Respraying a frame

[Halfmanhalfbike]

Just got an old trek mtb from the local bike recycling place. Thought I would use it just for the odd pootle off tarmac.

But................it's fluorescent yellow

If I respray do I need to rub the frame down to bare metal or can I just overspray?

Ta,

 

[longers]

If there's any rust or corrosion on it then you need to take it back to bare metal and treat it before painting. Otherwise you need to "key" the original paintwork and make sure it is very, very clean. Don't touch it with bare hands after cleaning it.

Are you doing it with aerosols?

If using aerosols then standing the can in warm/hot water for five minutes or so helps the coverage. Not too hot to make it explode though eh?

Or leave it as it is, added security measure

 

[PpPete]

If yellow paint is in good nick - just light rub down and go ahead. If any chips in paintwork then I think it depends if aluminium or steel frame - different primers

 

[wafflycat]

If I were doing it as a DIY jobbie, I'd strip it back to bare metal, prime it then paint it.

Then you may have a place local who would strip it down to bare metal & powdercoat it for a small sum. And powdercoating is *tough*

 

[Dave5N]

Probably work out cheaper to powdercoat it as well.

 

[e-rider]

If you are doing it yourself you'll find taking it back to the metal is really hard work and takes ages - and I mean ages! I would give it a quick rub down and then go over the top of the old paint - a bit of a dodge but will be OK.

 

[wafflycat]

Probably work out cheaper to powdercoat it as well.

You could be right... thinking back to what MrWC paid for primer & spray paint to do his old hack, compared to dropping one of MWCMnr's framesets off at a local powdercoat place... then there's the time factor to take into account on a DIY jobbie

 

[kyuss]

If I were doing it as a DIY jobbie, I'd strip it back to bare metal, prime it then paint it.

+1. I've painted a few bikes in the past, and sanding the old paint never works as well as taking it right back. It'll chip much more easily and end up looking rubbish. If you're using enamel paints you might get away with it, but if you want to make a good job get the nitromors out and get to work. It doesn't take as long as you'd think. Make sure you wear gloves, and especially safety goggles. You don't want even a tiny amount of that stuff in your eye unless you fancy going blind.

Important things when painting your bike are:
1) Get your primer and paint from the same manufacturer. They'll be designed to work together and have less chance of going wrong than if you mix and match.
2) Lots of thin coats rather than fewer thicker ones. The more the better.
3) Lightly sand between coats with a fine grit paper and rub it down with a tack rag. This will help keep the finish nice and smooth and helps each coat adhere properly. Obviously skip this step when clearcoating.
4) Take your time. Spend a couple of days on the painting if you can and do it somewhere warm. The warmer the better. Rattlecan paint won't dry properly if it's cold. Once it's finished try and leave it in a warm room for a couple of weeks for the paint to harden properly. It's a PITA having to wait but this step makes a big difference in how easily (or not) the paint will chip.

I quite enjoy painting bikes, but if all the above sounds like too much hassle, then as others have said you might as well take it to your local powdercoat place. You'll get a better, tougher finish for similar money though you might be restricted in what colours you can get.

 

[asterix]

Proper rust prevention requires phosphoric acid (naval jelly).

 

[Halfmanhalfbike]

Thanks for all the advice. Sounds like stripping it right back would be hard work so I'll try the qucik rubdown and overspray route.

As I said it's only an old mtb bought for peanuts so I don't really mind if it all goes horribly wrong. All part of the learning process.

 

[tyred]

As mentioned, use a little Jenolite or Hammerite Kurust on any rust spots that are present.