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Technical & Reference Section => Tech and Restoration => Topic started by: Swivel on August 01, 2008, 09:23 AM
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Hi. I've just called a place local to me and they want to charge £47 to strip my TA frame/forks. I thought that maybe a little toppy on price but they are around the corner so very handy. Anyway, they said that they would dunk the bike in Sulfuric Acid and this they said could potentially stay in the tubing if there is not a small outlet hole in each tube. I said, what about if the tubes are sealed and he said that doesn't matter, the acid can at times find its way in ?? ???
Anyone else heard this? I thought this maybe bollox but who knows. He did say that maybe sand blasting is the way to go as its less harmful to the metal. Has anyone removed chrome via sand blasting and what's the final effect like?
I'm gonna get this painted white by Dan once its done so want the final finish to be the best possible.
Let me know...
Ta,
Matt :daumenhoch:
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you can powder coat over chrome
just make sure any rough bits are flattened
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There was a thread on Vintage once where someone had had a National Pro,I think, rechromed. At first it looked mint but after a while the whole downtube just corroded away because they had left the stuff they used to strip it in the tubing. The bloke was absolutely gutted as you could imagine as the chrome wasn't that bad to start with he just wanted it better :crazy2:
So I don't think he is talking bollox but you would have to be pretty unlucky as that's the only one I have heard off, but if you are getting in powdered I wouldn't bother as theruler said you can powder over it as long as the rough bits aren't too bad.
Andy.
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Hiya Matt, I powdered over untouched chrome recently and there was like little holes in the powder where it had heated up and made bubbles that had then burst. So I had to start again, had the powder chemically removed to take it back to the chrome then had it lightly blasted for £20 but tbh a good wet n dry session would have done the same. Came back mint after that. So just key the surface and try and flat out any blistered and pitted chrome. It's very likely you'll end up with a smoother finish to work with less imperfections than taking it back to raw metal. And if it sits around the powder place for any length of time raw it'll oxidize and your smooth finish will be shit again.
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Ask Dan, maybe show him the frame
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What the plater says is true, as chromo steel has a higher chromium content.
So if the solution removes the chrome it will also start on the steel tubing.
It can be done if they are carefull, but you know what its like, they dunk it in a bath, walk away, come back
30 mins later to find most of the frame dissolved.
A caustic soda/water bath will remove chrome(with a 12v electric current), but it will not remove the nickel
plate (slightly more gold colour than chrome) that is underneath the chrome.
Nickel plate is easily sanded (emery cloth/wet and dry etc).
Sand blasting is generally not used, more likely steel blast media, very abrasive and will give a pitted finish to thin wall steel tube.
Aluminium oxide (pink alumina) media gives a finer finish than steel, but will not remove chrome.
So to remove plating on a frame successfully without causing damage would probably have to comprise of a combination of the
methods above.
Caustic bath to remove chrome, nickel strip, alumina blast to remove corrosion.
Explaning carefully to a plating company what you want to achieve so they can do their best to help you would be required.
Happy stripping :daumenhoch:
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my haro had real bad chrome on the front end , so my mate blasted it which took off the peeling chrome , then powder coated it looks the muts now
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Yes there is a link somewhere about a VDC that suffered from internal corrosion due to the acid used in the stripping process. It has pictures that will shock you. So please don't let another frame suffer to unsympathetic strippers!!!!! :'(
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I think I may well go down the sand blasting route. I spoke to another person yesterday and they have their frames done that way and the effect was very clean if not cleaner as it saves you rubbing it down etc... just takes it back to bare metal apprantly. We'll see. Will call about today and get a price ;)
Will keep ya all posted about this! Thanks again to everyone for their advice :4_17_5:
Matt :daumenhoch:
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Matt if you are gonna powder it then just get it blasted. It takes the chrome off and it looks loke a normal blasted frame afterwards but the nikel is still under it. You can just rub it down with some wet and dry to give it a smooth finish then send to Dan. To reverse the chroming process is normally around £50 for a f+f and a blast is about £10. You would never know the difference once powdered. ;)
If you was going to get it rechromed then obviously you would have to reverse the process.
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Matt if you are painting the frame just get it blasted by some light media such as walnut shell or glass bead, i guess a reputable company using sand would be ok but tell them that you need the welds to be kept looking og or they blast them flat. I powdered a gt once over the chrome and had the same issue as Mark above, it peeled back where some corrosion had occured over the years. Blasting is the way forward but nothing too aggressive or its bye bye to your serial number and weld detail :)
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Just a light blast to key the chrome is adequate, and just manually flatten out any corrosion. No need to blast to remove chrome, just key it. It'll take ages to remove, cost more and they'll have to use something agressive.
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Sounds good lads. I intend to get the Skyway TA powdered white by Dan so I think sand blasting or that glass blasting is the way to go. I will let them know my intentions so thanks for the heads up Dom about the welds and serial, top man ;)
Will try and get this done next week so will post up some before and after piccys!
Cheers,
Matt :daumenhoch:
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Alright lads, ok the TA frame/forks went to the sandblasters today. I had a chat about the drop outs (which are so clean and minty by the way) and the serial and they said that it can be done via a medi-blast or something that removes the top layer of chrome but doesn't damage the details, all for £15! So sounds good. Will be with me next week and i'm gonna give it a little rub down before it goes off to SBD.
Will post up before and after shots! :D
Cheers for the advice again,
Matt :daumenhoch:
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Keep the pix coming then Matt ... you shouldn't need to touch the frame once it's been blasted :daumenhoch:
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matt is the chrome that bad, :)
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Not overly bad, but the guy did a test and showed me how it turns out and it would definately be ok to powder over. Quite excited really, been after doing this TA for the last year or so.... once done, I'll pick it up and wack up a piccy ;)