Hello,
Over the last couple of summers I have re skinned two cab doors.The original skins were rusted out just above the lower crimped edge and the drivers door in particular needed general renovation
As you said removing the old skin is a pain due to spot welds. These are best drilled out using 1/8 TH INCH DRILL with extreme care. WIRE BRUSH IN CHUCK OF ELECTRIC DRILL TO LOCATE OLD WELDS AND CLEAN ALL OLD PAINT and patience so as not to drill the inner skin other than where the tip of the drill pokes thru on the angled point.
I re skinned doors using steel of similar gauge.
All photos I took for my album were taken with old fashioned film so Ii need to get access to a scanner to transfer the detailed pics.
I placed the old door skin on a pre primer painted sheet of steel, Paint on INSIDE FACE only. the reason why will be obvious later.Then using a 90 degree SET ANGLE and a steel rule, Masking tape and a pencil transferred all dimensions from the old door onto the primer and made a template to trim to size. Cut out the new door skin leaving a generous
amount of metal to form the folded over edges.
Using spare sheet metal as a test piece I then tried to make a metal former with a step in it press the upper door swage line but was not able to exert enough local pressure to get a clean line pressed into the metal.
Forming the body swage line took a lot of effort and a couple of dummy runs with trial and error on scrap metal i worked out the sequence i needed to follow. After all its only 35 years since i did any proper metal work at school.
However my brother in law Ray has a box folder / table with an adjustable clamping blade in his home workshop. His help lining up the metal was a great help. I showed him what i needed to do and I had taken along the old door skin as a pattern /to take measurements.
Taking the measurements from the INSIDE of the top edge.
There are 2 x 90 DEGREE folds and then the SWAGE has two actual folds. Neither of which are a full 90degree bend,We worked out that you need to work from the middle of the door ie this would be the first bend in the sequence IE the lower edge of the bend in the swage.
This is where the painted [ in] side and the plain Outside come into there own, Locate where the lower edge of the swage starts, Place the metal LOWER EDGE OF DOOR [narrow end of door skin] into folding bars with the painted side underneath. Lower top clamp and rigid edge tight onto metal making sure that the door skin is SQUARE to the fold and lock tight in place. Raise the bending bar which is below the steel sheet up till it bends the sheet to a touch over 45 Degrees. So that when you relax pressure it stays at that angle.
Remove the now Bent door skin and turn it over.
Measure the old door skin swage width. approx 1/8 th inch and pencil a line ON THE PAINTED SIDE above the first fold [widest end] Place this end into press SHINY side face down and lock in place using the pencil line as the set point.
Ensure it is parrallel with first fold.
Carefully raised lower bending bar and continue to raise it till the sheet of metal is bent till the second bending makes the sheet stick out level from the folding bar. The sheet will now have a step in it with a slope of about 45 degrees.This is actual swage line.
After this it is a matter of measuring the distance from the top of the swage to the first 90 bend, pencil on paint is first mark or use a sharp steel point to scribe line. Fold and repeat for final bend which will end up giving you a sheet with a 180 DEGREE channel along the top.
Lots of fun fitting the door skin to door inner skin,
You need lots of clamps. A hefty piece of angle iron to hold edges straight edges firm while bending. The inner curve was achieved by cutting a series of V s along the radiused edge to allow shorter bends where I needed to crimp skin in place, A spot weld to hold skin at edges would be a great help. As i have not got this I had to be extra careful, As you crimp the lower edge it pulls the door top edge lower that it should be so you need to be EXTRA careful not to distort the whole door top edge.
Good luck
