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  1. #1
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    raleigh technium project - removing paint

    I am in the process of modifying an older Raleigh Technium frame with a mix of Alu and steel tubes. The lugs are glued. I would like to remove the paint and worry that a chemical stripper might affect the adhesive. Best way to strip paint on this frame?

    Thanks for any suggestions.

  2. #2
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    Tape off the lugged joints and use chemical stripper on the tubes. Then use a wire wheel on a high speed drill or something that will generate enough speed and torque.

    You can use a heat gun with the wire wheel to soften the paint, but just be careful that you don't melt the glue in the joint. Warm it and test until it is soft enough to let the wire wheel do the work.

  3. #3
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    Pay someone to media blast it.

    _Walt
    Waltworks Custom Bicycles
    Park City, UT USA
    www.waltworks.com
    waltworks.blogspot.com

  4. #4
    The cat's name is jake
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    x2 on blasting it.

    You can remove paint by a variety of means, from burning it off with a torch, chemical strippers, hand operated mechanical means, etc. (and I've done them all), but by far and away the best for non-powdercoat paints is sandblasting or some variant.

    If you have a powdercoat, first burning it off with a torch (which really sucks), then sandblasting. Going straight to sandblasting a powdercoated finish takes a long time. If you are quick with a torch, it doesn't do much to the metal, but you have to be very careful. It sounds crazy, I know.

  5. #5
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    Is sandblasting a DIY project? Risks?

  6. #6
    The cat's name is jake
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    Sandblasting is a DIY project, provided you have the equipment. Lots of people have sandblasters, and it's not a difficult or highly skill dependent task.

    If you don't have the equipment, there are lots of businesses that do. It shouldn't be very expensive either. You could start by talking to paint/powdercoat shops.

  7. #7
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    Quote Originally Posted by Walt View Post
    Pay someone to media blast it.

    _Walt
    I'll go with Walt on this. As a non-DIY method media blast, not sand blast would be the superior method. Sand blasting can be a little harsh on the substrate and cause unnecessary work to prepare for fresh paint. Aircraft people use media blasting, so this might be a source to look for a media blasting business.

  8. #8
    The cat's name is jake
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    I'm curious, what unnecessary work would there be?

  9. #9
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    Quote Originally Posted by BungedUP View Post
    I'm curious, what unnecessary work would there be?
    From my background in auto collision, and restoration work any sandblasting I have done and seen abrades metal to the degree extra coats of primer-filler and subsequent sanding are required to a achieve a smooth paintable surface. Also green mtn. boy said he was dealing with aluminum which, depending on the series, is softer than even mild steel and would pit much easier.

    I my humble opinion, media blasting, using dry ice, cocoa bean shells, etc. would achieve a much smoother surface, provided it is not a powder coated paint.

    There is a certain degree of heat generated sand blasting, especially if using toxic silica sand, which in my region is now banned. In auto body repair sand blasting is not possible in the centre of the large outer cosmetic panels of a car - only the edges and frame works because the heat from sand blasting will warp the metal.

  10. #10
    The Fastest of Bananas
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    Don't sandblast it, media blast it. There is a difference.

    Sent from my Transformer TF101 using Tapatalk

  11. #11
    Nemophilist
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    Hey;

    Media is definitely nice. Sand blasting can indeed warp sheet metal, but is far less likely to do so to tubing. Warpage is most prevalent in trying to remove rust from sheet metal where the blast is concentrated in one spot for some time. Care must be taken in general when blasting any relatively flat sheet, but in my opinion does leave a nice tooth for primer to bite into. Most small shop blasters don't really pose too much of a threat, as long as the operator doesn't dally in one spot for too long. Large commercial operators need to be more careful.

    Eyes off of navals now, boys. Get it done. It's a bike, not a Bugatti.
    Most people ply the Well Trodden Path. A few seek a different way, and leave a Trail behind.
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  12. #12
    The cat's name is jake
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    That's interesting to hear people's opinions about sandblasting.

