Wet blasting. Freakin amazing

[68MoneyPit]

I saw a sand blasting attachment for a pressure washer on here and I decided to give it a shot. I saw several on the internet at various sites anywhere from 120 to 200 dollars. I ended up going to Northen tool and bought mine for $62.99. This thing is freakin amazing. I was out playing with it for about an hour and blasted about half of the frame. I also had a fender that I was not going to use and thought I would see what it did to sheet metal. I have seen several posts on here saying not to sandblast sheet metal because it would warp, but I did about half of the fender in about 20 minutes and everything looks good. NO WARPING. I am just using regular sand. Similar to play sand. The only drawback I see so far is that it uses a TON of sand. I went through about 100-120 lbs in two hours. Luckily for me I work in the oil field and we usually have about 10-20 semi trailers full of sand in our yard at all times. Here is my only question. Within an hour of blasting my frame I can see some orange. I don't really have enough free time to do the whole frame at once and prime it at the same time. What do I need to do about this. The whole rust removal and paint preparation is not my specialty. Is this orange anything to worry about or will I be able to get a primer that will kill it?