[CD_SuperV2]

I want to Uber my Super V this fall. While I have the bike apart I was thinking of powder coating my V frame. The local CD dealer will not re-paint MTB frames and recommended that I get it powder coated. The local powder coat shop told me to find out what type of aluminum it was made of so that he could make sure not to damage the frame while the powder coat dries (baking at 350-400 Degrees). I called Cannondale Cust. Service. She said the the aluminum is 6061T. She stated that blasting of any kind, baking or heating of any kind, drilling, etc would all void the warranty. I guess I will have to void the warranty when I cut the shock tabs. But will baking the frame (drying the powder coat) damage the frame? She (cust Serv.) suggested that I buy automotive touch up paint to touch up the few areas where paint is chipping. I have read many posts that say that paint will just chip off the aluminum.

I need some help here. For anybody that has repainted or powdercoated their 'Dales, please let mw know what is the best route here.

Thanks,
Nick

 

[steadite]

The aging cycle of the heat-treat is done at ~160C (320F). Any time spent above this temperature permanently reduces the strength/hardness. There will also be permanent dimensional "growth" as well as probable distortion. Even if the warranty wasn't an issue you shouldn't do it.

http://www.matweb.com/search/DataSheet.aspx?MatGUID=1b8c06d0ca7c456694c7777d9e10be5b&ckck=1

 

[ozvena]

The link doesn't work.

You do not use top coat on bare metal. I would google how to prepare aluminum for painting. Some sort of surface prep and base paint should be applied first. A clear durable coat as last.

 

[Speedub.Nate]

I would defer to Spectrum Powderworks' opinion on this subject. They do enough powdercoating of bicycle frames to be trustworthy source of advice. I encourage you to email them specifically about your alloy, and reference what Cannondale told you.

http://www.spectrumpowderworks.com/...nEnterFrame=[type+Function]&fadeIn=false#faq5

"Will the heat used in the process damage my frame?"

"No, the temperature used is less than 400 degrees and is no problem for titanium, steel, aluminum, magnesium or any other metal or alloy. We do need to take precautions when finishing Easton's Scandium (SC 7000), but it can be powder coated."

There comes a time in life when you say "to hell with the warranty" and make your bike your own. Is today that day?

 

[CD_SuperV2]

Thanks guys, I e-mailed Spectrum and will let you knwo what they reply. If anyone else has some input I'm all ears.

NIck

 

[ozvena]

Nice Picture Gallery they got there. :thumbsup:

 

[Speedub.Nate]

Nice Picture Gallery they got there. :thumbsup:

They do beautiful work, I agree. And FWIW, I've never heard reports of frame problems / breakages after powdercoating. But I'd be lying if I told you I knew much of anything about heat treatment.

 

[CD_SuperV2]

I spoke with Liz from Spectrum Powder Works. She said that they have done lots of CD frames. She wasn't familiar with the Super V frame specifically, but I doubt it is any different than any of CD other frames as far as this subject goes. She said that the only bicycle frames that you had to watch for is any scandium(spelling?) frames.

Nick

 

[ozvena]

Some aluminum frames are heat treated once the frames is welded some not. I would be concerned about my frame in an oven again without learning myself about this process first. Have you ever received a wrong advise from so called "experts"? That explains my signature below...

You know that you loose the warranty. One of the reasons is that Cannondale has no control over the oven used and accidents with incorrect temperature do happens.

 

[tlg]

I called Cannondale Cust. Service. She said the the aluminum is 6061T.

6061T____ ? What's after the T?

6061 is the type of Alum.
T is the temper.
6061-T0 (6061-0) is the anneald (softest) state.
6061-T6 is a heat treated temper. One of the most common alum.'s used.

I really doubt a frame would be made in an anneald condition. It'd be like butter.
By heat treating 6061-0 to -T6 you increase the Ultimate strength 250% and the Yield strength by 500%.

If your frame is truely in an annealed state, baking it can't make it any softer.

If it's heat treated you really need to be cautious. The process of annealing heat treated alum. is baking it at 650-750°F. Hope your powder coater has their oven calibrated and controlled. Otherwise you may reduce the frame strength by 500% :eekster:

"Some powder coating ovens running above 400°F have been known to reduce the temper on such aluminum alloys."

 

[steadite]

I specify heat-treats for a living....

The heat-treat condition of the frames would be T6. This means aged at about 170C (340F) for 8-10 hours (from ASTM B918, Table 2).

Aging of aluminum is a function of both time and temperature. The higher the aging temperature, the shorter the time to reach max properties. The attached plot shows aging response of 6061 at a variety of temperatures. It shows that peak strength is reached in ~10 hours at 171C (340F) or only 1 hour at 204C (400F). Also, the effect is cumulative; if the part has been aged to peak hardness at the factory and is later aged at 204C for another hour, the result will be overaging (softening).

