Ya see, no one wants to admit that they are having a problem with their tools for fear that people will think that they are not handy with tools. The manager at HF said that heís sold hundreds of these and I was the first one that complained he was having a problem, now thatís BS. Thatís like saying their customers have never had to replace the grinding wheels on their tool.
Fact: Nozzles wear out whether they are ceramic, steel, carbide etc. Rubber in the abrasive stream just doesnít work. However, they are not supposed to wear out in an hour. You should be able to get somewhere around a hundred hours out of a nozzle.
Joe, that gun/valve/nozzle on ebay is just exactly what I had in mind right after I saw what had happened to mine. I felt sure that it was happening with all of those that used a stop block. If I remember correctly years ago that ball valve setup is what almost all of the pressure blasters used. I remember seeing them on commercial blasters that they used for cleaning buildings. Since I have a lathe all have to do is find a readily available source for the ceramic nozzles and make an adaptor for it to fit a 1/2Ē or 3/4Ē ball valve. In fact I just bought a 1/2Ē ball valve at Blaneís F&F for less than five bucks on Monday. I was going to replace the 3/8Ē valve on the bottom of the tank to try to eliminate the clogging.
The other link you posted to NT&E shows a gun that eliminates half the problem, itís $50 and the same as the one Eastwood is selling for $72. The other half of the problem is that it still has a stop block, which will erode rather quickly and needs to be replaced very often to the tune of $8 to $15 depending on your vendor.
Yes, silica can lead to silicosis; by this point in time just about anyone that has been exposed to any shop environment has heard of this, OSHA has made sure of that. The major component in most sand is silica (silicon dioxide or SiO2), so if you think youíre skirting around the silica by using Play Sand, think again. For paint and rust removal probably the safest blasting media is Aluminum Oxide but is way to expensive to use in an open system and is only practical for use in a closed cabinet. Also there are many products that are produced by DuPont and used professionialy and I have no idea where you would be able to buy small quantities; http://www.titanium.dupont.com/NASApp/TTPORTAL/Mediator?action=4160
So the only practical media choices that we have are sand and slag. And like the paints we use today, we just need to apply some common sense when we use them.