Colander Repair

Now there's an idea.

The reason to care is appearance and the elimination of sharp edges and corners and places for rotting food to accumulate.

The problem with pop rivets (and hollow rivets in general) is that they loosen long before they pop out, because too little metal is carrying the load. A solid rivet won't loosen, if properly sized and installed.

Joe Gwinn

True, but you have the means to retighten them, and they are much easier to drill out without enlargening the hole. Hopefully they will hold until you happen onto some solid rivets, probably the day after you finish it.

I have two standards for workmanship, Unlikely to Fail for finished products that ship, and Easy to Change for prototypes that stay in house.

jsw

On Wed, 23 Dec 2009 11:07:04 -0500, the infamous Joseph Gwinn scrawled the following:

Excellent! Now you have a solid reason for new tools, Joe. Getchersef a brand-spankin' new doming die/dapping punch set!

Griz $80ish

HF $45ish ($36 local, GO FOR IT!)

eBay dapping punches, $20ish eBay dapping block, $67ish

Amazon $46; brass, may be too soft.

So did heat make a difference, or was it just not doable with that particular alum. alloy?

-- REMEMBER: The sooner you fall behind, the more time you'll have to catch up!

On Wed, 23 Dec 2009 11:11:21 -0500, the infamous Joseph Gwinn scrawled the following:

Kinda like a crush bumper, it might be just the thing the colander needs to survive yet another drop, eh? It may be worth considering copper or aluminum rivets instead of S/S.

-- REMEMBER: The sooner you fall behind, the more time you'll have to catch up!

Well, you know I'd do ANYTHING for you Joe! GL!

collander bowl istoo thin to countersink, the feet are too small to use proper sized rivets,

So the collander bowl is too thin to counter sink, the feet are too small for a larger rivet size, the leverage on the feet is too great, seems to me different approach is needed. other than remaking the feet in larger stainless sheet, how about a ring of 1/8thin stainless wire connecting the feet together.half way along their length? would replicate the circular collander bases other collanders have and spread the load when in use, ifv you havnt stainless wire then copper or brass or even galvanised plain would do. how you fix it to the legs depends on how the legs are formed.

We need a photo of it to devise a proper engineering solution. Im sure NASA would have the expertise to solve this .

The current nut and peened-over machine screws will last until I tire of looking at them.

Well I don't know that there is much to prototype in colanders, the design having settled at least a century ago, and I prefer doing such jobs at most once.

Joe Gwinn

The metal of the bowl and feet is soft enough that it will simply bend if the rivets hold.

Joe Gwinn

There's a thought - tools!

Dapping blocks and punches are not the same thing as a rivet head forming punch. But I bet McMaster carries the correct tools.

Or, for one use, I could make the tools from soft steel.

No, the issue was that it was too slow and too hard to heat the airplane up, and a WW2 airplane had tens of thousands of rivets holding it together.

Joe Gwinn

But then that wire ring would catch on everything. The usual alternative is to replace the separate legs with a sheet-metal ring shaped like a truncated cone. But this is far too much work.

I suppose I could make my own rivets from hobbyshop SS wire, which I recall is type 304.

It's a flat-bottomed hemisphere with three bent-strap feet spotwelded to the flat bottom. I didn't see any catalog offerings that look exactly like it.

Yeah - use at least four welds, so even if one weld fails the foot won't come off.

Or the conical ring spotwelded in at least four places to the bowl - this is a very common design, and the ring isn't going to come off so easily.

Joe Gwinn

Well, I appreciate that, but is a colander challenging enough?

Joe Gwinn

There's a tool for that, of course. I'm only aware of it because I hired a guy as a SS fabricator whose experience consisted of operating a thermo-dimpler in the Air Force. Unfortunately that seemed to be his only experience, and we didn't have anything that needed dimpling. Though we were willing to train him, he just stopped showing up one day.

I guess the modern alloys like to be warm when dimpled. I'm pretty sure that dimpling was done cold in WW2.

I have to wonder about someone who only learned how to operate a thermo dimpler in the USAF, so you may have dodged a bullet.

Joe Gwinn

On Thu, 24 Dec 2009 12:01:18 -0500, the infamous Joseph Gwinn scrawled the following:

Um, I thought you wanted to deform the colander foot holes, forming them for the head of the rivet.

"If you get the chance to buy tools, go for it!" I sez.

Yeah, that might take 3 hands.

-- REMEMBER: The sooner you fall behind, the more time you'll have to catch up!

Yes, but to accept flathead rivets, so that the rivet heads do not protrude into the bowl, which requires conical dimples, not domed.

Yep. McMaster probably has them.

Joe Gwinn

On Fri, 25 Dec 2009 20:02:44 -0500, the infamous Joseph Gwinn scrawled the following:

So check the Griz link again. It's for -conical- dapping. Looks like

100 degree, but you wouldn't be able to use the die base with it for a big colander.

Prolly so.

-- REMEMBER: The sooner you fall behind, the more time you'll have to catch up!

I know the picture makes the punches look conical, but a jewler's doming punch always has a spherical tip, so I distrust the picture.

Joe Gwinn

On Sat, 26 Dec 2009 09:31:13 -0500, the infamous Joseph Gwinn scrawled the following:

WhatEVER...

-- REMEMBER: The sooner you fall behind, the more time you'll have to catch up!