Bicycle Mechanics - what parts can or cant be sand blasted?

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Seat post
crank set
sprocket
break handle and break clamp part
Can all of those be sand blasted and powder coated?
Hirohsima
10-18-10, 01:36 PM
Anything Aluminum can be PC yes. However for the best finish, I would not sandblast as it will ruin the surface condition.
Steel can be PC and blasted (sproket, yes) but the chain would chew up the finish pretty quickly.
media blasting will clear the surface and it won't damage it as much as sand.
also, most powdercoats are 6mil thick, which is more than enough to make your seatpost not fit anymore. you'd have to get a smaller seatpost and then powdercoat it, or coat it with anodization or another process that doesn't add significant material on top of the object.
also, BRAKENOTBREAK
You got my point ;)
But thanks for the input :)
media blasting will clear the surface and it won't damage it as much as sand.
also, most powdercoats are 6mil thick, which is more than enough to make your seatpost not fit anymore. you'd have to get a smaller seatpost and then powdercoat it, or coat it with anodization or another process that doesn't add significant material on top of the object.
also, BRAKENOTBREAK
For the seatpost.. Just mask off the bottom where it will be sitting in the seat-tube (wherever that may be for you). Bear in mind that it will not be able to be moved down unless you strip it, though. It seems, however, that it may be more worth it to anodize all these parts in a batch, it may be cheaper than powdercoating (Depending on where you go). Unless, of course, you absolutely want a flat color instead of a metallic one. Not to mention, it won't add any dimension to your parts. It will, however, reduce your parts a negligible amount.
Skip the tires. They don't do well with sandblasting.
u really don't need to sand any of those parts.. If it's anodized, just de-anodize it.
If it's currently painted, i bought a origin8 stem once from an LBS but they only had black. So i took it home and stripped it. It's pretty fast and simple, plus no harm done to the parts.
I sand blasted my parts when I fell asleep at a nude beach when a wind storm kicked up.
I talked to three or four sand blasters in St. Louis. They would gladly sand blast anything ($) but recommended getting only the frame sand blasted in preparation for powder coating. The powder coat places I talked to had done bikes before. They were adamant about doing only the frame and fork.
I would avoid powder coating the crank set. As Hiroshima said, there'll be a lot of chain wear on it.
it's easy to mask the 'fits to another thing' parts on a frameset. not so much on small parts. powdercoat is thick. thicker than a plastic painting dropcloth, so it will efffect fitment. also, you want someone who knows how to ream and face the edges that can't be masked. it's important.
mihlbach
10-20-10, 01:46 PM
I talked to three or four sand blasters in St. Louis. They would gladly sand blast anything ($)
That should be your first clue that you should disregard what they have to say. They probably have no idea how thin bicycle frame tubes are or if the frame will be structurally compromised as a result.
Scrodzilla
10-20-10, 01:58 PM
It would most likely be less expensive to just replace the stuff you have with the color you want than paying a bunch of money to have your current components sandblasted, powder coated and potentially ruined.
mihlbach
10-20-10, 03:55 PM
It would most likely be less expensive to just replace the stuff you have with the color you want than paying a bunch of money to have your current components sandblasted, powder coated and potentially ruined.
Illegal post. BF rules require you to forfeit your common sense and logic when entering.
That should be your first clue that you should disregard what they have to say. They probably have no idea how thin bicycle frame tubes are or if the frame will be structurally compromised as a result.
They didn't tell me they would sand blast anything, I just expect that they would. As I said, they were adamant about doing the frame and fork. I saw first hand some of the work they did. Quality stuff. Great prices at one of them, too.
Cost is not an issue here. The issue is how well will the parts fit together. I decided the front sprocket wont get powder coated but the arms will. Neither will the seat post.
Scrodzilla
10-21-10, 01:44 PM
Whatever.
Whatever.
