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PostPosted: Wed Sep 15, 2010 2:39 pm 
Old School Hero

Joined: Wed Apr 02, 2008 7:22 pm
Posts: 209
Location: Midlands, UK
This was started a while back
http://www.retrobike.co.uk/forum/viewtopic.php?t=105277
might be worth combining into one thread Mods?

I currently have a frame at Mercian, i have only heard good reviews until now? CTK - what was wrong with your experience? I will post some pics up when I get it back (in about 5weeks)


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PostPosted: Wed Sep 15, 2010 2:44 pm 
Old School Hero

Joined: Wed Apr 02, 2008 7:22 pm
Posts: 209
Location: Midlands, UK
meant to say that I took plenty of time respraying my MTrax (link in signature below) frame using cans, a couple of good days between coats and I have a very tough finish. I used the orginal paint as a base.


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PostPosted: Wed Sep 15, 2010 3:00 pm 
Retro Guru

Joined: Fri Sep 25, 2009 3:22 pm
Posts: 419
I used to be a professional spray-painter and I wrote up a big long article on how to paint bikes, but I've lost the link so here's a short version.

I've used Hycote spray paints and I think they're my favourite. Obviously rattle-can paints are hard to work with (they need a lot of wetsanding to get them smooth) but Hycote is the best I've used so far. And it's cheap on ebay. Anyway:

1. If the existing paint is chipped, flaky etc, remove it with paintstripper. If it's good then go to step 2, provided that the red oxide primer doesn't react with the existing paint (spray a bit, leave for a couple of days and check)
2. Scuff frame with 250g paper, clean with thinners, leave to dry. It must be spotless
3. 2 coats of red oxide primer - this helps stop rust. One large can should do this. Dry overnight in a warm place
4. Fill in any dents with filler and sand. Sand frame with 600g paper (wetted with slightly soapy water (i.e. a drop or two of washing up liquid in about a litre of water))
5. 3 coats primer. Grey for most colours, black for dark colours, white for light colours. Dry overnight. 2 cans for this
6. Colour - a 6 pack of cans off of ebay is ideal, leaving you with a couple of spare cans for touch-ups later. I've found that rattlecan paint comes out tougher if you do it in two goes - two can's worth of thin coats (20 mins between coats), then wait overnight, wetsand with 600g in the morning, then the other two can's worth of thin coats, again waiting 20 mins between coats.
7. If you've picked a solid colour, you can move on to finishing and polishing (see step 9). If you've gone for metallic or pearlescent or anything fancy, it'll need a lacquer (step Cool. If you want to add decals, lug lining, box-lining or other patterns, put them on before the lacquer (even if you have a solid colour you can lacquer over it if you want to give the decals a layer of protection, or give a really deep shine to your bike).
8. Wetsand frame with 600g, wipe with clean rag, and do lacquering in the same way as painting in step 6.
9. Finishing and polishing is the fun bit. Give your frame for a full week in a very warm place to cure, or maybe two weeks if it's in the shed or garage. Then wetsand with progressively finer paper, starting at 600, then 800, then 1000, then 1200, then 1500, then 2000. The aim is to remove the ripples and bumps you get from painting to get a very smooth finish. The final step is polishing, which on a bike, is easiest done by hand. Get some polishing compound (T-Cut is too coarse) from Halfords/paint supplier/internet (G3 is my favoured brand) and use as per instructions. You're aiming for a glass-like finish. You can now assemble your bike!

Then you need to protect your paint. Normal Turtle Wax does a great job. Leave it for another week before waxing it.

Tips
Always use a sanding block. A bit of stiff foam (like a brand new washing up sponge) is good because it curves around the bike's tubes really well.
Make sure your paint and your frame are warm before painting. Pop the cans into warm (not hot!) water and keep the frame inside by a heater. It'll make the paint settle much more smoothly.
Make sure each layer of paint is absolutely perfect before moving onto the next one, and take your time! You can always go back and repaint a section if you sand through to the previous layer.
Don't let anything touch your frame for a week after you've finished painting. Even if the paint seems hard, things like brake calipers or band-on front mechs, or the floor that you're resting it, on will squash the paint over time. I stick a couple of old wedge-type quill stems in the seat tube and steerer tube (shimmed with old inner tube and expanded out all the way they hold the frame securely) and hang the bike from those.

With some care, it's easy to get a paint finish that's better than any mass-produced frame I've seen, although not as hardwearing as stove-baked enamel or powdercoat. Anyone who says home-painted bikes look rubbish just doesn't know how to do it properly! It doesn't matter a single jot HOW you apply the paint, whether it's from a gun, a can, or sprayed from an old bicycle pump - it's the prep and the sanding that's the key.

If you do want the ultimate cheap hardwearing finish, nothing beats powdercoat. For 40 to 60 quid it's as cheap as DIY. The finish isn't great (looks fine from afar but it's not very glossy and full of ripples) but it's so tough you'll dent the tubes before you chip the paint. No metallics (you can get lacquers with sparkles in it but I think it looks horrible) either. Also powdercoaters will only do a single solid colour on a frame - but you can easily paint over it to do bands around your seattube or lug-lining etc.