    I've worked for two of the U.S. bicycle production fabrication facilities, and at both places we've used sandblasters. The first place I worked for, we sandblasted frames (took a matter of minutes), then powdercoated them directly. No filling, priming, etc, but also no aluminum bikes (though we did make aluminum handlebars, which were also powdercoated). The place I work for now, we also sandblast frames, both steel and aluminum frames. These are then sanded lightly, primed, and painted. The second place spent a large amount of effort/money to put into place what appears to be pretty much a state of the art paint booth system. Compared to the frame mitering, welding, and brazing areas, the CNC machining and paint facilities are jaw dropping.

    That's been my experience in the professional frame fabrication world, so it's interesting to see that in other industries, such as car painting, other types of blasting are preferred. I did not know that. When I've done contract fabrication work (outside my regular job), all the other industrial shops that I've run across that do paint work of some type all use sandblasting - I've actually never run across anyone doing anything different. Of course that doesn't mean that they are using the best practice, and being primarily a fabricator, I don't know the coating procedures like the guys that do really high end work. Regardless, in my part of the country, that is the de-facto paint prep process.

    Personally, if I had to blast stuff all the time, and I got to choose what to use, I'd use something other than sand (assuming it still cut as well). I like the idea of using something like walnut shells, or something that isn't going to get everywhere and abrade things that it isn't meant to (like nearby machinery, shoe soles, etc.).

    Edit:
    P.s. It's all "media" blasting BTW. That terminology has been thrown around as if it is something different than sandblasting. Sandblasting is a type of media blasting, as is soda, walnut, etc. It's not probably important to anyone but me, but I'm often pedantic.

  13. #13
    The Fastest of Bananas
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    The only time I've seen walnut shells *needed* to be used was on a restoration on a corvette, they give the right texture for the transmission case.

    Sent from my EVO using Tapatalk

  14. #14
    Nemophilist
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    Hey;

    Plastic and walnut shells leave a nice unmolested surface. They remove soft material coatings, leaving the base material unabraded. The oil and fiberous nature in walnut shells leaves a very nice sheen on alloy parts, much like they have when they are new. Plastic does not warp soft metals, but arguably its biggest advantage is that it can be used without masking any brightwork or glass. Pull the vehicle in the booth and blast it clean. Done. Great for anything, but especially fleet work.

    Any hard abrasive media will work for steel. I'd use glass bead for aluminum.
    Most people ply the Well Trodden Path. A few seek a different way, and leave a Trail behind.
    - John Hajny, a.k.a. TrailMaker

  15. #15
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    The Blast Master - An Affordable Sandblaster
    It'll make a mess but get'r done.
    Probably needs at LEAST a 5hp compressor.
    I had a 3HP IR and could get 15 seconds of good blast then wait 30s to go again.
    Now the 10HP Rolair that replaced it will cycle off while blasting
    One would need a larger blast cabinet than the standard starter size unless you tape a trash bag to the door and move the frame around.
    Enco - Guaranteed Lowest Prices on Machinery, Tools and Shop Supplies
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    andy walker
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  16. #16
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    I'm with BungedUP and TM, the naval comment - priceless, lol.

    Technologies will vary, and the USA is a leader, but this does not really make any difference to the simple task of taking an older frame to a blast booth.

    Best advice is avoid using heat on a composite frame. Sand blast in a booth with something fine gritted. In a booth, sand is not toxic, if that's all you got. Sniffing rattle cans while painting is much more risky.

    Eric
    If I don't make an attempt, how will I know if it will work?

  17. #17
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    Lot's of food for thought. I have access to to a compressor and basic sand blaster. But I have a concern about the Alu tubes and adhesive bonded joints. I live in a little town in southern VT but will look around for a shop with experience. They would get it done faster anyway. Thank you.

  18. #18
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    The paint is what mostly held those together.
    I've seen the tubes where you could turn them by hand.....
    - Steve Garro, Coconino Cycles.
    steve garro el jefe/el solo. coconino cycles www.coconinocycles.com www.coconinocycles.blogspot.com

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