It's been a while since I hit on the bodywork instruction topic, but one of your breathren has run into a problem with oilcanning after welding on a new lower door panel, and my reply to him was fairly involved and detailed, so I thought I'd repeat it here for those who may run into similar problems, it's common when welding in a patch. He sent me a video to illustrate the problem. (maybe he could post it somewhere so others could see it?)
Here's my reply:
don't cry yet! All is not lost...
Yes you are correct in your assumption that the shrinkage from the patch welding is the culprit. That shrinkage needs to be addressed first before attempting to deal with the "soft" spots or oilcanning. Divide your door up vertically into 4 sections by drawing 3 equidistant vertical lines on it with a sharpie pen. Do the same on the other (assumed unmolested) door. Now you need to make 4 contour templates off the good door. I would suggest making them out of 1/8" hardboard (masonite) rather than cardboard for accuracy assuming you have a saber saw and belt sander. If not, do the following with 12" wide strips of heavy, never been creased, corregated cardboard with the corregations going horizontally. Use a new (sharp!) utility knife to cut it. Cardboard contour templates will require very careful handling to not damage the final contour edge or crease it while using. The following is all done on the "good" door:
Start by cutting some 6" wide strips off the 4' end of the sheet of hardboard. Hold 1 of the strips at the end of the door and trace the contour, make a witness mark on the template at the door bottom. This will be a rough cut line to start the process, so keep the contour as close to the edge of the strip as possible so you have material left to refine the shape, but fully encompassing the entire door panel from the bottom of the window to the bottom of the door. Cut to this line, but don't bother to refine it if a bit uneven.
Hold the board on the center vertical line, aligning the bottom edge witness mark with the bottom of the door. It is unlikely to fit as is so just hold in place without pressure. Use a childs school compass with a sharp pencil in it. Set it to slightly wider than the largest gap between the board and the door and trace the contour by sliding the point of the compass along the door face and marking a line on the board the compass setting away. IMPORTANT! hold the compass at right angles to the panel surface at the point of contact as you trace the contour, so you will need to roll the compass as you follow the door curve. Make sure the point follows the line on the door rather than sliding in and out. Take your time to get a SINGLE accurate line. Cut CAREFULLY this time along the pencil line. recheck it on the door and refine by sanding until it fits within 1/32-1/16" along the entire line. Mark any area where it doesn't quite fit onto the template and label it door center. Make two more templates the same way to fit the other two lines, being sure to mark the door bottom edge on each. Finally mark a horizontal line on the good door about the same distance from the bottom of the door as your weld seam on the other door, and make a horizontal contour template that matches the door contour along that line, witness mark both edges of the door. This one will likely need to start at the front edge of the door if you are working with the doors still on the truck in order to clear the cowl with the door open. Take your time making the templates as accurate as possible, it will pay off later.
Now you are ready to tackle the problem door! Hold your templates on the coresponding lines on the welded door. It's likely you'll see where the problems are immediately. Mark the door where it doesn't match the templates. Mark any high spots with a different color sharpie than the low spots.
Now you need to bring up any/all low areas. I am assuming the major problem is the welded area is low. Use whatever tools you have available to bump out the low areas. A shallow curved heel dolly used as a hammer inside the door, wooden pry or push sticks shaped on the ends so they match the skin surface so you don't put in sharp dents etc, working primarily on the deepest point of the lows, allowing the rest of the low to come out with the center. I just use my hand as a dolly on the outside to feel the metal move. Recheck the templates and remark the misfits on the door regularly. A paper towel dampened with alcohol works as a sharpie eraser to remove unneed marks. Do not worry about high spots yet unless they are making fitting the templates difficult, then tap them back with a slap hammer on the outside and a rubber heel dolly pressed tightly on the inside. A suitable rubber dolly can also be made from a hockey puck. Sand one side to a shallow convex curve with course sandpaper. If in pushing out the weld line you are creating high spots to either side then it is in need of stretching to bring up the low area without pushing the rest of the panel out too far. Stretch with the slap hammer on the outside and a very shallow curved steel dolly on the inside. Push the dolly VERY VERY hard against the inside and slap directly over it so you hear a ringing sound. Keep moving the dolly a small amount along the low spot after each slap. The slaps should be more like lightly spanking a baby's bottom rather than beating a rug! Check the templates often after each pass, you DON'T want to over stretch!
Once you have the low spots all out to (near) contour you are ready to tackle any remaining high spots, soft spots, or oil cans with heat shrinking. Get your door into this condition and let me know where you stand (video was good way) before shrinking and I'll go thru that with you. If done right and careful it will take all weekend to raise the low spots. BE PATIENT, work slowly and lightly, creep up on it.
Chuck

 

Ax,
I've been watching for this next installment... THANKS

 

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Sounds like we need a sticky or tech article for this great tutorial

 

I was thinking a stickie for this would be good but I`m sure that another one is totally out of the question after the last clean up.
We`d be better off with this it in the Read First: Cool Tips and tricks or Read first- FAQ and MANY more 1948-1960 Ford truck related articles.

