preparing for powder coating

[Ewan 500 K1]

Hi,

Just getting the frame ready for powder coating. Does anyone know if I need to remove the bronze bushes from inside the swing arm pivot tube ? They are in fine condition and I'd rather not have to buy new ones if I dont need to. Same with the taper roller bearings in the steering stem, do I need to take the bearing seats out ?   Last, I guess that the rear shock bushings on the swing arm will definetey need removed as they are part rubber ? I'd be interested in any other hints and tips for prepping for powder coating anyone has too

cheers

[Piki]

Take off all rubber parts!!!

[Ewan 500 K1]

A lot depends on whether the frame will be shot blasted or bead blasted. If bead then you can leave some stuff in but if shot remove everything.

Clean the frame, I mean really clean it, no grease etc otherwise if the powder coater isn't meticulous then you'll end up with areas or bead/shot which then get coated over and eventually the powder falls off as it has no adhesion.

Either fit old bolts into threaded holes or buy a good set of taps/dies to clean them up afterward.

Best powder coater I know is Index Triple S in Halifax, highly recommended especially for frames.

Cheers oddjob. I'll be using Triple S , seen so many good things said about them. They've moved to Bingley now. I managed to get the stubborn rear shock bushes off the swinging arm this morning , although the vice handle got bent in the prpcess . Will stick some phots on my build thread later tonight. I've also degreased the sterring stem tube and swing arm tube and every other hole that I could fit a toothbrush/rag into. I'm still not keen on removing the bronze swing arm bushes and steering race tapered roller seats as I dont want the expense of getting new ones.... getting to close to the daughters weddin.... do I really need to remove them, what do you reckon ?

[Ewan 500 K1]

Spoke to Andy at Triple S Powdercoaters ( http://www.triple-s.co.uk ). Andy says:

a) Leaving the bronze bushes in the swinging arm pivot tube should be fine
b) Leaving the seats for the needle bearings may be iffy because if there is any grease left behind the bearing seat it will melt when the part goes through the oven and spoil the job.
c) Triple S will blank off all holes and threads before applying the powder coat.

So ..... anyone know how to get the flipping needle bearing seats out of the headstock tube without damaging them ?

[Bryanj]

Problem with taper races is that there is no surface to tap on to get them out, only way i know of removal ie either a run of weld arround the race to shrink the or a dremel to cut them--both of which destry them.

The only possible way i can think of to protect them is to turn some hardwood or dense nylon cones to fit and hold them tight in with a length of stud bar through a hole in the middle of both, ask the powder coater what he thinks.--Possibly even steel cones

[pptom]

I always blank off the steering head when sending for powder - however, I've had the problem mentioned with grease 'melting' out and affecting the coating on the outside. - didn't clean it thoroughly enough.
My masking method is to use a long piece of threaded bar through the head then bolt on a flat plate at each end which will cover the holes. I'm always fairly meticulous masking for powercoating - i do everything before taking it in - sacrificial bolts in threads and duck tape over anything else that doesn't want doing (the coater replaces this after blasting with something else that will take the heat of the powder oven - sometimes!) - our local coater is 'ok', but I've learnt not to trust anyone to anything that you could do better yourself.

[Ewan 500 K1]

thanks all, this is really useful. Still finding this forum amazing, how would I have coped pre web. Well, not well probably. As Bryanj says , its not possibe to drift the bearing seats out as theres no surface to drift against. I've put a blowtorch on them which resulted in a tiny smidgin of grease comin out, barely anything to speak of, after gunking them I'm pretty confident that grease release wont be an issue, so will just leave them in and go with pptom's blanking off solution and use sacrificial bolts and mask off all holes so that the powdercoaters aren't in any doubt. Found out today why the bike had 550 front forks .... the sterring stem is bent so it must have been front ended at some time. Bit spooky, hope whoever was riding at the time didnt suffer. I've got another steering stem form the basket case that I could use... but its got a ball bearing race seat on it , damned if I can see how to get that off now. Its also got a sterring lock on it and I cant see how to get that off either .. see pics

[Ewan 500 K1]

ha , got an answer to the steering lock issue from the US forum: "my ko has the lock underneath the lower triple tree, you put the key in the lock and push up slightly and turn to the left and the lock should come out , there should be a little spring in there as well so watch out for it , if you have no key for the 76 you will have to drill it to destroy it then put a new lock in"  Just need to try and find the key !!

[pptom]

Leave the race on for powdercoating / blasting to protect the metal underneath (although you will still have to deal with the grease - especially in the seal), to remove, just tap a flat bladed screwdriver in the gap underneath - between the rubber seal and race and work your way around, gradually levering it up - you only have to displace them about 5mm before they ping off.

[Ewan 500 K1]

oh bloody hell, swop to straight stem and a new set of tapered bearings it is then.... the daughters going to have to downgrade  her wedding reception venue plans to the shed

[Ewan 500 K1]

the £30 quid straw on the thousand quid camels back ha ha ..... any excuse to get a downsize on the weding will do

[Ewan 500 K1]

got the roller bearing seats out of the headstock pretty easy now.. see my build thread