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G-tron wrote: Thought it might be some low grade stainless like 403 or some arb alloy blend. But thanks. surprised it held up so well for regular mild steel then.

IIRC the manufacturers had really good processes in place for painting the frames after they were built. I wouldn't be surprised if they had dipped the frames in acid before priming them.

A phosphate (phosphoric acid) etch is very common before painting. All the major auto paint manufacturers sell such a product. I use Kleenstrip Metal Prep as sold by Home Depot - about $14/gallon and it's reusable.

Regarding the Kawasaki frame paint quality from back in the day, I'm not impressed. There was lots of rust on my 750 frame because the paint was thin is places such as around the bracket tabs and underneath the steering head. One thing I found interesting was that the lower half of the frame had a special primer applied. I believe this was an additional barrier in case of road grime and salt attacked the finish.

Im doing my 77 kz as a pro street big tire. I had the frame of my other KZ years ago, powder coated. Im gonna keep this one so I'm gonna spend the little extra and have blasted and powder coated. It's so durable and I personally like it.

tomsbadkz wrote: Im doing my 77 kz as a pro street big tire. I had the frame of my other KZ years ago, powder coated. Im gonna keep this one so I'm gonna spend the little extra and have blasted and powder coated. It's so durable and I personally like it.

Yep, a properly blasted and treated frame with powdercoat done properly, will never rust again, modern powders are as thin as paint but much more durable...

I've stripped frames by chemical and sanding, and by media blasting, and hands down media blasting is the winner.

I now take frame, swing arm, and all the chassis parts such as stands right down to little brackets in at the same time. I string together all the smaller parts with mechanic's wire so they won't get lost, and my local industrial blasting outfit completely blasts all the parts down to bare metal, ready for a quick prep and paint, all for about $50 - $80. Then I paint the parts at home myself. I'll warn everyone - painting a round tube full double cradle frame is not as easy as it looks, and there is a lot of paint wasted in overspray, and it is very easy to miss entire sections from different angles. I find it best to suspend the frame horizontally from the ceiling by three points tricycle fashion, with the top most area about 44" off the floor. Start spraying into the hardest to reach or see areas first and work your way out to the easiest parts last. I prevent having to hand sand the frame in between coats by following spray applications within the flash off time recommended by the paint manufacturer. Apply the final finish coat on fairly heavy and wet, and work quickly to the outside to prevent dry pebble overspray finish on the first sections of tube sprayed. My buddy was a genuine expert at painting frames by the time he did his second one - as good as powder coat. I still end up getting a few spots with rough spots in a few places, but by working to the outside, I always end up with great results anywhere the frame is exposed on the finished assembled bike. For a quality job, I use an etching metal prep, and epoxy primer and paint, occasionally with 2 part clear on top. I only had one problem once with a swing arm and center stand where the paint started to flake off a few years later like big pieces of eggshell - I never did figure out why, as the frame didn't have the same problem, and I had sprayed everything at the same time...????

Powder coating requires a certain roughness / texture to the surface, so I just take the parts to whoever is applying the finish and they get them blasted according to their requirements - it costs more, but I don't risk having to pay for re-blasting, either.

Got some quotes today. Regular sandblasting $200.

Dustless (aqua based?) blasting and etch primer $60 from a private guy who runs a mobile service.

Seems like a no brainer. He reckons he etch primer stuff is massively durable, as its the only thing they struggle with when blasting it again.

I prefer to use an epoxy primer. If your frame is blasted clean there is no need for any sort of etching primer. In the past I used to use PPG DP epoxy but more recently went to Transtar epoxy primer because it's about half the price and frankly, it sprays beautifully and I can't tell the difference between it and the PPG. For the top coat I stumbled on some Nason fleet urethane black and let me tell you, that stuff is the best spraying paint I've ever used. It flows out super smooth and is not run prone. I can't recommend that stuff enough. Simple single part urethane and no clear to mess around with.

Shiny black frame - just as it should be! Beautiful! Ed