Spray-painting a bike frame

Discussion in 'The Bike Cafe' started by Mook2000, Feb 1, 2008.

  1. Mook2000

    Mook2000 New Member

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    Isn't it strange there's no section on bike modding? Apologies if I've go the wrong place.

    I'm buying a new bike with an absolutely hideous paint scheme (Silver+Pink) so I'm planning to spray it. Any advice on how and what paint to use?

    Also, colour choices? I really want to do purple+yellow (maybe metallic) tiger stripes once in my life but beginning to have doubts. Like the sort of smokey matt greys and blacks that some bikes have.

    Any input appreciated.
    Spin those wheels!
    Milo
     
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  2. gclark8

    gclark8 New Member

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    Search "Powder Coated/Coating" ;)
     
  3. kdelong

    kdelong Well-Known Member

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    Powder Coating is the way to go. It is much more scratch resistant than paint and lasts longer without fading. It is not something that you would be able to do at home though. It requires special equipment to apply the powder and a very large oven.
     
  4. ghostpedal

    ghostpedal New Member

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    To me, it would all depend on what kind of bike and what it is worth. Years ago, I had an MTB that was decent and I actually raced on it, but I couldn't afford to get it repainted. I did spray paint it, but I used that textured spray paint that was grey background with raised black bits all over it. It kind of looked like those spray in truck bedliners. I was careful to strip most all the factory paint and prime it beforehand. Because of the color and texture, it really worked well. I think normal colors would be harder because flaws would show up a lot easier. It actually looked so good that many people wanted me to paint their bikes for them, but I never got around to it. If it is a really pricey bike and you are picky about how it looks, I would go with powdercoating also. Good luck with whatever you decide.
     
  5. Rob Tunes

    Rob Tunes New Member

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    Mook, it depends on what the frame is made of:

    Steel is the easiest and cheapest. You can sand and prime, paint it yourself for the lowest amount. But, body shop, welding shops, etc, can prime and paint it, then clear it after decals, etc for a pretty low amount, especially if you talk with the manager or one of the techs. I've had them shoot it on their lunch hour for $25, which included a coat of clear about 30min after the base coat set up. Since it's a small job on hanging on a wire, they can put a lot of hardener in the paint and it dries pretty quick.

    Aluminum requires different prep because it can't handle heat as well during sanding, and has a different prep/primer material. Your best bet with that is to find a metals shop or a fabrication or welding firm. A lot of times, they've never done it before, but if you win them over and provide the paint, they'll often do it out of curiosity.

    Carbon Fiber, you're on your own, CyclArt is who'd I send it to.

    Powder Coating is by far the best finish, you can pretty much drop it on concrete and it won't chip. A metal shop/welding shop, etc would be best. Some auto body shops do it, but it'll be high. I have a local guy who will sandblast it, powder coat it, and then clear it for $200. I'm only into steel, so it works for me, but I have to get the frame pretty cheap and locally to be able to make the $$ work.

    Bob Barker on BikeForums is the guy to talk to if it's steel, he's rattle-canned 2 Centurions on the Ironman pic thread, would be a good source.

    I'll be setting up a site in the near future, just bought the domain today, where we'll offer strip/painting in local university colors, but nowhere on the scale/expertise level of CyclArt.

    Before I'd rattle-can paint a frame, I'd see if the painter at your local body shop could do it on the side. Most of those guys will do it with paint already in stock for a pittance. They like what they do and a bike is easy.

    Also, the local air-brusher in the t-shirt shop can do a bike in about 15 minutes, on top of the base coat and before the clear coat. They won't charge much, and can do it right in the t-shirt shop. You can get smoke, flames, etc.

    Speaking of purple and yellow, there's one in the photo gallery (mine). I'm currently having local airbrush guy fixing every nick and chip in the smoked fade.
     
  6. dangerousbiker

    dangerousbiker New Member

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    That's a well-found info Rob Tunes ;)
     
  7. Rob Tunes

    Rob Tunes New Member

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    Gracias, senor dangerous,

    I went for a group run this morning, said something about bikes, and a guy took me to his house, showed me his long-neglected Shogun, 1983 cro-mo 400 lugged Tange frame w/Champion tubes "bike." 52cm, everything else not so hot. The fixie begins, the dremel tool is warming up......
     
  8. reckon

    reckon New Member

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    here ya go:
    I have been painting motorcycles, cars, and bikes for something like 35+ years now.

