RaceDiagnostics
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Assuming you have a 200ml bottle of yellow passivate then add both bottles to 9.7l of deionised water.
- Thread starter Mr shiney
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foy9999
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Hi. Thanks for the reply and sorry for late response (I didn't get email notification, will need to check my settings).
Yes I noticed the '1%' and '2%' guidance on the bottle and 100ml is 1% of 10L so that explains the ratios. I am only doing small parts so miked up 2.5L and the yellow came out great but rubbed off easily.
I've naturally Googled this and enter a world of pain about alkalinity/acidity, zinc brighteners, nitric acid dips and heat to prevent to fix the yellow.
RaceDiagnostics
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The main problem is that Gateros no longer supply sodium dichromate passivation due to EU rules, it is some other concoction. This new stuff is rubbish, it gives a pale finish that rubs off easily.
I was surprised to see that their yellow passivation concentrate wasn't yellow, and was actually blue.
I have now bought some sodium dichromate from EBay and managed to also get sulphuric acid to make up the old school yellow passivation solution. Haven't had a chance to try it yet though.
I was surprised to see that their yellow passivation concentrate wasn't yellow, and was actually blue.
I have now bought some sodium dichromate from EBay and managed to also get sulphuric acid to make up the old school yellow passivation solution. Haven't had a chance to try it yet though.
RaceDiagnostics
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Most of the stuff you can get on ebay, for the hydrochloric acid the best you can get easily is 10% brick acid and for sulfuric look for this stuff in hardware store or line.
For sodium dichromate look here http://sodiumdichromate.co.uk/
For sodium dichromate look here http://sodiumdichromate.co.uk/
RaceDiagnostics
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Also, anyone else looking for that book if you google it and pdf, you will find it free to download somewhere on the internet.
Seadog
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RaceDiagnostics
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I bought my last lot from these guys on ebay from Russia, the delivery took about 10 weeks, if you order they will email you and tell you about the long delivery time and give you the chance to cancel.
This is the message I got from them but it actually took about 70 days, so you have to be patient. I haven't got round to using it, but it does look dirty compared to the pics on the ebay listing.
Hi!
You bought from me 200 gramm "industrial" sodium dichromate .
I warn you that in connection with "Covid-19" international mail working bad and slowly.
Delivery of a shipment Russia-UK may take up to 50-55 days.
If you are ready to wait, I will send your purchase. Your parcell wiil have a track number
If you are not ready to wait, I will send you a refund money.
This is the message I got from them but it actually took about 70 days, so you have to be patient. I haven't got round to using it, but it does look dirty compared to the pics on the ebay listing.
Hi!
You bought from me 200 gramm "industrial" sodium dichromate .
I warn you that in connection with "Covid-19" international mail working bad and slowly.
Delivery of a shipment Russia-UK may take up to 50-55 days.
If you are ready to wait, I will send your purchase. Your parcell wiil have a track number
If you are not ready to wait, I will send you a refund money.
RaceDiagnostics
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Here are some results to compare.
Zinc plated using the Gateros kit, then passivated using their new eco friendly trivalent chrome solution, unfortunately the passivation rubs off easily even after curing for a few days.
Below is using hexavalent sodium dichromate from ebay, 200g/3l water +10ml of Knockout drain cleaner. I polished the fuel pipe above with wire wool to remove the old passivation, gave it another 20mins of plating then 10 seconds in the passivation. Looks like I've now got it dialled in.
Zinc plated using the Gateros kit, then passivated using their new eco friendly trivalent chrome solution, unfortunately the passivation rubs off easily even after curing for a few days.
Below is using hexavalent sodium dichromate from ebay, 200g/3l water +10ml of Knockout drain cleaner. I polished the fuel pipe above with wire wool to remove the old passivation, gave it another 20mins of plating then 10 seconds in the passivation. Looks like I've now got it dialled in.
RaceDiagnostics
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I had been trying a quick etch first but this time I forgot and went directly from the plating tank to a wash then into the passivation tank.
I now need to work out how to get rid of 10l of the trivalent solution.
I now need to work out how to get rid of 10l of the trivalent solution.
droopsnoot
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Is it me, or does that later result lack the coloured effect of the normal passivating process? I'm struggling to describe what I mean, but you probably "get" it - like the colours you get when you see petrol on water. It seems more like a straight colour. It's a very nice result, don't get me wrong, but a little different than I'd have expected.
RaceDiagnostics
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The iridescent colours develop as the passivation dries and hardens. The amount of iridescent colours depends on the thickness of the passivation, thinner gives more, thicker gives less but better protection. I'm going for thicker and better protection. If I dipped for say 5 seconds Vs 10, there would be more green and pinks.
droopsnoot
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I see, thanks. That seems very quick, actually - I've had my Gateros kit for a few years, which I presume means that it has their earlier passivate, and I'm sure I have to do something like 30 seconds in clear, then 90 seconds in yellow. But yes, protection is the more significant thing.