Yup, whatever :thumb:
Build your own
10-21-10, 09:52 PM
I wish people would occasionally know what they're talking about on here.I've had thin sheetmetal stuff like like gas/oil tanks and fenders sandblasted with out any problems, a f***in' bicycle frame is gonna be fine.Same goes for any other parts.As far as PC, mask off where fit is critical.FWIW, i've painted chainrings before and the only wear occurs where the bushings meet the teeth.
stryper
10-22-10, 12:33 AM
arms of a crank are no issue at all. I had my miche cranks done in black when i first got them. He taped off the bolt holes, and 2 years later I have had no problems or wear on it.
heck, I even had spokes done when i first got the bike. Made it a bit hard to get em through the hub, but it worked just fine and since they were done at the same time as the rims, they matched perfectly. I don't think i'd do it again, rather go with anodizing next time on spokes and rim, but it worked with no issue.
mihlbach
10-22-10, 03:51 AM
I wish people would occasionally know what they're talking about on here.I've had thin sheetmetal stuff like like gas/oil tanks and fenders sandblasted with out any problems, a f***in' bicycle frame is gonna be fine.Same goes for any other parts.
Sandblasting is pretty harsh for lightweight road grade tubing. Are you sure you aren't talking about glass bead blasting?
Just because you can sandblast an oil/gas tanks or a fender does not mean that its wise to literally sandblast thin bicycle frame tubes. Bicycle frames are built to be as light as possible and still withstand tremendous loads, involving highly variable and complex combinations of tension, compression, and strain. The same cannot be said for tanks and fenders. Thinning the tubes slightly could significantly weaken the frame and shorten its lifespan. Just because a pro sand blaster (who needs work) says its OK, doesn't mean that it is unless they have lots of experience with bicycles, and even then I would have reservations. I may have less hesitation about sandblasting a cheap gas pipe plain-gauge frame, but I'm not sure the expense would be worth it on a low quality frame.
Mihl, i understand what you are saying. I figured litera "sand" blasting would be to harsh on the metal work so I have been using a different medium, silicon i think.
Scrodzilla
10-23-10, 06:23 PM
Wait...why is this even posted in SSFG?
Moving to the Mechanics forum, for lack of a better home.
fietsbob
10-23-10, 06:56 PM
bear in mind seatpost gets bigger with the layer of powdercoat.
I got a powdercoated handlebar,[ITM Trekking bar] ..
and had to remove PC to fit a Rohloff gripshifter on.
OD with coating was 22.5mm .
xizangstan
10-23-10, 08:33 PM
Just sell the thing and buy yourself a new bike. Bicycle salesmen need to pay their bills, too. :)
xizangstan
10-23-10, 08:38 PM
I sand blasted my parts when I fell asleep at a nude beach when a wind storm kicked up.
And the result is, you can't beat it!
Grand Bois
10-24-10, 08:41 AM
Sandblasting is pretty harsh for lightweight road grade tubing. Are you sure you aren't talking about glass bead blasting?
Just because you can sandblast an oil/gas tanks or a fender does not mean that its wise to literally sandblast thin bicycle frame tubes. Bicycle frames are built to be as light as possible and still withstand tremendous loads, involving highly variable and complex combinations of tension, compression, and strain. The same cannot be said for tanks and fenders. Thinning the tubes slightly could significantly weaken the frame and shorten its lifespan. Just because a pro sand blaster (who needs work) says its OK, doesn't mean that it is unless they have lots of experience with bicycles, and even then I would have reservations. I may have less hesitation about sandblasting a cheap gas pipe plain-gauge frame, but I'm not sure the expense would be worth it on a low quality frame.
Sounds reasonable, but it's just not true. It would be difficult to damage a steel frame with sand. You'd have to hold the nozzle in one spot for a very long time. The pro that painted my PX10 uses nothing but 50# sand.
http://inlinethumb53.webshots.com/46644/2997244730068014369S600x600Q85.jpg (http://rides.webshots.com/photo/2997244730068014369LwQnIg)
http://inlinethumb48.webshots.com/39919/2598152940068014369S600x600Q85.jpg (http://rides.webshots.com/photo/2598152940068014369OkFUTT)
Retro Grouch
10-24-10, 09:10 AM
I wish people would occasionally know what they're talking about on here.I've had thin sheetmetal stuff like like gas/oil tanks and fenders sandblasted with out any problems, a f***in' bicycle frame is gonna be fine.
1. I absolutely agree with your first sentence.
2. All bicycle frames aren't the same. Not even close. Most people are surprised at how thin quality bike frame tubes can be. Nivecrom tubes, for example, aren't nearly as thick in the middle as your sheetmetal fuel tanks.
DannoXYZ
10-24-10, 02:47 PM
Yeah, fuel-tanks and fenders are typically 3mm thick. High-end steel bike-tubing can be as thin as 0.4mm.
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