    I started off like most, with rattlecans in the garage or driveway, but I got bitten bad by the kustom kraze in the early seventies, and wanted to airbrush, and pinstripe, just like ed 'big daddy' roth, so I went out and got brushes, a paasche VL (good ol airbrush) and just completely screwed up perfectly good looking motorcycles, cars and bikes for a year or so (all my own, thank god), but eventually I learned the rattlecan way, the hard way, the easy way, the fast way, the super uber quality way, and just about everyway in between.

    since most of you can probably (or already have) figured out the hard way, the rattlecan way (which looks good=not for long though), the easy way, and the fast way, I'll detail the "reasonably fast, but still high quality way" which is, by the way, a PERFECT way to paint a something metal if you hate sanding; I have never met anyone who loved to sand things down, so I'll assume most of you will be with me on this.

    this assumes you have access to a compressor, a HVLP or LVLP paint gun (a detail gun also helps), a charcoal canister dust/mist respirator and a space to paint free of any ignition sources, and with good ventilation (usually outside with the ground wetted down, and then the piece moved into a sealed up garage after painting works VERY well) be VERY careful about overspray settling onto neighbors property (nothing will piss off a neighbor more than finding a the family car dusted with paint overspray)

    here's what I do with just about every bicycle frame I paint now:

    A)TEAR IT DOWN COMPLETELY: headset cups, BB and all, nothing looks more amateur than tell tale overspray on chrome or shiny bits, because they should have been removed, not masked off. IF you are removing any braze ons, eyelets (or brazing new ones on!) or cable stays, do it now before the next step.

    B) TAKE IT TO THE BLASTER, and have them blast it: note! tell the blaster if the frame will be powdercoated or painted, because they will want to use different blasting media, for each type of coating.
    this is usually something like $20-$40
    I HATE chemical strippers for ONE REASON: you cannot get all the stripper off: it's impossible there will be tiny specks left in crevices, and once painted these specks will start to remove YOUR PAINT JOB! so take my advice after 50 or so bike frames, and too many motorcycle frames to count, GO TO THE BLASTER, it's easy, it's fast, you get bare metal, and no residue (just remember to blow all the leftover media out of all the tubes!)

    C) CLEAN THE DANG THING! paint will not stick to oil or grease, hamburger drippings, or taco juice and that includes the oils from your hands. (taco or not)
    steel can be cleaned with alcohol or mineral spirits.
    for aluminum I reccommend PPG's aluminum cleaner ([email protected] body shop supply houses or "color shops") once cleaned DO NOT TOUCH IT WITH BARE HANDS, USE GLOVES. (NOTE: if powdercoating, now you would put it in a plastic bag, and deliver it to the powdercoater)

    D) SEAL IT/FILL IT/SEAL IT AGAIN
    : using a decent 2 part EPOXY BASED NON SANDING SEALER. (PPG, House of Kolor, DuPont etc,...)
    this is special stuff, and is just a god send if you remember acid etch primers.
    this sealer is designed to go over just about any type of bare metal, sealing it off from oxygen (no oxygen=no oxidation: rust) and provides a topcoatable surface that can be directly painted over with NO SANDING NEEDED, for something like 5 days. follow the "p" sheets (instructions) available online or where you buy the paint and shoot two good coats, waiting about 15 minutes between each coat (USE A TIMER! DON'T GUESS)
    in the old days, you had to scuff the etch primer after it cured or your stuff would peel off in sheets,...not anymore.
    now if you removed braze ons you'll need to grind all the braze on sites so they are a tiny bit LOWER than the surrounding tube, use a file, or a angle grinder, but obviously be careful, and don't go very deep at all, you just can't have anything sticking up from the repair area. to fill the tiny grinder marks or little indentations where you removed the braze ons, you use a GOOD QUALITY filler (NEVER, EVER, EVER, EVER USE "BONDO" brand from kragen/shucks whatever, EVER!) I use "METAL2METAL" from evercoat, it has powdered aluminum in it, so it's like filling with lead, except no stunted growth or brain and nerve damage from lead fumes! (no I never used lead, nice try :D ) sand the filled areas down with 180 grit sand paper on a HARD block of some sort: if the block is longer than the area you are sanding, and you sand along the length of it, the area will be nice and flat when done. you should sand in a "X" pattern for round tubes, so the filler profile after shaping/sanding matches the tube profile, and you get an undetectable repair. NOTE!! only sand down the areas you are repairing. If you had braze ons added, and they look a little rough around the weld, you can dress them down a bit with some emery cloth super glued to a popsicle stick and use it like a file until the area is smoothed down. (sometimes after brazing you see little "nibs" sticking up around the brazed sites, and these are what we are dealing with here)
    now blow on another two coats of the sealer, and after 30 minutes look at the frame, it should be all smooth, and even, with no tell tale sanding or grinder marks visible anywhere,...if you see some sanding scratches, wait another hour, and then shoot another coat of sealer, and check it again, if you STILL see some grinder marks, or deep sanding scratches, you can wetsand the sealer down AFTER 24 HOURS or it clogs the sandpaper BAD (use220grit/ 2 drops-detergent/ 2gal water) and then after wiping down with mineral spirits (or "wax & grease remover"=same thing) shoot another coat of the epoxy sealer,..that should do it.
    REMEMBER: the basecoat paint will NOT hide anything (except white paint), in fact it will highlight ANY surface imperfection ESPECIALLY if you are going to use a metallic or pearlescent color coat, so make sure the surface is as defect free as you can stand it, befoer going to the next step.

