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Repair of broken strainer

Problem

There was a kitchen strainer, made from thin stainless steel sheet, with spot-welded handles. One of the handles gave way. After inspection, it turned out that the spot welds were more spotty than welded.

No wonder. IKEA goods are made from paper. Even the ones made from metal.


Broken handle

Broken handle

Broken handle

Broken handle

Solution

There were choices available. Epoxy was decided against due to the possibility of leaching of chemicals into food and due to the heat cycling of the assembly. Mechanical joining with rivets was kept as a backup choice. Brazing with a silver alloy was also kept as a backup, due to the cost of the filler metal and need to heat a fairly large amount of metal.

Stick welding was chosen as the way, to test it on thin stainless sheetmetal.

An acidic rutile-based electrode, OK68.81, with 2mm diameter, was chosen.


Electrode used

The middles of the handle pads were drilled, to provide edges for the weld.


Drilled handle

Drilled handle

Drilled handle

Drilled handle

The behavior of the electrode was tested on a sacrificial piece of stainless sheetmetal. It was found that the prescribed 40-60 amp current is way way too high. The welder was dialed down to about 12 amps. It was also found that a single layer metal burns away fast, while two layers are much more resilient.


Test weld

Test weld

welder setting

The handle and strainer were placed in a vise, secured in position, and welds were placed in the drilled holes.

At the edge of the first weld the electrode slipped and scraped the sheetmetal body. The resulting spark melted through.


Weld

Weld

Weld, inside

Weld, inside

Welds were also placed on the other side pads, to make sure they won't break too. It turned out later that they did not penetrate through.


other side weld

other side weld

other side weld

The handles were mechanically tested. An attempt was made to break them off, to observe how the thin sheetmetal deforms and where the joints really are. During this procedure, the other side handle broke off, a testimony to the lousiness of the spotty IKEA welds.


broken other handle, body

broken other handle

broken other handle, spot welds

broken other handle, spot welds

broken other handle

The beads of the welds deposited at the preventive attempt that did not penetrate through turned out to be a problem. A half-hearted attempt was made to drill them off. Holes were drilled through the centers of the pads and welds remade properly.


weld

weld

weld, inner side

weld, inner side

weld, inner side

The welds were ground with a Dremel tool, and cleaned off and made smooth.


finished

finished

finished

finished

finished

finished

finished

finished

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