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  1. #1
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    Painting, what am I doing wrong?

    Hey all,

    I've got a project bike which I'm working on as a single-speed conversion, but I am having a really hard time with the painting. The first attempt was understandably ruined by poor attention to the weather forecast, but after that, I sanded it down again and re-painted.

    After over 48 hours of drying, I was working on the bike on my Park stand, and when I let it out of the stand, I found the paint chipped off. While tightening part of the headset, I accidentally hit the top tube with the end of the wrench and that chipped the paint. Finally, I managed to chip the paint on the fork as well.

    Basically, it just seems to be a very fragile paint job and I'm mustering up the patience to sand it down again and start over, but I'd love some advice about what I may be doing wrong and what I could do better.

    Here's what I did on the second attempt:

    Sanded the frame down to bare metal / used some chemical stripper around the curves and bends. It was entirely clean except for some small parts around the bottom bracket.

    I started off with 3 coats of Rustoleum Primer spaced 30 minutes apart. It was dry to the touch. I then sprayed 3 coats of color spaced 20 minutes apart. It was not entirely dry to the touch. I then finished with 2 coats of clear coat 20 minutes apart and let it dry for over 24 hours before handling. It was at least 72 hours before I put it up in the stand.

    Everything I've ever read seemed to say that 2-3 coats of clear coat were fine, and the instructions on the cans seem to suggest it's okay to spray a new coat before it's fully dry, but I'm clearly not doing something quite right, I'd love some advice.

    For my next attempt, I was thinking of using this metal primer instead, but I'm wondering if the problem isn't more with the clear coat than anything else.

    Thanks.

    IMG_0520.jpgIMG_0517.jpg

  2. #2
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    What you're doing wrong is using rattle cans. There is simply no way to create a durable finish with rattle cans.

    So, your choices:

    A) Use rattle cans and live with lots of chips

    B) Purchase and learn how to safely use toxic, good quality automotive paints and applicators

    C) Pay someone who is already up to speed on B) to do it for you

    or D) Spend $70 bucks on powder coat, which looks decent and lasts essentially forever.

  3. #3
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    Is it aluminum? If so, it's not porous enough, and needs to be chemically treated. I think its called anodizing the metal.

  4. #4
    bike whisperer Kimmo's Avatar
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    Three coats of primer? I'm not sure that's right... IMO one coat should do it.

    Perhaps you should experiment on a bit of scrap steel in order to figure it out?

    Quote Originally Posted by Six jours View Post
    What you're doing wrong is using rattle cans. There is simply no way to create a durable finish with rattle cans.
    It shouldn't be that crap. Also, I imagine you could make a rattlecan paintjob a bit tougher with some light baking...

    Quote Originally Posted by cpt. Howdy View Post
    Is it aluminum? If so, it's not porous enough, and needs to be chemically treated. I think its called anodizing the metal.
    Anodising is something else entirely. An etch primer would be called for.

  5. #5
    Senior Member WickedThump's Avatar
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    Give each coat at least 24 hours to dry.

  6. #6
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    Quote Originally Posted by Kimmo View Post
    It shouldn't be that crap.
    As a young teenager I rattle canned a dozen or so frames. Each time I did one it would quickly start to chip, from exactly the sorts of things described by the OP. So each time I would try something else - some different combination of primer, color, and top coat; different kinds of paint; and eventually trips to specialist shops to get advice and paint from professionals. None of it worked. I did end up with some very good looking paint jobs, but every one ended up looking like crap within a few weeks, because - as I was told by numerous painting professionals - "There is simply no way to create a durable finish with rattle cans."

  7. #7
    bike whisperer Kimmo's Avatar
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    It'll always suck next to proper paint, but then again, it shouldn't just fall off the tubes like that.

    Allowing a day between coats would have to help, I guess...

    Quote Originally Posted by Six jours View Post
    As a young teenager I rattle canned a dozen or so frames.
    How long ago was that? There's a fair bit of tech development goes on in the world of paint. The epoxy-based stuff isn't all that shabby.

