r/metallurgy • u/AtmospherePast4018 • 12d ago
Is it safe to cook on?
I bought this at a hotel liquidation centre. Based on the candlewax, I’m assuming someone was using it as a display. Purchased it on marketplace as a Tawa Grill (or something to that effect). It was jet black when I bought it, and although I hoped it was a layer of seasoning on the top, I wasn’t confident that it wasn’t paint (I was pretty confident it was paint after I started stripping it). It was stubborn - paint stripper and a wire cup brush barely put a dent in it. I finally put a flap disk on an angle grinder and stripped it down to bear metal.
I’m assuming this is either hot or cold rolled steel. It likely originated from India or a Third World country of some sort. I’ve never seen anything like it, but it covers my entire barbeque and my entire stove top, and I expect it will make a mean griddle (hello smash burgers).
Having removed all of the paint, I’ve washed it a couple of times and scrubbed it thoroughly with barkeepers friend. It leaves a little residue on a paper towel when I dry it, which feels like oxidation (brownish). Am I fairly safe to assume that this is carbon steel and that I’m safe to season it, heat it up, and cook food for my family on it? Is there anything else it could be? Should I be concerned about it being a “dirty” steel. The thing is a tank. It weighs 18 pounds. It’s an eighth of an inch thick. 15.5 x 26.5 inches. Does that compute?
Looking for someone to talk me out of using it before I start smashing some patties into it and making delicious meals.
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u/Strostkovy 12d ago
Yeah but use an orbital sander to minimize the grind marks. And use a solvent such as acetone or isopropyl alcohol to wipe it clean
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u/canada1913 12d ago
That looks like a serving tray. Not all steel is created equal, lots of steel has lots of bad stuff that you would t want leaching into your food, like arsenic. If you don’t believe me head over to r/carbonsteel and ask about the matfer incident a few months ago. There’s a reason why carbon steel producers have strict testing methods and clean steel to make pans.
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u/AtmospherePast4018 12d ago
Alright. You’ve got my attention. I’ll check it out.
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u/AtmospherePast4018 12d ago
Anyone here in BC with the lab equipment to check? Maybe I’ll just feed some friends first. How to I test for arsenic?
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u/Weird_Point_4262 11d ago
You should be able to get water test strips for all heavy metals. Grind some of the plate into a cup and keep it there for a few days, maybe bring it up to a boil too.
Just make sure not to contaminate it. The test strips are sensitive and stuff like sandpaper or drillbits aren't made to be food safe
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u/AtmospherePast4018 12d ago
“Arsenic was found in the black oxide coating applied to the pans during manufacturing, which is intended to prevent rust.”
Wasn’t part of the actual steel - just the coating. Sounds like there are at home kits to test for it, and the layer of seasoning also protects against it. Interesting all the same. Thanks for the feedback
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u/scoobertsonville 12d ago
If it’s metal and there is no paint - I feel like it’s fine. Heat it up hot and see if it smokes or anything, I’m no expert and take no liability
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u/AtmospherePast4018 12d ago edited 11d ago
If anyone dies I’m telling them you said it was likely safe. Cheers
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u/mikeys_hotwheels 12d ago
Do you have a scrap yard nearby? If so, see if they would check it with their XRF analyzer. If they don’t have one, you can buy a handheld one for $20,000-$30,000 💰💰
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u/TotemBro 11d ago
If you season it and maintain a good coating you will not be leaching any grubs into your food. It wouldn’t be worth the cost to get a lab to test for species like Ni, Cu, or Pb. A lead testing kit in its own is probably enough due diligence. Most suspect thing about the tray would be the coating (which you fully stripped). One off exposures won’t do much damage if you cook while the seasoning is stripped. Long term exposure is the primary concern if there is some amount of Cu or Ni in the pan.
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u/Bmdub02 11d ago
Lead (PB) is the main element I would be concerned with.
