Might Have Warped Rear Corner of Hood

[Driver_WT]

We were using a MIG welder to fill in the holes on the rear side of the hood where the 3100 emblem used to be. It looks like we might have warped one side the rear corner of the hood sligthly - it now is bent it about 1" in the rear corner. Is there a way to shrink the metal so that the warp comes out?

Thanks.

Wade

[MARTINSR]

Post photos, remember the reason this happened was the metal where you welded shrank! So shrinking more will cause more problems. The problem is being caused by where you welded, not where the problem is now.

Did you cool the welds when you welded? THAT is the number one problem that causes things like this. It is a MYTH that has mistakenly been made for years, I know I did it too. You do NOT cool the welds, that shrinks the metal more.

But post some photos, lets see exactly what is happening.

Brian

[Driver_WT]

Ok, thanks Brian. We are learning on the metal work so I was thinking that the metal had stretched, but shrinking makes sense. I will see if I can get a couple quick pics up today. I have to go out of town on business later this afternoon, so pics may not happen today. Essentially the rear corner of the hood has been sucked in toward the center of the truck by about 3/4 to 1 inch.

[dsraven]

a pic would really help but if there is room behind the weld you could smooth it out with a flap disc and then try the hammer on dolly routine. that will stretch the metal that has shrunk from welding. usually the welding will cause a shrinkage so it should be done in small spot welds and then planished while still hot, right after the weld is done, to help eliminate the stresses caused in the metal from the heat put into the metal while welding. there is a good little book that can explain a bunch of practical techniques to remove dents and weld panels, it's called "the key to metal bumping". at first glance it looks like a really old school book but the principles never changed so it is still relevant.
anyway, getting back to your problem, post a pic if you can, from both sides of the panel if possible, and maybe we can help you figure out what to do next. an explanation of how you welded the holes would also help possibly. did you use a backer panel on the rear, a heat sink copper plate backer, something else back there, did you simply weld around the outside of the hole like filling a donut hole in one step?

[MARTINSR]

Unfortunately, you couldn't plannish these welds as the hood inner support is right behind them.

In the future, a quick, hot weld so it penetrates properly then let it cool, then do another one a half hour later kinda cool, that's one way to get something like that done.

On the shrinking, think of it this way, the the metal gets hot and it does expand, the molecules separate and then when cooled they gather back together tighter than they were, that's how it shrinks. So you want it to cool slowly so they don't gather tighter.

Brian

[MARTINSR]

Originally Posted by Driver_WT

Ok, thanks Brian. We are learning on the metal work so I was thinking that the metal had stretched, but shrinking makes sense. I will see if I can get a couple quick pics up today. I have to go out of town on business later this afternoon, so pics may not happen today. Essentially the rear corner of the hood has been sucked in toward the center of the truck by about 3/4 to 1 inch.

You REALLY need to post photos to show right where the welds were. And we need to know if you have done anything to correct it already.

Brian

[Driver_WT]

Originally Posted by dsraven

an explanation of how you welded the holes would also help possibly. did you use a backer panel on the rear, a heat sink copper plate backer, something else back there, did you simply weld around the outside of the hole like filling a donut hole in one step?

Thanks for the help.

No backer panel and no copper heat sink, there were four holes to fill. We hit each hole with a little hit of the MIG welder, We did not fill the entire hole in one step but we were using the fill the donut hole method as you describe it, but not in one step.

[Driver_WT]

Back to Brian's questions. We did not try to cool the weld quickly with a wet rag or anything else. We have removed the hood support brace to fix some stripped threads for the hood hinges, so the support brace was not in place during welding of the holes and we could access the back of the hood. We have done nothing to try to correct the warp at this point.

If there were four holes to fill that were about one to two inches apart, are you saying we should do a little on one hole then wait for that to cool before doing anything to the next holes?

We did the same procedure on both sides of the hood, one side warped some and the other side seems ok.

[MARTINSR]

Yep, you literally can take hours doing something like that when you can't plannish it. And on those, you still can't plannish it a whole lot because of the recessed areas the holes sit in. When ever you have something that you can't control with plannishing to thin the metal in the HAZ (Heat Effected Zone) you need to keep the welding down small and allow it to cool before welding more.

That's just how I have done it for years and it works well for me. Doing those holes, I would weld half of a hole, at the rear then move to the forward most hole and do the same, then go to the other side of the hood and do the same. Then go onto something else on the truck (Goodness knows you have other things to do right?) then after they are cooled down so you can put your finger on it feeling only a little warmth, do the same thing to two spots keeping the welds apart, move to the other side, then let them cool. Come back and now those first spots are cooled completely, you can finish the weld on those then allow them to cool go get a lunch, a drink of ice water, get some other parts out to work on, something to kill some time. Then go do a few more welds, get the idea?

I have found like after putting a coat of primer or paint or something on, LEAVE, go in the house and have a cup of coffee, what ever, so you aren't starring at the parts and apply the paint or primer too fast between coats which is NO NO. So get away, relax, work on another part something to leave that set for a while.

