Preparing frame for powder coating

[We_are_Stevo]

WD - would all these apply to an Alu frame also?

I have one that's just ano'd, and assume they will media blast, but being retro Alu I don't particularly want it made any weaker...

Make sure beforehand that the coaters' used to dealing with alu - they all use sandblasting to prep for coating and alu disappears faster than a politicians promise at the hands of the wrong people!

Incidentally, if anyone living in or around Norwich wants any plain blasting done I always used Avocet (he's in Earlham near the UEA) for my motorbike parts. He's very good, will prime if required, and did a couple of alloy JMC swinging arms for me so I could colour-match them to the frames.

Back to the topic, most coaters will ask you to degrease the frame (I use Fairy Liquid then dry with a heat-gun) thoroughly, because when they heat the frame to melt the powder any grease leeches out and ruins the finish. Also ask them if they will mask all the threads or if you have to do it first. If you don't you may find you need a tap & die set when you get it back!

If you have a colour in mind ask to see their swatches - they have an amazing range to choose from and should be happy to advise. I just wanted my Explosif blasted and clear-coated and the coater I use in Eastbourne suggested having very fine Metalflake mixed with the clear powder - I wouldn't have thought of it myself but it looks great...

I personally would be reluctant to powder-coat an old (sorry, Retro...) alu frame because the heating process could make it even more brittle than it's already likely to be?

 

[kjarrett]

Super helpful information in this thread, thanks. Seriously considering getting my frame powder coated this winter.

Right now my main concern is masking the bottom bracket threads. Not sure if the powder coating firm I wish to use will require it but would like to know what to do if they asked me to. I do not have an old bottom bracket I can sacrifice. I do have several screws that should work for the brake bosses and other bits.

I also have some light chainstay damage from chain suck (present when I got the frame, see below) ... wondering how I should approach it. Sand it down? Something else? Since they will likely be blasting the frame I don’t think I can add any material.

Thanks, all!

 

[marc two tone]

Re:

Coaters that are are used to bikes will know what to do.

However, its worth pointing stuff out when you drop it of, just to affirm.

Old cantilever bolts in bosses with suffice. Bottom bracket, both sides, will be masked by them before paint gets applied. The prep stage was dealt with (at my chosen shop) by tightly rolled newspaper, in a wad form to protect bb threads during media blast.
Never had issues. Any gnarly burrs from chain suck, maybe file down high point and sharp edges. Not much else.

 

[kjarrett]

Perfect. Thanks!

 

[Peachy!]

Re:

I suppose the best advice would be to speak to your coater, find what they do, go and have a look at the type of stuff they are dealing with on a daily basis

WD

Best advise on the whole thread....

 

[WD Pro]

Thank you !

If you want the frame mint it’s possible to braze / silver solder some extra material in there and then sand it back - it will then go through the coating process no problem

WD

 

[kjarrett]

Thanks, I will look into that!

 

[Tootyred]

Re:

As others have said above. Its all about experience and skill.

A powdercoating company who does bikes regularly will know what to do and what to use. A good service imo, should include clean, blast, foil up, ask all the right questions and do a great job at a good price.

Media for blasting can go from walnut shell to metal beads and just about everything in between!

The other option is to consider with delicate frames is cerakote as it requires no heat. However, it does not hide imperfections as well as its very thin. Great for posts and stems as they still fit when you get them back!

 

[kjarrett]

Thanks! I am looking at several powder coating firms now, planning to visit the shops and look around before giving them my business.