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help, what undercoa...
 

[Closed] help, what undercoat !!!!

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[#1217123]

to use on an ali frame , cheers


 
Posted : 13/01/2010 2:52 pm
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Tartan?


 
Posted : 13/01/2010 2:54 pm
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lookout wierdo alert 🙂


 
Posted : 13/01/2010 4:50 pm
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If it's bare metal and you're spraying it you'll need acid etch primer.


 
Posted : 13/01/2010 5:04 pm
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Ah i see so acid etch primer and the a top coat, is that correct , or should i get it done by a paint shop cheers.


 
Posted : 13/01/2010 6:41 pm
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or maybe powdercoat , any more advice.


 
Posted : 14/01/2010 12:01 am
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powder coat will be much cheaper and more durable, although the finish is not quite as good.

if you're going to paint it, you should acid etch raw aluminium before wet flatting and a proper top coat put on.


 
Posted : 14/01/2010 12:12 am
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thank you !!!


 
Posted : 14/01/2010 12:53 am
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Etch then straight over with primer, nib it off and base up 🙂


 
Posted : 14/01/2010 1:08 am
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What topcoat are you using?

Good powdercoating gives a superb finish, better than (and no offence here...) a rattlecan job that starts with a post on an internet forum to ask what primer to use is likely to be 😉 Some people have concerns about damaging the heat-treating of the frame but I find that unlikely myself if you go to a good coater who'll not overbake it. And it's much, much tougher than most paint finishes.


 
Posted : 14/01/2010 1:35 am
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^^ expect to get stick for that, I did last week lol


 
Posted : 14/01/2010 1:58 am
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Yup. Though the person in question did stop short of telling Orange they should stop refinishing their bikes with powdercoat 😉


 
Posted : 14/01/2010 2:00 am
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For primer, acid etch from a rattle can is fine (U-POL acid #8 is excellent). Painting the colour with Halfords tins however, should not be confused with proper 2K (or two-pack paint), 2k is MUCH tougher, and IMHO has a finish far better than any powder coat.

Two pack cons :- Best find a friendly/local auto paint shop, to apply the 2K, as it is extremely toxic if breathed in 😯


 
Posted : 14/01/2010 8:40 am
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Northwind - Member

Yup. Though the person in question did stop short of telling Orange they should stop refinishing their bikes with powdercoat

Ohh I'll get my handbag warmed up.


 
Posted : 14/01/2010 8:56 am
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[url= http://www.flickr.com/photos/takisawa2/sets/72157623137723780/ ]THIS [/url]was a rattle can job, but only after stripping back to alloy & having it powder coated at work as a base coat. (We only do an industrial matt black finish). Paint was Plastikote Acrylic from Wilko's on recommendation from someone on here. Pics don't really do it justice, colour aside it looked very good. Took a few weeks to go off though.
2-pack would always be my preference. Its just as tough as powder but can get some amazing finishes from post buffing etc. Badly done powder can be awful. Probably why we don't powder coat cars.!!!


 
Posted : 14/01/2010 9:50 am
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Plasticote does take a long time to go off because its mostly enamel based paint. Tractors are painted with the same stuff, give it a fortnight to go off.

If anyone does need a friendly 2k paintshop i may know one 😉


 
Posted : 14/01/2010 11:50 am
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Plasticote's great stuff for the hobbyist but I always find it a sod to get a good consistent finish on, even on simple shapes so I don't fancy my chances of doing the triangle joints without getting at least one bit I'm not happy with. And you can't cut it back effectively without putting a further coat on, or repair it easily if it's damaged.

Hammerite is another decent option, easy to spray though not all that durable, it chips quite easily especially around square edges. And very solvent vulnerable. Still, it's a very nice tactile finish if you use either the wrinkly spray, or use the smooth but shoot a dry coat on top of your last wet coat, gives a powder finish (and, helpfully, is easy to get a very consistent finish for!) though again, impossible to repair. I like it though it's more a fun finish than a serious one IMO.

2-pack in my limited experience on bikes (motorbike frame not pushbike) is hard but a little brittle, though not to the extent it's a major problem. Difficult to work with of course but otherwise very good...

Oh, and halfords sprays or similiar, just say no, they're fine for what they're designed for but cellulose is just not tough enough to last at all on a mountain bike. Put it this way, I resprayed a panel on my motorbike with halfords stuff as a rush job (a crash 2 days before a big event) and though it did look absolutely fine on day one, by day 2 it was scratched, and then it got chipped. Not by a stone, no, by a BEE. Now, if you think your mtb will never be hit harder than my bike was, when striking a bee at 100mph, perhaps cellulose is for you but rocks are harder and jaggier than insects.


 
Posted : 14/01/2010 10:50 pm
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cheers all , so iif you used halfords or sim , and laqured over the top would that not protect it.


 
Posted : 15/01/2010 1:20 am
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Well. Depends what laquer. I know a guy who's used a cellulose (not Halfords but basically the same) primer and base then cleared it with 2 pack, and it's tough- though it's still a poor substrate so not as tough as a proper basecoat would be. But, the thing is, if you're going to clearcoat it with a decent product, why not spray it with a decent product? 2-pack on cellulose is like building a shack out of sticks and mud and giving it a gold plated roof.

But, here, the thing is that if you're buying all what you need- primer plus a base coat plus possibly a clearcoat depending on your paint, plus nitromors, maybe a wire wheel to remove existing corrosion, wet and dry paper, and cutting compound if you're using a paint that needs its clearcoat polished... Well... That's more than powdercoat from a good shop. Even leaving aside the labour, which is considerable.

If you just want new paint then BBQ paint is easy to work with, tough and cheap. Job jobbed.


 
Posted : 15/01/2010 1:25 am
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Halfords paint is 1k acrylic and not very chip resistant at all.

Either spend £40 getting it powder coated, or get some one to paint it in 2k, otherwise you'll kick yourself in 6months time when it's fallen off.


 
Posted : 15/01/2010 1:42 am
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Is it acrylic now? Used to be celly.


 
Posted : 15/01/2010 1:48 am
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It's been 1k for a long time. Celly got removed from mass production quite some time ago. you can still buy it though for spraying, just not in a can.


 
Posted : 15/01/2010 1:54 am
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ok proper paint it is lol , cheers all some good info for sure.


 
Posted : 15/01/2010 7:52 pm
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Ah, guess I'm out of date, cheers. I knew cellulose was on the way out due to the VOC regs, and also possibly due to being s**t 😉


 
Posted : 15/01/2010 9:29 pm