whats under the chrome?

i am going to rechrome some parts on my commando starting with the foot pegs. i have dipped them in hydrocloric acid to remove the old chrome and underneath the old chrome is something norton used to fill pits and flaws in casting. can anyone tell me what that is? reading about chrome online some people have used silver solder to fill flaws. my natuaral inclination would have been to use brass to fill any imperfections, but don't want to use anything incompatible with what is already there. thanks in advance for any information.

Are you doing th chrome yourself?

Quality chrome on steel or pot metal has a copper base, then a nickel strike, then chrome.

I did consulting for a company that was Cu-Ni- Chrome plating plumbing faucets and fixtures, many of which were of the pot metal type. These were for some of the major fixture mfgrs you know well. I never saw any filling with solder or other metal, but that may have been done in a shop I never poked into.

It seemed to me, pits were filled with copper, sanded, then put back into the Cu-Ni-Cr line.

Slick

swooshdave said:

Are you doing th chrome yourself?

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i am thinking about it. the prices that i was quoted for for a chrome shop to do it was a more then new price. i am also thinking about just doing nickle rather than doing a chrome top coat

texasSlick said:

Quality chrome on steel or pot metal has a copper base, then a nickel strike, then chrome.

I did consulting for a company that was Cu-Ni- Chrome plating plumbing faucets and fixtures, many of which were of the pot metal type. These were for some of the major fixture mfgrs you know well. I never saw any filling with solder or other metal, but that may have been done in a shop I never poked into.

It seemed to me, pits were filled with copper, sanded, then put back into the Cu-Ni-Cr line.

Slick

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under the chrome was a nickle plating there didn't seem to be any copper under that. there where some substantial casting flaws that norton or whoever did the foot pegs for norton filled in with something, reading about prepping for plating there was talk about using silver solder to fill in holes. someone else suggested that what was used might be nickle, not plated, but applied with a torch. if there was not something already there my natural inclination would be to use brass, but i am scared to mix brass with whatever is already there whether it is silver solder or nickle or something else. i know from personal experience that you don't want to try brazing something that has already been solded even if you think you have cleaned off all the solder.

One cannot weld after brazing. Electroplating is a different process. I am not saying one can or cannot electroplate over a soldered or brazed fill. I do not know. You will need more research.

With steel foot pegs, filling with weld and grinding/sanding smooth ought to be the way to go, but I agree, solder is easier if it works.

Nickel plating makes a good fill, but it is very hard, and is usually used to bring bearing journals back to over size, then ground to size.

Slick

The basic difference between soldering and brazing is the temperature which is necessary to melt the filler metal. Soldering is a low-temperature analog to brazing. ... Metals that can be soldered include gold, silver, copper, brass, and iron. If the filler metal melts below 840ºF the process being performed is soldering.

silver solder is as much as 50% silver or more

Cu - 34%
Zn - 16%
Ag - 50%

texasSlick said:

One cannot weld after brazing. Electroplating is a different process. I am not saying one can or cannot electroplate over a soldered or brazed fill. I do not know. You will need more research.

With steel foot pegs, filling with weld and grinding/sanding smooth ought to be the way to go, but I agree, solder is easier if it works.

Nickel plating makes a good fill, but it is very hard, and is usually used to bring bearing journals back to over size, then ground to size.

Slick

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i am trying to figure out what was used by norton on the pegs to repair the flaws. i know from experience that you can solder over brass brazing, but you cannot braze over something that has been soldered with regular mostly lead solder and i would guess silver solder. i'm pretty shure welding is out of the question whatever the filler metal is. it looks like maybe you can braze brass over nickle because the melting point of brass is lower than nickle, but i don't want to try it on a maybe it will work basis. also i still don't know what that filler metal is, silver solder, nickle, or something else, the only thing i am shure of is that it isn't brass. i should be able to plate over anything that that is conductive, they even plate plastic, they just paint it with a paint that is conductive first. normally platters plate with copper first and sand and buff to fill flaws, but the flaws are way to big for that with these pegs, the only places that had really nice chrome were where they used that filler metal. it isn't a mater of easy, easy would be to buy new pegs from andover norton, but as i am retired, i have way more time than i have money. if i considered it on an hourly basis my motorcycle habit is way to expensive, i should just buy a new bike rather than mess with all my old ones. but that is a flaw most of us gear heads exhibit, we play with a lot of old broke machinery and equipment even when it makes no economic sense. i do a lot of odd or weird things just to see if i can.

Once they refered to CHROME as ' Triple Plateing ' Copper as the filler / base . Maybe it ? .

slow said:

i am thinking about it. the prices that i was quoted for for a chrome shop to do it was a more then new price. i am also thinking about just doing nickle rather than doing a chrome top coat

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Nickel is much easier to do at home than chrome. With chrome, to get the strike you need to reverse etch at about 100 amp/square foot, then throw the reversing switch. With nickel it is a straight forward plate, but you are much more likely to get hydrogen embrittlement of any high tensile steel. Also, the solution slowly becomes contaminated if the anodes are not bagged. It is normal to keep the parts moving in a nickel bath. If you get an interruption in the current, you can end up with double-plating and beads of nickel on your component. If you don't keep the parts moving, there is all sorts of shit that floats around in nickel baths - if it settles on your parts you can get pits.
I don't like your chances of getting good plating on parts which have been filled with a dis-similar metal.
When you chrome plate, the reverse etch causes an oxide to form on the surface. When you throw the reversing switch, you cause an over-potential and the chrome is forced through the oxide layer. Theoretically, you cannot plate chrome on steel, but the reverse etch makes it possible. If you have dissimilar metals, you also reverse etch those.
I don't know what would happen to silver solder or brass. A better option might be to do a heavy copper plate, then polish it back before applying the chrome or nickel.

You cannot plate nickel on nickel. It will double-coat every time.

I worked as a chemist in both the Government Aircraft Factories and the Ordnance Factories, in Melbourne. We had the biggest metal-finishing shops in Australia. - All gone now.

slow said:

i am thinking about it. the prices that i was quoted for for a chrome shop to do it was a more then new price. i am also thinking about just doing nickle rather than doing a chrome top coat

Click to expand...

Perhaps acotrel will correct me on this, but I think nickel on copper is porous. You might get pitting if exposed to the weather.

Quality chrome plating is expensive, mostly due to environmental protection. While a quality triple plate may exceed the price of new, one has to wonder these days if new parts are plated up to the same standards as they once were.

Slick

If your parts are the fork staunchions, the usual repair is to have them centreless ground then hard chromed. The bath for the hard chrome is refrigerated. Tex is right about the EPA requirements. Once you have used the solution, then you have the problem of disposing of it. If it ends up in the sewerage farm, the bacteria might stop working. Hexavalent chrome burns everything. A friend of mine w3as rebuilding car clutches. He made a tank in his factory which was concrete blocks against a side wall. The chrome leaked into the factory next door. - Pretty disgusting.

What! He didn’t get the wall tanked?