Jesses' 48 PU

[dsraven]

don't you love it when a plan comes together? seems like we do a bunch of work and it looks the same. then one day it just seems to shoot ahead.
by sandblast profile I meant roughness of the surface. some abrasives are pretty rough and leave actual visible high spots. if the high spots aren't sanded down before primer the primer can just sink into the low spots and the high spots (we're talking about using magnifyers to see this but you can feel it) will end up with no paint on them so they start to rust quickly. there are 2 types of blast media. cutting and non cutting. glass bead is an example of non cutting. it blasts the paint ertc off because it spins when it exits the nozzle and hits the work. that removes the product you want to remove but the spin has less effect on the metal when it hits bare steel or aluminum. aluminum oxide is a really common cutting abrasive, like I use in my little portable blaster. it removes paint etc pretty quick but leaves a taller profile, though, so the blasted part needs to be sanded prior to primer. sorta like the difference between fine sand paper and course sandpaper. fine paper could be primered over and the abrasive would be covered with the primer. if you sprayed the same amount of primer on the course paper there would be the peaks of the grit not covered by the primer. in my blast cabinet I use garnet because it doesn't turn to powder right away and lasts longer. the profile isn't as big as aluminum oxide but I sand stuff anyway afterwards. aluminum oxide is really hard so it leaves a bigger profile than sand. sand is softer, like a #4, and explodes on impact so has less profile than alum oxide, a number 9. silicone carbide, a number 9.5, is even harder than alum oxide. when blasting and not recycling the blast media sand works fine. a blast cabinet automatically recycles the blast media.