    E) BASECOAT: I prefer modern urethane basecoats which will chemically bond with both the substrate (the epoxy sealer) and the clear topcoat, creating a nearly solid paint layer from bare metal to surface: VERY tough and durable, and polishable YEARS after painting. the only real tips I can give you for this are: 1) use the proper temp range reducer for the painting area (thinner for urethanes) this is CRITICAL if you are applying a metallic or pearl basecoat or the tiny flakes wont settle properly and the surface looks grainy and bumpy, this is called "MOTTLING", less critical for solid colors.
    2) less is actually,...less: only shoot enough LIGHT coats of the base to get "HIDING" (you can no longer see whats underneath) once you get hiding STOP SHOOTING. the basecoat dries in minutes so a common mistake is to just start hosing the thing down with multiple coats, DO NOT DO THIS! shoot for hiding, and even color and then stop.

    F) CLEARCOATING: (USE A FREAKIN RESPIRATOR, DUH!) this is the most technical step; everything usually goes GREAT until you get to the clearcoat and then it falls apart fast, so tips learned the hard way: USE A PRACTICE PANEL FIRST!!
    the BIGGEST (and most common) rookie mistake is to try and "learn" how to shoot clearcoat ON the thing you are trying to paint, again DO NOT DO THIS unless you have experience shooting urethane/polyurethane clearcoats ON TUBULAR SURFACES, and thats the rub, just because you know how to lay glass on a car hood, or motorcycle tank, don't think you can just start shooting tubes and not have a learning curve.
    so "ALL PAINTERS MAKE MISTAKES, BUT THE PROS MAKE THEM ON TEST/PRACTICE PANELS NOT THE PROJECT PIECE"
    I would get a section of steel pipe and set it next to the frame and when you use the epoxy sealer/primer shoot the pipe at the same time, and shoot the base on the pipe as well when you basecoat, NOW you have a perfect practice panel, and if you screw it up (orange peel, or runs, it'll happen) you can just wipe it all off with thinner and start again: the epoxy can be topcoated 20 minutes after shooting, same with the basecoat. once you feel proficient THEN you shoot your beloved PX-10, grand jubilee, colnago whatever.

    (TIP)shoot a coat of clear: thats ONE even pass over each surface: for tubes I shoot lengthwise once on top, once for each side, and the bottom, so four passes (with about a 50% overlap) then move to the adjacent tube. for bicycles I like FOUR COATS, BUT!!! you MUST WAIT AT LEAST 15 minutes before shooting the next coat: here's a great trick for determining when the previous coat is ready for the next: on the masking (headset or bottom bracket) touch your gloved finger to the clear after shooting and pull it away: directly after shooting it will pull away clean, after 2 minutes you see "strings" when you pull away, and after about 15-20 minutes it will just be tacky, and will no longer "string", now it's ready for the next coat. (this is assuming a 70 degree painting area, colder will take longer, hotter will be faster, don't paint under 60 degrees or over 85 degrees for best results)

    (TIP)now keep in mind that the clearcoat has a hardener, and that hardener starts doing it's thing the moment you mix them both together, how long you can work with it is called the "pot life", so only mix enough for for two coats, and then mix another batch for coats 3 and 4, or your 3rd and 4th coats will go on gloppy and you'll get orange peel of biblical proportions.


    you don't paint your bicycle frame to save money, if your trying to save money, have it powdercoated, you paint your frame because it's a very satisfying feeling to ride something you painted, when you stop, and people ask "who painted that"?, you get to say "I did" and then bask in the compliments, or simply ride feeling like you took part in more than just the selection of components and assembly of your steed.

    you can get books on how to paint a motorcycle, and they will have a section dealing with the frames (HP books has two I recall) which cover more of this in greater detail, but this should get you started.

    peace love and isocyanates
     
  9. Rob Tunes

    Rob Tunes New Member

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    Well, there it is, real info from a real person who really does it. Can't get much better than that.
     
