Masking for shot blasting and powder coating?

As in the title, I have masked the frame but the swinging arm is causing me to scratch my head. Threaded holes get a well greased bolt. I can plug the shaft tube at the UJ and diff ends with wooden plugs and hold them together using studding, penny washers and nuts, I have done this for the steering head bearings in the main frame. I would think that it will not be an issue to have paint blow into the the drive shaft/UJ tube as long as I can clean off the paint to fit a new drive shaft support bearing and also clean off the mating face for the diff.

However the bearing surfaces in the swinging arm pivots have me stuck. I could use the old bearings but these would fall out. I could drill through from one side to the other and use plugs and studding as above and then seal up the holes afterwards. With all of the above I could just apply a good coating of grease where I don’t want paint but I doubt this would survive the prep for painting (blasting and degreasing)

So has anyone recently done this? Any ideas? I had the frame powder coated about 30 years ago and can’t remember what I did then, I think I didn’t bother and spent a long time cleaning the paint off the bearing surfaces.

I have found that the companies who carry out the abrasive blasting and powder coatings normally have a good selection of plugs and masking materials. All you have to do is to point out the specific areas which need masking.

If you do get powder coat into areas where it may cause a problem it will dissolve in acetone or thinners anyway so you can clean out overspray fairly easily.

Many thanks, I will talk to them

If it’s a Tonti frame make sure that no grit can get into the top tube/breather reservoir. If it does it’s a real pain to get it out again and if any trace is left it will find it’s way into your engine oil.

Mine is an early Tonti frame (1974) and does not have a top tube breather as far as I am aware.

I have found a few powder coaters locally but so far I have been quoted £200 for blasting and coating frame. swinging arm, main stand and brackets (I did away with the side stand when it fell off it once)

Waiting for a few more local firms to come back to me. I have a friend who does it in his factory, and I can get it done for free, but I will have to wait for him to get his frame ready so we can do two at once, but that could take him months.

Yes t’was the later models had the breather in top frame tube scenario ~ this was a modded Tonti frame?

Chris…we use Cambrian near Oswestry and usually get the work done for about 100 - 120…long way from you I know…regarding the fine thread swing arm pivots…we have an old pair especially for the purpose…we do have the correct size tap n die also…in case owt goes wrong…

Kate, I have found a few places locally with prices from £150 - £300 but I am still holding out for mate’s rates! Your powder coater is a little too far to deliver the parts and I don’t want to get into carriers.

I like your tip for the swinging arm pivot threads, I have masked these with a penny washer each side bolted through, but this leaves a cavity that the powder coat oven doesn’t like

I’ve just used a company in Ware. They did my Tonti frame in black gloss, complete with protective zinc pre coat, swing arm and a load of bits for £200 incl VAT. I’m really happy with the quality. There was another Tonti already prepped waiting to go when I arrived.
Amwell blast and coat, Furlong way, Ware SG12 9BE
01920 462828

Thanks for that I will contact them

I picked up my powdercoating today from a local firm that i’d not used before, but had come recommended… they did a good job of masking so we had minimal thread and hole cleanup to do today… :slight_smile: everything was done (by them) with tape and some kind of paper rolled up in the holes… i’d be wary of using greased bolts as the grease might run out during the heating part of the process and affect the finish? best bet is to find someone who’s either recommended or is known for doing bikes and let them mask it, after you’ve confirmed with them what bits are important…