I have a SS DPMS lower and I want to remove the black teflon paint. I bought  a sand blaster kit and I need help with the blasting element. What is the difference between the
sand
silica
glass.
I want to give a nice smooth texture but not to round the edges.

Aluminum-titanium oxide is the best media for this kind of work. Its almost the consistency of powder. Probably have to do some shopping around to find it.

If you are going to re-finish with some type of paint on bake on finish then don't use glass beads. The finish will be too smooth and hard for the paint to adhere well.

Just do a web search on a lung disease call sillacosis and you will thing twice about using sillica sand.

I can't comment upon the other item mentioned.

I don't have a box, I will go in the driveway tomorrow. I will use long sleeve somethig, protective glasses and a face mask. I want to keep it in natural metal finish, no paint or coat on it after that.
I got silica sand 30 grit 100 lb. bag.  Hope will do the job. I am looking for a nice, smooth texture finish.

If it is paint I would try leaving the part in paint stripper of lacquer thinner.
I did a lot of commercial blasting on cars & aluminum aircraft parts. I used plastic media. This media does not stress or heat the aluminum.
Only problem with plastic is you need a large volume of air. I was using 250cfm of air at about 20 lbs of pressure or lower out of a 1/2 inch nozzle.
Look in the phone book and see if someone local does plastic media blasting.
Also remember if you do decide to use you blaster wear a respirator, the dust that blasting makes is very toxic, stop often and allow the part to cool. Paint gets gummy from blasting and you start to eat away the aluminum.
Hope this helps
Gary  

I took sand paper on it before and now is not black or metal. I like it like Wilson frosted finish.

I had a DPMS stainless steel lower in it's natural steel color.

After having the lower for about 10 months one day during a really through cleaning I noticed it was showing some surface rust.

Now that lower is done up in an OD Green and Earth Brown teflon finish.

The natural steel color starts to look real dirty after some time exposed to the elements and all the dirt/grease from your hands.  That's also why I did my stailess steel barrel that had a bead blasted finish.

Pics of the gun before and after it went through it's cosmetic change can be found here,
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