Preparing a steel part for chroming

[marcus9x9]

Hi,

I have had a steel turn signal bracket from my motorcycle sanded from 80 up to 2000 grit. The surface looks real nice and smooth now, looks like chrome in the dark. The marks from the 2000 grit paper can be seen though.

I want to remove the marks and turn it to mirror finish before sending it for chroming, so that the chrome will look like new (perfect), without any polishing marks.

I have thought about using the white rouge/autosol with a loose cotton buffing wheel. Not sure if this will remove the existing marks without leaving newer marks from it's compound.

Any advise is appreciated

Thank you
Marcus

[woodjames]

Don't bother, the levelers/brighteners in the baths will take care of it. The chromer will have to color buff the copper anyways, and it's much easier to buff out the copper than steel. Buffing is 90% of the work in a plating operation, you'll be paying for it either way, sounds like you've got the part in good shape.

Originally Posted by marcus9x9

Hi,

I have had a steel turn signal bracket from my motorcycle sanded from 80 up to 2000 grit. The surface looks real nice and smooth now, looks like chrome in the dark. The marks from the 2000 grit paper can be seen though.

I want to remove the marks and turn it to mirror finish before sending it for chroming, so that the chrome will look like new (perfect), without any polishing marks.

I have thought about using the white rouge/autosol with a loose cotton buffing wheel. Not sure if this will remove the existing marks without leaving newer marks from it's compound.

Any advise is appreciated

Thank you
Marcus

[marcus9x9]

Hi James,

Thank you for commenting on it.

The reason why I am sanding the part myself is because the chroming factory did a bad job of it. The marks from the sanding/buffing could be seen clearly on the chrome finish. It was a total screw up. I am in Malaysia where there isn't many option to look for a another chrome factory. Their work was good years ago, not right now.

You quoted, "The chromer will have to color buff the copper anyways,".

They also told me that copper is not plated on steel parts, that it is only plated on aluminum parts, acting as a bonding agent between aluminum and nickel. Is this true?

Can I still depend on the levelers/brighteners in the baths alone?
What are the baths?

Thanks
Marcus

[woodjames]

Sorry to hear that!
Nickel can be plated directly onto steel, which is probably the case. As far as the aluminum goes, most likely they are only using copper as a strike plate, which is very thin, to thin to be buffed out, and is only used for adhesion purposes.
I don't think I'd count on them doing much for quality if that's what they are telling you, I understand now why you are doing what you are doing. The problem is this, and I'll try to keep it as simple as possible...
They'll use an acid right before they plate, the purpose is to expose a fresh layer of steel for the nickel to bond to. The problem is that you'll go through all the effort to make your part looking the best it can, but the pickling process using that acid won't keep it in the same condition. It'd be close, but never perfect. A bright nickel bath, which is most likely what they are using will smooth things out, but it'd be tough to get perfection from the process. I'm sure it'll be close. So in this case, the better looking that you've got the part, the better looking you'll receive it back.
After the sanding that you've done, hit the piece with white compound on a loose wheel, don't worry about the finest ''scratches'' from the compound those will be fine.
After that, look for another plater! You can always ship things out.

-Jimmy.

Originally Posted by marcus9x9

Hi James,

Thank you for commenting on it.

The reason why I am sanding the part myself is because the chroming factory did a bad job of it. The marks from the sanding/buffing could be seen clearly on the chrome finish. It was a total screw up. I am in Malaysia where there isn't many option to look for a another chrome factory. Their work was good years ago, not right now.

You quoted, "The chromer will have to color buff the copper anyways,".

They also told me that copper is not plated on steel parts, that it is only plated on aluminum parts, acting as a bonding agent between aluminum and nickel. Is this true?

Can I still depend on the levelers/brighteners in the baths alone?
What are the baths?

Thanks
Marcus

[marcus9x9]

I will be looking for another plater. In the US, do chrome platers use copper on steel? Do you recommend it, how much of it and will it make the finish look better than without it?

Thanks
Marcus

[woodjames]

It's part of the process to get a ''show'' chrome finish. Steel being so hard is tough to buff out compared to copper, so typically a thicker layer of copper is applied, and most of the buffing is done to that copper layer, and it comes out incredibly shiny, and the nickel will bond very well to it. That and if any repair work has to be done, the copper layer accepts solder well, so solder is applied as part of that stage as well if it needs it. I don't know that I'd narrow it down to any part of the world in particular, it's just common practice to show quality work. I've done straight nickel to steel in the past, but mainly on fasteners, where too much plate affects how they fit. And in those cases, I had to go back and buff out the nickel to get the best look from it before chrome is applied to the nickel.

Originally Posted by marcus9x9

I will be looking for another plater. In the US, do chrome platers use copper on steel? Do you recommend it, how much of it and will it make the finish look better than without it?

Thanks
Marcus

[marcus9x9]

This is what I've been waiting to hear from someone. I can't agree more.

I suppose buffing nickel won't produce the kind of shine buffing copper would?

Thanks
Marcus

[woodjames]

It will, it's just more work, as the nickel is harder than the copper. That and nickel is more expensive than copper, so it's better to expend the copper than the nickel. Also, the nickel is very dense, and considered the protective layer, so you want it as thick as possible to provide protection.

Originally Posted by marcus9x9

This is what I've been waiting to hear from someone. I can't agree more.

I suppose buffing nickel won't produce the kind of shine buffing copper would?

Thanks
Marcus

[marcus9x9]

Great! What would you buff the copper with?

[woodjames]

Spiral/black after sanding to 600 grit is a good starting point. From there you can finish it with white on loose.

Originally Posted by marcus9x9

Great! What would you buff the copper with?