ready for wet sand blasting

More info.
The wet system in this case runs at 90 - 120 psi and the large compressor was a direct feed with no holding tanks inside so as you use it makes a noise and more air. The green hopper is where he puts the water solution with the grit and in the bottom there is a vibrator that keeps the grit moving so it doesn't block anything up and flows nicely and evenly. The rate of grit to water can be adjusted but ideally the 4 25kg bags of grit and the water fill this hopper and they should both run out at the same time that way you have the right combination to do the job.
The coarse grit used on the tractor skid is very coarse and if it got near a copper line or brass or even a bit of tinware it would pit it quickly so you need to be careful around those things. So he used a finer grit on the tinware and the finish on them was good. After all the blasting he then washed off the grit that hangs on using a gernie with the water solution with the anti corrosion stuff in it. It did work on the tinware and other metals but surface rust started on the cast iron parts quickly. Even after all the washing you still get sand hiding in the little nooks n crannies so the air blower got a work out today to get rid of it. At the end of the blasting you still are left with a bloody large sand pit so I raked it all across to be under Lorry where there is no grass and wont do any harm there.
You can see that the skid is almost done and the finish of bare metal is good. Also you can see how much grit stays on the job and needs washing off and then another good clean off with the air gun. The trailer set up was very well done and balanced well. You may not be able to see it but there is a 1000 litre water tank up the front of the trailer but he only half fills it when one the road and incase there is no water where he goes into paddocks.

The other wet system is just plain water at very high pressure.......the min effective is 30,000 psi,and the units go up to 60,000 plus for removing everything down to white metal........they also use water with garnet fines added to cut holes in the tanks without sparks.

Well I nearly have everything in etch primer and would have if medical appointments didn't interfear wih important stuff. Anyway I should have it done tomorrow and then clean up some small parts that the big blaster would have sent over the back fence and hit someone, so it's into my own little blasting cabinet for those bits.
It is amazing that no matter how many times you go over the bloody thing you continue to find more grit hanging on in places and hiding away where you can't see it but then all of a sudden it is in your line of sight. So I am slowly winning with it and will continue to bat on still with a big grin on me dial as I am finally moving in the right direction.
Something that I am finding is how far this Hi Chem Super Etch primer will cover. I am getting great coverage and it seems to be impossible to get a run in it. I was stuffing about adjusting the spray and as soon as I pulled the trigger I thought OOPS (not really, but you can guess) and said well there is a run but none formed. Time will tell when I go to rub it back as I have been told it is a tough primer and takes a bit to rub back.

Well here is the pic of the back end of the trailer with the blasting gear on it. There is also a 1000ltr water tank up front. The green hopper is where the grit and water go and is then all hooked up to the air. At the bottom of the hopper is a vibrator which keeps the grit in suspension.
Almost everything is in primer now except the fuel tank, it has pin holes in it so I am now soldering them up. Very happy with the progress and it makes you feel good when this happens.

I generally don't sand etch primer as it is very thin and only there to give primer filler something to adhere to. In fact after sandblasting you don't need etch primer as the surface is already etched and you can just go straight to primer filler and save a step.

On this old girl the top of the gearbox, bell housing, sump and steering box are alloy and I feel they need the etch primer on them. Not being a painter I am just following the instructions offered up by the paint shop and other restorers within our Club. It might not have been necessary but I feel better knowing it is done.
I have and do use Rust Guard by White Kight paints which is an epoxy paint in a pressure pack can. I have been spraying it straight onto bare metal with brilliant results with coverage and high gloss. Only time will tell how it will stand up to UV light against fading like the Rust-O-Leum paint does. A great product that covers well but looses its lustre from about 12 months on.

No need for any etch on sandblasted ally done with crushed glass...........more likely you may have lots of glass grit embedded in the ally.

I was led to believe sandblasting can be problematic, in that it can be a bugger to really get all the fine silica out. The surface/crevices 100% clean of the stuff.

Years ago ,cops came to the yard at Darra looking for a compressor stolen from the hireservice.......they parked right in the middle of the blast yard,when they come out of the shed,their copcar windscreen was frosted..........sand actually sticks into glass like its sandpaper ,and then rips the wipers to bits.

I can support the idea of it sticking up in some out of the way places but the alloy bits feel nice and smooth so I'm happy with that bit. You really need a good air gun and get right up and personnel with everywhere to blow out the grit. It really hangs on and in layers. Where it sits on the ground you have to break it apart, not hard but it sticks to itself quite well.
Got the pin holes soldered up in the fuel tank and the base of the oil bath so tomorrow I will squirt some primer on them as well.