Bodywork

[RickL]

patch

Harris/Tonkadoctor,

It appears that we have arrived at a similar conclusion. My idea was to cut out the bad patch to good metal make a new patch and flange it and then get someone with a TIG welder to weld it in.

I am mainly concerned about further damage, inexperince of present staff(me) and concerns about getting the cab done and painted while I still have reasonable weather to paint it.

Rick

[tonkadoctor]

TIG is Definatly the best way to go for this problem

I applaud your efforts Rick you never know until you try. Welding and bodywork is something that takes practice but it's not beyond your grasp.

If you have it tig welded in place you won't have to worry about warpage just let the welder know that it is a major concern and ask him to tack and then slowly connect the tacks until it is welded solid.

Also with tig it could be butt welded and you wouldn't have to flange it . Just cut out the old piece with a die grinder taking your time so you don't build up too much heat when grinding and then fabricate a new patch that is an exat fit in the hole.

For extra strength of the butt weld it could be "fishplated" from the bottom.

[JimmieD]

Fascinating gentlemen!

I've long wondered whether ox/acetylene brazing is feasible, when considering that MIG, TIG and Arc welding are relatively new processes within metalwork and automotive body fabrication and repair. All of those indescribably beautiful bodies on Alfa Romeo, Bugatti, Chrysler, Delahaye, Delage, Maserati, Pegasso, Talbot etc. of the 30's to 40's MUST have been done with gas welding, so....?

Yes, one little secret is that they were able to design the body panel sections beforehand with the knowledge that there would be heat shrink, and therefore a simple [?] matter of adding a bit of selvage for intended shrink.

Of course most of us just don't have enough time in our lives to learn all of the craftsmanship trade secrets used by the masters and passed on to apprentices. I sure appreciate what's being passed down here!

Regarding the question of future cracking: it's my understanding that the final step in this process, before using body finishing fillers, may be to gently heat the entire area if possible, if you had to heat/quench excessively. The quenching is what changes the temper in the steel; where left to its own as to air cool, it will not change the molecular structure to make it brittle.

Yes, I see problems with that again, of potential warpage, but if it is a more important consideration to prevent cracks from embrittlement while also accomplishing the repair, it may be considered at least? I'd appreciate any comment on this aspect as well.
JimmieD

[RickL]

fishplating

Tonkadoc,

Which is better fishplating or flanging the patch panel?

Thanks,
Rick

[tonkadoctor]

I'd probably Flange it

Rick, In this case I'd Flange it and Tig weld it on both sides it's a little stronger and a whole lot easier because it doesn't have to be as precise of a fit and less pieces.

JimmyD. Your right about the molecular changes of the metal when quenching.

Heat Shrinking has really gone the way of using lead in body panels (very few people know how to do this these days, and most of them probably have resparatory problems) and now is pretty much used only for concours quality show cars, I haven't seen anyone, including myself, use it since the mid '80s and then we only used it for hail damage because it was faster than filling a thousand dents with filler.

I preffer to just get the metal as straight as possible making sure there are no high spots and use a thin layer of a high quality lightweight, easy sanding body filler (one that you can purchase at an autobody supply shop like sherwin williams automotive paint stores, NOT Bondo, that you purchase at walmart)

[JimmieD]

RE: Heat shrinking

Years ago I was in a small metalworking shop and was often called on to straighten some large steel forms. These were cylinders up 72" diameter and maybe 10-15 feet long made of 3/16 to 1/8 steel and used in a production process. They had to be as straight as physically possible. Unfortunately they'd often get dinged by forklift forks or other equipment, and into the shop they'd come.

If the crease is imagined as vertical, I'd start at the south and very end of the crease, heat a spot cherry red, and then move to the north end, heat a spot cherry red, and move back south. The prior area had cooled some while doing the other end, and I would move up the crease a little from the last spot each time.

By progressively heating the farthest points, moving inward, I was super-stressing the unheated center, much increasing the pressures in the metal to return to its former shape. It was very interesting to watch the molecular memory in the steel bring itself to restoration with just a little help!

Also a few years back I brought a badly warped driveshaft into a small machine shop that specialized in same. The maestro, and he truly was, chucked it in his lathe. My mind saw dollar signs coming. He got out his dial indicator and indicated it out while slowly turning the shaft by hand. It was about 1/2" out overall.

Next came the acetylene torch with a very small tip, maybe a 1? He proceeded to heat a spot the size of a dime in a place precise to his measurements. He had it cherry red and said, "Watch...." and to my amazement the dial indicator's pointer spun furiously as the shaft began to straighten! I knew the science but had never seen it applied with such precision.