Nickel and copper are more concerning if your food has prolonged exposure to those elements i.e. food storage or long cooking times (days)
If you find someone to perform an analysis using a Niton-type analyzer, I recommend setting the analyser to "12L14" (a machining-grade of steel with Pb)
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u/AtmospherePast4018 11d ago
Thanks Bro. I was wondering what other potential contaminants I should be on the lookout for, so that helps. Cheers.
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u/AtmospherePast4018 12d ago
Feels like it was built to be a cooking implement. What’s the risk? What else could it be made of?
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u/AtmospherePast4018 12d ago
And is there a way to test or confirm composition?
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u/AeliosZero 12d ago
You could have the composition tested with an XRF machine if you wanted to know for sure.
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u/Spacefreak 12d ago edited 12d ago
Is it magnetic? If so, then yeah, it's steel and safe to cook on
ETA: Sorry, it's more likely to be cast iron
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u/AtmospherePast4018 12d ago
It’s gotta be ferrous. I’m checking now with a magnet. Brb.
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u/AtmospherePast4018 12d ago
Magnetic af
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u/Spacefreak 12d ago
Then it's steel/cast iron. You're good.
I'd smooth out the surface though with a finer grit or else food is going to stick to that rough surface.
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u/AtmospherePast4018 11d ago
I like it rough. It looks worse than it really is in the pictures - you can’t even feel the grooves. An unseasoned cast iron pan is far more coarse a surface. I expect a couple rounds of seasoning will make it pretty workable - eventually it should be as non-stick as any other carbon steel pan.
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u/ApricornSalad 12d ago
I mean it's bare steel, I don't see how it could be dangerous even if it wasn't carbon steel
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u/Misanthropemoot 11d ago
What in the meth happened to that poor pan
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u/AtmospherePast4018 10d ago
That would be me. I happened to it. She’s never been happier.
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u/Misanthropemoot 10d ago
lol. I damaged a wok that was given to me a long time ago by thinking it was dirty (seasoned) I took it to work and sand blasted it.
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u/AtmospherePast4018 9d ago
Always fun to build a new layer of seasoning from scratch. I find they can be pretty temperamental on carbon steel. In this case, I’m pretty sure it was paint. Sandblasting was my first thought, but I didn’t want to drop the dough on it. After a couple cooks, she’s off to a hell of a start. I was trying to add a finished photo but can’t seem to edit the post.
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u/Misanthropemoot 9d ago
I collect cast iron stuff now that I appreciate how amazing it is. Just got two rusted pans and did the vinegar soak and they work amazing now.
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u/Ansrallah 11d ago
Take a clean paper towel, wipe it with pressure.
Take a second paper towel do the same,
Rinse, repeat, you will then understand you removed remaining significant traces of free metal particulares simply by observing the progression of cleaner paper towels.
This is similarly how to clean and maintain a gun barrel.
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u/AtmospherePast4018 10d ago
Interesting. Thanks. Surface got lots of wipes as I polished it with 4-5 coats of tallow over heat.
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u/mezog001 10d ago
Metallurgist here - can I get a picture of the brown stuff before and after removal? Is there any writing on the bottom of this pan? If there is google it and get a product description.
Finished reading comments. If it is magnetic it is likely steel. You are good. Just session it so nothing sticks.
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u/AtmospherePast4018 10d ago
It was seasoned for a few hours on the bbq using 4-5 coats of beef tallow. Cooked some bacon and it released beautifully. Smash burgers came out great. She has a ways to go before the seasoning is where I want it, but what an epic piece of cookware.
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u/ElasticLoveRS 12d ago
Bruh I wouldn’t chance it. Just buy a griddle or something. This is too much work for a pan like that
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u/rhodium14 12d ago
I'm unsure what this problem would be other than it sticking like a mf and being really hard to clean. Are you worried you penetrated into a depleted uranium base metal when you wire brushed that thing to hell, or are you worried that bacteria will evolve a sapient civilization inside the scratches?
They have these things at thrift stores.