metals and coatings for mash tuns?

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okstatepike

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I am working on a cooler-based mash tun and I am having trouble finding a certain part, and it leads me to a question.

I have been looking for a stainless steel 3/4" washer for the internal side of the bulkhead. All I have been able to find is a zinc coated washer. Is the zinc coating a problem? Any negative interaction chemically with the mash? If so, where can I find a washer like this that is stainless steel?
 
zinc is a electrically active metal, they use it on boats to prevent corrosion on motor parts, so i wouldn't think that in your acidic wort would be a good place. i found my SS washer at the local farm supply store .(tsc)
 
Yup, 3/4" stainless washers are in the specialty drawers at Lowes. The closest lowes is always out of stock on them, but a newer one a little further away has them all the time.
 
Any marine supply or Chandlery will have stainless hareware and washers by the box full.
For inside a round MLT pre bend the washer to match the radius first before installing unless it's a square MLT with flat mounting surfaces. Many 3/4" washers are rather oversize in the ID, this is where a 5/8" almost fits then a quick bore on the lathe for a nice fit is required.
 
The ACE hardeware store in my small town has stainless not only in washers but SAE, Metric including left hand thread nuts, bolts and screws. True-Value has 1/10 of ACE, don't care plus higher priced.
 
If you mix zinc (galvanized) metals with copper in a mildly acidic liquid you will be creating a battery. Both metals will corrode quickly.
 
OK, I've been looking through tons of old threads on this topic.

I had picked up some zinc washers for my new cooler/mash tun build at Home Depot. Realized that was a bad idea. Then I found some washers at the local ACO hardware store that were just labeled "steel SAE". I picked up a few, but now I'm wondering if they are actually what I need. Of course, there was nobody around the store that seemed like they would have a clue enough to give an answer that I'd be willing to trust.

So, what do you all think? Is a "steel SAE" washer for $.50 OK, or do I need to go to Lowes to get the stainless steel ones that are $2.50 for 2 of them.
 
So,...

uh, Happy New Year...

If it just said steel, then what is it? Is it something that will cause a problem, or is it just something that is likely to corrode relatively quickly?
 
It's probably not stainless. If it is coated it will probably be zinc (silver colored) or cadmium (yellow green colored) plated. If it's magnetic then it isn't what you want regardless of the surface coating.
 
Steel is a broad definition of an alloy of at least carbon and iron but can have many other elements added for various reasons. Stainless has chromium added. If it's not stainless, it's going to rust pretty quickly. Spray it with a little starsan or wet it and sprinkle some salt on it and check on it the next day.
 
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