Ready to powdercoat, please look (pic)

[fastar1]

I call BS, Ive coated hundreds of motorcycle parts, and they all get cured at 350+

Not to mention tons of times I have aluminum parts welded 6061, cast, etc, the heat generated during the welding is well above 275 degrees. And it does not weaken the aluminum. Alot of Scuba tanks Ive seen have the top welded onto the bottle, how could they weld that on without more then 275 degrees heat....

If those welded parts had any tempering treatment (T4, T6) then they lost it during welding, meaning they were weakened. If they haven't failed yet it's either because they weren't tempered to begin with, or you have been lucky. Either way you need to know the materials you're working with before you 'fix' them.

If I understand dmctaggart correctly, curing heat from powdercoating has some tempering effect so wheels that are not tempered to begin with will lose ductility and gain strength and brittleness after PC. To him, it is not enough to be concerned about but then he didn't mention which curing temps he was using for his bike. Hotter curing equals more brittleness.

Since only the wheel engineer knows the strength and stiffness requirements of the wheel, I would choose the low temp powdercoating to avoid inadvertently changing the properties of the material. And that is true for all aluminium parts.

As for the scuba tanks, they would simply be heat treated after welding to acheive whatever strength/ductility target they needed.

[fastar1]

why not just leave the holes the way they are. just bring it over to my shop once it is done and you can chase the threaded holes with a tap. it might turn out cleaner that way since you'll only be removing the powder coat inside the threaded hole, where as with a bolt, you'd end up with a spot the size of the head that isn't coated. odds are i have 99.9% of the sizes you'll need. i'm sure they are all metric, as long as there is nothing bigger than M20 or something like that. i have some large metric taps, but am limited on pitches available.

i won't charge you anything, i'll do the first couple to get you started, then you can do it. just don't break a tap. it'd be pretty hard to do in a hole that is already threaded anyway though.

Chasing threads will weaken them because the thread shape out of the factory is not the same as used on taps and dies.

Have you ever noticed that when you chase threads you're not just removing foreign material but some of the metal too? Taps and dies have sharper points so they cut sharper grooved threads, which makes them weaker. Plus as DY said, with powdercoating being so thick it is very hard to be sure that you are cutting the same threads that were there already there.

Besides, isn't easier to just spin bolts into each hole before powdercoating?

[fastar1]

That's what this thread is for, I want as many alternatives as possible.

Nice job on the wheels, and I love how you just wheeled the frame around in a cart while looking for bolts. You should have tried putting a bar code sticker on it and asking the cashier to scan it on the way out. Would have been interesting to see her reaction LOL