I was lucky enough to be gifted a 2017 aluminum Giant TCX SLR by a customer. It’s a cool bike and I don’t mind it as it is, but I like the idea of making it raw aluminium with subtle vinyl graphics to make it less ‘slightly aged CX bike’ and more ‘not-quite-up-to-spec gravel bike’ in style & appearance.
What’s the best way to remove the paint from the aluminium without having to sand it?
I’ve just patch tested some Effetto Mariposa ‘Carogna Remover’ and it’s definitely softened the clear coat enough to scratch off after 50mins so that could be a good option - plus I’m fairly comfortable with it as it’s non-toxic and I’ve used it to safely remove logos on carbon fiber wheels a few times in the past.
Anyone else have any better advice and/or experience, though?
I brute-forced it and went toxic with Selly’s paint stripper. I got the full gas mask, goggles and gloves set up, put down an old sheet for the drips and paint and got the job done.
It’s not perfect, I still had to do some sanding, which is fairly tiresome, but I got some good results. I now have a polished bare aluminium track bike, a roughly-sanded aluminium trainer bike and another track bike for my daughter I repainted.
If there’s an option out there where the paint just drops off and there’s no sanding needed I’d love to know what it is.
The Effetto Mariposa ‘Carogna Remover’ is for safely removing old tubular glue from carbon wheels - you leave it on for 45-60mins then scrape. When you use it on carbon wheels that have water-slide transfer decals rather than stickers (e.g. some Fulcrum Racing Speed wheels) the transfer crinkles and can be scraped off easily. That’s the effect I’m aiming/hoping for.
I might do another patch test tomorrow leaving it on a bit longer…
Not sure if it helps, but I’ve accidentally remove clear coats on aluminum frames (i.e. E5 Specialized Roubaix and the like) with 99% isopropyl alcohol in the past, so that might be an option. I also feel dripping methylated spirit on an older Easton EC90SL forth and lost the decals on one side. Fork seemed okay, still using it, so that could be another option.
Not sure if you can get it in Australia, but here in the USA there is a product called Aircraft® Ultra Paint Remover. It’s definitely nasty stuff and not available in all states because of that, but it will remove everything back to bare metal. I used it on an old steel (Columbus SL) frame and just really stood there and watched the old paint bubble-up. Washed off with water and had to redo a couple of areas but not much.
When I lived in California and couldn’t get the Aircraft paint remover, I used a much less toxic product called CitriStrip. This normally took a few goes but did eventually work. The trick I found with that product was to wrap plastic around the tubes after applying the stripper and leave it for at least a day. Plastic wrap stops it drying out and keeps it effective.
I didn’t say sand per se - the shop should be good enough to know what media to hit aluminium with. But one man’s “pointless expense” is another’s “well etched surface without spending weeks sanding the paint remnants out of every crevice”.
It’s not so much the abrasion, but the heat from the sand blast process that can cause warping in the frame. If you’re going to polish anyway, then the abraded surface left from sand blasting is a fine starting point. As pointed out, there’s a wide variety of blast media, and this would be the most efficient and environmentally friendly way to remove ALL of the paint, especially in the welds. If your environmental conscience allows it, brush on paint stripper would likely take care of 90% of it; blasting and sanding can remove the remaining 10%.
By way of an update, the Effetto Mariposa did a good job and I was starting to see bare metal, but I got bored of the apply > wait > scrape process after 2 rounds so, in my ultimate wisdom, I decided it was time to start sanding… Oh dear.
Well, I needed the exercise anyway. I am now getting closer - most of the main tubes are now bare metal, but I still have the fiddly bits around dropouts, BB & welds to sort, then sanding to less coarse grits to get a nice finish.
I’m not aiming for a polished finish necessarily, but I’ll likely go to 1200 grit or a fine ScotchBrite.
I’ve decided to replace the fork rather than strip that back to raw carbon as that then means I can run more stem options by eliminating the Giant OverDrive2 with a change of upper headset bearing. I’ve found an adventure fork option at a good price through one of my suppliers that matches the Giant fork spec well and will suit it nicely.
Then I’ll find a nice vinyl colour to match the saddle and bar tape I plan to use on it to create some subtle logos on my vinyl cutter, before the GRX rebuild to finish it off…
It’s a little late now, but I have used Citristrip (not on a bike), and it is really effective. It’s citrus-based, so it’s “safe,” but definitely wear gloves because that stuff burns.
Not too late as it may be the way I go with the fiddly bits, but it was also mentioned above - we don’t have it in Australia, but there is an equivalent.
Citristrip is not really citrus based, the main ingredient is benzyl alcohol (CAS 100-51-6) which is present in fruits but isn’t derived from them: it’s made industrially by hydrolysis of benzyl chloride. The other ingredients are diethylene glycol monobutyl ether (CAS 112-34-5) and 2 aminoethoxy ethanol (CAS 929-06-6).
None of these is toxic: benzyl alcohol is commonly used in things like shampoos as a preservative. Despite this the material is considered hazardous: this is pretty common as anything that attacks paints is also likely to attack the fats in your skin.
Got it to 400 grit and decided to see what alu polish does with it like that - exactly the kind of ‘brushed satin’ I was aiming for, so I’m calling it done:
