hamtaro145
Dirt Disciple
on a section of the cannondale website they specifically state do not powdercoat the frames....must be a reason for this
The effect of powdercoating heat treated aluminium.
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Why coat an aluminium frame in the first place, polish it 
There is absolutely no risk at all in (re)powdercoating aluminum frames. None. Don't re-powder a so-called "scandium" frame, but shit, don't buy one of those disposable things in the first place.
(Spoken from a collected dozens of thousands of frames worth of experience over the last 30 years)
(Spoken from a collected dozens of thousands of frames worth of experience over the last 30 years)
Mickey":1iqnxcqb said:
Yes there is, the risk is the dirt cheap powder coaters people use don't really care what the oven is set at.
For the MTB frame we would prefer the low end required for proper baking but they might have that set anywhere, especially as more heat = faster in a lot of peoples minds. When you talk to some powder coaters it is clear they just follow tradition (ie 'what works') and don't really have a great understanding of it.
I'm sure there are good and bad ones out there but it is worth considering what your frame will share the oven with that day...probably not a load of bike frames.
Slightly off-topic, but part of the risk in having an aluminium frame powdercoated is that powdercoaters generally shot-blast all their items ready for coating, but that will damage an aluminium frame so you need to find one who will prepare the frame chemically.
And obviously if they ignorantly stick your frame in with a batch of items that need a high temperature, that won't be good news (and you wouldn't necessarily know about it).
As the owner of a ten year old Easton scandium frame, I find Mickey's comment puzzling. So called scandium frames are made of a 7000 series alloy with an additional scandium content of just 0.6%. That makes the tubes stronger and better able to withstand welding temperatures, so the frame can be made lighter for the same strength as a standard 7005 frame. Obviously a frame could be designed too light and be fragile, but that's unlikely with an Easton frame as Easton are very choosy and wouldn't give the builder warranty cover unless they used an approved tube spec.
And obviously if they ignorantly stick your frame in with a batch of items that need a high temperature, that won't be good news (and you wouldn't necessarily know about it).
As the owner of a ten year old Easton scandium frame, I find Mickey's comment puzzling. So called scandium frames are made of a 7000 series alloy with an additional scandium content of just 0.6%. That makes the tubes stronger and better able to withstand welding temperatures, so the frame can be made lighter for the same strength as a standard 7005 frame. Obviously a frame could be designed too light and be fragile, but that's unlikely with an Easton frame as Easton are very choosy and wouldn't give the builder warranty cover unless they used an approved tube spec.
Anthony,
7005 aluminum is already "stiffer and stronger" than it needs to be when compared to 6061, the benchmark for reliability and durability.
Adding an additional grain enhancer to 7005 helps to highlight the primary failure mode of a too-light alu frameset, cracking due to fatigue.
Thinner, "stronger" material makes for a bike with a shorter service life. You want a material that "stretches" instead of snaps, essentially, and you want more metal at the tube junctions to "pull" on.
There is a lot of junk "metallurgy" promulgated by marketing types that makes claims based on elemental characteristics instead of the specifics of sound real world design.
There isn't framebuilder worth his salt that sold anyone a scandium frame with a straight face without making it very clear up front that they were building you a disposable one or two season frame. To have the same overall service life as a 7005 frame a sc7000 frame needs to be as heavy or heavier due to the brittleness of the material.
The aging temperatures on the sc7000 tubes are very low, enough so that it wasn't a good idea to powder them.
Specialized's duralcan ceramic frames(m2-m4, iirc) were an even worse exercise in materials application. Why you'd want a material that is sextremely strong in compression and relatively brittle in elongation in an application that calls for optimal elongation properties is beyond me. Looked great if you wrote and read the ad copy with blinders on though...
On media blasting-
If you want good powder flow and adhesion you have to blast and solvent dip a frame, especially on 7005. 7005 corrodes quite quickly when exposed to salt. Once the silica starts to precipitate off the tube it will take up big flakes of powder. A non-uniform surface does a great deal to prevent that from happening by presenting a greater surface area for the powder to stick to.
The take home message we can all agree on- don't let some clueless inexperienced chump powdercoat your frame!
