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Cosmetic Aluminum 'Hole Plugging' Help Needed

Hello.. I have an aluminum radio chassis that I am in the process of restoring. By restoring, I mean that I have dissassembled the radio to the bare natural aluminum chassis and am polishing out most of the scratches, etc. On the back of the chassis, there are two holes approx #10 screw size that were drilled by a previous owner for no telling what. Anyway, I need some tips on how to patch these holes in an attempt to restore the original 'look' of this chassis as best I can. Here are the options that I have thought of:

Place a screw/nut into the hole and live with it.

Use a press in stud. Do they make aluminum studs?

Have someone attempt to weld up the hole with aluminum and grind/feather the surrounding aluminum.

I've considered, epoxing a piece of Al disk to the back of hole on the inside of the chassis. Cutting another disk of Al which would fit the hole as best as possible and epoxing. Sanding and feathering would then follow.

What are your opinions as to how and approach this? Since I want the natural aluminum look, painting is not an option. Thanks for any advice you would be willing to share.

Jim

Reply to
Jim Flanagan
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Jim Flanagan wrote: I need some tips on how to patch these holes in an

Flush rivets.

Kevin Gallimore

Reply to
axolotl

Aluminum can be soft soldered with the correct solder/flux combination. I would consider dimpling the hole from the outside in, and soldering an aluminum disc in place on the front side, and then feathering it in.

Tig welding the hole shut would produce a nearly undetectable repair - but of course in both cases the chassis would have to be nearly completely stripped of components to avoid heat damage.

Jim

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Reply to
jim rozen

Greetings Jim, This is a little work but will leave an undetectable repair in bare aluminum. Go to the hardware store or hobby shop and get a length of aluminum rod that is close to the same size as the hole. If it doesn't fit close, that is within about the thickness of a hair or two, then get the next size up and a drill the same size. Drill out the hole carefully so it is round. Then hammer lightly on the end of that rod you bought. Just enough to swell it about 1/64" to 1/32" right at the end. Hacksaw off this end so it that when pressed into the hole it protrudes about 1/32". Clean both pieces so there is no oil on either. Sand lightly the plug before installing. Now, put an anvil of some sort under the swelled end. A good one would be a flat end punch about twice the diameter of the hole held in a vice. Use another flat ended punch placed on the sawed end of the punch and give it a good whack. This will swell the rivet in the hole and expand the side you are working on. It is OK to hit it more to get it really tight but don't over do it. The hammering is going to harden the aluminum and eventually crack it. After the rivet is tight you can file and sand it flush. If the aluminum is not anodized it will not show. If you clear coat it will never show. If left un-coated it will probably eventually show. Either as a really fine ring or, if the alloys are really different, one may be slightly darker than the other. Cheers, eric

Reply to
Eric R Snow

This sounds like something that I can do.. Thanks Eric. I will give it a try. Take care..

Jim

Reply to
Jim Flanagan

One of my mechanics was telling me today that at Grumman they used to cool aluminum plugs in liquid nitrogen, stick them in the hole and machine the excess off. You could not tell where the hole was after the process was done. He did not do the process himself but witnessed it being done as a repair for misdrilled/oversized holes.

Reply to
ATP

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