[How do I?] Steel selection, dealing with mill scale.

I would think that electrolysis would be a good way to remove mill scale. It is just iron oxide after all. A battery charger and a washing soda solution. A length of PVC pipe and end caps should work well for a container. I would do it outside though. There will be gasses given off.
 
I just use Muriatic Acid to remove mill scale. I use a metal container outside my shop to soak the parts until the scale falls off and then put the remaining acid in a spare bottle that I use until it is too weak to do anything. Then I just dump some bicarb in it to neutralize it (converts to water) and dispose of it. One gallon of acid has lasted over a decade and I still have a lot of it left.
 
RJSakowski said:
I would think that electrolysis would be a good way to remove mill scale. It is just iron oxide after all.
Click to expand...

Hmm, I didn't think to try that when I had the electrolysis bath set up during the non-freezing season (this year: May through Sept). Maybe when I set it up next year I'll throw some hardware store steel in and see what happens.
 
either make the first cut deep enough to get under the scale or soak the parts in vinegar.
For long sections I have a couple of plastic plumbing pipes capped at one end for the flats I just use a plastic bowel.
It works very well and really thick scale wipes off usually with an overnight soak.
Before the soak
https://www.hobby-machinist.com/threads/the-giant-binocular.55688/ post 1
after the soak post 4

BUT.... they need a fast rinse in water then a quick neutralise in some bicarb, dry and oil else they rust very quickly.
 
My vote is for the electro bath also, if it gets the job done. Much nicer to deal with than nasty HCL
-Mark
 
Of course if the part is small, and you're not doing a production run, you can just take it over to the file board and be done in a minute or two.

And yeah, I could've removed the scale *before* slotting, but this is a bit of a try-and-fit project.
 
What is this trickery...? I've never heard of a file board. What does it do?
 
Keep meaning to pick one of those up. What stops me is it'll probably just sit there gathering dust like everything else that requires me to fire up the air compressor.
 
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