width of the MIG wire, no more.

2) TAKE YOUR TIME welding

3) TAKE YOUR TIME grinding

4) don't let that panel get too hot

this is the inside of that same deck lid. a piece from a donor deck lid takes care of the unusual amount of rust this one had on the inside. it was a quickie/freebie job so i did'nt take as much time as i would have on a customer car or my own but you get the idea. just a little more work for the body man is all .



i used the same methods as above to build new SMOOOOTH bedrails on this late model Ford. from the factory it had some hideous plastic bedrail covers that snapped over the rail. you can see the old bed rail i cut off laying across the new smoothy bedrail. the entire inside of this bed is gettin smoothed. definately NOT a work truck .

 

well SHEEEEOOT!! guess i can't get the pics from there. i'm too damn tired to fix this tonight. if someone is able to fix it for me i appreciate it. otherwise it'll have to wait till tommarow night. sorry for the teaser ...

Mike

 

What kind of gap do you have around the patch? Also, when welding in floor pans, should you butt weld those or should you overlap the patch? I've heard it both ways on the floor plan thing, so I've never been sure which way to do it.

 

I think in areas where the joints won't be too visible, it's preferred to overlap ajoining pieces. If you can get to both sides, weld both seams. Stronger that way. That's how I'm doing my floor anyway...less flex in the floor, especially if you don't have a bead roller to add some stregth to flimsy sheet steel patches.

 

If you overlap on floor repairs, don't forget to seam-seal [top and bottom] or you'll get moisture between the two thicknesses and it'll rust again.

 

What about flanging patch panels and the structure to which the patch panel will be attached or joined?
I would think this manner would be stronger and with seam sealer applied, would probably be "waterproof".
I have a couple of spots on the lower cowl panel of the 47 that I think I will try the flanging method.

Jim

 

Flanging is probably the best route. You can pick up one of those hand-held air powered flanger/punches for cheap and they put a nice 1/2 wide step in the metal. Makes for nice tight joints. And of course, like Rocky said, use sealer wherever you have an "open" seam.

 

the problem i have found with flanging is that it doubles the thickness of the metal compared to the surrounding metal, which can make it difficult to work especially if it has a slight crown to it. i usually mark where the replacement panel is going to go, then use a cutoff wheel on a 4 1/2 inch grinder, the thickness of the cutoff wheel gives me the right amount of "gap" for mig welding, then i can grind and work with hammer and dolly.

 

RACEFAB, I just noticed your title!

pretty cool!

there is nothing sweeter than looking inside a panel and seeing nice metal finishing, you can't get that without a but weld.

on the other hand some factory lapped panel joints, after you remove a half inch of lead, look like they were put together with a sledge hammer and stick welder.

Paul

 

Racefab, that is a good point.
The places on my cowl panel are rather "flat" and are hidden with the rear of the front fenders.
In my case, structural integrity is more importnt to me than cosmetics.

Jim

 

yea paul,the title thing kinda suprised me when i saw it, i think Ryan must be playin with some features on this new board

JIMC, thats just the way i do it, i would do as mentioned by everyone else and seam seal good on a lap joint

 

Kustombuilder: I think Yahoo has changed things so you can't link to pics from outside.

 

For those of you who are making their own floor boards, like MercMan1951, Harbor Freight has a bead roller on sale for $99.00 (was $189.00). I picked one up myself.

Be sure to print out the add and bring it with you when you go to the store. (I ran into a bit of a hassle without it).

http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=34104

 

Greazer, have you used it yet? I think there was some talk on here about that one, but people were adding strength to it with gussets welded to the backside because it tended to flex.
If it works well, I may consider that one, thanks for the tip!

 

I haven't used it yet because I don't have any sheet metal thinner than 16 guage in the garage at the moment. (Says not to use anything thicker than 18 guage).

I did notice some flex when I was setting it up in my vice. Stiffening it with gussets does sound like a good plan.

I figure that for a tool that can lay beads, flanges and cut sheet metal, it's still a pretty good deal.

 

What about that weld thru primer? Would that work for when you overlap a panel or is the seam sealer the best way to go?

On the HF beadroller, my buddy has one and it works pretty good. There is a little bit of flex at the roller ends when using thicker gauge metal. He said he was planning on reinforcing the back to help it. later plmczy

 

weld thru primer is a good idea, but it still burns off around the welds,so seam seal it also.brushable hydroseal is good stuff,dunno what its called over there,its a hardware store type stuff, for gutters and wet areas,dries semi hard,kinda like tar.Weld seems to start rusting quicker than base metal,i guess coz any coating has been removed by the heat.

 

over lap bad, on outside body panels . with the double thickness it will expand and contract differently and sometimes (like on a hot sunny day) you will see the repair, even after it's finished and painted. nothin like seeing that patch panel THROUGH yer new paint job. not good.


yes i would use weld thru primer AND seam sealer on a lapped seam such as on a floor pan. as far as which way I would patch the floor it depends on where in the floor you are patching. if it is in an area that had a lap seam before the rust out i would lap it. if it is a rust out in the middle of the floor i would butt weld it. but then i'm a little anal retentive that way. just depends on how nice you want it to look under the carpet. i'm weird about stuff like that though. i actualy think to myself "what will some one think years down the road if they have this apart?". told you i was "weird".


now lets see if i can't get those pics moved to Starphoto and start all over again . DAMN YAHOO!!! ...give me a bit before ya start bustin my balls. i'm a fabricator not a computer geek ...

 

FIXED IT!!!!!

 

Sweet... cool post Mike..!!
I'm just about ready to do my floor patch panel on the Riviera...

I just got new rubber/seals installed on my doors and rear 1/4 windows...
oh yeah, and a new windshield too...guess how much all of that was..??!!



later, Snacks...

 

$20,000?????

 

well Snacky, you gonna keep me in suspense??? how much??????

 

Hahahaha..!!
sorry Mike, I haven't been online since last night...

labor to install new rubber in/around the doors,
a new windshield, new seals,
plus labor to install the windshield,
it came to just under $700 total...

I was seriously expecting it to be more than that...
very glad it wasn't though..!!!
a NEW windshield is the best thing ever..!!!
I can see driving into the sunlight now..!! woo-hoo..!!

later dude..!! ...Snacks...

 

SWEET! ....but what does any of this have to do with welding patch panels??? LOL

 

We should link this post every time some dude asks about glue/bondo/plastic/whatever for filling holes.

Your welds don't look perfect but are probably better than mine and in the end it all grinds out nicely and you have the peace of mind knowing that what's under there is all going to move around uniformly just like from the factory.

 

Great tech post kustombuilder! Already bookmarked it into my favourites for future reference. Many thanks! Regards, Dave.

 

glad you like it. now if we can get our lazy ass moderator, RYAN, to put this one in the Tech-o-matic everyone will be able to find it easily when they need it !!! and you prolly wondered why Ryan changed my title to "SCENESTER"! LOL.... we love you Ryan

 

Good post. What seems simple to youse guys is exactly what some of us need to see.

 

allways glad to help.

 

I really need to get a welder. Inspiring post!