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Old 03-19-12, 10:39 AM   #1
Superfebs
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Painting a Brompton rack

Hello everybody from Italy; new to the forum.

Straight to the point: my Brompton's rack is quite worn and scratched (actually the whole bike is. I got it used from eBay and it wasn't as pictured).
So: I am considering painting it to give it a new shine.

I am wondering if that could be a good idea, though. As far as I know, Brompton racks are always sold unpainted and perhaps there is a reason why (being prone to bump into plenty of stuff, maybe, the painting would wore off too easily?)
Or, maybe, painting could be just effective and there's some other reason (market strategy?) why they don't sell any painted racks. Dunno: I'd love to hear your advice.
I would spray a primer on it and then a spray paint for car bodyworks.

Thank you!
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Old 03-19-12, 10:53 AM   #2
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Powder coating might be more persistant, it's cheap, and wears well. Though I did the wheels on the Jeep with a rotary wire brush (see below) spray primer and rattle-can paint. They lasted a year already.

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Old 03-19-12, 10:54 AM   #3
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Wheel metal brush attachments for a drill are commonly used in metal restoration.
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Old 03-19-12, 11:39 AM   #4
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I bought a rack second-hand and it appears to have a layer of semi-metalic paint over the surface of the main cast aluminium piece. I assumed that that's the finish Brompton apply to the rack. . . it must be as the stays have a different finish and they're not detachable or possible to mask cleanly.
The metallic paint appears to have a grey primer underneath so it doesn't wear straight to aluminium. The result is kinda odd, an anodized finish would look much nicer. Perhaps Brompton have switched to an anodized finish in recent years as they have with the brakes.
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Old 03-19-12, 11:46 AM   #5
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you must drill the rivets out, to remove the stays,
to do processes like powder coating,
then re attaching them with Pop-rivets or bolts and nylock nuts..

I'd think wire brushing off surface corrosion, and then rattle can clear coat
will be sufficient, for most purposes.

if you are going to chuck up a wire wheel in the drill-motor, wear safety glasses!

Last edited by fietsbob; 04-12-12 at 05:21 PM.
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Old 03-20-12, 06:59 AM   #6
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You can remove the old paint easily with a brush-on paint stripper, or with Permatex spray-on gasket remover (available at auto parts stores). The toughest paint you can apply yourself is spray epoxy. It takes a long time to dry, so find a dust-free place to apply it. Epoxy paint is resistant to scratches and wear, though is not as tough as powder coating. On the other hand, it would likely cost less to buy a new rack than it would to powder coat your old one.
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Old 03-20-12, 07:13 AM   #7
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Hammerite is your friend !!
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Old 03-20-12, 07:33 AM   #8
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On the other hand, it would likely cost less to buy a new rack than it would to powder coat your old one.
The Brompton rack is around 100, I've no idea how a piece of cast aluminium came to cost that much other than that's in keeping with the Brompton spirit.
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Old 03-20-12, 08:51 AM   #9
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Hello, thanks all for the replies.

I already cut-off the rivets: I used a Dremel, because I can't drill straight 'cause of the shape of the rack itself (a very long bit would had been necessary) and yeah I used safety mask and glasses

Hammerite looks easy. We have similar products in Italy but the problem with them is that they shine for about one year, then they become opaque. Does Hammerite suffer of the same problem?

I didn't even thought about a wire cable and looks very interesting too. And fun. I will need to find a solid place where to attach the rack while I wire cable it; I live in a apartment and I don't have a work bench. But I can find a solution to that.

Most important, I am now wondering if I can repaint the whole frame that way. Would such a treatment damage the frame? I was considering a hot gun also, I remember that dad used one twenty years ago (ehm ) to remove paint from wood and that worked perfectly, but probably with steel it's a different story.

About wire wheel, there is one you would recommend?

Thanks buds!
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Old 03-20-12, 11:26 AM   #10
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Aluminum melts easily - I'd be careful regarding a heat gun. Otherwise, you might be better off keeping some of the old paint on, as it is difficult to paint aluminum over. Principally you need to use a special primer and you might treat scratched old paint as that primer and use actual primer only on the areas where metal shows. Wire wheels are primitive products and long time around - I would not agonize about the brand.
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Old 03-20-12, 11:38 AM   #11
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I think, you need more heat than a hand held heat gun can generate, to melt aluminum.