  8. #8
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    Been wondering about that....as I just refurbished a clothes dryer with white epoxy "appliance spray paint." It seemed like pretty tough stuff. Too bad it doesn't come in many colors.


    How long ago was that? There's a fair bit of tech development goes on in the world of paint. The epoxy-based stuff isn't all that shabby.

  9. #9
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    Thanks for the replies, they've all been pretty helpful. It's a steel frame, but it sounds like the consensus is that rattle can spray jobs are just not a good idea. Guess I'll start looking into local body shops who might be able to spray it with better paints or find a place to get it powder coated.

    Kind of unfortunate, I was pretty excited when I started painting it since I'd spent such an absurd amount of time sanding it down.

  10. #10
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    How did you clean the frame after sanding/stripping? If you do give it another shot, try cleaning the frame with some soap and water, dry and then wipe down with some denatured alcohol or rubbing alcohol. That should remove any oils/residues from handling it. Just keep in mind that any time you touch the frame from here on out will leave new oils which will reduce the adhesion.

  11. #11
    Senior Member BCRider's Avatar
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    A chemical stripper will make the job go SOOO much faster at stripping the paint if you decide to try again.

    From your original post the big thing you did wrong was to recoat way too often and way too soon between coats. 72 hours for that mess of paint to fully dry simply was not enough.

    Of all the spray or brush paints I've used Rustoleum has to be one of THE WORST for durability. The only one worse is Tremclad paints.

    Two options which are far more durable are Flecto brand colour enamels and some of the engine and brake part paints sold at the automotive suppliers.

    Primer is simply that.. a primer. Primers are formulated to bond well to the metal and give a good bond to subsequent coats put on top. But primers are SOFT! You should only use enough primer to get full coverage of the metal and no more. Allow to dry for 24 hours.

    Spray on the colour according to the re-coating rules on the cans. Some like to be fully dry and others have a "window" for recoating. Obey what the instructions tell you.

    It's also seldom any advantage to use more than a couple or three coats. Once the colour is what it is then adding more won't make it look better. But it will increase the thickness of the paint film and make it LESS resistant to pressure damage instead of more resistant. So put on enough to look right and develop the proper colour but no more than that.

    If you really MUST use a clear coat try to use one which is compatible with the colour paint. The other option is to allow the colour to fully dry or to bake it (more below) and then apply any stickers you get made up and only THEN clear coat over the colour and stickers. Super thin vinyl stickers with a matt finish suitable for being clear coated are available from many sign and label shops.

    After the colour is applied it's not a bad idea to bake the paint. Allow to dry at normal room temperature for 24 hours then make up an "oven" by tenting a thick blanket or two over the frame. Another option is to get a cardboard bike box from one of the local shops. Put the frame and a 100 watt old style incandescent lamp into the box. Cut only a couple of small holes for ventilation. One each about the size of a quarter near the floor and up at the top. Or simply prop the opening flaps at the bottom and top slightly. Ensure the lamp isn't touching the cardboard or the bike. Or maybe use two lamps with 60 watt bulbs instead while still ensuring the bulbs don't touch paint or cardboard. Close the box or tent and leave it for a good 24 to 36 hours. The elevated temperature in the "oven" will speed up the final drying and hardening of the paint. Once it's done and cooled off the paint will be as tough as it can get.

    Myself I've used the Flecto enamel on some motor cycle parts. When fully dry either from waiting a week or from using the "oven" idea the paint has been pleasantly durable. A buddy used the engine enamel on his own motorcycle parts. In his case he baked them as I described. The parts he did are down where the rider's boots and any leather pants are in constant concact with the paint. He found that the paint only got very slight dulling of the finish from this. So engine enamels would appear to be quite hardy.
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  12. #12
    Senior Member duckliondog's Avatar
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    Hot tip: self etching primer.

    You buy it at an auto paint store. While you're there, have them make you a spray can of real auto paint. Your life will be better. Pro grade results if you're careful.

