From: Pete Albrecht
Newsgroups: rec.crafts.metalworking
Subject: Re: Wanted tips on welding rust repair panels-autos
Date: 21 Sep 1998 16:03:25 GMT

Oxy-acetylene puts more heat into the work, much more likely to have buckling
of the panels.

Mig welding, once you get the knack, is easier, quicker, requires less work on
the weld area later. Don't use the cheap "gasless Mig" (an oxymoron, like dry
water) as it won't make a very clean weld.

For cutting, I use a gadget called a Fein saw. Made in Germany, it has a
vibrating rather than rotating blade. I can cut through two overlapping layers
(like new patch laid over old panel) and have the patch fit perfectly into the
hole, with only a .020" gap (the width of the vibrating blade), perfect for
clamping and welding. For roughrer cuts I save the Fein saw (blades are $40
apiece) use the usual cutoff wheel but this is too crude for good tight fits.

For butt welding, you can buy from Eastwood (at $8 a pop, I think) or make
yourself some clamps that pull the edges of the panels together so you can tack
weld them together flush. You want the panels to fit absolutely as tightly as
possible before you even start welding. Big gaps greatly increase the
likelihood of blowthrough and really ugly welds. I made my own clamps out of
some Home Depot 1 1/4" square steel tubing, some .020" blue steel shim stock
from the industrial supply store, 1/4-20 threaded rod and wingnuts. Look at the
pictures of the Eastwood clamps and you'll get the idea. The clamps pull a
piece of rod against the back of both panels, with the shim stock acting as a
blade between the panels. Of course you have to be able to get to the back of
the weld later to remove the piece of rod. Tack the panels together at about 1"
increments around these clamps and you're more than halfway there.

With tight gaps, careful tacking, welding, then grinding down the weld, you
should have a patch that will need no or almost no filler. The best metal guys
don't use lead or plastic filler at all, needing no more than primer/filler.

Good luck,

Pete

From: Pete Albrecht
Newsgroups: rec.crafts.metalworking
Subject: Re: Wanted tips on welding rust repair panels-autos
Date: 22 Sep 1998 17:24:01 GMT

Comments on the comments. Ditto that on getting a quality MIG welder. I have a
Lincoln Idealarc SP-100. I think it's been superceded by the SP-125. Don't mess
with the Home Depot specials. ("But you can convert them to gas!!!" By the time
you add it all up, you could have had a quality unit for about the same money).


Butt welding is NOT that difficult. Like anything else in welding it requires
practice. And the right settings to avoid burning through or making welds that
looked like a chicken took a dump on it. But it IS possible. I have done things
like replace a complete tail clip on a Porsche 356 (the last foot or so of the
car, from the middle of the engine lid on back) and once the welds were ground
down, no filler was needed. This is how the factory did things in the first
place (you can still see the weld lines if you strip the paint) and that's the
way it should be restored. The factory had a secret tool though, which made
such welding fairly brainless: a metal (steel? copper?) clamp went on both
sides of the sheet metal and both sides of the weld, leaving a thin gap. Then
they just gas welded it together and had an apprentice file off the bead. The
clamp is a great big heat sink. Not practical for one-off restoration.

Lap joints are the easy way out but unless they are completely sealed, are an
invitation to rust.

For more help on body fabrication and welding, pick up the two Ron Fournier
books, the "Sheet Metal Fabricator's Handbook" and "Sheet Metal Handbook." The
way he does things is the way it should be done.

I can again recommend that Fein saw (best price is from International Tool in
Florida, high $100 dollar range). You can use Clecos to hold a rough, oversized
patch in place, cut through patch and parent metal with the saw, leaving a gap
about as wide as your welding wire, hold the patch in place with those special
clamps I described, and run your bead over the gap. Works like a charm.

What exactly on your VW needs welding/patching?

Pete

From: Pete Albrecht
Newsgroups: rec.crafts.metalworking
Subject: Re: 1938 Ford body panel restoration (shrinking sheetmetal).
Date: 23 Oct 1998 05:07:49 GMT

>>I've read every book I can get my hands on on the topic (except that
>>Bogsess book, and I'd be grateful for a fuller reference, Mr. Albrecht)

OK, I found it at a used bookstore. It was printed during the war when the idea
was to get people making airplanes as quickly as possible. Well worth the $3 I
paid, I learned a few new tricks from it. "Aircraft Sheet Metal Work: Bench and
Repair Work" by H. Edward Boggess, Pitman Publishing Corp., 1941.

After posting the earlier message I noticed another book hiding in my shelves.
"Aircraft Hand Forming" by F.S. Brown, Goodyear Aircraft Co. Training Division,
1942. Excellent guide for beginner in the shop (who was expected to turn out
his parts of an FG-1 Corsair with minimal training...) In fact I think this is
better than Boggess. Paid $2 at a used bookstore.

Pete

From: mike@headwaters.com (Mike Graham)
Newsgroups: rec.crafts.metalworking
Subject: Re: 1938 Ford body panel restoration (shrinking sheetmetal).
Date: Fri, 23 Oct 1998 14:42:40 GMT

On Fri, 23 Oct 1998 03:20:51 GMT, rdanzey@seidata.com wrote:

>I've only successfully shrunk sheet metal one time, and while I wanted to do
>it, the results really were a lucky accident.  Slick body work shrinking is
>not only an art form as PLAlbrecht suggests, but I'm convinced you need a
>little black magic in your blood, too<G>.

