Letter 18650

Blackening tin  

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I have some galvanized tin sheets that I want to blacken. Want kind of chemical will work for that application and where would I get it.

Thanks,

Mike Evans
- Denver, CO, USA

'Galvanized tin', huh? I suppose it's possible, but it's unlikely. Unfortunately, you can't even think about chemical treatments for metal until you know what metal you are dealing with. Why do you think the material you have on hand is galvanized tin sheets? My suspicion is it's galvanized steel.

Ted Mooney, P.E.  finishing.com Brick, New Jersey

Ok, I think you are right. It is gavanized steel. How can I blacken it? If you know, please.

Thanks,

Mike Evans
- Denver, CO

Black for tin(maybe for tin plate too):

• bizmuth nitrate.....5 gm
• nitric acid.........5o ccm
• tartaric acid.......8o gm
• water...............1 lit
• Hot immersion(7o C)!

Black for tin II:

• iron chloride........2oogm
• water................1 lit
• Cold immersion!

Goran Budija
- Zagreb,Croatia

WHAT CHEMICAL CAN I USE TO BLACKEN STEEL? IT IS STRUCTURAL AND ALREADY IN PLACE.
SEAN

SEAN LOCKYER
- PALM SPRINGS, CA USA

There's always black paint, Sean :-)

Most good black coatings, like black zinc plating and black chrome plating will prove impractical for work that is already in place. You could apply a cold black oxide (gun bluing), but this requires that the steel be very clean, and it offers no corrosion resistance--you would have to keep the steel oiled, which might be impractical.

 
Ted Mooney, P.E.
finishing.com Inc. - Brick, NJ

I found out accidentally that galvanized steel can be rusted by using muratic acid, I was cleaning my pool filter in my galvanized tub. Afterwards the tub started rusting over the next few weeks.

Tammy Rasmussen
- Lakeland, FL, USA

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