View Full Version : Door Patch Panel Warpage Problems
BRENT in 10-uh-C
12-21-2003, 06:44 AM
I recently put a patch panel on a Model A Ford front door and even though I applied some "english" to the panel by forcing a socket between the inner structure and the panel, when I flanged the existing door skin, it flattened the door skin panel taking out the original contour. The socket actually pushed the skin outward beyond it's original location, then the patch was Cleco-ed and tacked with it pushed out, yet when all was said and done, the outer skin is low in that area by probably 1/2"!! Since the backside still has the inner panel on it, can anyone give me some suggestions on how I can raise the skin?
If you want to look at the whole skinning process from start to end, you can look at the pictures. Maybe you can see what I did wrong... www.metalmeet.com/photopost/showgallery.php?cat=3166&ppuser=739
12-21-2003, 08:24 AM
Good morning Brent,You are getting an education on one of the harder things to learn in panel work.You are having problems probably in several areas. First if you are installing an aftermarket repair panel in the bottom of your door , the panel is only somewhat close to the original panel.Usually they have the detail areas close to the original panel but the flat area usually does not have any compund shape in it and does not have any strength so it will move or bend all the way to the lower bead which does have strength.In order to use this panel without a large amount of filler you would have to put shape in the flat area your self or have someone who knows how do it for you. You can do this with a sand bag and hammer or slapper and dolly,english wheel or air hammer etc. You have to create a stretch on the surface of the panel so that it will have a low crown equal to the panel you are replacing.
The next thing you will have to do is learn to properly weld the two panels together with the equipment you have. You do a but type joint with nice fitup and then tack panel every inch with very small tack.You then hammer and dolly the tacks to stretch them as everytime you weld anything the blue area of the weld known as the heat affected zone (HAZ) will shrink.This is your other main problem on your weld joint. The weld joint has shrunk so badly that it is very hard to restretch it back to its original state. After you have your tacks all stretched back to original you can now start your finish weld. If you are using an acetalene torch or a tig torch you can start welding on one end and weld all of the way to the other end. If you have limited experience you will do short welds and hammer and dolly them to restretch them as you go and things wont get out of control. If you are welding with a mig welder you have to go a lot slower. You can only put a tack weld dot about every five inches and can not add another untill it is cool enough to put your hand on that area and not burn it. You also hammer and dolly each tack as you go to restretch it. You can also grind down the tacks as the weld bead gets going as that gives a larger area for a heat sink and heavier shrinking.You have to use tack welds only untill you are completely done or you will overshrink the area and have a hard time restretching that weld area.
The panel that you put in your door can be saved by a lot of hammer and dolly work on the weld bead first untill you get it stretched back and then doing a controlled hammer and dolly stretch on the flat area of the panel to put a low crown shape in it. If you do this and stay with it you will learn a lot but it will not be easy and will go slowly. Dutch
12-21-2003, 12:16 PM
IMHO it would be easier to cut the patch panel back off and start over (been there, done that also). You'll probably get different opinions on whether to flange or butt the panels. I like to flange when I don't have access to the back of the panel, but flange or joggle the repair panel only. A joggle can distort your panel depending on the crown. Now you can reshape the patch to fit the repair area. When dealing with a doorskin of similar, make sure your panels naturally fit together (ie without any fasteners). Don't rely on fasteners and welding to shape your panel. All aftermarket panels I've ever used require reshaping. Your panel prabably lacked the crown required to mate to the doorskin correctly.
Practice on srap first. Try joining using a joggle and butt welding. Make contour gages to see exactly how the panel is distorting and how to correct.
12-21-2003, 01:10 PM
---Brent, I have been refurbishing some doors for a 1921 Overland. I have had to fabricate the inner structure and add the lower section of the outer skin. If you notice I don't like to flange the door skin. I like to butt weld the door skin and make access to the back side for metal finishing.
12-21-2003, 01:36 PM
I always say, if I ask ten people for their opinion I'll get twenty answers, each a valid point. I'll throw in my two answers for your consideration. Laying the door on a stand as you have is the best way to do the repair. Heat rises, so when the panel is laying down the heat is rising away from the surrounding metal. First, after checking all my patch panels for fit and indexing, reshaping as necessary I would have welded in the inner panel last. I used to lap weld patches, however I butt weld them now. much easier to control the metal. After tack welding the outer panel with mig or torch, with just enough tacks to keep everthing in place I would start welding with the torch. The bottom of the door would be left open for access to the weld with a dolly for correcting warpage as I go. Being right handed I would start on the right side of the panel and go left. With just enough heat to complete the weld, no more than nessasary. If you have to pull the torch away to stop blowing holes you have too much heat. As I weld across the panel I like the metal to rise up, if it sinks I stop and dolly the area and go back at it until it is fully welded. DO NOT at anytime cool with water. Let it cool on its own. Most of the time the shrinkage of the weld will bring the panel back to proper shape. Then finish the repair as you like, planish and metal finish, skim coat of filler, whatever.
Don't forget to weld in the inner panel, you will know when to put it in depending on you finishing method.
Now option two. Not everyone can afford to pay for Rolls Royce quality and you are the one to judge the needs of the job. Use a weld on stud puller to raise low areas to the point where only one eighth of an inch or less of filler is required and finish her off.
The more you practise top quality work the easier and quicker it becomes. However, if you look carefully at magazine articles on rod and custom build ups, you will see most of the high dollar cars are finished with a skin of filler too. Some have lots of highbuild primmer.
