There is nothing wrong with the plastic fillers except when they are used as a band-aid to cover poor work, I use filler myself. If you need more than 1/4" thick, you haven't finished the metal work IMHO. The other problem is that warpage can bow a panel out as well as in, and you need to know how to deal with that occurance or better still how to prevent it in the first place.

 

I don't think its the heat thats the proble but the cooling! It shrinks as it cools. Anyway adding some pics of my panel weld job to my gallery. Keep in mind this is my first time - ever. I'm thinking of just going out and buying full quaters, little bummed out on how it turned out but than again I have nothing to compare to. have a look at tell me what you think.

thanks.

 

It's pretty hard to judge from the pics, but it doesn't look too bad, especially for your first attempt at this. You still have some hammer and dolly work to do.

You might have started with a more aggressive grinding wheel. The wheel shown is for getting the scratches out after grinding, so if that is what you are using you might be doing extra work.

It takes patience. Are you saying that the panels are warped?

 

boss-

Overall, the job looks pretty good. The pics don't show evidence of the warping you are talking about. You are right about the shrinkage from cooling. That's why you hammer "on dolly" to stretch the tack weld to compensate for the local shrinkage and shape the panel back to contour.

From one of the two closeup pics, it looks like you used tack welds and ran them end-to-end (like a zipper) to weld that seam. From the other pic, it wasn't as obvious and looked like you used tacks, but some were added after the others unlike a zipper. The second method would be preferred.

if you do a running weld in sheet metal, the heat (and the attendant shrinkage) is high, very concentrated and soaks the panel farther out from the weld seam edge. This requires a lot more hand work to save the shape.

Usually, the seam is partially tacked by skipping around to spread out the heat, then cooled (by compressed or ambient air - or even a wet rag), then the welds are hammered flatter to regain the panel shape. Then another round of tacks...etc. The slower and more carefully you go, the less shrinkage and hand work.

The last pic of the finished ground welded panel looks great. In fact, the whole job looks better than anything I did early. I have redone a couple of those areas on my truck because I got better with practice. So will you.

Are you always this hard on yourself? Inquiring minds want to know...

 

Just a question for the group - please do not think I am criticizing your work. The pictures show that the panel was cut square with a long welded seam just below a body line.

My question is if it would not be better to have cut a circle out over the wheel opening, still replacing the rusted metal, but without a straight seam to catch your eye?

Of course, with perfect body work it would make no difference, but it does seem to me that a circle would be more forgiving (less noticeable) if the bodywork is less than perfect.

 

I agree wit Bdox and Randy, first the flap disk is the right tool for grinding the welds but you want a 40 - 60 grit one, too fine a grit will heat up the metal too much. Be careful when grinding that you are only grinding the weld bead, NOT the panel on each side and be careful not to heat up the panel, you can do more warping with the grinder than the welder! If you can't lay your bare hand on the panel right after grinding it's getting too hot! When welding in a patch your tacks should be no closer than 12" to the one before it unless the panel has completely cooled. Skip around the panel tacking every 12", allow it to cool then do a tack centered between each of the previous ones. Allow to cool then do a tack between two others but no closer than 12" from each other, allow to cool completely between each go round. repeat until you have a solid weld all around. No it won't look pretty (you're going to grind it anyhow so who cares) and will take a while (but a lot less time than fixing the heavy warpage you'll get from rushing), but you'll have a lot less warpage. If you are doing both sides, alternate sides as well between tacks. Like you said the warpage (shrinkage) happens during cooling, so allow to air cool naturally don't force cool it and don't get any area hotter than absolutely necessary. You need a couple of straightedges of different lengths and/or contour gauge or accurate templates for curved areas to determine exactly how much warpage you actually have and where. Check both across the weld seam and on either side of it, as well as across the entire panel. When checking across the weld, the weld is likely going to be low due to heat shrinkage and will require stretching by light hammering "on dolly" where the dolly is pushed HARD against the panel directly behind the seam and the weld hammered directly over the dolly. There should be a ringing to each hammer tap. Go easy and slow, working evenly along the seam. DON'T hammer like you are driving nails!!! (putting your index finger along the back of the handle pointed at the head will reduce the tendency to hit too hard and will increase your control) Check your progress with your straightedge and/or contour gauge after each run down the seam until the seam is nearly at or at the proper height when checked across the seam. If in checking parallel to the seam you have some areas that are low and some that are high compared to where they should be, you can work "Off dolly", where the dolly is pushed HARD behind a low area while you TAP down the adjacent high area. Here you do NOT want to stretch the metal so you do not want to trap the metal between the dolly and hammer face. The hammer taps in "off dolly" work should produce a dull thud sound NOT a sharp ring. Using a plastic faced hammer rather than a steel faced one will help reduce the risk of stretching when doing off dolly work and the lighter hammer will reduce the tendency to hammer too hard. Remember to always be pushing HARD with the dolly, not just resting it against the panel, the dolly does as much/more of the work than the hammer in body work. It often requires the use of a "spoon" dolly to get in behind braces and into tight places. A spoon dolly looks like a slightly to heavily curved heavy steel spatula. You want to do all hammer and dolly work as needed until the entire repaired area is at or no more than 1/4" below the finished contour when checked in all directions. Then (and ONLY then) is it time to break out the filler.

