Learned the hard way on this deal now to try and fix?i have a jaw type shrinker but don't know if it will fit on the top edge that's now wavy and have no clue as to how and fix the middle of hood that has caved in?! I read about using a shrinking disc but I really don't no where to start or if I should try and replace any tricks would be appreciated!
Are those two beads of weld running the center of the hood? If so its already shrunk. You'll need to stretch hammer-on-dolly to get it back. Watch hitting the welds, if mig they may crack. I recently welded in a giant hole cut for an air cleaner, it took a lot of stretching to get it back in usable condition.
Yeah welded the center strip molding shut.so from behind hammer it back out t? That it huh? Thanks for your reply
well, not quite, you need to stretch the shrunken metal by "pinching" it between your dolly and hammer. You will still need to be very carefull not to overstretch it either. You may get some 'oil canning' in the process as well. This is NOT an easy task on large low crown panels.
Ugh I knew it took skills I didn't have but my bad! So do I start at the edge of sunken spot and work in or work out from center? An old body guy told me to press as hard as I could with dolly to shrink and hit lose to stretch? Thank you for your help
This is a pretty tricky operation, and a beginner might not get it right, just to warn you! The problem is not the sheet metal on the hood, it is the weld seam, THAT is what's shrunk. To correct the problem you need to stretch the weld seam. If you screw around with the sheet metal around it, it will be disastrous. Hopefully, your MIG welds are sound and strong, if not they will crack, as oldrelics said. Grind down the welds until they are almost flush...I usually go down around 80% or more of being perfect. I leave a little "meat" on the weld, just to be sure it doesn't crack, due to being too thin (with MIG welds) Use a a dolly that will be the same contour as the metal should be when finished. Hold it up to the weld firmly, and hit the weld with a flat body hammer, being sure to hit the dolly directly, this is called On-dolly work. You should hear a distinct loud ring. If you don't hit the dolly, you'll distort the area around the problem making it worse. OK, make a hit about every half inch on the entire seam. Go back and survey what you've done, seeing where it need more work. It IS hard to judge, with little experience. After the first p***, I'd do it once more,, though, as MIG welds are pretty hard and difficult to work. After 2 p***es, it should look better. You might be able to judge if it needs any localized attention, but again, it is hard to see that. You might just go over it again, with a lighter touch and see the results. Depending on how much heat you put into the panel during welding, and how flat your panel is, how hard you hammer, you might have a little, or a lot of hammering to do. Most times this is done by correcting each tack weld, and hammering and dollying each seam segment. This way you can see if the the seam you just did is brought back to where it should be. Doing a whole lot confuses where the most damage is. Easier to weld and correct each part rather than tackling a whole seam, though pros can do this. It is also easier to use a TIG or gas weld for this, as they are softer welds, that will stretch and work much easier than a MIG weld. Good luck..you're gong to need it!
Thank you for your detailed instructions ! I'll give it a honest try and we'll see? I don't know if it matters but the welds you see are not from cuts, the hood had a recess there for trim with holes up the lenght . I cut a small strip of 16 ga. And **** welded it too the sides of the recess. So the original skin is underneath it. Maybe hard to coax back out **** I'll see what I can do! I really appreciate you guys helping it's the reason I love this site! Thanks again
Just to add a bit to chopolds statement, make sure that BOTH sides of your mig welds are cleaned up and at about 80%. Failure to take the lump or stick through wire off the backside of the weld will result in tons of tears and tool throwing... Trust me, it was part of my learning curve. The next time you do a long low crown panel like this, as chopolds said, tack, grind the tacks, hammer the tacks, then proceed with more tacks. It's maddingly slow, but it's about the only way to get a warp free weld on a long panel - ANY long, low crown panel. You can do this!
Maddingly slow , ha ha I like that. I'm sure that if one were to look at the entire job from start to finish that its actually a lot quicker that way VS welding it up and then trying to get it back into shape. It takes a good few smacks on the tacks to bring them back but they move so much easier than a solid weld. For some perspective- Just figure a plainishing hammer hits at 3000 smacks per min. It takes a few mins maybe 5 to planish a foot of weld. 15,000 hammer swings will toughen you up and really try your patience and there's no way you'll get 3000 of them in a min. You'll be doing well if you can average 150 a min holding the dolly on the other side and that's a few hours worth. It might even be faster to cut it loose, hammer and bump it back into shape and start with the tack hammer tack process. Leaving the welds 20% proud of the metal really helps too, it concentrates the stretch and gives you some metal that much easier to push Back into the shrinkage.