Though I know, you can melt holes in the bottom of a thin aluminum pan boiled dry,
left on high, on the stove.
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Old 03-20-12, 12:18 PM   #12
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I think, you need more heat than a hand held heat gun can generate, to melt aluminum.
I think I've done it with a heat gun left operating for a while on its highest setting. Since different unfortunate cases of melting alu tend to merge in one's head, though, I'd have to repeat the experiment to make sure.
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Old 03-20-12, 12:20 PM   #13
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If you could post some pictures documenting the stages of the process that'd be great.
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Old 03-20-12, 02:25 PM   #14
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My bicycle is old (for sure pre-2003, don't know how much older) and as far as I've read the older models had a steel frame, so I think mine could be the steel kind.
In this one both the "eazy wheels" are to be mounted on the outside of the rack, whilst in the new model one goes in and the other out.
My rack weights 314 grams (just measured with a kitchen scale).
I like the idea to share pictures in the while, so here it is:

Close-up:


Now, I have to consider if I want to get a wire wheel or not. Being sure that it could be used to remove all the old painting and rust from the frame without compromising its solidity, that would be the choice.

Thanks!
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Old 03-20-12, 03:39 PM   #15
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Nope, that the rack surface, other than the struts, is an aluminum cast piece.
polish it
or media [sand, walnut shells etc] blast it to get it clean enough
to powder coat, they do that , [it has to be clean and oil, including touching it, free]
or paint..

Last edited by fietsbob; 03-20-12 at 03:49 PM.
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Old 03-20-12, 05:38 PM   #16
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OK, thanks. I will go for the sand though it will take a darn long boring time.

I certainly don't want to sand the whole frame, though. What could be a good option for that?

(never heard about walnut shells, they are not common here. At least not for that purpose
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Old 03-20-12, 06:43 PM   #17
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what do you have in mind ? clear lacquer? powder coat,rattle can?
the rear hinge bushing is an expensive proposition
if it wont go back together easily.. the reaming tool is about $300.

walnut or other organic materials are for delicate thin stuff, that sandblasting eats away..
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Old 03-21-12, 04:41 AM   #18
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I've seen a few articles on the net about having Bromptons re-powdercoated. I don't think it's cheap given the number of parts, though I think it's possible to leave the rear frame attached to the mainframe (certainly one example was done that way). I also saw an example of a short wheel base Brompton that'd been given a raw lacquer type of treatment and the result was good, slightly different in colour to the official version.

As for a DIY solution I'm guessing that only a urethane paint would be strong enough. It might be worth starting with just the fork or stem and seeing how that works out. Something like KBS RustSeal might work:
http://www.kbs-coatings.com/RustSeal.html
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Old 03-21-12, 11:47 PM   #19
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About 12 years ago,when I used to fiddle with motorbikes, powder-coating, and the prep was very cheap, as was chrome plating. I had the steel gas tank of the bike blasted and chromed for about 60. A chrome Brompton?
Woo! But would the brazing take it?

Dunno about the rack. Hammerite is on the Jeep wheels, and refuses to come off in the English 'climate'.
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Old 03-22-12, 09:06 AM   #20
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Aluminum needs a special primer for painting. Don't let anyone convince you otherwise. The primer is also used for painting galvanized metal.
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Old 03-22-12, 10:37 AM   #21
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A chrome Brompton? Woo!
Please, we are talking Brompton here, not Apolo, so let's make that cadmium plating.
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Old 04-12-12, 03:13 PM   #22
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Did you get any further with this, Superfebs?
Perhaps with something like this:
http://www.sharkhide.com/
you could keep the bare aluminium finish.
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Old 04-12-12, 05:25 PM   #23
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Know any aluminum Anodizing facilities, that would be the way to go..
Polish it then get it anodized, once that far then a color can be added .
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Old 04-16-12, 03:24 AM   #24
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Hello all, unfortunately the project is pending because now I am planning a pretty long trip by bicycle (that's about 600 km with 9000+ meters uphill) so tuning the Brompie became a low priority. I will keep you up to date when I'll have news... Thanks!
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Old 05-01-12, 01:56 AM   #25
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Hi again, the project is resumed. I bought a angle grinder and some tools that should remove rust and paint from metals, here's a pic:



I will opt for the smaller wheel, maybe. It is said to be used to "clean the weldings of metals with no iron, like copper, brass or aluminium".
I am not going to clean any welding but to remove painting. I hope I will not make any disasters.
The bigger wheel is said to be used to remove "rust, painting or color", and actually it should fit better to this task.

I'll update you with more pics.

Maybe this is going to be an EPIC FAIL but it's going to be fun nevertheless

Cheers and thanks!
Attached Images
File Type: jpg smerigliatrice.jpg (55.8 KB, 7 views)

Last edited by Superfebs; 05-01-12 at 02:00 AM.
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