working with pot metal?

[oldguy]

Several issues here. damaged turn signal bars, damaged grill surrounds, damaged headlight eyebrows. I may have to use some of these, so what are the options? Can they be welded, like aluminum? does anyone know the correct rod/wire to use? heat range, etc.
Can they then be rechromed?
If not welded, any other practical way to repair them to be filled and painted?
Lastly, to achieve the "frenched" look, can the pot metal eyebrows and rear turn signal housings be used somehow (?) or do you have to fabricate a replacement out of steel to weld to the fender?
Thanks for any guidance.

San antonio TX. 53 Champion Coupe, to be brought back from the dead.
"Of course it will fit, I have a torch"

[PackardV8]

No, probably not. Pot metal refers to an alloy of inexpensive, low-melting point metals used to make castings for automotive parts and accessories. There is no scientific metallurgical standard for pot metal. A typical zinc diecasting alloy, Zinc#3, has the following composition

* Aluminum 3.5-4.3%
* Copper 0.25%
* Magnesium 0.02-0.05%
* Iron 0.100%
* Lead 0.005%
* Cadmium 0.004%
* Tin 0.003%
* Zinc ca. 95%
Pot metal is known for its instability over time, as it has a tendency to bend, distort, crack, shatter, and pit with age. The low boiling point of zinc and the fast cooling of the newly-cast part often allow air bubbles and zinc oxide to remain within the cast part, weakening the metal. Many of the components of pot metal are susceptible to corrosion from airborne acids and other contaminants, and the internal corrosion of the metal often caused chrome plating to flake off. Because of the internal degradation of the metals within the alloy and the low melting point precludes traditional welding or brazing. Low-temperature soldering has not proved satisfactory because of the incompatibility of flux to zinc and the inability to prevent oxidation, which inhibits solder's ability to flow and bond. Pot metal parts can be re-plated at great expense. The CASO method is to sandblast to remove all the chrome, fill pits with spot putty, re-sand and then paint along with the body.

It is not possible to use the pot metal trim to "french" headlights and taillights. Failure is assured. Sheet metal, welding, grinding and much talent is the preferred method.

thnx, jack vines

PackardV8

[Swifster]

Has anyone played with this stuff? It looks too easy but very interesting. It's supposed to work with low heat to avoid melting pot metal.

http://www.muggyweld.com/super1.html

---------------------------------------------------------------------------------------------------
Tom - Mulberry, FL

1964 Studebaker Daytona - 289 4V, 4-Speed (Cost To Date: $2125.60)

[PackardV8]

No, haven't used it. This looks like the same stuff flogged at car shows and state fairs. Bad form to dismiss it without trying it, but when professionals who stand to make some serious money for a successful repair tell me pot metal can't be welded or soldered, I've always just kept on walking by the demonstrations with my money in my pocket.

PackardV8

[Dick Steinkamp]

quote:Originally posted by PackardV8
but when professionals who stand to make some serious money for a successful repair tell me pot metal can't be welded or soldered,

I have had pot metal parts repaired by the folks that did my chrome plating. There were a few cracks in the '53/54 grill surrounds, holes to fill since I used one '54 surround with '53 grill bars, pits to fill in other pieces. I have no idea how it was done, but all still looked good when I sold the car 35,000 miles and 12 years later.

[oldguy]

Informative. I did not know pot metal was mostly zinc. I expected the rest of the answer, but you don't know till you ask.
The Muggy Weld videos are most impressive. Who are the most talented welders/solderers on here? Maybe several of us could chip in the cost of an order and have them do a "mythbusters" test for us. I have Spares of several parts to practice on, but with my skill level it wouldn't be fair to the product. (I find the welding of pot metal to steel just beyond my credibility)
Has anyone had success using JB Weld or Epoxy to repair a crack, and then fill/paint over it?
I find the quick cure type pretty useless, but the regular stuff has worked well in some places. Never used it on a critical part, nor where it was going to be visible, or painted.

San antonio TX. 53 Champion Coupe, to be brought back from the dead.
"Of course it will fit, I have a torch"

[bams50]

quote:Originally posted by PackardV8

No, probably not. Pot metal refers to an alloy of inexpensive, low-melting point metals used to make castings for automotive parts and accessories. There is no scientific metallurgical standard for pot metal. A typical zinc diecasting alloy, Zinc#3, has the following composition