 

Good info.

In regards to the templates, has anyone tried those adustable ones offered by Eastwood/etc? I'd assume they're resusable forever...until you run over one

 

I have one of those Eastwood contour gages and have used it successfully. The problem with them is that they don't lock. However, once you have the contour shape, it can be transferred onto wood or cardboard and used that way. I used it to make these contour templates: https://www.ford-trucks.com/user_gal...126097&width=2

 

Randy jack,

If only i had a talent like that. Nice gas opening

JimG

 

The biggest deficit to the finger type gauges like Eastwood is they are too short for most areas. Ron Covell had a homemade one they used in his chopping and sectioning DVD that was great for larger surfaces.
After looking ar John's pictures of his templates and problem areas my answer was as follows:

that doesn't look that bad, I think it can be salvaged. You'll need to push/bump out the low areas until they match the contour first. A baseball bat might come in handy as a tool, sand the end to a 1/2 ball shape and you can pry or bump with it. When prying put pressure against the panel until you see it move out, then slide it along the panel while applying pressure. Make several such sliding pushes close together horizontally starting at the lowest area working out in both directions You may even want to consider cutting out the inner door skin a couple inches from the frame and inside the front hinge bracing, then putting it back in later after reshaping the outside. You'll only need to tack the inner skin back in ~ every 4-6" afterwards if you are upholstering the door panels, the panel and some seam sealer will cover a lot of "sins". I did that on one of my rear doors where the hinge doubler had broken loose (plus the inner panel was heavily dinged and dented from loads shifting etc.). then you can use a HMW plastic torpedo mallet to bump the metal. That would be my choice.
Chuck

 

New installment!
56panelford (see pix above) sent me an email about his progress. He said that the replacement door skin patch didn't have as much curve (bulge) as his original door, and he hasn't been able to recreate it by hammering off dolly.
My reply:
Off dolly hammering will only move the existing metal to a new location. To increase the amount of loft (the compound curve that gives the metal a saucer or dome shape), you need to add more metal surface area to the metal within the center of the sheet without stretching the edges. Think of making a pie crust: rolling the dough to the edges thins and expands the sheet until it reaches the size of the pie plate, but it remains flat. To fit it into the plate, you place the flat sheet over the pie plate securing the edges so they won't expand, then stretch the center of the dough by pushing it down into the pan. That stretching of the center makes the area of the center of the dough sheet larger relative to the edges, so it forms a saucer (or pie plate) shape.
To form a higher curve in your door skin where the edges are already secured to the frame (like sticking the edges of the dough down on the pie plate) you need to stretch the center of the panel. There are a couple ways to accomplish this:
1. hammer all over the center of the sheet "on-dolly" This is the best way to do a light to moderate stretch over a larger area. Use a large faced body hammer with a shallow crowned face (most body hammers come with a flat face, you want to modify at least one of your hammers to have a smooth shallow domed face. A belt sander or ******* file and DA works best to rework the face. Take your time and check it often with a straight edge to be sure the dome is smooth without any flatspots and centered. Finish to at least 400 sandpaper without leaving any file or courser sandpaper scratches), and a shallow crowned dolly. Technique is important when stretching to not get a wavy panel. Sit down at a comfortable height while you work, the more comfortable you are the less fatiqued you will get and have less chance of running out of patience. I rest the elbow of my hammer hand on my knee so I only use my arm from the elbow to the hammer head. set up a strong light so it splays across the panel at a very shallow angle and back towards you. This will allow you to see the hammer marks on the panel and the panel crown in silouette. Assuming you are right handed, hold the dolly in the palm of your left hand (a leather glove will help keep your hand from getting sore) and the hammer in the right. Hold the hammer handle near the end of the handle just tight enough that it doesn't droop, and extend your forefinger down the back of the handle like you are pointing at the hammer head. Lock your wrist! From now on your forearm and the hammer are all one, you do not change your grip or bend your wrist, you swing from the elbow only, like a mechanical bell ringer. This is VERY important! You want every swing to be the same strength and control exactly where it lands.
Note: the first few times you do this, sand the panel first with 320 or 400 sandpaper or a nylon stripping wheel so you have an even finish pristine surface to help see the hammer marks.
Now for the actual hammering... start at the edge of the area you want to stretch, push the dolly HARD against the back of the panel, you should be able to see the panel bow outwards from the pressure and the dolly should not bounce off the panel from the hammer. Arrange your position so that when you swing from the elbow with the elbow planted on your knee the hammer face will fall flat on the panel over the dolly. Now swing the hammer with a light swing, we are NOT driving nails, rather we are ringing a bell! You should hear a distinctive sharp metallic ring. Now stop and examine the panel, you should see a round hammer mark about the size of a dime. If you don't see a mark, swing just a little harder next time. If you see a very distinct impression and your ears are ringing, EASE OFF MONGO! Try it again, overlapping the previous mark by 1/2. Now comes the test of your patience! run a line of hammer blows from one side of the panel to the other overlapping each by 1/2 and leaving the same size mark each time staying back at least an inch from the edge of the panel. Move the hammer blows by moving your elbow forwards ~ 1/2" after each blow, DO NOT remove your elbow from the support! Eventually once you get used to swinging from the elbow only, you can lock your elbow to the side of your body instead of on your leg, but do it this way for now.
Now move up (or down depending where you started) 1/2 a row and repeat to make another overlapping row of marks overlapping each other and the previous row. Check your template often to see your progress, you'll be amazed how much the panel will grow and bow outwards from just those light taps! Don't get carried away or you'll end up having to shrink back out some of your work! You'll soon learn how to control what part of the panel to hammer on to reach the contour you need.

