Bicycle Mechanics - bike painting
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12-09-01, 08:48 AM
I am working on a couple old cruisers. I wish to repaint them, but dont have a compressor or sprayer. I have them stripped down to bare metal. I am looking to repaint them without getting into alot of money. I found some colors at an auto parts store that i like. They were aerosol cans and I believe they were laquer. From what ive read, i can prep the steel frame with denatured alcohol to remove any oils. A couple coats of primer, a couple coats of paint, some pinstriping, a couple coats of clear...is my intentions. Im looking for some advise on whether the regular grey primer that comes in a spray can will suffice. Do I need to sand the primer afterwards? Will the spray cans of laquer work with this primer? Is denatured alcohol sufficient for prepping prior to primering? Do I need to alcohol between primering and painting? Im looking for advice on this project. Also...one set of wheels are pretty pitted and rusty. Is there any special procedure for painting rims other than a wire brush, steel wool, alcohol, primer, and paint? Will primer and paint stick to chromed wheels? I have another set of rims that cleaned up pretty good. They are chromed, but scratched and pitted a bit. Can I clear cote them to eliminate them rusting again from moisture? OK, fellow forum members...lets hear it....lol....thanx.....Pix
12-09-01, 10:55 AM
I am no expert on metal painting, but I have done some wood finishing. See what the instructions on the can of primer recommend as far surface preparation. Unless one is very familiar with the properties of different products, it is always best to use primer and top coat from the same mfr and line as they are intended to be used together. The primer instructions should also tell you whether light sanding between coats is recommended and the type and grit sandpaper to use. It usually is, but not always. Light sanding smoothes stray bumps on the surface and leaves a nice uniform pattern of tiny scratches for the next layer to cling to. You will probably not be able to achieve a super slick, super glossy finish, but you can probably get a pretty decent result. Several very light coats are better than 1 or 2 heavy coats.
Mike has done quite a bit of this and can probably offer better advice.
12-09-01, 11:11 AM
From helping a friend repaint a wing on beaten up car at university I would strongly advise a light sanding between coats and lots of thin coats from a good distance away.
On a related subject I spent five minutes rummaging through a reduced basket of nail polish on Saturday, and much to the assistants amazement bought a bottle of deep orange/yellow :D
You dont' know what you are getting into. :D
I looked at doing something similar a while ago.. you can do a search for car painting on the net there are a few resources.. basicaly you need to use a lacquer primer.. otherwise it causes like spiderweb's in the paint. You can get a nice glossy finish.. basicaly what it takes is.. spray primer.. sand down with 600 grit sandpaper.. spray again use like 800 grit.. paint with color you want.. use 800 grit.. spray again.. use 1000 grit.. spray again use 1000 grit.. spray lacquer.. user 1000 or higher grit.. spray lacquer again.. In actuality to get a nice finish you should do more coats and more sanding then that.. but that should get you a decent finish..
Lacquer does look the best.. but is ALOT of work.. you will have nice strong arms by the time you are done.. The hardest color of all is black since it shows all imperfections.. Honestly though when you are done.. you will have alot better paint job then probably any other bike out there.. since you can take the time and do it right..
12-09-01, 05:04 PM
The canned paint will work, But it will chip very easily. You can have your frames powder coated inexpensivly, it's VERY durable. If you go for the powder coat have a coat of clear paint put on over the powdercoat, Imron is probably best. Water will get under powder coat if not sealed with paint.
Painting correctly is a lot of work.
By your question if paint will stick to chrome, I gather you haven't completely disassembled the bike. This would be a must to do a job that you'll be happy with in the end. Completely apart.
Sanding and cleanliness are a must.
Take Pats advice. Prep the frame and bring it to a professional to get it powder coated. It'll look great forever.
Okay, not a painter, but I have painted a few things in my time! By older frames, I am assuming that they are steel. At any rate, use a primer appropriate for the frame material. The grey primer will work okay, but personally I like zink chromate-like (OD green) or iron oxide (red.)
If your frame is clean of old finish, as said before, wet sand with 600 grit wet or dry sandpaper. Then clean the frame, alcohol would work okay. I have even used vinegar (glacial acidic acid) with good results. While and after cleaning the frame, wear cotton gloves so your hands don't leave behind oils that will prevent the paint from sticking.
Spray on your primer, let it dry, then wet sand and clean again. Then another coat of primer. When you are satisfied with the primer, then wet sand again, this time using finer paper (800 or 1000 grit.)
Then, start applying your color coats, lightly sanding between each coat. Your paint will adhere best to dull surfaces, as it has more 'tooth' for the paint to grip to. Once you are happy with the frame, then sand again, and apply your clear coat. Nothing to this stuff?!
As far as painting chrome, I have never tried it, but it would seem to me the same procedures as above would apply. The only thing different would be that before any painting is done, you would have to aggresivly sand the area to knock the gloss off. And, I would also clean that area with the vinegar as the acid might help to etch the surface of the chrome.
One last thing, if you are appllying decals, they do not stick well to gloss paint either! So, after applying your second to last coat of clear and sanding and cleaning, then apply the decals to the dull surface, then apply the top coat of gloss, and your decals will look like they were painted on!
I've painted two or three bikes with car paint now. The paint does chip pretty easily, although a coating of turtle wax afterwards has helped a bit. I prime with grey, then laquer if the paint requires. I'm really impatiant, but I do wait for approximately 24 hours between coats and before reassembling, and give a light sanding between coats.
I've never known what I was getting into either, and I try not to let it stop me. After all, how else do I learn? ;) Although I'm not about to attempt this with my latest bike. The bikes I've done this to, two were pulled out of skips and one was about to be dumped if I couldn't fix it up, so I didn't have much to lose.
Also, really make sure you don't do this in a place you have to live in at all for the duration. At college the only place I had to do this sort of thing was in my room, so I just moved into my S.O.'s room for the duration. The fumes really do do fun things to your head! :o
12-12-01, 03:39 PM
Thanx for the input on painting. I was surprised that my last coat of color had to be sanded PRIOR to clear cote. I wouldve thought sanding prior to clear cote would dull the color, thereby sealing a dull color under the clear cotes.
And yes, the bike is TOTALLY disassembled, including crank and neck. Ive removed and cleaned all the bearings, and even though they are about 50 yrs old, they are excellent and I intend to put the originals back in after packing them with grease. Those older bearings are better manufactured than the bearings they use in bikes today. You can tell just by looking and handling them. (evidently still made in USA back then).
Thanx again for all the advice.........Pix
ps...Richard, why are you buying nailpolish?...lol...:confused:
12-14-01, 02:16 AM
I've bought nail polish too, it was the BEST touch up paint I've ever found for my Masi. The stuff goes on easily, rarely runs and is tough as Hell!
Ride well painted
12-14-01, 02:39 AM
Why anyone would produce nail-polish the colour of my frame is anyone's guess :D, still as Pat said it's perfect touch-up paint.
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