* Aluminum 3.5-4.3%
* Copper 0.25%
* Magnesium 0.02-0.05%
* Iron 0.100%
* Lead 0.005%
* Cadmium 0.004%
* Tin 0.003%
* Zinc ca. 95%
Pot metal is known for its instability over time, as it has a tendency to bend, distort, crack, shatter, and pit with age. The low boiling point of zinc and the fast cooling of the newly-cast part often allow air bubbles and zinc oxide to remain within the cast part, weakening the metal. Many of the components of pot metal are susceptible to corrosion from airborne acids and other contaminants, and the internal corrosion of the metal often caused chrome plating to flake off. Because of the internal degradation of the metals within the alloy and the low melting point precludes traditional welding or brazing. Low-temperature soldering has not proved satisfactory because of the incompatibility of flux to zinc and the inability to prevent oxidation, which inhibits solder's ability to flow and bond. Pot metal parts can be re-plated at great expense. The CASO method is to sandblast to remove all the chrome, fill pits with spot putty, re-sand and then paint along with the body.

It is not possible to use the pot metal trim to "french" headlights and taillights. Failure is assured. Sheet metal, welding, grinding and much talent is the preferred method.

jack vines

WHEW. Great tutorial on pot metal. I didn't know any of that, and always wondered about that stuff. Over the coming years people will ask about pot metal again, and this thread will be re-quoted many times.

Wish it was better news, but thanks for posting some useful info!



Robert (Bob) Andrews Owner- Studebakeracres- on the IoMT (Island of Misfit Toys!)
Parish, central NY 13131

"Some people live for the rules, I live for exceptions"- 311

"With your Lark you're on your own, free as a bird, alive as a Lark. You've suddenly discovered that happiness is a thing called Larking!"

[nels]

I think the way repairs are made is: first the part is stripped, pits are cleaned and a cracked area is milled down below surface level, the part is then copper plated. This copper plate is now compatible with solder. The pits are filled with solder and the crack gets a copper or bronze thin strap to bridge the crack. The strip is "tinned" prior to bridging. Part is carefully metal worked and then plated.

[rockne10]

The professionals who repair and replate cracked and pitted pot metal-at huge expense- could explain what must be done; but then, they would have to kill you.[)]

[studeski]

I thought Eastwood had some stuff to weld pot metal years ago. I haven't seen it lately.

Claude Chmielewski
Studeski

http://www.studeski.com

Fillmore, Wisconsin
47 M-16 Truck
62 GT Hawk
63 Lark
64 Commander Wagonaire
50 Champion Regal (parts car)
[img=left]http://www.studeski.com/62hawk/dakota01.jpg[/img=left]
"One after another they volunteered how in their families and in their
communities they were expected to be responsible for their behavior, how
honesty was assumed to be the rule, not the exception. They also talked
matter-of-factly about the sense of duty to their country, a sentiment not
much in fashion anymore."

[buddymander]

that muggyweld stuff looks like the real deal. I'm going to order some.

[Lark289]

Very funny, but probably true.

I have had some luck with pot metal parts being replated at huge expense but that was many years ago.

Ready for a trip to the beach!

[Swifster]

quote:Originally posted by buddymander

that muggyweld stuff looks like the real deal. I'm going to order some.

Put up a review. I need the belt mouldings done on my Daytona and I've been kicking this around.

---------------------------------------------------------------------------------------------------
Tom - Mulberry, FL

1964 Studebaker Daytona - 289 4V, 4-Speed (Cost To Date: $2125.60)

[whacker]

I have heard of small parts being used as masters for a lost wax metal casting mold, which is then used to make a one-off brass replacement part. The brass part is then plated. Sounds expensive, but it may still be cheaper than repair and replate of the pot metal part. It only works for small parts, I understand the '53 grill surrounds are too big. I read a magazine article about it, but I've never known anyone who actually did it.

[stellarrestorations]

I'm not familiar with Muggy Weld, but I've got another product that's probably very similar that repairs pot metal and diecast. It's not fun; I get nervous working on parts that might be hard to replace, but so far so good.

Pot metal is worse than aluminum for not changing color when it's hot and then all of a sudden just "disappearing".

I use a J-40 victor torch with very low heat. The pot metal gets kinda "mushy" when it's hot, and the rod gets added to the mushy area.

Eastwood has a heat sink product that also works good for holding the broken parts together while welding.

The plating shop I had previously used repaired broken pot metal like mentioned by Nels. Strip and copper plate the broken pieces, then use a low temp silver solder to make the repair. Plating shops do not like soft solder, because it tends to fail under the heat of the plating process, and it can easily get lapped out of the repair during the buffing.

If you would want to post a picture of your part, I could try to give you some perspective on the repair from the little bit of experience I've had.

Tim Bowers, owner
Stellar Antique Auto Restorations

http://www.geocities.com/stellarrest/LinksPage.html

Instructor, McPherson College Auto Restoration

http://www.mcpherson.edu/technology