RaceDiagnostics
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Similarly the new gateros kit recommended 60s or so with the eco passivation. I think they are using a much more diluted solution, to save cost perhaps.
I looked up the original Cronak patent for passivation from the 1930s, it seemed to recommend 200g/l of sodium dichromate and a 2 second dip, probably to speed up production. I have gone with just a bit more than the AJ Poyner Plating book recommendation of ~ 60g/l and 8 to 10 seconds.
One potential problem I had though was sourcing the sulphuric acid. I've gone with the drain cleaner but there is no way to tell accurately it's strength. From its weight it is close to or above 90%. Luckily the amount needed to be added doesn't seem to critical.
I looked up the original Cronak patent for passivation from the 1930s, it seemed to recommend 200g/l of sodium dichromate and a 2 second dip, probably to speed up production. I have gone with just a bit more than the AJ Poyner Plating book recommendation of ~ 60g/l and 8 to 10 seconds.
One potential problem I had though was sourcing the sulphuric acid. I've gone with the drain cleaner but there is no way to tell accurately it's strength. From its weight it is close to or above 90%. Luckily the amount needed to be added doesn't seem to critical.
Bluemotion
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Ok I know this thread has been running since forever and a day although I've never done any but I'd like a play with this plating process. I've various fixtures and fittings for several bikes I need to clean up on. I dont suppose I particualy need any type of specific plated finish at the moment as its not that important. Although the basic questions I have are... I'll start first with
1, Whats the easiest coating to plate? Would it be Zinc, copper, chrome, nickel? Basically which is the easiest kit to work with?
2, To do say passives, what base plating is needed? I've read some stuff on here but I don't quite understand the smaller details
3, Whats the easiest base metals to apply plate to?
4, Kit or separates? Im happy to buy a kit although what company offers the best 'understanding' help?
5, I've read above @RaceDiagnostics that one of the proper chemicals are no longer available therefore the finish is sub-standard and a failure, so any recommendations? Also would that be on all types of plating or just passive linked?
6, I'm quite passionate and take serious interest in what I do so would a decent power supply be more of a sensible buy?
1, Whats the easiest coating to plate? Would it be Zinc, copper, chrome, nickel? Basically which is the easiest kit to work with?
2, To do say passives, what base plating is needed? I've read some stuff on here but I don't quite understand the smaller details
3, Whats the easiest base metals to apply plate to?
4, Kit or separates? Im happy to buy a kit although what company offers the best 'understanding' help?
5, I've read above @RaceDiagnostics that one of the proper chemicals are no longer available therefore the finish is sub-standard and a failure, so any recommendations? Also would that be on all types of plating or just passive linked?
6, I'm quite passionate and take serious interest in what I do so would a decent power supply be more of a sensible buy?
droopsnoot
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Getting a decent power supply seemed to make a difference to the quality of the stuff I did. To clarify:
I bought a Gateros kit, which comes with a fixed power supply and a coil of wire to adjust the current output - like cheapo arc welders, you move a crocodile clip along the coil and that acts like a rheostat, it's all a bit trial and error. I got some pretty good results, but not terribly consistent. When I set the kit up again earlier this year to plate some more things, I bought an adjustable PSU and that seemed to make things better. The main thing was that it shows the current actually being drawn, and it made it easy to see when I had a bad connection. I can't say that I couldn't have got similar results with the coil, but it made things much easier for me.
I bought a Gateros kit, which comes with a fixed power supply and a coil of wire to adjust the current output - like cheapo arc welders, you move a crocodile clip along the coil and that acts like a rheostat, it's all a bit trial and error. I got some pretty good results, but not terribly consistent. When I set the kit up again earlier this year to plate some more things, I bought an adjustable PSU and that seemed to make things better. The main thing was that it shows the current actually being drawn, and it made it easy to see when I had a bad connection. I can't say that I couldn't have got similar results with the coil, but it made things much easier for me.
mtt.tr
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Here are some results to compare.
Zinc plated using the Gateros kit, then passivated using their new eco friendly trivalent chrome solution, unfortunately the passivation rubs off easily even after curing for a few days.
Below is using hexavalent sodium dichromate from ebay, 200g/3l water +10ml of Knockout drain cleaner. I polished the fuel pipe above with wire wool to remove the old passivation, gave it another 20mins of plating then 10 seconds in the passivation. Looks like I've now got it dialled in.
I am far to much of a wimp to use any form of dichromate