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    I have read that "1 Shot" enamel, made for sign painters, works well. It is brush on, and apparently contains the hazardous chemicals that make paint durable. I wish someone would actually try it and report back

  14. #14
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    Quote Originally Posted by MarkWW View Post
    How did you clean the frame after sanding/stripping? If you do give it another shot, try cleaning the frame with some soap and water, dry and then wipe down with some denatured alcohol or rubbing alcohol. That should remove any oils/residues from handling it. Just keep in mind that any time you touch the frame from here on out will leave new oils which will reduce the adhesion.
    After soap and water, go over the frame with Dupont Prepsol 3919S, then a final going-over with a tack cloth immediately before spraying. Rattle can paint isn't the best but this treatment will give it the best shot at adhesion. You will always need the appropriate primer over bare metal.

  15. #15
    Senior Member kv501's Avatar
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    +1 for powder coating. You'll love yourself for doing it.

    Powder booths are much more common and reasonable than they were even 5 years ago.

  16. #16
    Senior Member zukahn1's Avatar
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    Quote Originally Posted by duckliondog View Post
    Hot tip: self etching primer.

    You buy it at an auto paint store. While you're there, have them make you a spray can of real auto paint. Your life will be better. Pro grade results if you're careful.
    +1 If you use a better grade of auto paint and primer combined with a clear coat with a hardening agent like Spramax you can get fairly proffesional job if you take your time. The catch is time and money wise you won't really save much of anything over getting a basic one color powder coat.

  17. #17
    Retro Grouch onespeedbiker's Avatar
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    Powder is great and will last a long time, but you will be limited by the colors available. After working in the enameling business for 10 tens (what a dirty job) your problem is quite obvious, the primer isn't sticking. The issue is trying to get something to stick to chromoly, which is not easy. The industry standard is Zinc Chromate, but it's only available commercially. If you're still interested in using a spray can (BTW you can do an excellent job with spray cans) there are some spray can Zinc Phosphate primers http://www.skygeek.com/tempo-a-702-g...FWM0QgodeUa9iw that will do a good job. Another issue is if you are going to do more than 2 coats, let the paint dry all the way and sand between coats otherwise the bottom coats will not dry.
    Last edited by onespeedbiker; 04-16-12 at 11:39 AM.

  18. #18
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    I painted 2 frame with tremclad spray paint in the last 6 months, I stripped one to the metal, cleaned it with acetone and it worked out real fine. the second I just sanded a bit, cleaned with acetone and it worked fine too.
    There is already 650 kms on the first one and no chip.
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  19. #19
    Lover of Old Chrome Moly Myosmith's Avatar
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    Sounds like too many coats too close together. I know it seems like a long time, but no more than two coats primer, then 72+ hours if it is hot and dry, sand lightly and wipe down. Then two or three light coats of color applied as evenly as possible, another 72+ hours. Lightly scuff, then decal and clearcoat and (you guessed it) another 72+ hours before working on the bike. You still have to be very gentle with the finish for several weeks. Rattle cans can produce functional finishes but you need to stick to the automotive brands. Check with your auto finish supplier and you'll get pointed in the right direction. Dry to the touch and fully cured are very different things. Dry to the touch means it won't finger print with gentle handling. It can take weeks or even months for full cure and maximum hardness.

    If you like a semi-matte black, Rustoleum came out with a rattle can finish for truck box coating. It isn't the thick textured stuff but is kind of a very lightly textured satin finish. Looks pretty decent and has held up well for my beater. I sprayed it over their rust converting black primer and so far just a couple of minor scratches despite numerous transports and getting kicked around a lot.
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  20. #20
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    I'm no expert at painting, but I have rattle-canned a few frames. Here's what I have learned:

    1) Surface preparation is critical. This means, clean, no grease or oil, or even fingerprints. A phosphate etch or light sandblasting is helpful. Handle the clean, prepped frame with clean cotton gloves before paint to avoid leaving skin oils from fingerprints.

    2) Fresh paint is VERY fragile, even when apparently dry to touch. Do not clamp anything on the frame where it will leave a mark -- this includes repair stand clamps. Put a seat post in the frame and clamp on the post instead. Baking fresh paint will help it harden faster, but few of us have an oven big enough to accept a bike frame. If you have an attic, leaving the frame in the attic for a few sunny days is also often effective.