7005 aluminum is already "stiffer and stronger" than it needs to be when compared to 6061, the benchmark for reliability and durability.
Adding an additional grain enhancer to 7005 helps to highlight the primary failure mode of a too-light alu frameset, cracking due to fatigue.
Thinner, "stronger" material makes for a bike with a shorter service life. You want a material that "stretches" instead of snaps, essentially, and you want more metal at the tube junctions to "pull" on.
There is a lot of junk "metallurgy" promulgated by marketing types that makes claims based on elemental characteristics instead of the specifics of sound real world design.
There isn't framebuilder worth his salt that sold anyone a scandium frame with a straight face without making it very clear up front that they were building you a disposable one or two season frame. To have the same overall service life as a 7005 frame a sc7000 frame needs to be as heavy or heavier due to the brittleness of the material.
The aging temperatures on the sc7000 tubes are very low, enough so that it wasn't a good idea to powder them.
Specialized's duralcan ceramic frames(m2-m4, iirc) were an even worse exercise in materials application. Why you'd want a material that is sextremely strong in compression and relatively brittle in elongation in an application that calls for optimal elongation properties is beyond me. Looked great if you wrote and read the ad copy with blinders on though...
On media blasting-
If you want good powder flow and adhesion you have to blast and solvent dip a frame, especially on 7005. 7005 corrodes quite quickly when exposed to salt. Once the silica starts to precipitate off the tube it will take up big flakes of powder. A non-uniform surface does a great deal to prevent that from happening by presenting a greater surface area for the powder to stick to.
The take home message we can all agree on- don't let some clueless inexperienced chump powdercoat your frame!
Your response is nice to hear from someone who clearly understands what he is doing and produces to top quality work.
I fear that most people convince themselves that they get your quality from a back end industrial estate powder coaters. There is the reason you charge $225 to PC the frame, some guys here are looking for something like $50-75 jobs and I'd be afraid at that price.
You have some very beautiful frames, are they all in powder?
http://www.spookybikes.com/files/imagecache/product_full/hawk 282.jpg (This is awesome!!!)
I fear that most people convince themselves that they get your quality from a back end industrial estate powder coaters. There is the reason you charge $225 to PC the frame, some guys here are looking for something like $50-75 jobs and I'd be afraid at that price.
You have some very beautiful frames, are they all in powder?
http://www.spookybikes.com/files/imagecache/product_full/hawk 282.jpg (This is awesome!!!)
I can't compete with your knowledge, but obviously you're saying I'm not a real man, otherwise I would have proved it by breaking my Rocky Mountain long since!Mickey":2nt1a44g said:
I'm not the original owner, but I'm pretty sure that RM gave a lifetime warranty on the frame to the original owner, and my understanding is that Easton stood behind that warranty in the case of material defects.
I was on a team sponsored by Rocky in 2001.
We broke every element and vertex we had. I worked at a Rocky dealer the next season and all of the sc7000 frames we sold broke too.
Chris at 3d had almost all of his Scandium frames break prematurely, every builder I've ever shot the shit with says the same thing.
Paul at Rocklobster is the only guy i've ever talked to that has had success with the stuff- he bought out Kinesis USA's stock when they closed up and used it mostly for cx bikes and made it clear that the frames had no warranties. He averaged about 3 seasons per frame.
Those frames were built with xc tubes and weighed 200 grams more than an equivalent frame made out of thr standard Easton road tubeset.
The only truly durable sc7000 bikes I know of were the Merckx bikes. It's hard to break a 3.5 pound road frame!
We broke every element and vertex we had. I worked at a Rocky dealer the next season and all of the sc7000 frames we sold broke too.
Chris at 3d had almost all of his Scandium frames break prematurely, every builder I've ever shot the shit with says the same thing.
Paul at Rocklobster is the only guy i've ever talked to that has had success with the stuff- he bought out Kinesis USA's stock when they closed up and used it mostly for cx bikes and made it clear that the frames had no warranties. He averaged about 3 seasons per frame.
Those frames were built with xc tubes and weighed 200 grams more than an equivalent frame made out of thr standard Easton road tubeset.
The only truly durable sc7000 bikes I know of were the Merckx bikes. It's hard to break a 3.5 pound road frame!
