carlgeldard
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| posted on 21/1/06 at 09:30 PM |
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Powder coating
How do you remove powdercoating from an old chassis before I do some mods and re-coat it. I have been told by a shot blaster that they can not remove
it. They told me to use heat and scrap it off. Any other sugestions.
Carl
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flak monkey
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| posted on 21/1/06 at 09:31 PM |
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Shot blasting should get it off without a problem...  Maybe they just dont have any way of shot blasting a whole chassis?
[Edited on 21/1/06 by flak monkey]
Sera
http://www.motosera.com
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Dave Bailey
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| posted on 21/1/06 at 09:37 PM |
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I agree.... I have spoken to a company locally who is happy to grit blast to clean the powder coating off!
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big_wasa
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| posted on 21/1/06 at 09:55 PM |
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My local place said that once its on, its on and that blasting it would just make a mess ?
I have stripped a few bits that I felt was a crap job and it was a  of a job 
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caber
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| posted on 22/1/06 at 12:05 AM |
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I think the problem is you need very aggressive media and some companies don't want to use the stuff as it causes a lot of wear on their gear.
it will also attack any of the chassis that is bare or thin so they may be worried about giving you back steel lace instead of a chassis!
Caber
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steve_gus
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| posted on 22/1/06 at 12:17 AM |
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my undertstanding is that powder coating is a process and not a specific type of paint. When I had my bike frame coated, the paint was as destructible
as any other - i had to touch up a place where it got scraped.
Try scraping it with a screwdriver or using nitromoors on it - might not be as tougth as you think
atb
steve
http://www.locostbuilder.co.uk
Just knock off the 's'!
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JohnN
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| posted on 22/1/06 at 12:36 AM |
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I once had some alloy wheels which I thought had been powder coated but needed re-finishing. I sent them for blasting & painting, however the grit
blaster wouldn't touch the finish, it was like a plastic coating. In the end I had to have them chemically stripped.
So the moral of the story is..... try it and see, some comes off easily some doesn't
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jambojeef
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| posted on 22/1/06 at 12:43 AM |
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I just heated it up with a blowtorch!
Sort of melts and if you wire brush it it totally just falls off!
Well maybe this was old powder coating but give it a try - whats the worst that could happen.....breathing in nasty poisonous fumes that give you
horrible illnesses aside of course....
hth!
Geoff
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mranlet
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| posted on 22/1/06 at 10:16 AM |
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Heating will melt it off, but it's best done uniformly to aviod flexing the frame.
KML makes a high-power solvent that would most likely take it off. I have used Sno-Bol industrial cleaner to take powder coating off as well, but
I'm not sure of it's availability over there.
Paint removers won't work for the most part because powder coating is not a paint. Theoretically, if you could reverse the polarity of the metal
the coating would take itself off.
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MikeR
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| posted on 22/1/06 at 10:45 AM |
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errrm, thats not my understanding, the polarity thing is just to make sure you get even coverage. Make the paint + (or -) and the chassis the other
and they attract each other.
I thought power coat is a type of paint that cures with heat. So you paint the chassis and bake it. Depending on whats in the powder coat / how the
chassis was prep'd depends on its properties - will it chip etc.
It is just a paint - a special paint, but a paint. Just like enamel, gloss, primer etc.
(i'm now waiting to be shot down in flames by someone who knows what they are talking about)
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andyd
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| posted on 22/1/06 at 11:47 AM |
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Well I don't know what I'm talking about but as the name is "Powder" coat, I'd assume it was a powder not a paint as
such. 
It may of course be made of the same stuff just in a different form.
AFAIK (from watching various on TV), it's applied electro-statically and then baked to a high temp and is some form of plastic based material.
I'm not sure if it truly bonds itself to the metal though so I'd have thought chipping it off would work.
Better to find a chemical stripper place and ask them I reckon.
Andy
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indykid
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| posted on 22/1/06 at 11:57 AM |
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powder coating is just that! a coating of powdered plastic, usually polyester. it is not a type of paint.
the part to be coated is given an opposite static charge to the powder gun, so the powder is attracted to all surfaces of the part. once coated,
it's baked in an oven, which melts the plastic powder, and makes it stick together and to the part. once cooled, it's effectively like
wrapping the part in a layer of polyester except it's stuck onto the steel.
there are different grades of coating, as well as different types. early stuff from mk was paper thin, and chipped really easy - just ask mkblade
tony it seems to be a thicker coat now and is a lot more durable. might be a different type of powder, maybe just thicker. don't know. it will
still chip if hit hard enough though.
anyway, ime, as jambojeef says, the best way to get it off is to use a blowtorch, heat it till it smells plasticky, technical i know, then wire brush
it off. it comes off perfectly cleanly, and doesn't leave any residue. it's not very practical for a chassis though. as for grit blasting,
some companies will, some won't and again, it depends on the grade of coating. the more industrial a place you can find though, the more likely
they'll be to do it. a chassis is a pretty big thing for most blasting booths though.
good luck carl
tom
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the_fbi
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| posted on 22/1/06 at 12:47 PM |
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quote:
Originally posted by mranlet
Theoretically, if you could reverse the polarity of the metal the coating would take itself off.
Don't take this personally, as I'm not laughing at you, but thats the best thing I've heard this year 
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the_fbi
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| posted on 22/1/06 at 12:49 PM |
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Would an acid dip take it off?
Probably be the safest (in terms of not warping the chassis) although probably not cheap.
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MikeR
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| posted on 22/1/06 at 01:39 PM |
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but the acid won't know the difference between metal and paint, ok, suppose its minimal really.
just don't leave it in all weekend (assuming it normally takes an hour or two to work)
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the_fbi
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| posted on 22/1/06 at 02:08 PM |
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quote:
Originally posted by MikeR
but the acid won't know the difference between metal and paint, ok, suppose its minimal really.
just don't leave it in all weekend (assuming it normally takes an hour or two to work)
If you can acid dip an aluminium head (albiet not to remove powder coat) I'm sure a mild steel chassis will be OK.
You just need to get it washed off and coated with a rust inhibitor (or re-powdercoated) ASAP after.
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MikeR
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| posted on 22/1/06 at 04:24 PM |
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heard about blocks being degreased using acid dips......
you have to paint them as soon as they come out of the dip - within an hour you can see the rust forming.
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NS Dev
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| posted on 25/1/06 at 08:40 AM |
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Acid dip doesn't really touch powder coating. MikeR is quite right, the acid will attack the mild steel chassis faster than the powder coating.
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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