Preparing a steel part for chroming

[marcus9x9]

spiral/black(emery)? Wow, that sounds like sanding a rough surface? I thought that the copper only needs a final buff when the bare metal underneath has been sanded to 2000 and buffed with white rouge.

[woodjames]

It's a balance between speed and a good finish. The copper cuts fast with compound, not much of a need to sand any finer than 600 or so. See attached.

spiral/black(emery)? Wow, that sounds like sanding a rough surface? I thought that the copper only needs a final buff when the bare metal underneath has been sanded to 2000 and buffed with white rouge.

[marcus9x9]

I have had a steel turn signal bracket sanded to 2000 grit, then buffed it with spiral/brown and loose/white. It looks almost flawless now.

Next, I will send it to the plater and tell them to triple chrome plate it.

You were saying that the plater will be deeping the part into a solution to expose as much of the metal. This solution will attack the metal too. This is one reason why the part should be plated with thick copper, and then buffed to a mirror finish.

Craige advised me to plate the steel with flash copper prior to triple chrome plating. What do you think about this? If the part is plated with flash copper, should the plater still deep it into the solution?

Thank you

[woodjames]

Yeah, the plater will still have to activate the copper to accept plate. The activation is done with a mild acid, which basically eats away a very tiny bit of the surface to expose fresh metal. I haven't noticed any pitting or other heavy attack on copper when I activate it, so you should feel comfortable that they way you are giving it to them is the way that you'll receive it back, albeit in a different metal obviously.

-Jimmy.

I have had a steel turn signal bracket sanded to 2000 grit, then buffed it with spiral/brown and loose/white. It looks almost flawless now.

Next, I will send it to the plater and tell them to triple chrome plate it.

You were saying that the plater will be deeping the part into a solution to expose as much of the metal. This solution will attack the metal too. This is one reason why the part should be plated with thick copper, and then buffed to a mirror finish.

Craige advised me to plate the steel with flash copper prior to triple chrome plating. What do you think about this? If the part is plated with flash copper, should the plater still deep it into the solution?

Thank you

[marcus9x9]

That's great to know.

What other negative effects does the mild acid solution does to the bare steel? Does it speed up/cause the bare steel to rust underneath the copper or nickel, showing up few years later.

Do you see any mechanical/chemical disadvantage plating the steel with flash copper prior to acid copper? e.g. bonding strength between the bare steel and flash copper.

Assuming that the part is taken care off, I would like to see the chrome in great shape without pits/rust forming for another 5 years at least.

Thank you.

[woodjames]

It will have no effect on it rusting down the road. It will remove any rust or oxide that develops on the surface, getting the best possible adhesion.

Steel cannot be plated directly with acid copper, it needs the strike coat of flash copper. Flash bonds to steel like glue, as long as the steel is prepared correctly.

The biggest part of having chrome last is keeping it clean. Wax it with a good wax. Certain environments can be detrimental to chrome. Acid rain, being near the ocean...etc.

That's great to know.

What other negative effects does the mild acid solution does to the bare steel? Does it speed up/cause the bare steel to rust underneath the copper or nickel, showing up few years later.

Do you see any mechanical/chemical disadvantage plating the steel with flash copper prior to acid copper? e.g. bonding strength between the bare steel and flash copper.

Assuming that the part is taken care off, I would like to see the chrome in great shape without pits/rust forming for another 5 years at least.

Thank you.

[knossos]

Can Flash Copper be used to build up the copper thickness, or must Acid Copper be used for thickness? I'd like to stick with just my flash copper setup if I can avoid buying and using acid copper.

[woodjames]

I wouldn't. The flash doesn't deposit too much. With acid copper you can really stick it to the part and build a lot in very little time, plus with brighteners it saves a lot of time polishing/surface prep.

-Jimmy.

Can Flash Copper be used to build up the copper thickness, or must Acid Copper be used for thickness? I'd like to stick with just my flash copper setup if I can avoid buying and using acid copper.