I finally finished last night after almost 6 hrs of fuzzing around. Super frustrating with all the blockages. In total I have probably close to 14 hrs of time into this. Sometimes it would run fine for a few minutes, but ultimately it would stop. After recovering the media and filtering it with a large seive, I think only 2 blockages were due to large pieces of glass. At times it appeared blockages were due to moisture in the air. So, I drained my compressor tank before I started yesterday, but only two small margarine containers of water can out. After what seemed were more issues with moisture, I added a small water separator directly to the blaster, but it collected absolutely no water (I have another water separator located in my garage).
I agree that the plumbing at the bottom could be streamed lined a little. I will take mine apart and redo. To keep the media flowing, I resorted to tapping the bottom of the tank and fittings with my 2 lb brass hammer which helped at times. Twice I had to remove the drain plug at the bottom of the vertical plumbing below the blaster and remove the blockage with a piece of coat hanger. I could see that the glass media was damp. It seems just a little bit of moisture will cause the media to stick and then jam. It seems that for long continued durations, some type of large type desiccant drier is required or refrigerated drier unit, as the compressed air gets very hot, and it was only something like 45F outside=condensation in the long air house I had coming from garage to my tempo. I have used the slag before with some success when I did my trailer hitch a couple years back. It produces a rougher finish which is more suited to thicker metal that had more rust scale. I originally started out with "medium" crushed glass, but it was a bit too course and left a rough finish. It worked well where there was some heavier corrosion, but left a touch surface where the surface was rust free and I just needed to remove the powder coat. So, I basically redid the whole bumper using the "fine" crushed glass which left a nice smooth finish for paint. To summarize my lessons learned for blasting with this type of blaster:
1. Have a compressor rated for 100 duty cycle that can provide at least 12CFM @ 90psi.
2. Do the blasting in an enclosure with tarps on the ground to maximize recover of media and to keep your neighbours happy.
3. Use a professional grade full face mask covered by a blasting hood. I had a 3M face shield that came with peel and stick protective plastic cut outs that could be placed directly on the face shield to protect it. The cheap hood I purchased was garbage. You need one that covers your shoulders. I ended having to make several replacement "windows" using a sheet of clear plexiglass I had lying around, but they didn't last long. In total I probably went through 5 or 6 of these, resorting to covering the last one clear shipping tape which was almost impossible to remove. In the end, I ditched the blasting hood and just used it as a shield on one hand.
4. Choose media and grade best suited to what you need to accomplish.
5. A means to remove moisture is absolutely necessary. The centrifugal type water separators are not enough.
6. Last but not least, keep the swearing and cursing to a minimum so as not to have your neighbours think your some type of alien looking madman.
