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Robert Noel Reddington
Grand Master
Username: bob_uk

Post Number: 1019
Registered: 5-2015
Posted on Thursday, 07 July, 2016 - 06:10:   Edit PostDelete PostView Post/Check IP

Practical classics July 2016. Page 133 step 5.

They say that chrome pitting can be filled with non lead free solder. I guess lead solder.

I though that solder would be scooped out when polished.

Chrome has to be removed first still. Suggest the harder plumbers solder not electrical solder.

The article is about DIY chrome plating.

I went to a plater and he suggested 300 quid to weld and rechrome the rear centre section.
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David Gore
Moderator
Username: david_gore

Post Number: 2109
Registered: 4-2003
Posted on Thursday, 07 July, 2016 - 08:42:   Edit PostDelete PostView Post/Check IP

Robert,

Many years ago when we did electroplating as a subject in my metallurgy course, we were given a practical exercise to Bright Chromium plate a section of corroded steel tube.

From memory, the procedure was as follows:

1. Linish the tube to remove surface rust and scale then dip in a weak acid pickling solution to remove any rust in deep pits.
2. Plate the tube with pure Copper and linish afterwards, if pits in the plate were still evident, repeat the plating/linishing until the pits were filled in by the Copper then buff the Copper plate with a stitch mop and paste. Degrease with Trichlorethylene.
3. Plate the tube with Nickel and buff with the stitch mop/paste. Degrease with Trichlorethylene.
4. Bright plate with Chromium followed by buffing with a soft mop and mirror finish compound. Degrease with Trichlorethylene.

I can remember the elctroplater who taught he course advising trying to fill pits/scratches with solder was not sufficient to avoid visible imperfections in bright chromium plates. His experience from many years of plating was the pits/scratches were best rectified by the initial Copper plating and polishing; the use of solder and the hardness difference between the solder and parent steel meant linishing would always result in uneven flattening between the steel and the solder filling. Proper and thorough linishing between plating was essential for obtaining a pristine flawless bright chromium finish.

P.S. "Foreign orders" were mandatory during this course and I made several bright chromium exhaust tips my my car and my father's car.
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Robert Noel Reddington
Grand Master
Username: bob_uk

Post Number: 1021
Registered: 5-2015
Posted on Friday, 08 July, 2016 - 04:43:   Edit PostDelete PostView Post/Check IP

That's what I thought. The lack of hardness of solder in comparison with steel means uneven surface.
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Nigel Johnson
Prolific User
Username: nigel_johnson

Post Number: 160
Registered: 12-2008
Posted on Saturday, 09 July, 2016 - 07:58:   Edit PostDelete PostView Post/Check IP

Would silver solder not do for small areas of pitting then copper plating on top? I repaired both the corners on Geoff's Corniche by welding in 1/8th plate shaped to suit and remaking the brackets behind. I asked the plater to let me have the parts back after stripping but to no avail. The pitting was still there after chroming. If you pay a cheap price you get a cheap job. What a waste,some platers here are just bodgers.
Regards, Nigel.
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David Gore
Moderator
Username: david_gore

Post Number: 2112
Registered: 4-2003
Posted on Saturday, 09 July, 2016 - 09:42:   Edit PostDelete PostView Post/Check IP

Nigel,

There would still be a hardness differential between the steel and the various grades of silver solder as would be the case with the various types of soft solder.

As you have found, a reputable plater will do the job properly and a "bodger" will not. The cost of surface preparation is the biggest cost element in plating and the area where short cuts often occur to the detriment of the finished item - this also applies to painting.

Done professionally, the pits can and will be removed by proper use of Copper base coat plating with linishing between plates to level the surface to allow the plate to be deposited in the pits.
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Robert Noel Reddington
Grand Master
Username: bob_uk

Post Number: 1024
Registered: 5-2015
Posted on Sunday, 10 July, 2016 - 05:18:   Edit PostDelete PostView Post/Check IP

I think the solder is a bodge that lasts a few years then Pitts and flakes.

The process is simple but a rear centre bumper is too big for DIY.
Poor quality re chrome is rife.
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Nigel Johnson
Prolific User
Username: nigel_johnson

Post Number: 161
Registered: 12-2008
Posted on Sunday, 10 July, 2016 - 08:10:   Edit PostDelete PostView Post/Check IP

Thanks David. I regret to this day entrusting the job to that firm.. I think many a valuable part has been ruined in the past and will be in the future.
Regards, Nigel.
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David Gore
Moderator
Username: david_gore

Post Number: 2114
Registered: 4-2003
Posted on Sunday, 10 July, 2016 - 08:13:   Edit PostDelete PostView Post/Check IP

Robert,

The real problem is the cost of bright chromium plating has "gone through the roof" due to the cost of disposing spent plating solutions due to their heavy metal content and volume - a plating tank has to contain a lot of fluid to allow plating of large items.

The "Tri-plate" process using Copper. Nickel and Bright Chromium is getting harder to find and the motorcycle fraternity are the best source for information on local electroplaters as they insist on the quality of the Tri-plate finish.

The cheaper process is to use Copper, delete the intermediate Nickel plate and then bright Chromium however the appearance of this method is inferior to the Tri-plate process.

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