Last edited by lae on Wed Sep 15, 2010 3:14 pm, edited 1 time in total.

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PostPosted: Wed Sep 15, 2010 3:04 pm 
Retro Guru

Joined: Sun Dec 14, 2008 2:11 pm
Posts: 303
Pointer wrote:
meant to say that I took plenty of time respraying my MTrax (link in signature below) frame using cans, a couple of good days between coats and I have a very tough finish. I used the orginal paint as a base.


Always risky to use the original paint as a base. Unless you know for sure what the original paint is you could be setting yourself up for a nasty reaction. In your case you were lucky.

I've come across wrinkled, crazed and none curing finishes as a result of reactions between incompatible paint types. The none curing type can be the worst since they can be a sod to remove. You can buy barrier coats that are supposed to prevent this sort of thing, but I've never tried them.

Once saw somebody paint the whole front end of a Mini and a couple of days after he'd finished spraying it started to wrinkle up, it took a couple of days to reach it's full horror. So if you do follow the instructions and test on a small unobtrusive patch of paint make sure you leave it a few days before you decide it's passed the test.


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PostPosted: Wed Sep 15, 2010 3:13 pm 
Retro Guru

Joined: Fri Sep 25, 2009 3:22 pm
Posts: 419
^ that's good advice actually. I forgot to put that in my little tutorial!


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PostPosted: Wed Sep 15, 2010 3:47 pm 
Old School Hero

Joined: Wed Apr 02, 2008 7:22 pm
Posts: 209
Location: Midlands, UK
GarethPJ wrote:
Pointer wrote:
meant to say that I took plenty of time respraying my MTrax (link in signature below) frame using cans, a couple of good days between coats and I have a very tough finish. I used the orginal paint as a base.


Always risky to use the original paint as a base. Unless you know for sure what the original paint is you could be setting yourself up for a nasty reaction. In your case you were lucky.

I've come across wrinkled, crazed and none curing finishes as a result of reactions between incompatible paint types. The none curing type can be the worst since they can be a sod to remove. You can buy barrier coats that are supposed to prevent this sort of thing, but I've never tried them.

Once saw somebody paint the whole front end of a Mini and a couple of days after he'd finished spraying it started to wrinkle up, it took a couple of days to reach it's full horror. So if you do follow the instructions and test on a small unobtrusive patch of paint make sure you leave it a few days before you decide it's passed the test.


Hmm good advice, maybe I was lucky, it's been well over a year since I did it. I used a grey primer over the Raleigh paint (which I had rubbed down) then sprayed multiple layers over. I was really surprised at how good the finish is.


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PostPosted: Wed Sep 15, 2010 10:37 pm 
Retro Guru

Joined: Sat Aug 15, 2009 9:30 pm
Posts: 413
Location: Leighton Buzzard
Any idea where I can get Acrylic Enamel?
I was going to get my frame powder coated, but I think I'll loose the details in the lugs, and it might look a bit too chunky?
I have sprayed many old cars back when you could buy cellulose, so I have all the kit. However I can't find paint suitable for mixing and spraying. IIRC cellulose was banned.
I'm also after an unusual colour so I need to be able to mix the paint.
Any suggestions.


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PostPosted: Thu Sep 16, 2010 8:57 am 
Retro Guru

Joined: Fri Sep 25, 2009 3:22 pm
Posts: 419
Yep cellulose was banned for general public use. I used to own classic cars, I think you can (or could) still buy cellulose if you said it was for a classic car that originally used cellulose paint (from the 40s or 50s) or if you were painting a boat.

Cellulose is nice to work with. You could spray it on with a bloody football pump if you had to, and with a bit of sanding it'd still come up perfect.

Powder coat isn't 'thick' but it does certainly have a thickness that is noticeable on close inspection. I wouldn't get a really nice frame powdercoated.
http://www.lfgss.com/thread17439-16.html#post1649857
this thread has a lot of examples of powdercoat. Most of them were done by Armourtex in London who are pretty popular.

As for acrylic enamel I'd just ring round your local paint suppliers.


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PostPosted: Thu Sep 16, 2010 4:11 pm 
Retro Guru

Joined: Sat Aug 15, 2009 9:30 pm
Posts: 413
Location: Leighton Buzzard
Just found a local guy that will do the job for £40. Found him though a Jaguar parts supplier, he colour codes parts for people de-chroming Jags.
Been to see his work and it's fantastic, far better than a specialist job I had done a few years back.
£40 might be mates rates and I've taken it back to bare metal.

I've posted a picture of a frame in the colour I want and he will do his best to match it.
It'll look far superior to powder coat


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PostPosted: Thu Sep 16, 2010 4:50 pm 
Retro Guru

Joined: Fri Sep 25, 2009 3:22 pm
Posts: 419
40 to spray a frame or for the paint?


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