2. heavy stretch: usually only needed when forming a strong compound curve in a new patch panel like for a cab corner.
To make a pattern: cover the area you will be forming smoothly with overlapping strips of masking tape roughly mark out the edges of the patch on the tape with a sharpie. Carefully remove the entire tape covering without pulling it apart. Hint: try using a layer of blue low tack painters tape first to make removal easier covered by a layer of regular tan masking tape to help hold it all together. Cut out the tape pattern along your lines. Lay the pattern down on a sheet of cold rolled steel with the edges flat without creases or wrinkles and the center bulged up. Mark around it with a sharpie then add another line 1-1/2 - 2" outside of the pattern line. Cut to this larger line to be sure you have enough material to trim when finished. Lay your pattern back in place while smoothing the dome so it stands up and draw a contour map of sorts in steps indicating where the pattern bulges up the most. This is where you'll concentrate your stretching along these lines working from the edges to the center of the highest bulge.
Now we will need a couple special tools, a torpedo mallet and a sandbag. You can make both or buy a HMW plastic torpedo mallet and a leather sandbag. To make your own, cut about 6" off the end of a wooden baseball bat. or buy a wooden mallet at the hardware store. If cutting a bat, cut a couple more 6" sections out of the narrower portions to make a set of different sized mallets. Drill a hole in the center of each section and epoxy in a hammer handle. Now sand the larger end to as close to a 1/2 ball as you can. Sand the smaller end to a taper like sharpening a pencil until it is ~ 1/2 the diameter of the large end. Sand the very end to another 1/2 ball shape. Your hammer should look like a torpedo or stretched out teardrop shape. Dip in some tung oil or penetrating finish to seal and let dry.
To make a sandbag: Drag out that pair of nearly new jeans in the back of the closet that you outgrew a couple years ago but are saving "just in case I lose weight". (Admit it, we all have at least one of those pair...) or if your wife finally threw them away, pick up a pair at the thrift store. Cut off one of the legs just below the crotch and again 12-14" further down the leg to make a denim tube. If your SO has a sewing machine and is willing to assist you, have her fold over one of the open ends ~ 1/2" and run two lines of long stiches to sew it closed. If you need to DIY and aren't good at sewing don't worry, fold the end over 1/2" and again to make a 1/4" double fold. now with a needle and heavy duty thread whip stitch it closed (whip stitch is easy: push the needle thru the fabric next to the double fold from bottom to top. pull the needle towards yourself and around underneath the fold then bach up thru the fabric ~ 1/8" away from the previous stitch. pulling the thread tight should form a stitch that wraps around the folded up fabric holding it tightly closed).
to fill the sandbag: pour in enough DRY sand (or better yet lead bird shot from your neighborhood gun shop. DON'T use steel shot tho) to make the bag ~ 1" thick pillow when sewn shut. Close the bag.
Now lay your piece of metal on the sandbag on a very solid support. Select the mallet with the head curve closest in size to the finished curve of the panel. start hammering on the piece along the outermost contour line with overlapping blows. You DO want to hit it hard enough to make a dent in it with each blow! Continue hammering around each ring until you reach the center. You should now have a lumpy bowl form with wavy edges. Straighten the edges roughly by hammering out the high spots while the edge is resting on a steel anvil or hardwood block. Check your progress by placing the new panel over the area you'll be patching and noting where the contour needs adjusting. Adjust the contour and start smoothing out some of the lumps by doing more hammering on the sandbag as needed, re-smooth the edges and check your progress. If you are doing a deep curve you may need to use a shrinker to smooth out a very wavy edge. Lacking a shrinker, you could clip out a number of thin wedges of metal then weld them up and grind smooth. The welding will also shrink the edge. When it gets close to shape, you can smooth down the bag of walnuts surface with a flat hammer and a dolly with a matching or slightly smaller diameter curve just hammering down the high spots without stretching, or else use a shrinking disk to smooth the surface. Trim the patch to fit and weld in place!

 

WOW, thats better than watching a instructional video. Lov the details. Will be next winter before I get to try them out. Thanks

 

This definitely deserves a sticky. Thanks Ax!