Powder Coating - Advice Please

[Chris400F]

I am contemplating getting a frame and other parts powder coated at some point, never having had this done before.
From reading various threads I know the recommendation is to strip out swinging arm bearings and replace with new after coating.
What do people do about steering head bearings? I may be wrong but my understanding is that replacement of the various
parts is less of a DIY proposition than swinging arm bearings.

[royhall]

I always fit the steering head bearings before powder coating as I like to heat the frame and freeze the bearing races so they just drop in. I protect them for powder coating with two large steel washers and a length of thread bar through the steering head tightened up with two nuts. I also do the washer thing on the swing arm bearings, the bottom shock mounts etc. If you use the older type swing arm bushes that fit below the surface I put them in before coating and do the washer thing, if they are the later bronze bushes fit them afterwards. But fit the protective washers anyway as getting the powder coat out of the swing arm afterwards is impossible.

Then I use some scrap bolts to screw into all the threads on the frame as getting hard powder coat out is a real pain, and if you re-tap the threads some can get damaged. Dont screw the bolts right through open holes through as the bolt gets powder coated as well and you wont get it out again. Just screw them in so they just show on the other side.

If you need to protect male studs such as the top shock mounts, screw a line of scrap nuts along the threads until they are completely covered. If you need to mask off areas you will need to use special heat resistant masking tape. Available on eBay. http://www.ebay.co.uk/itm/40mm-x-66m-High-Temperature-Polyester-Tape-Masking-Powder-Coating-upto-220c-/221765029699?pt=LH_DefaultDomain_3&hash=item33a239cf43

I have also found that things can be protected with copperslip. As its heat resistant it doesn't run and can be wiped off later along with the powder coating.

Hope that helps, Cheers Roy.

[captaink]

Hi, I have had about 10 frames and many parts powder coated over time and always strip them down with nothing left on them, they get heavily shot blasted prior to coating but never had any threads damaged.you can put a bolt in but you should re tap the tread afterwards anyway.
I also fit headstock, swing arm bearings or whatever after coating, I would never have bearings put through the coating process as there's a lot of heat to bake the powder coat on, it might effect any sealed bearing grease etc.
Just blank off any holes and tell the coaters to watch there covered.
Thats what I do and never had a problem,  others may differ in there views.
Also there are good powder coaters and crap ones, get the opinion of someone who uses the one your proposing.
Regards keith

[mike the bike]

Some powder coaters insist on the bearings being removed first.  It's not a big deal to tap the bearings out.

[Chris400F]

Thanks for all the comments, they are very helpful.
It gives me a good idea of the sort of things to consider if I go down that route.
Chris

[royhall]

Hi, I have had about 10 frames and many parts powder coated over time and always strip them down with nothing left on them, they get heavily shot blasted prior to coating but never had any threads damaged.you can put a bolt in but you should re tap the tread afterwards anyway.
I also fit headstock, swing arm bearings or whatever after coating, I would never have bearings put through the coating process as there's a lot of heat to bake the powder coat on, it might effect any sealed bearing grease etc.
Just blank off any holes and tell the coaters to watch there covered.
Thats what I do and never had a problem,  others may differ in there views.
Also there are good powder coaters and crap ones, get the opinion of someone who uses the one your proposing.
Regards keith

You must really trust your powder coater Keith. I've used 3 and although all of them did a superb job I wouldn't trust any one of them to miss bits or blank things off. I always blank everything off myself, threads included.

As for grease in bearings, there isn't any. They are just taper races and plain bushes that are greased later on. To be honest I can't think of anywhere on a frame that would have a sealed bearing? And standard ball races may be easy to tap out, but removing a bottom taper race is extremely difficult.

The amount of heat used for powder coating is way below the tempering range of a taper race, and has no effect whatsoever.

I do it that way so the amount of work done after coating is minimised, and so is the chance of damage to the coating trying to fit bearings and remove all the hard powder coat that got where its not wanted.

I always retap all the theads as its easy to do without damage as the theads will be clean. If your theads get powder coated its hard to find the start of the thread and they can easily be damaged. The bead blasting won't do any harm to your theads.

Each builder has there own way of doing things, but I have tried both ways and this works extremely well for me.

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[royhall]

Will have to post some pictures of what I am talking about.

The rubber bushes are always removed and replaced with new. I always use new taper roller head bearings not the standard ball races. There is no residual grease as I clean everything well before fitting the taper race (that's just a tapered steel ring). I should make it clear that anything that would burn or melt is obviously removed first. All areas that I don't want powder coat to get to I protect with steel plates tightened on with thread bar and nuts. Zero blast beads or coating has ever got into these areas.

Watched a friend once trying to remove powder coat from areas that were not correctly protected, and what a job that was. When he had finished scraping filing and dremeling the poor old frame was almost scrap. How do you refit the rubber shock bushes if the holes have been powder coated (he couldn't), you cant trust the coaters to blank them off, I certainly wouldn't.

In the pictures you can see the blanking off on the swing arm, frame, and centre stand. The reason I put the head races in first is this. I do not use hammers and mallets on the frame at any time. The bearing races are frozen first, then I heat the area around the head race with a blow-lamp (this is why I don't do it after its painted) then the cold bearing just drops into the hot housing. I then press it down with an old bearing (that's been ground down on its outside diameter so its loose) on top of the new race and tighten it all down with a large G clamp. Give it a few minutes for the temperature to equalise then remove the clamp and packing piece, and its done. No hammering, no punches, no presses, no stress to frame/bearing or me. Then I protect it from blasting and powder coating with steel plates and bolts.


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Hope these pictures explain what I mean. When my frames come back from the coaters I have nothing at all to do on them and the build up starts right away. Can't show the inside after coating as I didn't take any pictures, but I promise you the results were perfect.

Hope that clarifies the point I was attempting to make (badly).  

Or of course you can do the nightmare scenario, geez this makes me laugh every time I see it.  https://www.youtube.com/watch?v=3H-G111JXbU

Cheers all.

[royhall]

Hi Oddjob. Everybody likes to defend their way of doing things, each to their own I suppose. Point taken about the later years replacement though. As long as you get a good job in the end that's what matters. But did you watch that YouTube video in the link. Funny bloke, love it.

[captaink]

Sealed greased bearings are fitted on the rickman Honda spoked wheel, I have just had my wheels powder coated, the wheel refurbishers won't touch the wheels with bearings in.
Also of the many frames I have had powder coated dating from 1924 some have pre greased or sealed bearing replacements.
Whichever way you do it , it will be ok in the end im sure.

"The frames are dating from 1924 not me by the way"
Regards to all
Keith

[royhall]

Funny how people stick to one make. I to have a cb1300, a half faired SA model.

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[totty]

Funny how people stick to one make. I to have a cb1300, a half faired SA model.

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So do I. It seemed the natural choice of modern bike.

[totty]

No, I tried several times but couldn't get through the registration process. I gave in, but to be honest I could do without spending time tinkering with that bike anyway,  my cb550 rolling resto turned into use as is two years ago.

[haynes66]

going back to bearings, i've always tapped my bearings in with a hammer. it's very satisfying when the tone changes from a ringing noise to a more solid bong. mind you, my apprenticeship was on farm machinery...