re-powdercoating a chassis

[Paolo Nunzio Licary]

I’m planning on repowdercoating a chassis. I have a powdercoating stripping process available to me that uses a chemical dip and them a bake off ramping up to 850 deg F them immediately allowed to air cool. The tubing is 4130 cro moly. My question is, Has anyone done this and has it affected chassis handling characteristics? This kind of thermal treatment falls in the category of tempering, which restores ductility for parts that were previously heat treated. Since I dont believe the chassis are heat treated when they are manufactured im unsure what the effect will be. Definetly dont want a wet noodle for a chassis…

[Walt Gifford]

You can’t heat treat or un-heat treat chomalloy it’s not high carbon steel it’s alloy steel.

FAA certified jet engine and aircraft technician,
Nicholson Speedway class champion 2001,
Yamaha KT100 Service Center,
41 years karting experience

[Paolo Nunzio Licary]

You might want to double check that info, as it’s incorrect. Also it’s chrome moly. Not sure what chromalloy is.

[Paolo Nunzio Licary]

http://matweb.com/search/DataSheet.aspx?MatGUID=a2fe6ff24cf44bf1bdebf35b1b2b6259&ckck=1

[FREDDY SANDOVAL]

I believe most guys sand blast the old paint off the frame, then re powder coat them.
Either way, I honestly don’t think there is any way around heating, as they bake them and put in the oven to finish the powder coating process.

So either way, it will get hot one way or another
I honestly rather removing the old paint with anything else other than heat.

[Howie Idelson]

The heat used in powder coating is too low to affect the structure of the material. Go forth and powdercoat. Mask anything with tight tolerances.

[FREDDY SANDOVAL]

Yeah! Mask all holes, where spindles go, rear axle cassettes holes, any chassis tuning holes, all holes.
Or leave them alone, and then scrape off the extra coating with a knife, or drill bitt.

[Tim Koyen]

The bake off temp of 850 is what would make me nervous.  I know I’ve owned karts before that are heat treated in different ways, to achieve certain results.  I’m not a metallurgist, but that would concern me.

I use aircraft stripper on chassis and then sandblast the hard to reach areas.  Powder coating itself is only around 450F, and obviously the karts were all powdered at one time, so that part doesn’t bother me.  That super high temp of 850 is what they use to bake off the residue left on the hanging hooks, I just wouldn’t do it to a kart, but that’s me.

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Don't bother PMing me, it doesn't work. Email is best: tim@kartlift.com.

[Paolo Nunzio Licary]

You nailed it. It is the process used to clean off used hooks for powder coating. I found some tensile test data that showed an increase in tensile strength if tempered around 1000 F for 4 hours but this is nowhere near that long. It would be an interesting experiment, but not worth it this time. I think I will make up some samples and do some testing though. It would be nice to use it in the future as it’s fast and easy!

[FREDDY SANDOVAL]

Paolo
Who hit it right in the nail?
Tim Koyen, or ME? Lol
No just kidding, he’s a good guy, and smart too. I just put in my 2 cents, it’s all good.

Good luck with your powder coating, man, and hopefully it’s a nice color
Post some pictures when you’re done…… Fast Freddy.

[Paolo Nunzio Licary]

Haha sorry Freddy, I did mean Tim. I’ve done this a few times using the standard sandblast to strip and actually did make the mistake of not plugging the close fits of the shifter lever and steering column spherical bearings on the first one.

 

Although I think it wouldn’t change the properties of the frame, I’m not going to bet a chassis on it and play it safe until I do some tensile and hardness testing of cheap sample pieces. And the color will be the original Italkart red, or at least as close as I can get!

[Sebastian Sarmiento]

I’m new to karting, but I’ve asked the re-powder coating question to several well seasoned karters and most of them agreed that the chassis never handles the same way after a re-coating (second heat cycle).

Although some say that after recoating, if you change your chassis settings, it can get close to what it was.(it all comes to personal experience and preference I guess?)

I’m curious about this myself, as there’s a chassis I would like to re-coat.

I wish you twice as much of whatever you wish for me. : )

[FREDDY SANDOVAL]

Hi, Sebastian

As Tim Koyen mentioned here above, I wouldn’t be too concerned about 450 degrees, just like he said, brand new chassis right after they were built were powder coated next.

 

It is the 800 to  1000 degrees that would really be a concerned

I am powder coating my Son’s OTK, as soon as the season is over, it will look pretty again, not to mention it will cover most flat spots at the bottom. LOL

Just kidding, but it will cover quiet bit at the bottom for sure.

No worries about the handling man, we have never seen any changes in chassis behavior at all.

