Paint removal
 

I am thinking about getting my road frame powdercoated within a couple of months.

Do I just use any type of paint stripper? It is an aluminum frame.

Do you have any tips to make it easier to strip the paint?

Also, is the head tube and the bb all that I will need to tape up? Or will I need to somehow tape up the rear derailleur bolt as well?

Ask your powdercoater about prep. They usually blast the frame to have a perfectly clean surface so the powdercoat will adher properly. You may be able to just let them handle it.
Ask them about taping as well. With true powdercoating the stuff is applied electrostaticly(sic) and will go everywhere so you need to cover everything that is threaded or needs to be machined back flat or plan on running a tap thru all that stuff and getting some things refaced.

You will need to remove everything off the frame and plug the BB and the head tube so the powder will not get into the shell or the head tube, if it gets inside it can be a real pain to clean up, you will have to run a tap all the mounting holes and reface the head set. I had a frame redone and they did not plug the BB, it took me four hours to clean up the BB.

Sand blasting a bike frame is tricky, if the sand is too coarse you can remove more then just paint. I have seen frames ruined by removing using too coarse abrasives. Make sure the person striping the frame knows just how thin the tube wall is and what the frame is made of. Before the frame is redone inspect it for any cracks or damage.

To blast alluminum you would use crushed walnut shell or synthetic beading and lower pressure.
I realize that none of this has been a direct answer to your question but I am not a big fan of paint strippers. They are tough on every thing they touch, the post waste is hard to get rid of, and if any gets in the vent holesit might show up again after your paint and screw it up.

to cheaply repaint a bike could i just sand off the old paint by hand? would that work? why not?

I was told by the powdercoaters that I would need to strip the frame because he doesn't want to be responsible for it.

As for sanding it would take a long time to sand it down to the metal.

Give the powder coater a call and ask. I have spoken to a powdercoater here in New Orleans about doing a bike for me. They take care of all the prep work - bead blast, degrease - so they can guarantee the job. I would be surprised if anyone in the powder coat/paint business didn't insist on doing the prep themselves. Prep is included in the price which runs $125 for a very basic one-color job at this shop. They do mostly motorcycles, but they have also done many bicycles and assured me they plug and mask the head tube and bb shell. I am sure I could do a decent paint job myself with spray cans of auto primer, paint, clear coat, and I would love to do it myself. But, frankly, I don't have the time for the thorough prep and multiple coats. $125 sounds like a bargain from that standpoint.

Hi Lowcel

I reccomend strongly against the use of paint stripper on aluminium alloy frames. Most common paint strippers are extremely caustic i.e. they contain sodium or potassium hydroxide at high concentration. This will attack (eat for breakfast) aluminium & its alloys. Unless you are able to find a paint remover designed for the job I would not take the risk.

"Gentle" blasting as mentioned by Rev.Chuck is probably the best way, but I'd seek out some professional opinions on this if it were my frame.

Good luck with the project,

Ed

Thanks, looks like I may be looking for a different powder coater. This one mainly does motorcycle parts and show car parts. I'm going to start looking for someone experienced with bikes.

Thanks everyone.

just because they dont do bikes doesnt mean they don't know what they're doing.

in fact, i'd prefer taking my bike to someone who did motorcycles and show cars. HUGE money in that industry, and if they've got a good reputation it's been earned. when you're dealing with $50k motorcycles and $100k+ cars it's your work that speaks for you, not your marketing.

the basic process is the same for powdercoating most anything. strip it, clean it, charge it, powder it, bake it.

ephemeralskin, if you just want to put another color (spray can job) then as long as the bike isn't rusty,treat the existing paint as the base. Just scuff the old stuff to give the new paint something to hold onto and clean the frame good.

Fore, they are the ones that said that they do not want to strip the paint. To me that tells me that they are not familiar with the aluminum. I am not making any assumptions.

If they had told me that they could strip it I would have let them do the job. Believe me, I would much rather have the job done locally.

Ephemeralskin, I am not looking to do it cheaply, it is not a cheap bike so I am willing to spend the money on it.

I am also going to do the same, but why take the old paint off?

Old paint is smooth, which will provide a smooth surface for the new paint. It also protects from corrosion in case your new paint will fail. The only thing that needs to be done, is to degrease the surface very well...

That is how I am going to treat my bicycle...

BTW, is it safe for my carbon seat stays to be powdercoated? Would I need to tape them off or just forget about the whole project?

rev is so right if you are powder coating avoid chem strippers, media blasting is the best way, but you should let your powercoat guy take care of that because if you touch the frame with your hands you will get oil spots and the powdercoat may be affected