szrdave Posted January 18, 2012 Report Share Posted January 18, 2012 I've got a slightly grotty (and blue) disc spider and manky master cylinder cap in aluminium I'd like to take back to bare metal and clean up for re-painting. I also have access to a shot blaster that uses 316SS shot at work. Would it be ok to use it to strip the above parts? Or is it likely to be too aggressive? Link to comment Share on other sites More sharing options...
alexp5 Posted January 19, 2012 Report Share Posted January 19, 2012 Stainless shot on aluminium is a little aggressive i think. You may end up with dust. Glass bead is the way to go. You'll get a nice satin finish and enough of a key for paint to stick. Use etch primer. Crushed walnut shells is another alternative. HTH. Link to comment Share on other sites More sharing options...
lorenzo Posted January 19, 2012 Report Share Posted January 19, 2012 I wonder if it'd be a good idea on the brake centre as the aluminium would perhaps get work hardened and become brittle? Link to comment Share on other sites More sharing options...
alexp5 Posted January 19, 2012 Report Share Posted January 19, 2012 I wonder if it'd be a good idea on the brake centre as the aluminium would perhaps get work hardened and become brittle? Wouldn't of thought so... Soda blasting mebbe? Link to comment Share on other sites More sharing options...
overload Posted January 19, 2012 Report Share Posted January 19, 2012 I've got a slightly grotty (and blue) disc spider and manky master cylinder cap in aluminium I'd like to take back to bare metal and clean up for re-painting. I also have access to a shot blaster that uses 316SS shot at work. Would it be ok to use it to strip the above parts? Or is it likely to be too aggressive? Waaaay too aggressive!!! The finished item will end up looking like grey charcoal! Soda blasting is the way. Link to comment Share on other sites More sharing options...
Mark/Foggy Posted January 19, 2012 Report Share Posted January 19, 2012 Talking of blasting, I've got some Magnesium being Aquq-blasted as we speak. This is actually to clean up the sweated and rivetted on steel spoke ring on a set of wire hubs. Anybody know a chemical way of colouring and protecting the raw mag when I get them back. I've got some zinc paint coming, it's a nice satin grey colour and should weather a little in time, but it won't look perfect. Link to comment Share on other sites More sharing options...
2T Institue Posted January 19, 2012 Report Share Posted January 19, 2012 Talking of blasting, I've got some Magnesium being Aquq-blasted as we speak. This is actually to clean up the sweated and rivetted on steel spoke ring on a set of wire hubs. Anybody know a chemical way of colouring and protecting the raw mag when I get them back. I've got some zinc paint coming, it's a nice satin grey colour and should weather a little in time, but it won't look perfect. Magnesium needs to have a chromate appliied before painting. Chromate is the corrosion protection http://www.mb-racingwheels.com/magnesium_protection.htm Link to comment Share on other sites More sharing options...
Superdunc Posted January 19, 2012 Report Share Posted January 19, 2012 Talking of blasting, I've got some Magnesium being Aquq-blasted as we speak. This is actually to clean up the sweated and rivetted on steel spoke ring on a set of wire hubs. Anybody know a chemical way of colouring and protecting the raw mag when I get them back. I've got some zinc paint coming, it's a nice satin grey colour and should weather a little in time, but it won't look perfect. You want mag to be Chromated as allready stated. The part will end up very dark grey in colour. These peoplecan sort it for you and are fairly local. http://wdkmotorsport.com/contact.php Speak to Ian or Simon. Link to comment Share on other sites More sharing options...
Cibbersicks Posted January 20, 2012 Report Share Posted January 20, 2012 I'm going to need to have my magnesium sprocket carrier machined down on the sprocket face. It's currently a light gold colour, I don't know what the coating is though. I'll have to do something to protect this freshly machined face presumably? Any ideas what? Link to comment Share on other sites More sharing options...
Mark/Foggy Posted January 20, 2012 Report Share Posted January 20, 2012 Magnesium needs to have a chromate appliied before painting. Chromate is the corrosion protection http://www.mb-racingwheels.com/magnesium_protection.htm Ya see, it's all about the knowledge. I'd got it in my head that chromating was an electro process, probably 'cause of the old Electron name for mag alloy. Now a big bubbling vat of a witches brew is right up my street. Was worried about the steel and there are a couple of phosphor bronze bushes that I don't want to move. Ta You want mag to be Chromated as allready stated. The part will end up very dark grey in colour. These peoplecan sort it for you and are fairly local. http://wdkmotorsport.com/contact.php Speak to Ian or Simon. And my friend, I'll be looking these guys up on Monday. Don't think I need to stretch to 6kg of chemicals for a little job. Link to comment Share on other sites More sharing options...
Superdunc Posted January 20, 2012 Report Share Posted January 20, 2012 And my friend, I'll be looking these guys up on Monday. Don't think I need to stretch to 6kg of chemicals for a little job. Simons on Holiday so speak to Ian. Link to comment Share on other sites More sharing options...
2moto Posted January 20, 2012 Report Share Posted January 20, 2012 Talking of blasting, I've got some Magnesium being Aquq-blasted as we speak. This is actually to clean up the sweated and rivetted on steel spoke ring on a set of wire hubs. Anybody know a chemical way of colouring and protecting the raw mag when I get them back. I've got some zinc paint coming, it's a nice satin grey colour and should weather a little in time, but it won't look perfect. I've had very good results with using aqua blasting that has a corrosion inhibitor in the media. I've done magnesium engine cases that way and other magnesium bike bits. They come up looking a satin bright colour. I've not applied any secondary coating and even after two years of use, they show no signs of corrosion. You could paint, of course. Don't ask me what the "corrosion inhibitor" is. It does seem to work, though. Link to comment Share on other sites More sharing options...
Fatbloke Posted January 20, 2012 Report Share Posted January 20, 2012 I know someone with a vapour blaster if you are interested? Based in East Yorkshire. Fatbloke. Link to comment Share on other sites More sharing options...
szrdave Posted January 21, 2012 Author Report Share Posted January 21, 2012 In the end I couldn't be arsed with sanding or chemically removing the paint, so I gave it a go on the shot blaster. Turned it down to 15psi and it's cleaned the spider up a treat Link to comment Share on other sites More sharing options...
Cibbersicks Posted January 22, 2012 Report Share Posted January 22, 2012 I'm going to need to have my magnesium sprocket carrier machined down on the sprocket face. It's currently a light gold colour, I don't know what the coating is though. I'll have to do something to protect this freshly machined face presumably? Any ideas what? Any ideas on the above at all folks? Link to comment Share on other sites More sharing options...
kanerdog1x1 Posted January 22, 2012 Report Share Posted January 22, 2012 Any ideas on the above at all folks? you need to get it chromated. the gold colour you have on it is probably 'alocrom 1200'. it would be ok for a few weeks, but would soon fur up, and its not only the surface that corrodes, if left untreated microcracks can form and corrosion will burrow inside like woodworm. not that much of a problem on something like a cush drive, but on a wheel could prove catastrophic. Link to comment Share on other sites More sharing options...
kanerdog1x1 Posted January 22, 2012 Report Share Posted January 22, 2012 double penetration. Link to comment Share on other sites More sharing options...
Cibbersicks Posted January 22, 2012 Report Share Posted January 22, 2012 Muchos gracias Kanerdawg... I'll look into it when the time comes. Link to comment Share on other sites More sharing options...
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