Progress with the new sand blasting cabinet (is as follows)
The design of the filtration system could have been done with some care. I could have at least done some rough calculations on the back of envelope like this =>
However, I didn't bother I used the used the much more common "How much? I'm not paying for that!" method. I decided to buy two rather beefy air filters to filter the air coming in and out of the cabinet. The filter on the way in is more to stop sand and dust from coming out (as is the other one actually).
I resorted to what I know so I applogise to the any Land Rover owners reading this - I bought air filters for a Mercedes non turbo OM61X engine. These are nice big beefy filters that have a metal reinforcing strip on the inside and a cushioned rubber ring on the outside that loves to be squashed (to make a nice seal).
These cost about 11 euros a pop. Which isn't too bad in the bigger scheme of things (fits in with the "How much" design criterion)
As I don't want to crawl into the cabinet to change the filter I've built it on the outside
Two M8 bolts used to stop the filter from sliding away when I'm fitting it to the cabinet
Welded a M8 nut onto a bit of crappy 1mm thick steel box section that then holds a bit of threaded bar which then holds the filter cover and filter in place.
The cover will hopefully stop other dust and muck from falling on the filter. There's a gap at the bottom of the cover (of course?!) to allow the air to get in...
...the plan is to get some of that fleece stuff that people bung into cooker hoods as a cover for the filter on the cabinet side: (With any luck) This should stop large silly aimed spurts of sand from settling in the filter.
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Holes for hands and gloves have been made
I've gone for the cramped 125mm straight plumbing connector option because I found one and liberated it from the rubbish - yet again fitting in nicely with the "How much?" criterion
...fits like a glove...
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Front is fitted and door hole is cut and reinforced
As you can see there are some horizontal planks at the top of the hopper so I can scrounge some wire mesh and place that on top of it and hopefully stop the stuff from falling into the hopper when I'm blasting.