So, I’ve sent more parts out to the sand blasters and powder coaters and I forgot a cardinal preparation rule, and have paid a minor price for it. I’m writing this post as much to remind myself as inform anyone who may be going down this route.
So, if there’s stuff you want protecting, you don’t wrap in in duck tape. You wrap it in newspaper, then you wrap over the newspaper with duck tape. If you just wrap with duck tape then the heat of the coating process melts the adhesive and sticks the tape much more tightly to your piece. Hence you wrap the paper around it first. What you get back is a really stiff mess that can be easily cut away.
If you wrap it in paper and only seal the ends with duck tape, then there’s a chance the blaster will go through the paper, and very find sand at 90psi will get everywhere.
In my case, it went into the steering column top bearing, which couldn’t be removed (due to the weld-on quick-release boss). So, I’ve washed it out, air blasted it and now I have to hope for the best (i.e. pack it with LM grease). it doesn’t really do much – just provides a loose top mount for the column. Worst case of all is that I ditch the column outer and use a rose-joint at the top to support it.
So, silly me.
The good news is that you can get universal-joints blasted and powder coated (think steering column lower linkage). Rather than try and protect them, I just thought I’d take a chance and if they were mullered then I’d make my own.
They came back looking lovely, and the gentlest of turns cracked the seal around the joint mating surfaces and they work a treat. The heat when setting the coating didn’t make any grease leak out of the seals. Some good news then.