I think you have too much going on with the patched area for it to work to get it straightened out. The patch needs to be **** welded without anything in behind so that you can hammer the seam. Also your patch is to heavy. Find something around 20 gauge. Option one. Cut out the welded area and start over. Get the hood to lay right and then spot weld the patch in and hammer the spots as you go. Option two. Grab the body filler. Not the best option. Option three. Punt. Find someone to give you some help with this. The repairs to low crown areas are tough. DESCLAIMER: I have no training in working with sheetmetal, just a hack with a big hammer. Neal
If I've read your description correctly of what you've done to the hood, you have added a filler strip over top of the stock hood recess. That means you won't have proper access to the backside of the weld. You will not be able to hammer stretch the weld unless you can fully back the hammer hit with a dolly. I suspect anything you do at this point is going to make the problem worse.
I cut a small strip of 16 ga. And **** welded it too the sides of the recess. So the original skin is underneath it. Missed that one point ^^^. Hammering probably won't help much. I'd say you have J'sts option 1 to do this right, and might need option 3 to pull that off. Then that's why they make option 2 but this has limits
Yup, you ruined that hood. Welding sheetmetal overlapping is a sure way to guarantee Bondo stock to go up. Scribe a line about a half inch outside each weld and carefully cut your double thickness mess out of there. Gently push the two floppy sides up to their correct position, and make a new patch to **** weld into that gap. Make sure when you weld that you are holding the floppy sides in the place they need to be. If they are sunk down or standing up too much when you weld your patch, it will be worse when you are done. Welding this should be done slowly with short 1/2 inch welds, AFTER you have gotten the patch tacked in the full length of the hood. When it's tacked, it should have a good shape. Don't think you will be able to reshape it much after welding. Very hard for a beginner. After complete welding, carefully grind the welds flat and tap it to shape like described by the previous posters. I noticed you had an "expert" tell you that hitting hard on-dolly will shrink and loose will stretch. That's not true. Any time you smack the metal between two hard objects, it will stretch it. If you want to shrink or move the high spot to another location, you will need to hit off-dolly.
Yes, you added the part of welding right over the factory recess later...you can't possibly hammer and dolly that area back into shape with it like that. Ovelapping a joint and welding it would also be difficult or impossible. You have to cut that area out and start over...Jerseymike had a nice how-to on putting a peak on his Ford's hood. He bead rolled a peak with a custom roller (though you could use a peak off another hood, or similar) on a strip of metal, and then cut out the center of his hood and welded the piece in iwth the peak. Nice step by step job. In fact I am asking him to do one for me, to weld in my 46 Chevy!
I too missed the overlapped peak section. I have been wondering the last day or so about the possibility of cutting the original out from the inside just inside the weld line and working the metal from there. It would probably be far easier to cut the whole mess back out and do it correctly, but I might be inclined to try this first. The thing your going to find is, the second you cut the welded section out if you do chose to do it the right way, the metal itself will relax quite a bit back to it's natural shape. It's actually kind of amazing how much weld does shrink something as strong as steel.
Oh man, I wish I had a dollar for every time someone came to me with a hood that was screwed up by welding the seem. Like said above anytime there is multiple layers of metal + welding = disaster and really the only hope is to cut it all out and **** weld in new metal. Even with 30+ years experiance it's a tough job and very time consuming so most time I recommend finding another hood. Unless they are rare and expensive it's often cheaper if you're hiring the job out to start over. Years ago I had a guy bring me a hood like yours, all warped for welding the seam. I told him it wasn't worth fixing and to find a clean hood to start over, I'd fill the seam for $400. I even found him a good hood for $200 so He'd have $600 in a good filled hood. He didn't want to buy another hood so he took it to another shop that said they could fix the old one, imagine his surprise when he was presented a $1200 repair bill on his hood!
You guys are awesome! I only wish I would have read this first! I guess iam guilty of leaping before I look but iam just tryn to learn and well I got lucky before a couple times and I deserve this I guess. It actually seems easier to cut the center strip and re weld a new piece than to hammer out! Sounds like a great plan and the info is invaluable thanks for giving away your hard earned secrets! I bought a new hood too just in case and well if I can't fix old one I'll know how to try again thanks for your time. And just cause I want you guys to know iam tryn hard here's a picture of my project. I did all the work myself with **** homeowner tools and the hamb as my guide! Before you rip me a new one remember we all start somewhere ! Thanks again
Why cant he turn the hood over and use a cutoff wheel to remove the recess, then hammer and dolly the welds?
Most of the time one learns by making mistakes! I did this exact same thing to a hood, Big hood scoop helped cover up the mistake. I would try what Mark T suggested, you can't hurt it much now by cutting the back side off. I'd give it a quick try, but most likely you will have to cut the whole welded area out and put in a patch the right way.
It would probably work if the seam was gas, or TIGed, but the combination of the hard MIG weld, and the difficulty in getting the underside ground down very close without any extra metal hanging around (hammering it flat would add extra material to the area, making it warp-y) would also be a difficult task for a beginner. If his tolerance for bondo thickness isn't fussy, he could probably save it. I just like not having too much thickness of bondo anywhere, but esp. on a hood, where heat and vibration are the worst.
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