Galvanised No No (Yes??)

Discussion in 'General Discussion' started by artesanoahumado, Nov 15, 2014.

  1. Hi all, came across a large piece of metal which would be ideal to use in constructing an inner door to my fire box (which is too large but don't want to cut it down). It was used to mix cement on back in the day...

    Problem is it looks like it's been hot dipped in zinc.

    My question: Given that it's mild steel (low carbon steel) underneath the coating (it looks that way as I've taken a little of it back - the rest looks dull grey-almost black) would it be safe to use after I either got it sand blasted or took it back to bare shiny metal myself.

    Thanks in anticipation!
  2. radioguy

    radioguy Smoking Fanatic

    That would be safe to use provided you removed all the coating.  Guys on here have used muratic acid to etch the zinc off.  I have had no experience removing zinc that way.  I'm sure some other guys will jump in. 

  3. Hello.  Below is a link to our last discussion.  You will find folks on both sides who will not change their minds.  Kinda like fat side up or down.  Soak wood chips or not.  I can say I agree with RG.  IF  you can get off ALL the coating then go for it.  Have a read of the various posts and then decide for yourself.  Keep Smokin!

  4. Thx Danny and radio. I did do a looksie before posting though didn't see anything to gain an informed opinion, especially when shot blasting it off.
    No sign of the link Danny but not in any rush
  5. The zinc galvanization process creates an intermetallic bond between the steel and the zinc.  Just removing the visible zinc layer is not sufficient, as there is still zinc in the outer layer of steel.

    Zinc starts fuming as low as 200F.  Zinc Fumes can make you extremely sick and the smell/taste is not one you want on food.

    If you really want to use this piece of metal - take a layer of steel off after you remove all the zinc (1 mm is probably enough).  Then, I would try to find a way to heat it up to 500+ degrees for a while to cause any remaining zinc to outgas.  (Why 500? - the hotter it is, the faster it outgasses).

    Personally, I would never use any galvanized metal in any cooking appliance, no matter how well I thought I cleaned it.  it is not worth the risk to me of getting my family and/or friends sick.
    remmy700p likes this.
  6. WHOOP! THERE IT IS!!!   Sorry.  I just had too.  Keep Smokin!

  7. Thx tucson, that's swayed it for me. I did look at the process of galvanisation (and almost understood it) but didn't understand how far in the zinc would be 'soaked' up by the steel.

    Apologies to you metal workers out there if my terminology sucks....

    Coming from a catering background (so far back I don't remember the bad points) I knew of the dangers, but also like to re-cycle....though not if it's likely to cause harm to either the food or the end user!

    Looks as if I'll have to pay for a piece - and probably through the nose for it, though I expect there won't be much difference in price between blasting or buying, most of the fabricators around here do tend to rip one, even for offcuts.

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