Repairing Potmetal

Folks,

Anyone have any tried and true trick to stabilizing and or patching/repairing our nemesis potmetal? I'm tackling a sound-box from a Berg Artone portable. It's solid but moderately cracked.

Regards,
J.

Hi John:

I've been out of town, and away from a PC for about a week, so sorry for the late response. I'm sure this will raise a few eyebrows among collectors, but I've used Krazy Glue to stabilize crazed/lightly cracked pot metal sound boxes.

The latest example is the one I'm using on my 4-40, which was full of light surface cracks when I got it about eight years ago. I pained the entire exterior surface with a light coat of Krazy Glue, and a tiny paint brush. A few months later, I applied a second coat, and then a third coat. So far--seven years later--it has held up just fine, with no additional cracking, and no swelling.

I've also used Krazy Glue to repair cracked tone arm bases on some 1940s era portables I've owned.

HTH,
David

David,

Actually, you're the second person to say crazy glue. I'm looking for something called Devcon to try, but haven't had any luck so far.

Regards,
John

Neophone wrote:David,

Actually, you're the second person to say crazy glue. I'm looking for something called Devcon to try, but haven't had any luck so far.

Regards,
John

Hi John:

I googled DEVCON EPOXY and found their corporate website -- http://www.devcon.com -- which describes a variety of epoxies and glues, as well as some sellers of Devcon products -- http://www.hobbylinc.com/prods/rga_dev.htm

Not sure wich Devcon product your friend was talking about, so you might want to check into this further with him.

D,

Yes I was looking it over myself. I assume he's referring the "Plastic Steel" it's sold on-line at a site called grainger.com. It comes in one pound tubs. I think I'll give the JB Weld a shot on at least a part of the shell and report back. Maybe I can try the super glue on part of it as well. Thanks for your help D!

Regards,
J.

I have an Orthophonic reproducer that has some cracks and I am afraid to try to dismantle it, but I'm playing with the idea of making a carbon fiber band around the circumference to reinforce it before trying to unscrew the back. This type of banding is commonplace in my musical instrument repair shop and I've used it to repair cracks in oboes, clarinets, and even wooden drums (tabla and pakawaj). It might not even look so bad, although hardly original, but my player is for listening to and not looking at. I'll post photos if I get brave enough to try it.

David

Hi David:

Collectors are always looking for new repair methods, so by all means, keep us posted.

Though I've never used it, I've heard that some collectors have had luck with a bonding product known as JB Weld.

Not sure if you know this, but new production Orthophonic shells are also available, and sold on sites such as eBay from time to time, but they aren't cheap -- http://www.shenandoahrestoration.com/motor.html .

Also, since the quality of the pot metal used in Victor Orthophonic sound boxes varied, you might also want to track down a good condition spare, such as the type used on the portables, and keep it for "just in case" use.

JDS

Hi Joe, thanks for the response. Finances dictate that I try and eek out the most performance with the least amount of $'s spent, but boy it would be nice to have the best right off the bat. I've scored a couple of reproducers off of ebay so I'll hopefully have the back-up parts if things go wrong, but that has to wait for them to arrive.

Any tips on how to unscrew the back? I'm thinking of modifying a bicycle bottom bracket spanner tool to fit the slots. I made one for the tuning barrel necks on vintage Conn saxophones but the slots run the wrong way. Is there something better to use? Should I be thinking of applying penetrating oil before starting?

David

Hi David:

About the most I've ever done was to replace the ball bearings, and clean the racers, as described here:

http://www.gracyk.com/orthosound.shtml

Anything more demanding, I've left to the experts. But, prior to removing the back-plate's retaining ring, I'd definitely recommend using some penetrating oil. Most of the collectors I've known have used a simple homemade tool to remove the retaining ring--basically, a piece of wood with two posts or cut off nails of the appropriate size aligned with the slots in the ring. I believe it unscrews counter-clockwise.

JDS

There is a low temp rod solder and flux for potmetal, sold by Muggyweld. I have good results with it with a cool flame.
Give it a try, however it is for breaks, not crackling.