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I'm thinking about giving my stainless steel pot volume markings on the inner wall, like in 250ml increments, with a multitool and fine diamond tip. Various info says that scratches in stainless are benign since the material is the same throughout. Also fine scratches don't appreciably increase surface area and hence alloy release.

Yet even a fine engraving mark would be pretty micro-rough, and the first increment would be just one cm above the bottom. So there's a possibility I'd create a strong stick and burn spot.

Would you dissuade me from going ahead?

ariola
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6 Answers6

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Go for it. Stainless steel is quite stick-friendly already, and the added unevenness from the microtool won't really make a difference. Also, this is a soup pot, and the side instead of the bottom, so you wouldn't really expect sticking.

I'd suggest that you try to make a wide marking, not just a groove, for sanitary reasons. You want water to easily come in and wash out everything, so a width of at least one milimeter would be good, two milimeters better. You can just align the bottom of the mark with the needed position, so you don't have to eyeball the middle of a wide mark.

This will be a bit difficult to do if the pot diameter is small, because your router-stick-on-thingy* is supposed to go onto a plane surface. But maybe you'll find a way to do it. In any case, really use a router bit with some width, not the side of a small cutting wheel. Ideally, the resulting mark will have an oblong cross-section, with a flat bottom, vertical sides, and a rounded connection between bottom and sides. If you don't have such a bit, make it vertical with a 90 degree angle at the bottom. The worst option would be a v-shaped groove, that would gunk up quickly, like a condo for bacteria.

And if you find it not so practical, either because of the "catches dirt" possibility or because you can't find a way to hold the bit vertically to the surface one centimeter above the pot bottom, consider acid etching instead. Chloric acid at home-improvement-store concentrations should work on domestic grade stainless steel.

* sorry, that was my best try translating Oberfräsenaufsatz into English. If you have the microtool, you know what I mean.

rumtscho
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Another method is using a cold chisel as a marking punch. place a piece of wood inside the pot for use as an anvil, and then place the chisel on the outside where you want the mark directly across the side of the pan from the anvil and hit once with a medium heavy hammer. done.

hildred
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I've done this before. I didn't notice any significant sticking. I would suggest not making marks extremely low on the pot, as the lower areas get much hotter during cooking and I'd imagine carbon deposits in the scratched area would be basically impossible to remove.

Sneftel
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In the past, on aluminium, I've engraved the outside. I found it good enough to match the water inside with the marks outside outside - this is never going to be a precision measurement. Marking the outside is easier, and allows you to engrave actual numbers as well as just marks. You can also use non-food-safe materials to fill in the markings and make them clearer (e.g. nail polish).

I did it for camping kit, when I wasn't going to carry a measuring jug but didn't want to waste water.

Chris H
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As an alternative to engraving, it's possible to etch the stainless with salt, acid (5% vinegar) and an electrical source (9v battery). This really only creates a very fine surface difference, so should not present a food/bacterial trap.

  • Mix the salt and vinegar, the ratio isn't critical, just to make it conductive.
  • Attach the negative side of the battery to a cotton-swab (use a stick-swab)
  • Attach the positive side of the battery to the pot (anywhere metal is ok).
  • Mask-off the lines with tape or similar.
  • Carefully and evenly "draw" on the pot with the swab

Work in a well-ventilated space, and wash the pot well afterwards to remove any chemical by-products.

A good reference is: https://byo.com/project/etch-your-kettle-projects

Kingsley
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Any mark is going to be a potential bacteria trap, which will be a potential problem on any pot used for water-based cooking i.e. where the temperature doesn't normally go above 100C. However this also applies to scratches from normal cleaning etc., so is probably insignificant in practical terms.

Electrochemical marking, as described at e.g. https://hackaday.com/2015/01/15/etching-steel-with-a-dc-wall-wort , will have the advantage that the surface and edges will be somewhat rounded rather than being sharp scratches, which is probably desirable in this context.

Apart from that, the warnings given about thin stainless surfaces on some other metal apply.

Mark Morgan Lloyd
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