 

*****, yes a curved seam is more desirable whenever possible, taking into account also where you can get a dolly behind the seam. A curve is a shorter distance than a square corner so you will have a shorter weld seam to deal with as well. Unfortunately when dealing with body rot it is usually the entire lower edge that needs replacing, so a curved seam is not always possible.

 

Agreed, but I'd say anymore than a 1/16th of an inch is too much, unless you get in an area you can't beat on and don't have the tools to pull it out.

 

Thanks Randy, I did bounce all over the place with the welds - never more than 1/2 inch at a time and that was after I did 100 or tack welds, basically I just joined the many tack welds togeather, kind of a game of connecting the dots.

I think I should have done the horizontal first than move into the verticals, I think I would have had less warp, The warps are a serious of small waves, nothing fill wouldn't fix. But still not as good as a complete panel replacement, but I can always do that later.

I was thinking of using a tourch to heat up some areas than beat it flat, but I'll have to try that on scrap first so i can get the feel of it.

This thread has been a big help and the more I learn on how to improve on things the more I feel about giving the left side a try. I was just going to order a full replacement panel after doing the right side, but I would like to see if I can do better.

I guess those shows like american hot rod leave out a few steps, you see them welding and than grinding and its perfect!

Thanks All.

 

Don't even try this! It's a sure recipe for disaster, the last thing you need to do is add more heat! Repeat this 1000 times: Heat is the enemy of body work, I shall avoid it if at all possible...

If you are the type that has to have everything proven, take a nice flat piece of sheet metal, say about 24 ga 3'x3'. Heat it up with a torch, hammer it, jump on it, beat it with a roll of quarters in an old sock, or just let it cool. Doesn't matter what you do that piece of metal is going to end up with more warps than a potato chip. Yes, a torch can be used to shrink stretched metal, but it will NEVER EVER make it flat.

 

WiilyB. Thanks for the validation, my friend. HSS and the other steels are a ***** to work with. They don't even hammer well for hammer/dolly work. Today's vehicles call for cutout and replace rather than fix and repair. I'm a welder from a long time ago and I learned from guys who worked on Auburn's, Cord's and Dusenberg's and others that did did heli-arc on shot up F-4 Phantom's in Viet Nam
But the days of hammering and welding all of the patch panels for trucks are slipping away unless you are building your own panels from sheets of known steel composition.
Having said all that, I've also met guys who can bond anything to anything with adhesives. So, maybe the day is already here where brackets and braces are welded and body panels are glued and never the two shall meet.

 

LOL good to know ... heat is the enemy!

 

1/16th on an inch! Ouch, yeah thats the way I would like it, but I don't see that happening with this panel. Perhaps gluing them on is the better way with this newer crap, that way i'm only filling to the thickness of that patch.

I'm going to have to find some older tin to hammer on cause this weltal in my bronco doesn't seem to respond well to hammering - kind of springy.

I've ordered that sheet metal video that was recomended.

 

The suggested way is to fit the two panels together just like you were going to butt weld them. You then add a 2" strip of metal behind the joint, and glue each panel to it.

You use screws or rivets to hold the panels in place while the glue is drying. Once dry you grind the heads off the screws. Where needed you can also us countersunk rivets and leave them in place - just fill over them.

I have both an air operated and a hand flange making tool that bends a lip on one panel such that it slides behind the second. I have never used flanges for any joint, but will be trying that when the time comes.

 

It does seem to me that glue would have the advantage of providing some rust protection on the inside of inaccessable panels. The entire operation could be done cold, sawing out the patch area, gluing in the patch.