Colander Repair

All stainless pop rivets. I get them from an outfit in Phoenix for marine work. I've got several bags of them in various length 1/8 inch diameter hanging from the pegboard in the shop. No clue what alloy they are. They pop in easily enough. I suppose for "finish" work I could knock out the stub of the stem, and then used a center punch and then pin punch to spread and flatten the pull side.

Smallest pops I've seen are 3/32" diameter.

Send it to me and I will spotweld it.

Stanley does or did make stainless pop rivets. 1/8" dia X 1/2" long is part # PTT48, bar code 45731 13090. The store where I found them sells imports, closeouts and overstock so I don't know a good quick source elsewhere.

jsw

I do not think that hot riveting would have any benefits. The length of the shank is maybe 1/16th of an inch. Not a lot of shrinkage in that short a length.

=20 Dan

McMaster Carr has countersunk stainless steel solid rivets:

I didn't consider pop rivets because they yield this big sharp thing on the blind side, and are weak relative to bolting or solid rivets. There is actually a lot of force on these feet, given the leverage and general banging around any kitchen implement receives.

The drive the stem out and upset with a punch approach will improve strength and appearance but sounds like as much work as upsetting a solid rivet, and yields something not as neat looking.

Joe Gwinn

Thanks Tawm, but I have already drilled the welds out and bolted it, so now I'm more or less committed to replacing the peened-over bolting with rivets, which are also very common in cookware.

Joe Gwinn

I think you are right that these rivets are too small. I was asking more for future reference than current need.

Joe Gwinn

I did think of this, but there is a twist. The bowl material is too thin to countersink, but there is a standard dodge from the airplane industry - one countersinks the piece to which the sheet will be riveted (the foot in the present example), and dimples the (bowl) sheet to match. But it's going to require some tooling to make those dimples in stainless steel sheet.

This dimple-the-sheet method is the reason for 100 degree flathead screw/rivet heads: In WW2, it was found that the aluminum sheet used for airplane skins could be cold dimpled to 100 degrees included angle without cracking, but 82 degrees was too severe. (Don't know about the

Joe Gwinn

The color was no issue - milady would not have cared, and copper is easy to get and to form.

My worry is that copper is too soft and weak for such rivets to work for long. The colander foot is fairly long compared to the space between the welds/rivets, so the leverage is large, and I figured it would shear off the first time the colander was dropped.

Joe Gwinn

I agree with the make-it-a-feature approach for sure.

As discussed in my answer to Gunner, I didn't think that copper was strong enough. Nor do I have space for 1/4" rivets - the foot might be

So, button-head or truss-head SS rivets may be the solution.

Joe Gwinn

You are making a lot out of a simple task. Countersink the foot if you like, then pound the rivet head and the bowl into it with a flat piece of steel drilled for the rivet shank. For neatness you could pull the shank only enough to snug it in the hole, then remove it, Flare the end with a center punch and knock it down with a ball pein hammer.

In my experience salvaging stuff the sheet metal will deform considerably before a stainless steel pop rivet breaks.

jsw

Here is an example.

As usual I found a source for commercial parts only after making my own, so that section of flue is out in the woods under the snow with other second-hand stainless now.

Look at the cat con heat shield photo to see how much abuse stainless can stand. The sheet was originally the outer shell of Metalbestos chimney and I opened up the hem and hammered it out flat without cracking. The curved louver slots were slit with a chisel, pounded back flat, then hammered into a groove in the edge of a disk. Crimping pliers tapered the ends.

I've hammered other stainless steel cookware into costume armor without breaking it. IIRC the rivets were cut from stainless steel woodscrews.

jsw

Rivets should make a strong reliable repair, and look good, too. My concern would be if drilling holes in the legs would make them weaker.

Another option would be to solder the legs on with lead-free silver bearing solder (tin with 5-6% silver) such as Harris Stay-Brite #8 and a flux suitable for stainless steel (Harris Stay-clean).

The Harris #8 solder doesn't require a torch, so it won't cause discoloring or rusting. The working temperatures are 430-530F, so it wouldn't be suitable for cookware or utensils subjected to cooking temps.

Well, It's too late now, but any metal fabricator that does any work in stainless steel will have a spot welder that could have quickly fixed your problem. The last time I had a stainless spot weld repaired, they didn't even charge me as they had just finished a spot welding job and the equipment was still hot and ready to go.

Paul

Maybe you can just use countersunk backing washers for the rivets. Then you wouldn't need to worry about countersinking the colander parts. My guess is that the stainless would take the dimpling without tearing, but that's my WAG.

Or use a truss-head rivet for much the same effect.

The SS will surely take the dimpling. The problem is making neat dimples without the right equipment, and no scrap stock upon which to experiment.

I've dimpled soft aluminum (Bud boxes) with a flat-head SS screw drawing the sheet into a countersunk recess in an aluminum block by tightening the nut on the SS screw. Not clear that this will work with SS, which is far stronger.

Joe Gwinn

Yeah, that would have worked too. There must be many SS fabricators around here (suburbs of Boston).

Joe Gwinn