My first model A was a 28 AR roadster, back in 1959. I had a very early AR with open end bumpers many years ago, but my friend needed more parts to complete his roadster with open end bumpers, early front and rear fenders etc. He ended up having three open end bumper cars. Good luck and have fun.
12-21-2003, 02:54 PM
Would you grind the weld down first and then do your dolly and hammer work?
BRENT in 10-uh-C
12-21-2003, 06:09 PM
Hey Dutch, coming from a Master I am honored to have you even give me some advise. Since you cannot see everything in the real, your advise is probably right on but let me tell "the rest of the story" as Mr. Harvey would say. :D
I agree that most "store bought" patch panels rank from pittiful down to pathetic but these are hand crafted by Bill Underwood in Signal Mtn., TN who is highly regarded in the Model A industry for his patch panels and other sheetmetal for 1930 & 1931's only. That being said, his panels are about as good as they get and it did have some curvature in the top.
Where I got into trouble on this particular piece is that I recently purchased a Panel Flanger. If you notice in the pictures where the skin has been pulled away, the panel curvature is still there. As I flanged across the skin, it just took on a shape of it's own. I tried to lift it somewhat but it seemed to take on a shape of it's own. I probably SHOULD have stopped right there but like they say, " 'sperience is what you have AFTER you need it. ". I did Cleco everything in place and stuck a 1/2" drive socket lengthwise between the inner panel and the inside of the door skin to push the shape back into the panel.
I have been putting in patches for years but I have always used the butt-weld methods. Matter of fact you can look at the other pixs on our website to see they metalfinished out superbly. Personally, I think it was the Flanger that got me into trouble. I have read what you suggested and quite honestly I did pretty much what you already said and wrote that into the picture captions. The panel is not wavy .... it is just about a 1/2" low in the center of the welded area or ... IOW the skin wants to be flat from left to right through the middle.
I guess what I am thinking my next move is to soot the panel and anneal the metal to try and relax it some. Maybe it will get friendly with each other enough that I can stretch it outward some. Brett I understand what you are suggesting but I think starting over would be a pretty drastic measure don't you think. Again, it is not warped or wavy, just low.
I think Tony is right, I'll go back to butt-welding using my copper buss bar as my back-up. The idea about the using a studwelder is a super one. I have a buddy that has a UniSpotter that will probably be exactly what I need. You are correct that 2K primer and catalyzed putty is something we use on almost all panels.
I would love to say that I can metalfinish all of my panels, but truth and reality is, we only do 3 to 4 frame-off restorations a year and metalwork is only a small fraction of the total scope of what we do, so I just don't get enough "practice" to become a Master.
I do appreciate all the advise each and everyone is giving though!!
12-21-2003, 08:08 PM
You don't have to soot the panel for annealing on steel. Only on alum. If you use heat be carful that it doesn't pull inward. At the slightest movement inward pull the torches away. Pay close attention to the movement of your metal. You might have to use some pressure on the back side before using your torch.
Just some food for thought & good luck!!!!!!!!
Happy holidays to everyone!!!!!!!!!
12-21-2003, 10:31 PM
Hi Brent ,
Here is a a good test to do and it will help you understand what happens to the metal when welding in a door skin lower repair.
Take and shear two pieces 12" x 12" lengths of 19 , 18 or 20 gage steel. Make sure you shear them very accurately 12" square . Then roll them a little so the have the same arc as the door skin that you were working on You won't need to put a compound curve, just a simple roll into the test piece.
Clamp the two pieces together and butt weld them with the method you usually do. ( mig? ).
Tack weld them first and then stitch them up the whole 12". Now measure the llength of the seam . Also measure the the panel up and down.
The same test could be done using a tig and gas welding and then compare the results. The measurements should be all slightly less than 12" at the weld seam with the tig welded seam showing less shrinkage. and the gas welded seam showing the most
After measuring the shrinkage,knock off any excess weld bead and then planish out the seam using a post dolly and hammer.Make sure all of your hammer blows are right on the weld. As you crush the weld monitor the length of the seam, it should start growing .
As the seam lengthens the panel distortion will lessen. When the seam is 12" the distortion will be gone. Make sure you only hammer the weld seam and nowhere else.
Try it and take some photos.
12-22-2003, 05:28 AM
Brent, The flange it self would not create any problem. The one thing that happens when you first start using a flanging tool is that you tip the tool a little and then press an angled flange and this causes the panel to deform. The bad thing with a flanged panel is when you go to straighten it you now have a double panel to work with. Probably the best way to straighten it now would be to cut and access hole in the inner door panel and then hammer the welded area on a post dooly and stretch it back in shape. The unispotter and pins with the slide hammer will have a hard time pulling it far enough to get it close to being straight. A flanged joint is actually good for people who can`t do a but weld well.You do the flange and then only tack weld the panel to the flange. This way you don`t get enough heat to shrink the joint.You tha use the short fibered fiberglass bondo to finish the seam. You can also use the two part ureathane seam bonding system to get the job done.
If you anneal the panel you are going to cause more shrink with the heat and make the problem worse. Dutch
12-23-2003, 03:43 PM
Brent...putting a flange in a shaped panel adds two more dimensions to work with or to work against you. butt(!) joints take a little more time to fit but don't give the feedback...sometimes severe. plus you can't actually work the joint....you end up working what is almost one plane welded to two.....adding more distortion....sometimes devloping a mind of its own. wingnut clamps and copper work great. plus a butt joint has strength in itself and can make super distortion even if done to your best. :shock:
01-02-2004, 08:01 PM
Brent, how did you solve the warpage problem?
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