30 minutes later I drove out with a driveshaft that was straight and true as William Tell's arrow and I, filled to the brim with yet a little more information and poorer by only $20, was a happy guy.
JimmieD

[tonkadoctor]

Pretty much how we shrunk hail damage

but not cherry red, just enough to burn off the paint. We would start at the outside of the ding and spiral quickly to the center and watch the metal actually rise like a mini volcano, sometimes they would go back into place before you could quench it. Usually we could file the metal flat by hand and never even have to use "bondo"

The Maestro as you call him gave you more than a little knowledge he gave you enough knowledge to make a living if you chose too.

[JimmieD]

Ah, yes, and I've just been given an acetylene set, with owner tanks, if my buddy will ever remember to deliver it! I already have some other torches and tools, and my next real purchase will be welding equipment, such as a Miller 175 or 210, to go with my old arc welder. I won't go hungry....and I just love playing with metal and Dodge Power Wagons and trucks.
JimmieD

[Alex]

Curved surface repair

I am restoring a 1942 WC-54 and have been following the thread on "Body Work" I am concerned about warpage like what happened with Jimmie D...

How would you gents tackle a curved surface like I have shown in the picture below ? This is one of three locations where the dripline has rusted through. I know I need to replace the rusted metal, but do you have any tips on how to get the contour of the replacement metal to match the contour of the original dripline?

Also what about attaching new metal using adhesives?

Any of you have any experience with the new adhesives that are being used in body shops now ?

[tonkadoctor]

Curved Metal Replacement

To bend a nice curve in a piece of sheet metal simply put a piece of pipe , (steel, PVC, etc...) in a vice or clamp it to your workbench and you can easily bend it to a nice radius by hand or pay a sheet metal shop the big bucks and they will roll a piece for you.

If you need a complex piece for , say a cab roof corner, you can carve dies out of wood and use a big vise or press to form the metal in between them (NOTE: the dies will have to have a sharper radius then the original piece due to the memory of the metal wanting to spring back a little due to it's original flat state) and press a new piece. Not easy to do but it does work or have a sheet metal shop hammer out a new corner on their machine.

ADHESIVES Don't Do it. Personnally I wouldn't trust any adhesives to hold metal to metal. If you are going to take the time to repair this classic sheet metal weld it or have it welded. You would really kick yourself if the adhesive didn't hold and the piece popped out going down the road while you were on your way to a parade or a show.

The warpage that occured on Rick's truck was due to too much heat.

Cut out and flange the metal like was discussed earlier in thi post and tack weld in the new piece with MIG or TIG welding ( a 1/8" tack every 1" is fine. With TIG the piece can be welded solid after it is tacked down ) If you go with MIG then just leave it tacked and fiberglass over it with something like a product called Tiger Hair ( a resin gel that has fiberglass strands mixed into it ) to waterproof it, grind it into a rough shape and then use a good lightweight plastic filler like Featherweight filler to bring it to the final shape.

Hey RickL did you get her straight yet

[Bruce]

Tuff One?

Hey Alex,
That looks like a tough one, I could not tell if it was the hood or the roof of your cab? No experience w/ the new adhesives, but a contour guage might be a start? I had a feeling that tonkadoctor might give better advice than me<LOL>!

[tonkadoctor]

Adhesives

There are too many Wonder products out there. (wonder if it'll really work the way they show em "as seen on TV".

I tried alot of things out there (especially when I was a teenager that didn't know better and didn't have the right tools) and always go back to the "right way" of metal work. IE JB Weld is a good product some people swear by but I'm not impressed, welding and helicoils work better and you don't have to "Wonder" if the repair will hold.

One brand of adhesive products that I do trust is 3M, they have always made very high quality automotive products that do work and they are used by almost every body shop out there. I couldn't tell you if they have a metal adhesive for patch panels but with the curves in this project I'd still weld the patch in because bent metal has a memory.

[RickL]

bodywork

No, I have not. Hope to get to it soon.

Rick

[JimmieD]

Yes, and there's some fine print on most similar products: effective working temperature range. The finest of products may soon fail at 50+ below in Alaska, or when the vehicle is left parked in the sun, 130+ degrees, in Death Valley!

Most attach by occlusion in addition to a hoped for molecular bond, and extreme temperature can easily break even a very good bond, especially if any condensation has invaded the joint. That was the method used to quarry huge boulders weighing hundreds of tons in bygone days! Drill small holes, pour in a bit of water, and wait for freezing weather.....BOOM!

JimmieD

[Alex]

Thanks Everybody

Shaping the contour sounds easier than I had counted on.
Also thanks for the comments about the adhesives. I am kindof old school myself. I teach at a Technical Center and the instructor of the Auto Collision Course wants to repair the metal with the adhesive. I have access to a TIG welder and I talked to the Welding instructor today. He agrees with us about welding vs adhesives. His comment was the same as yours Tonka, "Why take the chance?"

I enclosed another image so you can see the overall picture. I never thought about the closeup not really indicating where the rust is located on the vehicle... I know this thing like the back of my hand now and didn't think of how others would see the piece. DOH !

Thanks again, I really appreciate the advice.