WSM,
I'll post the clothes dryer blasting cabinet instructions for you:
Remove back of dryer and take out old motor and drum, everything.
Then cut a rectanglular hole in the top of the dryer and put in a piece of heavy plexyglass so to see what you are doing.
Next cut two circular holes in front toward the top edge for inserting your arms.
The front loading door has old weatherstripping around it and has a "locking" device (anythhing to secure a tight seal).
While the back is off make a steel table from tubing and heavy gauge (1/8") plating and sit it inside to hold the item to be blasted.
Next replace the back and by welding etc. seal it shut, doing the same to the bottom, this keeps sand from flying everywhere.
To seal the round holes for the arms make circular plates with a combination of heavy weight arms from an old rainsuit and leather welding gloves, these are secured with sheet metal screws.
You can use a small portable sandblasting/air nozzle that is placed through one side of the dryer and of course that hole is sealed as well.
Most of what he has done are manifolds, so far what he refers to as "rough" items, and he so far has just recirculated the sand, but merely uses a shop vac to clean it out when the rust particles begin to discolor the blasting sand. The same principles of the store bought cabinet I guess ?
Hope this saves you some typing.
P.G.
