Colander Repair


A few days ago, a foot broke off of my wife's favorite colander. I was
going to replace the colander, but she has had for at least 30 years,
and likes its now uncommon wide and shallow shape. So, I must repair it.
The colander is completely made of stainless steel, the bowl being about
12" in diameter and 5" deep. Alloy unknown, but it is not magnetic.
Fabrication was a bit sloppy. Each foot is spot-welded to the bowl in
three places, at least in theory. The foot that came off instead had
one weld plus two good-intention dents, and the one weld eventually
fatigued and broke. The other two feet were each missing at least one
weld, but it was hard to tell without pulling the joint apart.
I don't have a welder, and silver brazing was going to leave a very
large and ugly heat-affected zone, which could well rust. (Not knowing
the alloy, I have to assume that it is one of those that can rust if
raised to red heat.)
So, I drilled foot and bowl to accept three stainless steel 2-56 machine
screws and nuts, with the screwheads inside the bowl. I also put one
screw apiece in the other two feet, replacing the most obvious missing
welds. The bits of screw shaft protruding from the nuts were then
peened over with a ball peen hammer to form a rough rivethead.
So far so good - it will not fail in my lifetime. But it does look a
bit crude, and the peened thread ends are a bit sharp (as I didn't form
a real rivethead), and I think real rivets would have been better.
Copper is probably too weak, ordinary steel rusts, so the rivets should
be made of stainless steel.
The question is what alloys are best for making SS rivets. This is two
questions, actually, as one may wish to cold rivet (as I did with the
2-56 screws), or hot-rivet.
Whatever alloy those SS 2-56 screws are made of certainly would work as
a rivet. These screws were intended for use on airplanes, as the
flat-head screws have 100-degree heads, so they were probably made to
some MIL-SPEC.
Googling on "stainless steel rivet" yields that lots of rivets are made
of 304 and 316 alloys, so perhaps that's the best answer, at least for
cold riveting. But then there is hot riveting, where the rivet is
heated red hot before hammering into shape.
Joe Gwinn
Reply to
Joseph Gwinn
Loading thread data ...
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.

Reply to
Bob La Londe
Smallest pops I've seen are 3/32" diameter.
Reply to
cavelamb
Send it to me and I will spotweld it.
Reply to
Buerste
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
Reply to
Jim Wilkins
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
Reply to
dcaster
McMaster Carr has countersunk stainless steel solid rivets:
formatting link
might look less obvious..
Reply to
Denis G.
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
Reply to
Joseph 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
Reply to
Joseph Gwinn
In article , " snipped-for-privacy@krl.org" wrote:
I think you are right that these rivets are too small. I was asking more for future reference than current need.
Joe Gwinn
Reply to
Joseph Gwinn
In article , "Denis G." wrote:
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 90 degree heads used in metric screws, but I bet that 90 degrees is also too severe.)
Joe Gwinn
Reply to
Joseph 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
Reply to
Joseph Gwinn
[snip]
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 1/2" wide. The holes I drilled are 3/32" diameter.
So, button-head or truss-head SS rivets may be the solution.
Joe Gwinn
Reply to
Joseph 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
Reply to
Jim Wilkins
Here is an example.
formatting link
The flue pipe was joined with stainless pop rivets. The circular flange is on the end of the main section and the straight piece beyond it, nearest the anvil, is separate. That flange took a lot of work to make the end a light press fit into a Metalbestos chimney. I saw no sign of cracking despite all the hammering back and forth.
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
Reply to
Jim Wilkins
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.
Reply to
Wild_Bill
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
Reply to
co_farmer
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.
Reply to
Denis G.
In article , "Denis G." wrote:
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
Reply to
Joseph Gwinn
In article , " snipped-for-privacy@co> > > A few days ago, a foot broke off of my wife's favorite colander.  I was
Yeah, that would have worked too. There must be many SS fabricators around here (suburbs of Boston).
Joe Gwinn
Reply to
Joseph Gwinn

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.