Uhhhh... to late. Got my 40 pound soda blaster, 4 different size nozzles to try, a dead mans gun (switch), and a bag of soda. Gonna try it this weekend on some M105 saddle bag style toolboxes. I'll give another opinion when finished. Price was $149 on sale, normally $249, then I had a 20% coupon that they honored, made it about $120. Deadman switch, which is a gun with a different nozzle, $19.95. Bag of soda about $34. Person who purchased it, not so smart, but priceless. Now I know why the Northern tool ones went up to $1200. Carburator huh? And I thought I would do a M109 with it.
If this doesn't do the hardtop on a M109A3, then I'll go buy me a new carburator and do that.
Vinegar will neutralize rust. It is a great rust remover, but you have to rinse, dry, and prime within 24 hours or it will start right back. I have used it a lot on my green stuff, and experimented with it for months over a broad range of time for different materials. One-two cups white vinegar per five gallons. Keep the surface wet for 10-15 minutes, the entire time if you cannot submerge. Wear some gloves and wet, wet, wet, and wipe. After 15 minutes, brush off rust and/or debris. If necessary, repeat. With rust, two cycles will do it. Rinse, dry, prime. The worst of the rust conditions will start to appear orangy within 24-48 hours. The light rust areas being worked will start to oxidize once again in 48-72 hours. It not only eats the rust, but eats into the metal or metal surfact coating if left on over 15 minutes. I tried it on some shackles leaving it in the bucket overnight and it ate all the maker's coating off. Powerful stuff on metal.