  21. #21
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    Quote Originally Posted by Kimmo View Post
    How long ago was that? There's a fair bit of tech development goes on in the world of paint. The epoxy-based stuff isn't all that shabby.
    Long damn time ago, so you have a point.

    OTOH, if managing 400 miles without ruining the paint is considered a bragging point, then maybe you don't.

    Fortunately for me, the powdercoat place is only 15 minutes away, so I can't imagine putting in the time and effort required to come up with a good-looking rattlecan job, regardless of how much less rattlecans suck these days.

  22. #22
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    Have not read any of the previous postings but i'll tell you what are you doing wrong...

    1 - dont ever use rustoleum paint. That thing wont hold in a bike, it will chip really quick as in your pictures. Big NO NO to rattlecan paint unless is something else like car polyurethane paint in a rattle can.

    2 - rustoleum clear coat sucks, that simple. Besides being way to soft to paint a bicycle the thing turns yellow after 6 months to a year because doesnt have UV protection. This is when i say again... polyurethane car clear coat. Big difference between a 3 bucks a can versus clear coat for cars that is like 30 bucks the quart plus the hardener (50 bucks total for a quart), the results are way different as well. The rttle can will take like 6 months to cure versus a clear that can be sanded and polished after 12 hours.

    3 - Curing time, dry time and curing time are 2 different things, rustoleum will take like 6 months to cure and get hard because it dries using plain air... car paint dries chemically so the paint gets harder to touch maybe after 4 hours, after 24 you can put the bike together and the paint will be intact. Sure after 48 hours that rattlecan work is not even dry yet and you havea lot of finger prints here and there... right?

    This is what you have to do but it will cost you...

    1 - sand the frame to bare metal and use sand 400 sand paper over the frame to etch it.

    2 - Get something called U-POL #5 High Build Primer, this is a comercial car repair shop primer in rattle can, get 2 cans and follow the instructions. Comes in 3 colors, your choice but light grey is the most common. After the 1st coat you will notice that this is a serious product not that cr@p of rustoleum. Sand imperfections if you like... apply like 3 coats. That primer will be ready for paint in 15 minutes. This product is sold in car paint supplies shops.

    3 - In the same place you got the u-pol ask for the cheapest car paint they have, and ask for a pint, a pint is all you need ok? If the guy wants to sell you dupont or any other fancy paint just look somewhere else ok? There are some places that sell omni that is good an non expensive paint. Get generic reducer and in the smallest bottle they had... maybe 2 quarts. U will need this. Ask the guy the ratio of paint:reducer the paint uses. Usually is like 2:1

    4 - sure you dont have a spray *** or a compressor so... go to home depot or in the same store you got the paint they should have something called Preval sprayer, get 3 of those with the bottle. You will paint with this.

    5 - The clear coat part now... the cheapest clear with UV protection is the U-pol #1 clear, this thing will shine and will be ready for sanding and polishing in hours... 3 to 4 light coats... 2 cans to play safe. You will love this one.

    6 - extra materials, wet sand paper... 400 ... 600 .. 1000 and 2000 grit, this is to take off the imperfections in the paint and clear. If you dont care and you got a few runs, just dont buy it. If you sand the clear coat you will need to polish the paint, ask for the cheaper paint polisher, that will do the job. If you sand the paint it will get dull (matte), dont worry once the clear is in it will get shiny again. Car paint w/o clear coat goes from shiny to matte as it dries, thats why u need the clear.

    Pretty much that's what you have to do and what you need.

    This is what you get after a lot of sanding and polishing....

    Last edited by ultraman6970; 04-16-12 at 08:35 PM.

  23. #23
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    Interesting post. And great picture of your floor. Too bad there's some random bike part interfering with it.

  24. #24
    Senior Member consumes's Avatar
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    good write up ultraman ! thanks
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    For the record thats the cheapest way to do it at home ok?? Clear is always a problem because even the smaller can of car clear coat will need activator and the price will go up big time. Probably 80 dollars more if you choose to use something like dupont clear, clear coat costs more than paint.

    Red, oranges and Greens costs more than blue paints for example. Red components costs more than blue color components.

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