The thing to do is ask them how long the frame spends at temperature....if it's just a couple minutes at say 375F, then it's probably fine. If it spends an hour at that temperature, the (previously aged) 6061 will almost certainly be overaged. Not only will overaging reduce the strength, but there will also be dimensional growth, so fits like the headset counterbore could be loose.

Ask them if they've measured mechanical properties of any 6061 frames before and after their process (at least hardness).

 

[CD_SuperV2]

tlg,

The service rep at Cannondale did not mention anything after the T. But she did say that the frames go through a heating process.

Well is sounds like the heat curing that powder coating requires could be potentialy fatal to my frame. If I were to get it bead blasted, can I paint it myself. My powder coater said he will liquid paint it, but the cost would be double (the powder coat cost) or more. Can I use shaker cans or brush on. Special primers? Or would the paint jsut chip and flake off after a few rides?

-NIck

 

[tlg]

tlg,

The service rep at Cannondale did not mention anything after the T. But she did say that the frames go through a heating process.

Most likely heat treating. A heating process could also be annealing, but not likely.

Well is sounds like the heat curing that powder coating requires could be potentialy fatal to my frame. If I were to get it bead blasted, can I paint it myself.

Absolutely. But you have to do it immediatly! See below.

My powder coater said he will liquid paint it, but the cost would be double (the powder coat cost) or more.

Maybe he's not geared to liquid painting. Powder coating is an expensive process. Look around for other painters. Also look for someone who does electrostatic painting and uses epoxy paint. It can be just as good (or better) than powder coating. At a company I use to work for, we had a paint booth and used electrostatic paint guns with epoxy paint on outdoor industrial equipment. The stuff lasted years.

Can I use shaker cans or brush on. Special primers? Or would the paint jsut chip and flake off after a few rides?

You can use either. Spray will give you a better finish. Brushes will leave streaks. You want a primer that's specific for aluminum. The most important part is proper preparation which can be difficult.
Read this article. Especially the Painting of Aluminum Boats and DIY Applications part. If you're going to have your frame blasted, have it scheduled, have your home "paint booth" set up, be at the blaster when the frame is blasted, and take it home immediately to paint it.

 

[ozvena]

Or have it blasted and be done with it, leaving it with no paint????

 

[Dan Gerous]

Or have it gold plated!

 

[jdp526]

Powdercoat paint material is much much cheaper than automotive paints that have several different chemical components. Powdercoat paint is sold by the pound and I have seen it for less than $20/lb.

If you have a small to medium size compressor, a paint touch-up gun, you could paint the frame yourself. And as tlg mentioned above, the preparation is the hardest part of the job. You can either sand the old finish down and paint over it or find someone that can soda blast the frame which will remove the paint and leave an extremely smooth finish that would require minimal prep before painting. If you remove all the paint you should probably use an epoxy type of automotive primer like PPG DP40. And then use an automotive topcoat, either a single-stage paint that doesnt require a clearcoat, or a dual stage that does. Either way, I would suggest spray a couple of coats of clear so that you can color sand the finish to remove any dust and orange peel.

You may be better off locating an auto painter that will already have supplies because you could easily spend a min of $100 - $200 just on paint supplies to do it yourself, but you will have an extremely durable finish. You could just provide a pint of paint and have them spray it for you. Auto painters will already have the primers, reducers, thinners,clearcoat finishes,hardeners, etc that you will need if you did the job yourself.

I like to do as much work myself so I dont mind spending the money on tools that I would be paying someone else and then you will have the tools/equipment for years for other projects that come along.

 

[CD_SuperV2]

I finally got an e-mail back from Spectrum and this is part of what was in the e-mail:

"The frame should be just fine. We have done thousands of aluminum frames. We cure at about 375 degrees. You would not want to cure under much lower. It has more to do with the time spent in the cure oven. We are not an industrial powder coating facility so, you do not have to worry about the frame being damaged. You would be in the $300-$325 range for this job and our turn around is at about 5 weeks right now."

These guys specialize in powder coating bicycle frames. This make me feel a little more comfortable getting it powdered. But I though I would share this will all.

Nick

 

[CD_SuperV2]

PPG evidently makes some powders that only require a cure time of about 15 minutes at 285 degrees. I am waiting on some guys to get bake to me with more info.

 

[CD_SuperV2]

PPG evidently makes some powders that only require a cure time of about 15 minutes at 285 degrees. I am waiting on some guys to get bake to me with more info.

 

[alias]

?

Why don't you forego all the warranty worries and FIVE week lead time and have Cannondale re-paint your frame?

Your first post states that your DEALER does not repaint....but C-dale does....