Powder coating a frame

I have an old aluminium hardtail frame in my parents loft that I’d like to tidy up and use. The paint is in a bad way so I was thinking of getting it powder coated. The only reason I say powder coat and not paint is I have had a few motorbike parts coated and generally they seem to hold up to abuse better than paint.

Anybody done similar with a bike frame and have any feedback? Is the powder coat durable enough or should I stick to getting it painted?

I got my daughter’s bike powder coated, definitely looks the part and apart from a chip where she dropped it on a granite pillar it’s spotless still.

In my experience home-spraying is cheaper but a lot more dependent on your ability and the quality of the paints, but a professional paint job is more expensive than powder coating.

Do check that the powder coater you use knows what to do with bike frames (mine said just strip the frame and they’ll handle masking the bottom bracket/headset/bottle threads), and remember that depending on how well they mask you might need to get it re-faced: even if they carefully mask the headset there might be a bit that needs removing, and they won’t mask the rear disc mount so that may need facing too. I ended up paying £100 for the coating and £25 to my LBS to face.

Just be careful with Aluminium, I’ve seen frames wrecked by powder coaters who were too aggressive when they grit blasted off the old paintwork.

I’ve had a few done over the years. Normally paid £40-60 and been very happy with the results.

An alternative to having it blasted, which can indeed damage alloy, is to have it acid dipped. That’ll soon strip the paint off. Looks like me and @rossburton’s daughter have the same taste in colours. Greggs Blue 😀

This was acid dipped, a matt powder coat, then a gloss lacquer over the top. E-Reg coatings in Burnley did a cracking job. Everything was properly masked off but I had the bottom bracket faced by the LBS just as a belt and braces job

A couple of good points mentioned previously regarding shot blasting. If you do get it powder coated try to find out how they’ll remove the old paint. Paint stripping should only be done using a chemical strip, if chemical stripping isn’t an option steer clear unless you or they want to spend hours rubbing the frame down to remove the old paint. Blasting isn’t and shouldn’t be used as a method of removing the old paint, blasting should only be used to prep the metal for coating. If the coater does blast after paint stripping, make sure they ‘sweep blast’ or at the very least used aluminium oxide blast media.

As with any painting, preparation is key to a good finish.

Binners, did those decals (loving your work with the Greggs!) go on between the matt colour and the clear gloss coats or afterwards?

Isn’t vapour blasting (which a lot of places do now) an alternative to chemical dipping, as it’s much gentler than normal shot blasting?

what about soda blasting is that easier on alu frame?

OP, if you are down south go to Trestan Finishers in Southampton, do a great job on bike frames c.£40, they do loads and properly cover threads, careful blasting & zinc phosphate prime etc. They are still open at present although taking longer obviously as short staffed. For another tenner they’ll do a clear coat lacquer over any decals you want to put on.

Basically get it done by someone who understands and has a good history of working with bikes. They’ll know how to do it without hurting the frame, what to mask, and they’ll also know the higher expectations on finish compared to, frinstance, a fence. Motorbike business is a good sign too, since there’s a higher number of bikers that’ll kick your arse if you do a bad job.

Another good option is anodising, I had my last 2 frames done by Steve the Anodiser and I love the finish- it’s a bit more expensive but not horribly.

Just quiz them a bit. I think people have covered it above. What your asking is not difficult but needs attention. Most important for me is making sure threads are covered. Where thas has been any over spray I’ve always been successful cleaning with a scalpel. BB threads, headset and BB faces etc.

It’s not necessarily the fact it is a powder or wet applied coating that makes the difference. You can get variety within each. But as a general rule more decorative things are wet coated and more industrial powder coated so you’ll get a tougher coating with a powder coating.

If it’s nothing fancy then powder coating works well. Had a few done now and always impressed. Finish is good enough for all normal purposes. Coating was tough, cheap, quick and it bough old frames back to life.

@convert – I had the stickers made by Slik and put them on over the lacquer. I reckon its 5 years since that powder coat was done. Its got the odd ding, but the stickers and the powder coat still look great

Zinc phosphate pre treatment mentioned above is for steel. Aluminium is usually etched before powder – not sure what the exact chemical is.

Powder is far more durable than anything from a rattle can (and often cheaper overall).

I’ve just stripped (wet sanded) my old Kona aluminium frame and resprayed it.  I decided on a metallic pearlescent paint, in rattle cans from Halfords and then obviously finished with clear coat, again rattle cans from Halfords.  I’ve no real experience of spray painting but I took my time, didn’t rush the prep and read up on technique.  Cost me the grand total of £22 and I’m really pleased with the finish.

I have a set of new decals in the post, so should look pretty good.

Isn’t vapour blasting (which a lot of places do now) an alternative to chemical dipping, as it’s much gentler than normal shot blasting?

I wouldn’t really consider it an alternative to chemical stripping, you could aquablast a frames but it’d be lot more labour intensive. Great for prepping the stripped frame though.

what about soda blasting is that easier on alu frame?

As above, highly labour intensive method which might not even remove the old coating.

Zinc phosphate pre treatment mentioned above is for steel. Aluminium is usually etched before powder – not sure what the exact chemical is.

Ordinarily yes, Zn Phos pretreatment would only be used on steel although some primers use Zn Phos as an ‘active’ anti-corrosive pigment.
Aluminium can be etched with either acid or alkali, acid is more common and won’t need a de-smut, although the majority of job coaters are unlikely to have a full blown aluminium pretreatment. If you’re going to pretreat either do it properly or not at all. There’s not much worse than poor pretreatment.

Slight hijack from op:

Leeroysilk – have you had any experience with steel parts and manganese phosphate? One of our old materials lab chemists used to rate it but I’ve never found anywhere that could offer it (only place was for industrial size batches to car manufacturer supply chain). Even somewhere with the full zinc phos dip system is hard to find (I know of one locally but somehow they are useless at the powder bit).

@mick_r I’ll drop you a pm.

Thanks! No hurry – I’m not making a frame at the moment but really useful to know for future builds.

I’ve just stripped (wet sanded) my old Kona aluminium frame and resprayed it. I decided on a metallic pearlescent paint, in rattle cans from Halfords and then obviously finished with clear coat, again rattle cans from Halfords. I’ve no real experience of spray painting but I took my time, didn’t rush the prep and read up on technique. Cost me the grand total of £22 and I’m really pleased with the finish.

interesting, that looks really good. been considering powdercoating an old frame, but your results there are making me think twice about having a go myself.
how difficult was it to strip the frame? and why wet sand instead of say nitromoors or whatever? how long did it take to strip?

thanks

Thanks for the feedback, looks like it may work. As soon as lockdown is over I’ll get it from my parents and get started.

Nothing beats powder coating for durability. My year 1999 sunn was powder coated from new and still looks good without any chips or marks
Rattle can paint jobs are awful for durability

Hi @mick-r you have mail 🙂