  I am by no means an expert, but I have had some luck with body work
shrinking primarily because I spent a couple of months of Sundays
trying to figure out plate straightening.  I found a bit of info on it
in "Practical Blacksmithing", and just banged around on warped plates
until I had a reasonable success rate.

  Someone mentioned hardwood slappers.  Good idea.  Basically,
shrinking metal is kind of like forming a rivet.  When you're putting
the head on a hot rivet you hit it hard once or twice, and this
expands the shaft of the rivet, then you tap on it to form the head.
The point is that hitting it *hard* affects a lot of metal, but
tapping only affects the metal locally.  It's not exactly a startling
conclusion, but when you see some people whaling away at a dent with a
BFG it makes you wonder.

  So pick up a body hammer or five.  Cheap ones work fine if you file
the edges of the face smooth, and polish the face.  These body hammers
are quite light, and encourage you to tap, thereby improving results.

  As for hot-shrinking, I'm not a big fan, but it works.  Here's how
you do it:

  - sand all the paint off the area to be worked on

  - first use the hammer and dolly so that the metal bulges outward,
rather than inward (assuming a dent stretched the metal inwards) and
you have what looks like a normal fender (or whatever it is) with
'bumps' where the metal was stretched.  Don't do the hot-shrinking
until the bumper is almost completely back in shape.

  - heat a small area the size of a dime in the center of a bulge
using a neutral flame.  Note that this is a *small* area.  Go for a
cherry heat.

  - whack that spot sharply with a flat-polished-face body hammer

  - before the area can cool hold a dolly block behind the panel and
return the area to the basic contour and shape that you're looking
for.  This should only take a few hits.

  - as soon as it's back in shape, quench the area with a wet rag.

  - continue on doing small areas adjacent but do *NOT* reheat the
same spot.    If you screw it up, then you can try heating the whole
area to dull red with the torch and piling sand-bags against it to
anneal the area so you can try again.



Mike Graham        <mike at off-road.com>
Caledon, Ontario Canada

  Mangler of metal.  User of many grinding discs.
  Cut with an axe, beat to fit, paint to match.

From: Robert Bastow <Tubal_cain@hotmail.com>
Newsgroups: rec.crafts.metalworking
Subject: Re: 1938 Ford body panel restoration (shrinking sheetmetal).
Date: Fri, 23 Oct 1998 19:00:25 GMT

Mike Graham wrote:

>   I am by no means an expert, but I have had some luck with body work
> shrinking primarily because I spent a couple of months of Sundays
> trying to figure out plate straightening.  I found a bit of info on it
> in "Practical Blacksmithing", and just banged around on warped plates
> until I had a reasonable success rate.

Straightening plates is a precise science, an art form and requires a little
black magic too!

As an apprentice I enjoyed watching our "Stretching Gang" at work. These
were three or four of the widest guys I have ever seen out side a zoo!
Arms like utility poles.  Their job was to straighten heavy plates from
the presses, flame cutters or annealing furnaces etc..1" to 3" and
thicker.

They worked with 32lb sledge hammers on a 10' dia x 3' thick, solid steel
"anvil".  A warped plate would be swung in by the overhead (100ton!!)
crane and dropped on the table.  For a while they would sit around
"eyeballing" it and drinking beer from pint bottles. [workers in the
forge, press, furnace and heavy metal shops had a daily allowance,
supplied by the company of up to 8 pints...except apprentices!!  8^( ]

Then , one of the gang would get up, hammer in hand, and pace slowly around the
plate, occasionally squatting to get an eye level viewpoint.
Sometimes this process would take fifteen or twenty minutes, but eventually he
would reach out and make a mark or two on the plate with a piece of chalk.

Spitting on his HUGE palms he would swing his thirty-two pounder effortlessly,
and hit the mark dead on.  The plate would appear to shudder and visibly settle
and as often as not he would walk away, without a backwards glance, signalling
the laborers to take away the now flat plate and bring up the next one.

Not surprisingly, all the members of the gang were stone deaf and somewhat
"addled"!!

Robert Bastow

From: Pete Albrecht
Newsgroups: rec.crafts.metalworking
Subject: Re: Fein saws
Date: 7 Oct 1998 17:30:53 GMT

>I just had a question on what one was and how the cutting blade
>operated.  I guess, also, is a used one possible (or unthinkable).


Ever see those saws used to cut plaster casts off arms/legs/Bill Clinton's, uh,
member  after a counseling session? The blade doesn't spin, it wiggles back and
forth. So only a small portion of the teeth engage the work, unless you move
the motor as you go or stop and loosen the blade. But you can pick this thing
up by the blade, with your fingers right over the teeth, while it's turned on,
all you get is a buzz.

The cheap "detail sanders" they sell now do the same thing. But as far as I
know there are no sawblades made for them, and they're pretty wimpy as far as
power goes. In fact the Fein saw I have was sold as an industrial/tradesman
detail sander, I just bought the blades separately.

I suppose like anything else, you might find a used one.

Pete