Original thread for reference
Most relevant commentary from that thread.
Harold_V wrote: ↑Wed May 29, 2019 1:05 amYeah, soft materials are a great barrier for blasting. Fact is, it's soft rubber that is used in masking tomb stones so they can be "engraved" (sand blasted). It's readily available in rolls, with a self adhesive backing. Apply the rubber, then remove the portion you want to engrave. Hard rock is very quickly cut that way.
I used that same rubber (1/16" thick) to line the interior of my blast cabinet (to prevent creating holes). It's just now starting to fail, but only because it's gotten hard. It's been more than 25 years. It was never perforated in use, so it's extremely resistant to abrasion.
Traces of grease on objects to be blasted slow down the process something fierce, and it's never a good idea to introduce any to your blasting media. That's why I suggested degreasing before blasting. I try to keep my media free from oils so they flow properly.
BadDog wrote: ↑Wed May 29, 2019 4:04 pmMe too. I've got a rather large cabinet, big enough to put a few 16" truck wheels in. Either from the big door on one end, or the front side with the glove holes is split so it slides to each side for smaller items. It has a return funnel built into the base below the expanded metal work surface, and a 4" line going to a cyclone separator with suction/propulsion driven by 1(?) HP Baldor motor, and "fines" ejected out the back. It sounds like a turbine engine idling when it's running, very loud, and the fines are a problem for everything within 20 yards or more.
Between the fines problem and getting it out of my shop to run, I find I rarely use it even when it's the ideal tool. Since I live in Phoenix with nearly no rust problems, I wanted to store it out under my awning, and build a water bath on the ejection side to manage most of the fines. But a friend who had done that with a similar large cabinet advised against it. He said it was in good shape when put out there, but due to the perpetually raw steel surfaces generated by blasting, it developed terminal rust in only a few years.
With all that said, I'm interested in what you said about the rubber sheets used for granite etching. When I got it, the cyclone separator had abraded a hole in its case from the returned abrasive stream. I already was already on that path when I welded it up as I used a layer of silicone to provide a (hopeful) protective layer where the abrasive is hitting. But now I'm thinking maybe just clean it out and paint the inside to seal it up, and then line it with your rubber mask sheets. Same sheet also as an upgrade for the cyclone hopper repair. The turbine impeller also has severe erosion with a few perforations, which I suspect is part of why it's SO loud. Finding a replacement for that is much lower on priorities, and zero if I can't get it more generally useful.
No idea if that's practical, or will prevent decay, but storing it outside my shop would make it FAR more useful.
Question is, where do you get such sheets?
pete wrote: ↑Wed May 29, 2019 5:22 pmWhat about painting the items with a rubberized truck bed liner product Russ? Or MSC, McMaster Carr etc sell a variety of rubber sheets and the easy to get contact adhesive would be more than enough to bond it in place. In mining the conveyor shute's and just about everything in the grinding and milling process involves huge volumes of highly abrasive rock. Even the big ball mills get rubber faced bolted in replaceable liners. Lot's of parts get sent out to specialty firms for rubber lining bonded in place as the rubber will still wear out over enough time, but that's way to expensive for home shop parts. Can you hook a shop vac up to your blast cabinet with the vac's exhaust run outside for the dust?
Harold_V wrote: ↑Thu May 30, 2019 3:13 amHmmm. That's a good question. It would help if a guy knew the name of the product involved. I recall going to the maker of headstones to buy what I used, and that was many years ago, as I mentioned. With the proper name, it shouldn't be difficult to find and buy. Wish I knew more.
Here's a link that shows some being applied, and the results of blasting.
https://www.bing.com/videos/search?q=ho ... &FORM=VIRE
I may have found a source for the masking material. Give this a try:
https://www.hittmarking.com/category/sa ... -stencils/
RSG wrote: ↑Thu May 30, 2019 6:31 amBadDog, you can buy sheet rubber from MMC with or without adhesives on the back. In many thicknesses. It's what I used to line my one vibratory finisher. Look under the "Abrasion-Resistant Polyurethane Rubber Sheets, Bars, and Strips" subtitle
Harold, Your setup sounds perfect for the type of blasting you require. As you mention my setup requires more control for texturing and surface finish so different medias and pressures. They tell me if I keep my pressures under 20 psi the beads will last for a very long time as you are doing more peening than abrading. Regardless of research I have a lot of testing to do to refine, or "dial in" the process for my application.