Zinc plating

[Murf]

I need to get the bolts and nuts for my 550 resto zinc plated, I have read through past posts on the site about this and have decided that I am not going to do it myself.

Can anyone recommend a good platers that will do the whole process ie. cleaning, preparation and plating.
I would do basic cleaning, rust removal and degreasing of the parts before hand of course .

I am in the East Midlands but will send or take the parts to anywhere that is a well recommended company.
Thanks

[exvalvesetdabbler]

My local plater switched to anodising years ago and I haven't found any where that will do non commercial stuff or vehicle restoration bits.  I'm just in the process of  pulling a set of carbs apart, all needing yellow zinc.  Last summer I had 4 tacho/Speedo bases to do and the 3 quotes I got back from commercial platers ranged from 50 to 100 quid plus vat and postage both ways. I did them myself in the end but without proprietary brighteners in the bath the finish isn't mirror like but this didn't matter since they were covered over with black epoxy. The above platers were the ones that come out top on the search engines.

I searched around to see what I could find this time around, looking on car restorers forums and come up with  DDG plating in Nottingham and they seemed like a candidate to try this time around. Still a 3 hour round trip for me though , twice.

I'm also looking to alter my bath chemistry to improve things and try to source some proprietary brighteners in small enough quantities to make it viable.

There a lots of videos on u tube of people shining up dull plating with a wire brush and things do look shiny but without passivation the coating will degrade quite quickly, that's if they haven't brushed most of the coating away already.

Be careful with any high tensile bolts or springs as they will need  oven baking soon after plating to expell hydrogen to avoid  embrittlement.  Some platers can do this.


Regards
Dave

[AshimotoK0]

I think my mate Graham Curtis uses Derby Platers for zinc. Minimum order there though I think.

http://www.derbyplating.co.uk/services/

[McCabe-Thiele (Ted)]

I've used this firm on Abbey Street a few times over the latest 10 years for Chrome Plating, excellent job, turn
round time was long as they seem too always have a lot of work in hand.

[DomP]

I did most of the plated parts on my cb550, takes ages and a fair amount of room to do with some mixed results early on but soon got the hang of it.  Would I do it again? Maybe but only because I have the kit now, definitely don't rule out going diy

[Murf]

Thanks for the replies,
I believe Derby plating has ceased trading, they are just open to finish off orders they have but not taking any new work on.  Yet another one los.

DDG plating are only about 5 miles from me and they do hexavalent zinc plating which is supposed to be more corrosive resistant and less toxic and polluting than trivalent plating. I have phoned them and they will do small batches for restoring work. However they will not clean the parts, you have to clean them yourself. They told me that the parts go in the plating tank exactly as you bring them in, if they have rust or grease on them then they won’t come out very well.
  I have had a go at cleaning and degreasing some of the bolts I have and have given them a session in my ultrasonic cleaner, they have come out very clean but have a sort of brown rainbow colour to them. I suspect this is a reaction between the cleaning fluid and the remaining zinc plating.


I have no idea if they are ok or not to be replayed so plan to take some to DDG and see if I can get to ask someone there.  I am also worried about flash rusting on any parts I do clean before they get replated. 
I will keep you informed.

[exvalvesetdabbler]

A soak in white spirit to shift most of the grease then oven Pride is your friend if there is stubborn grease. Warm it up to speed things up.  If there is any deep pitting with rust in them they won't plate and you'll be left with black spots in the finish.  Either electrolytic clean or a long soak in warm citric acid solution so that the pits are showing metal.

Once past this stage they need to be kept dry to prevent further rusting because any residual plate will be gone.

The platers will degrease and pickle as part of the process but mostly to  clean off polishing compounds and cutting fluids from manufacturer of new components. Any black gunge might not be removed, also they don't want their baths crapping up.

I doubt they are still using hexavalent chrome as that has been banned through some end of  life vehicle directive. They will probably be using a  trivalent yellow passivate that gives a similar appearance to the old hexavalent finish.  If you need a clear passivate on some stuff best to bag them separately to those needing yellow.

Regards
Dave

[Oddjob]

Wasn’t hexavalent chrome the stuff in the Erin Brockovich film?

[kent400]

 I started re-plating parts a few years ago when the local plater ceased trading. A bit of a learning curve and research but now I get good results. Although most parts I'm re-plating are unseen.

The procedure place the parts in vinegar if rusty, that dissolves the rust and will also remove zinc plating. That can take a few days, then into brick acid and rinse. Dry off with heat gun. Some flash rust can appear.

Now ready to plate after a dip in caustic soda, a rinse and a dip in brick cleaner followed by a rinse. Now in the plating tank, It takes a bit of trial and error to set the amps correctly. Probably takes about half an hour on the larger bases and a bit less on smaller ones. Out of the tank, a rinse, into the passivate followed by a rinse. A drying cabinet would be ideal as despite a final rinse the passivate does sometimes leave slight stains.

 

 

[exvalvesetdabbler]

Those Speedo bases look shiny enough for me.

What bath chemistry and brighteners are you using? Alkaline zincate or acid chloride?

Not sure about using vinegar though, makes me cough and gag if I spend too long sniffing that.  One reason I started using citric acid for stripping. Works quickly enough if you warm it up to 'cup of tea' temperature.  Also citrate will chelate iron so more efficient than acetate for getting residual  rust out of any pitting.(Same mode of action as evapourust)

I'm currently using boric acid to contro/bufferl the ph around the cathode, again less smelly than vinegar. 

I'm just setting up to do all the metalwork on a set of carbs.

Getting hold of chemicals needed for making your own brighteners is impossible in the nanny state that we live in.

Regards
Dave

[AshimotoK0]

I just use the  zinc plating chemicals from Gateros. The  brighteners they use are spot on. I know they sell the top-up 'maintenance' brighteners separately but not so sure about the brightener they use on initial mixing of the zinc electrolyte. I did once try YouPlate zinc plating  chemicals but big mistake as the brighteners they use gave me crap results. I discussed this with them but in the end I just bolted with my feet at went back to Gateros. I have seen saccharine suggested as a brighter but never tried it.

[exvalvesetdabbler]

Thank Ash,

That's where I have been looking, there's the leveller make up and brightener available. 

Other brighteners could be aliphatic polyamines, furfural,thiourea, vanilla extract and derivatives.

Regards
Dave

[kent400]

I too use Gateros and just add a few drops of their maintenance chemical if the the plating gets dull. Getting the amps right and the temperature at 25c. Bags on the anodes helps to keep the electrolyte clean and filter it after each use.

Fair to say the vinegar does stink a bit so I just keep it out of the way and it does take a couple of days to dissolve the rust. Some parts might take longer especially something like that shown in the image that's in it now. The river it was found in has not been disclosed! 

[exvalvesetdabbler]

That's looking a bit of a mess. Though the plate inside looks like it's still there.

The worse bits I have seen on them is the outside at the bottom where they sit in water in the bowls and the pitting can be quite deep.

Regards
Dave

[exvalvesetdabbler]

[quote The river it was found in has not been disclosed!
[/quote]

Been magnet fishing?