P.S. Some times people don’t remember how to put the kart back together, on the same settings, camber/caster pills, their toe changes, their ride highth changes and that throws  them off, or most of the time is just psychological.

[Walt Gifford]

Ha, you ask a question then suddenly you’re an expert. The only heat treating, if you can call it that, they do on kart frames is to draw the temper out of the welds by localized heating to 1100F. Normalization of 4130 tubing happens at around 1650F. 850F should not effect a kart frame at all although, I can imagine a painter selling you a line of BS about 850F then cranking up the heat to make it easy to peal.

Still the same old kart under the pretty paint. Did I spell everything rite?

Gif

FAA certified jet engine and aircraft technician,
Nicholson Speedway class champion 2001,
Yamaha KT100 Service Center,
41 years karting experience

[FREDDY SANDOVAL]

Yeah, Giff! Learn how to spell Tamale. :) Chomalloy. Too funny.

[Paolo Nunzio Licary]

Sorry to ruffle your feathers Walt, and I don’t claim to be an expert. I wasn’t aware I had to be completely ignorant on a subject in order to ask a question about it. I do have a background in Mechanical Engineering and powder coating though and your initial statement was blatantly false, for which I wanted to set the record straight for other readers. Sorry you took it personally. I specifically asked if anyone had done what I proposed.

And again claiming 850 wouldn’t affect the frame at all without defining the duration is also wrong. It’s time sensitive. Look up tempering of 4130.

I’m not here to war with anyone or compare d*** sizes. Just looking for the truth and insight from someone who has already been there and done that.

[Sebastian Sarmiento]

Wow , you guys know so much!! and Thanks Freddy for the advice, I’m happy to hear re-powder coating is not an issue.

Freddy, By the way, beautiful track you guys have there!! and you know what, it’s not that far, I may comeback soon for the weekend and stay in a hotel nearby, may be you can show me the driving lines??.

Everybody here knows something that someone else doesn’t and that’s what make this forum so great!!

Thanks everyone for schooling newbies like me!!

I wish you twice as much of whatever you wish for me. : )

[Rod Hawkins]

Supposedly otk doesn’t powder coat their chassis because of the heat involved.

[FREDDY SANDOVAL]

Contact the company, directly and ask them

I’m sure inside those ovens they have a few cases of green rattle cans from Walmart to spray paint them, and to top it off, they have to spray them over, and over again to make sure it’s thick enough to endure brake fluid spills on the paint. ;)

http://www.tonykart.com/azienda_gallery_eng.html

[Austin Garrett]

Just browsed through some of the comments. I have powder coated smaller parts and the process consist of getting the part to bare metal, in this case your frame. I would sandblast or chemical treat the frame before heating it to 850 degrees. After the part is stripped to bare metal i usually bake the bare metal for 15 minutes at 350 degrees, this helps get a clean surface to spray on and helps powder adhere a bit.

I shoot the powder on the part while it is still warm, powder the part until it is covered than stick it in a oven at 350-375 degrees for 25 minutes. I let it cure for a bit and it looks great every time.

 

Im not a metal expert but heating anything to 850 degrees  thats not designed for it would warrant some caution.

[Mark Erpelding]

I was afraid of the 850 degree heat also..  Go to a real autobody paint store and buy some Aircraft stripper.   Brush it on the frame let set (not in the sun) keep moving stripper around with brush.   If you use a wire brush it will remove powder coat to bare steel and re- apply stripper and it will work from edges where wire brush went to bare metal and pop powder coat off easier.   After you have it stripped the only hard part to get removed will be around the welds.   Take it to car wash apply more stripper around welds let set  for about 15-20 min and it will spray off completely.   If you know of a slow car wash you could do it all there .   The wire brush really helps.  It will not rust.  The powder coater will lightly blast it..   Make sure u tell them not to put in stripping oven!  I did this to our frame.   Striped it on Wednesday , dropped it off at powder coater on Thursday, picked picked it up on Friday, assembled it Friday night.   Went racing with it Saturday and
Won first race with new paint and plastic..   Kart looked like New.   I used a Dremel tool with a sanding drum to remove powder coat in the spindles so the adjusters would turn freely.

We spend our money on Racin, Whiskey and Women.... The rest we waste....

[Tadas Ratkevicius]

how many lbs of powder coat need to buy for one frame?

[Tadas Ratkevicius]

Im stripping now. Aircraft paint remover and power wash. In 1 hour I got one side done of tony kart cadet. Put smaller tip on power wash. Do 2-3 times one side. Good luck!

Sandblasting at local shops $150

New Powercoat at local shops $150

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