Repairing a pinhole in aluminum pot

[klugesmith]

For decades I've used classic Hitachi rice cookers at home and work.   
One has been out of service because of a pinhole, as from pitting corrosion, in the thin aluminum pot. 
It's the one that looks better, and is 20% lighter than the other, so presumably newer.

It seems they don't make these any more. I can't get a replacement pot without buying a used cooker on Ebay.

Been meaning to ask here about repair options, before getting to work with "J-B Weld" (a 2-part epoxy resin putty) and a scrap of aluminum foil on inside surface.   

Pulse-arc welding, a TIG thing used in jewelry, is not accessible.

Aluminum soldering/brazing rods are shown in many online videos.  The filler metal would show on food side for about 1 square millimeter. Have any readers soldered/brazed on aluminum sheets with success?

I would consider using a solid aluminum rivet, hand-set with a small hammer.   Any hints about whether the joint could easily be leakproof, with or without some resinous stuff placed under the rivet head?

[edit] Maybe white tooth-cavity-filling resin could make a hard, durable repair. Could we expect it to stick as well as epoxy to a corroded aluminum surface?

[davekni]

I haven't tried gluing aluminum in some time.  Back when I did some gluing to aluminum, epoxy didn't adhere well.  Had better luck with silicone rubber.

Also had some aluminum solder decades ago (from Radio Shack).  No idea what it was made with.  Worked with some effort and a hot iron.

I see aluminum "welding" rods at Harbor Freight.  SDS lists only aluminum, zinc, copper, and magnesium.  Other internet results mention aluminum and zinc as primary ingredients of aluminum brazing rods.  One mentioned tin as well.

Glanced through this video of someone soldering a hole in aluminum pop can.  Might be useful:
   

/>Mentions a specific brand of solder, "blue demon", which I'm guessing may be this stuff:
    https://www.grainger.com/product/BLUE-DEMON-Low-Temp-Alum-Zinc-Rod-225N83
SDS lists same four metals as in the Harbor Freight rods.

Good luck!

[klugesmith]

Thanks for the encouragement. I found, from long ago, an unopened pack of "Bernzomatic AL-3" rods.
The label says they contain Al, Zn, Cu, no intentional Cd, and max 0.15% of other elements.
One appeared to make nice well-adhered puddles in a quick test on some Al scraps, freshly sanded and heated from far side with a refillable butane torch.  I didn't try a hot soldering iron, or a "precision" heat gun whose air temp knob goes up to 450 °C.  Note to noobs: I wear eye protection even for plain old soldering.  You never know when something will pop or splash.


I would not hesitate to use it for the pinhole repair.   But before the soldering test, I had an appointment with my dentist.
He had tooth-filling resin and curing light already out, and it took less than a minute to do the cavity in cooker pot.
It held up in a test boiling a little water to dryness.
Then held up cooking a batch of rice, where the long-idle thermal cutoff switch failed to open when water was all absorbed, so some rice got burned.

[Mads Barnkob]

I would not hesitate to use it for the pinhole repair.   But before the soldering test, I had an appointment with my dentist.
He had tooth-filling resin and curing light already out, and it took less than a minute to do the cavity in cooker pot.

He had tooth-filling resin and curing light already out, and it took less than a minute to do the cavity in cooker pot. Wins the price of the year for most unorthodox fix 

Dentists are usually pretty cool about trying out random stuff. I once brought a newly assembled radiation/dose meter and he agreed to give it a few test shots with the x-ray

[klugesmith]

Thank you, Mads.

I mixed up some J-B Weld from tubes first opened in 2005, and put a dab of that on outside of pot in a place with no hole.
That and the dental filling material are both still hard and well-adhered after two more cycles of rice cooking.
The dental stuff is now a light brown color, but still transmits light.  It's flush with metal surface on food side of pot.


In another visit, while waiting for dentist, I took pictures of a modern cordless curing light.
Its light pipe shows a retroreflective aspect when lit by phone camera flash.