A bag of sand would do say a door, fender/guard and more. I use bunnings dried sand at around $7 per bag. If you do it outside on tarps you recycle it but only 3 times or so as the sand starts to get to fine. Rough sand best for rust and finer sand for paint removal. People do say you should only blast one side of the panel as you can warp it if you do both but I haven't found this as it's not as strong as the big industrial ones but I would not do roof or bonnet both sides to be sure. The lance keeps you away which stops the pain sniffing the dust as well as allowing you to see. The helmet that comes with it lasted 10 mins as the sand destroys the plastic and safety glasses let it get in your eyes so lance is recommended.

G`day again Wiggy
Can you get some pics of your mods top and bottom? And what pressure are you running at?

If you want to use the helmet you can clear adhesive tear-offs for the visor, should be available from paint shops or those who sell abrasives for blasting.  Just like the ones the V8 super cars use but smaller!!  Len

Will do but in Melbourne for the week so can't until Next week. I run 100psi

Basically though up the top you have a ball valve at the air inlet and one further down feeding pressure to the sand falling out the bottom. I found though that too much pressure went to the top of the tank and blocked the sand so I added another ball valve between the water tap and pipe going to the top of the tank so I can vary that pressure if it blocks ( when it stops I turn the pressure down at the top and it clears it out). At the bottom the ball valve was just to small and blocked there to much so I think it was a 1/2 inch ball valve originally and I fitted a 3/4 ball valve with adapters which made a hell of a difference. Also the more expensive ones have a proper blasting handle which I think sucks. The cheaper ones which the picture shows is a ball valve tap with the ceramic attached (and my lance is just an extension to lengthen it) it works much better and you can vary pressure by how little or how much you open it but the best thing with the cheap ball valve one is if you do get a rock or stone that blocks at the ceramic tip you can turn the ball valve off unscrew the tip remove it and go again. The expensive handle one seals itself with metal and rubber it's awkward and doesn't seal correctly after five minutes of use also if it blocks as there is no way to turn the pressure off you have to depressurise the hole system to unscrew the tip and clean it out. Hope I made some sense but will post more pics when I can and maybe a YouTube video to show. Keith

Wiggy333
Basically though up the top you have a ball valve at the air inlet and one further down feeding pressure to the sand falling out the bottom. I found though that too much pressure went to the top of the tank and blocked the sand so I added another ball valve between the water tap and pipe going to the top of the tank so I can vary that pressure if it blocks ( when it stops I turn the pressure down at the top and it clears it out). At the bottom the ball valve was just to small and blocked there to much so I think it was a 1/2 inch ball valve originally and I fitted a 3/4 ball valve with adapters which made a hell of a difference. Also the more expensive ones have a proper blasting handle which I think sucks. The cheaper ones which the picture shows is a ball valve tap with the ceramic attached (and my lance is just an extension to lengthen it) it works much better and you can vary pressure by how little or how much you open it but the best thing with the cheap ball valve one is if you do get a rock or stone that blocks at the ceramic tip you can turn the ball valve off unscrew the tip remove it and go again. The expensive handle one seals itself with metal and rubber it's awkward and doesn't seal correctly after five minutes of use also if it blocks as there is no way to turn the pressure off you have to depressurise the hole system to unscrew the tip and clean it out. Hope I made some sense but will post more pics when I can and maybe a YouTube video to show. Keith

 
Makes sense, how did you thread the lance pipe? Good thinking on the ball valve enlargement, sounds like the obvious thing to do when you put it the way you have. Looking forward to a vid if you post it. I have three bags of bunnings play sand that I`ve dried and filled the blaster with (the rest  is in a sealed container, i only put about one bag in the blaster). Going to have a need for it soon, just got to do some rust first (yes i know wrong way round, but i cut out a good area around the rust)

I would think the playsand might be a bit fine. What state do you live in as Bunnings sell different sand in different states. I use the Builders dried sand which is in brown paper bags ( like cement bags which is coarse but to coarse) thing is if it's to fine it takes longer ( but is gentle) although it may turn to powder quicker which gives more dust and may only be able to be used once. Also the play sand is not always dry which is a pain to dry out unless you prepare it. I would recommend a trial but swap if you can.
For the lance I brazed the fittings on with the oxy so it took five minutes to build. And used the 19mm larger copper pipe not the 12mm smaller stuff ( didn't want it to bend and hit me in the head). Keith

Here are two pics one of the ball valve and start of lance, and the ceramic fitting at the end of the lance. I also get new tips from my engineering shop as they wear out after say 8hrs of use. I get them from AIS at Buttsworth in Windsor Sydney. 

Great stuff mate, no problems with the sand being damp, i`m in SA and i had the sand spread on a tarp for a couple of hours mixing it about 20 minutes or so during the height of summer. So 40 + degrees in the shade dried the sand out fine, i`ve got it stored in a sealed plastic drum so it wont absorb any moisture. Love the lance, great thinking and the ball valve at end of the lance is a ripper of an idea that i am going to pinch. Actually i think i`ll pinch the whole setup lol
Cheers
Troppo

No patent from me just like to share my experience and knowledge. And from memory you guys don't get the dried sand I'm talking about. The play sand is always in the garden section not in the trade section like we get. I just remember it was really fine sand which for what I do in bricklaying was beautiful but for sand blasting mmm. You should try a local landscaper I remember filling bags of 40kg of sand there for five dollars. Probably better than the play sand but heaps cheaper.