  10. Bro Deal

    Bro Deal New Member

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    Thanks for that, reckon. Great post.
     
  11. TheDarkLord

    TheDarkLord New Member

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    Great post reckon! If the mods were actually active ( :rolleyes: ), they would take such posts, make them into an article, and archive it where it will benefit a lot of people. But knowing this site, I don't have my hopes up.
     
  12. garage sale GT

    garage sale GT New Member

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    Has anyone got any info on carefully prepping the existing paint and painting over it?
     
  13. reckon

    reckon New Member

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    this COMPLETELY depends on the condition of the existing paint.

    this also involves sanding, LOTS of sanding,...

    typically if the original paint is in good condition, and you just hate the color, all you need to do is scuff the original finish very, VERY well with a red scotch scuff pad, some water and some scuffing paste (3M scuff-it, etc,...) until the surface is completely dull all over. you'll need to pay extra attention to crevices and corners ESPECIALLY the lug areas: if you try and paint over a shiny surface chances are it'll peel later on.

    then shoot two good coats of the epoxy sealer and let cure overnight, then proceed to the basecoat.
    you still need the sealer coat for several reasons
    a) it seals off whatevers beneath it, and epoxy is a fairly mild coating, so it usually wont react adversely with most coatings you'll find on bicycle frames painted in the last 25 years. b) it provides a nice open celled surface for the basecoat to attach to. c) it gives an even color to paint over: some basecoat colors are rather translucent (especially reds and yellows) so rather than use 97 coats of the base to get hiding, you shoot the sealer so it only takes 3 or 4 coats.

    the point here is, since you will be shooting the sealer ANYWAY, why not just take the frame down to a blaster and save yourself a weekends worth of sanding? plus you'll get better adhesion working from bare metal, and if the original paint is cellulose lacquer (painted in the late 60's-early 70's) it all has to come off anyway, as the cellulose has broken down FOR SURE, and would make a terrible "foundation" for your new paint job.

    the exception is carbon fiber, which was covered already in the above post, that you just scuff and paint.

    btw garage sale GT, I think that was one of dirty harry's best lines (but one of the worst movies of the series) :D
     
  14. kakman

    kakman New Member

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    Reckon, sorry but I gotta ask one question.

    What about anodised frames? I read somewhere anodised finishes require less preparation because they accept primer very well. Do you know if this is right?

    cheers

    /k
     
  15. reckon

    reckon New Member

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    again GOOD QUESTION, and no need to apologize.

    since anodizing is basically controlled oxidation (rust), I would say NO, it would be like painting over rust. now, I have no practical experience painting over an anodized surface (I always had pieces stripped so I could effect a guarantee), this is an educated guess, with a second opinion (I called a friend with 20+ years exp) this would be a great "test panel" situation.

    since it will be topcoated, no harm in having the anodization removed that way there's no guessing, and you don't end up with a failure of some sort down the road (peeling, wrinkling, etc,..)

    basically, there is no way to just grab a frame and paint it without SOME kind of prep work (and BELIEVE ME, I've tried EVERY WAY, because I HATE prep)

    which is why I like the epoxy sealer so much, because you just drop it off at the blasters, then when you get it back, you just wipe it down and then blow on a couple of coats of epoxy, and start painting,..with NO further prep or sanding needed.

    no other way I have tried is that easy, and have the paint last 15+ years with minimal care (no joke)
     
  16. kakman

    kakman New Member

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    Thanks for the reply. So can anodising be removed with simple sand-blasting or, if not, how is it done?

    Actually it was in wikipedia I saw the information:
    Anodising, is an electrolytic passivation process used to increase the thickness of the natural oxide layer on the surface of metal parts. On many other metals, anodizing increases corrosion resistance and wear resistance, and provides better adhesion for paint primers and glues than bare metal.


    I know nothing about it but I am in the market for a frame which just happens to be anodised. Whilst I have no intent to paint it now, I know I will in the future. :)

    /k
     
  17. reckon

    reckon New Member

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    I'll have to read up on this, and now you got me all curious (I have an old blue anodized BMX crank I wanna try this on :D ) that was a good question!

    yes, MEDIA blasting (they don't use sand anymore) will remove the anodization as it's a VERY thin coating.
     
  18. garage sale GT

    garage sale GT New Member

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    How about the hillbilly method? Burn it off!:D
     
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