I am working on those very same hood braces, while you were doing that, I was priming mine that just got sand blasted. Next my hood, I won't have to weld those holes up being the hood is being sectioned 2.5 inches. LOL

Brian

[Driver_WT]

Thanks Brian. Good to know. We will be welding up the center seam of the hood next to make a smooth hood, so we better know how to do that without warping the hood. Our plan is to MIG weld with silicon bronze (suggestion from a member on this forum) and weld about 1/4" to 3/8" every 12 inches, let it cool, then do another 1/4" to 3/8" weld in between the first welds, then let cool - then repeat until the hood is done.

So now that it looks like we have shrank the corner of the hood, what do we do to fix it?

Thanks.

Wade

[MARTINSR]

Originally Posted by Driver_WT

Thanks Brian. Good to know. We will be welding up the center seam of the hood next to make a smooth hood, so we better know how to do that without warping the hood. Our plan is to MIG weld with silicon bronze (suggestion from a member on this forum) and weld about 1/4" to 3/8" every 12 inches, let it cool, then do another 1/4" to 3/8" weld in between the first welds, then let cool - then repeat until the hood is done.

So now that it looks like we have shrank the corner of the hood, what do we do to fix it?

Thanks.

Wade

Post photos first.

Brian

[paulspickupparts]

Pictures would help find a solution. Hard to imagine what your hood looks like or what your problem is.

[Driver_WT]

Thanks for the replies guys. I am travelling for work until the end of the week, so I will get some pics up on Friday.

[Driver_WT]

OK guys, here are some pics of the warped corner on my hood. The pics are the rear corner of hood and the warped portion is in the black circle.

https://www.flickr.com/photos/157339...posted-public/

https://www.flickr.com/photos/157339...posted-public/

[DransportGarage]

Originally Posted by Driver_WT

OK guys, here are some pics of the warped corner on my hood. The pics are the rear corner of hood and the warped portion is in the black circle.

https://www.flickr.com/photos/157339...posted-public/

https://www.flickr.com/photos/157339...posted-public/

If it were me I'd just hammer that back out and straighten it with conventional tools -- but it does look like you put a little heat on it.

[MARTINSR]

Originally Posted by DransportGarage

If it were me I'd just hammer that back out and straighten it with conventional tools -- but it does look like you put a little heat on it.

I am thinking the same thing, plannishing what can be near the weld to thin it a bit.

Brian

[DransportGarage]

I should have added: I've done WAAAAY more damage that that with my welding skills!

[MARTINSR]

Originally Posted by DransportGarage

I should have added: I've done WAAAAY more damage that that with my welding skills!

LOLOLOLOL, when I chopped the top of my truck at 16 years old I warped the roof so bad I put TWO GALLONS of bondo (Ditzler 999) before I even touched it with sand paper, NO KIDDING! Years later using a 18" vice grip to measure, it was 1.5 inches thick at one point! LOLOLOLOL

So thankful that my mom took these photos.

Brian

[DransportGarage]

Originally Posted by MARTINSR

LOLOLOLOL, when I chopped the top of my truck at 16 years old I warped the roof so bad I put TWO GALLONS of bondo (Ditzler 999) before I even touched it with sand paper, NO KIDDING! Years later using a 18" vice grip to measure, it was 1.5 inches thick at one point! LOLOLOLOL

So thankful that my mom took these photos.

Brian

You always hear that those kinds of repairs don't hold up. How well DID it hold up? Any ill effects? (like, maybe it broke your foot when the blob of bondo fell off the car one night?)

[MARTINSR]

Originally Posted by DransportGarage

You always hear that those kinds of repairs don't hold up. How well DID it hold up? Any ill effects? (like, maybe it broke your foot when the blob of bondo fell off the car one night?)

You know what's funny Bob, it did have some very long cracks in it, not hardly noticeable unless you climbed up and looked down on it, not big cracks, kinda liked more just like the paint, could have been, I don't know.

As far as being hurt, I actually joked how I didn't want to run it in the old NSRA "Auto Cross" they use to have because I didn't want to flip the truck on a corner and have the bondo fly off and kill spectators! LOLOL

Brian

[Driver_WT]

Thanks for the info. We have never plannished anything before, so this should be interesting.

On another note, we will be welding the center seam of the hood with MIG welder and silicon bronze wire. Due to the flange on the hood seam, it will not be possible plannish each weld. Will this be ok if we go really slow and space the welds, then let it cool before the next round of welds? We are thinking of welding 1/4" to 3/8" every 12 inches, let cool for 20 minutes then do 1/4" to 3/8" welds in between the first set of welds, let cool for 20 minutes, then repeat until the hood is done.

[MARTINSR]

A 1/4" MAX on those welds.

If you do some searches here on the forum, there has been a lot of talk on that subject.

Brian

[dsraven]

I always try to spot weld the parts together along the whole length so, as they are welded, the 2 parts don'tend up warped too far apart to connect the dots. like Martin says, every foot or so. let cool well between spot welds. when actually welding do short welds and walk away between each one to ensure it is room temp before you weld again.

[dsraven]

hey Brian, love that steering wheel in the one old pic with the long hair,musta been hard on the elbows if you had to turn fast!

[MARTINSR]

Originally Posted by dsraven

hey Brian, love that steering wheel in the one old pic with the long hair,musta been hard on the elbows if you had to turn fast!

That was just during the working time on the truck. When I got it finished I had shortened the column three or four inches.

Brian