Fitz
Senior member
- Location
- Cheshire UK
Hello all, sorry I had missed this post. I run a vapour blasting business as well as my main business. It started off as a general interest for my own classic restorations then I got it into it seriously. Funnily enough I have just finished an SF750 of my own, you can see the state of the original engine and finished article in the attachments, I also race a Monty by the way, Gareth and I enjoy some great competition in the UK. I experimented with my machine manufactured by VHT in the States, I tried leaving assemblies together, sealing things up before blasting. My advice is to dismantle everything, don't skimp on a gasket set to avoid splitting engines and gearboxes, the blast media will penetrate most things. To explain how it works, you have a blast cabinet that has a sump in the bottom, my machine has two additional filtration tanks because I recycle the water back into the machine. There is a slurry pump in the main sump and I run a large 3ph compressor, the air is connected to the blast nozzle along with the slurry feed from the pump, it also drives an AODD pump to recycle the water and wash the viewing window. The process has a number of critical elements, the type of abrasive, the volume of air and of course air pressure, all of these can be adjusted to suit the process required, I have recently finished some work for a local company that manufacture precision parts for a motorcycle manufacturer, the parts had machining marks that would have shown up when anodised, after vapour honing the mark were gone. The "go-to" abrasive is glass bead, it is fairly round, quite soft but durable enough to recycle many times. The technical side of things is adjusting the machine to suit the process. The best part about the process is that I can blast anything, even machined surfaces, bearing journals, pistons, carbs, the honing process does not change the base dimension. I would recommend fitting screws and bolts into any blind threads, just to avoid having to tap them again when you get around to rebuilding. For a more aggressive process, there are any number of alternative types of media available, in terms of hardness you would start with glass, aluminium oxide, ceramics, even garnet. Be aware that to change the blast media can be expensive so avoid sending scabby old car engine blocks in with your aluminium engine cases. I am the UK agent for VHT as well these days, they have a range of small bench-top machines that can be operated from small portable compressor, fine for doing your own work but not suitable for commercial or heavier work. The unique thing is that I can blast something like a carb, without worrying about the different materials, aluminium, brass, steel, plastic rubber, other than being spotlessly clean, they will not be damaged
