Gunsmithing Sandblast prep...

[Wardy]

Did some searching (using the Google search function) didnt really find what i was looking for...

Getting ready to do some Duracoat and am planning on blasting my barreled action. But, I am EXTREMELY apprehensive about blasting inside the action itself. Would stuffing it with play-dough and taping ut off be sufficient as a barrier? (its completely naked with no trigger group)

I also have seen that aluminum oxide ~120 grit is the preferred, but, would glass be good enuff? I know that "penning" the barrle/action isn't what you are looking for, but, if I tone the psi down wouldn't it be ok?

Thanks ahead of time..
Steven

 

[m1k3]

Re: Sandblast prep...

Don't want to use glass beads. It won't give the "tooth" needed for the paint to stick well.

I use silicon plugs and tape on my jobs to block areas where you don't want to blast. Either way, you will always get grit in places you don't want. Clean the hell out of it after you blast it. Then clean it again.

mike

 

[Shooter21]

Re: Sandblast prep...

soda with low pressure may get you where you wanna go as well. glass will remove finish but won't grit it up as previously stated. plug your chamber and muzzle and blast it inside and out with the right stuff (aluminum oxide 120) blow it out, blow it out again. soak in degreaser for 2 mins again. bake at 200F for 30 min then paint without ever touching the metal with your hands. good luck

 

[Straight Shooter]

Re: Sandblast prep...

No, glass beads will not work. Beside smoothing the surface they leave glass residue everywhere that will not simply blow off. It has to be rubbed off. Alumium oxide blast anywhere you want the coating to stick. Nothing wrong with doing an action inside and out. The coating only goes on .001" thick. Most actions have .007"-.010" of clearance on the bolt. If you use Cerakote the coating will also provide some lubricity. I even do bolt lugs on factory rifles. Helps tighten things up a bit until it wears off. With Duracoat it will be off all the wear areas pretty quick anyway. Just do not blast or allow coating into the chamber or bore.

 

[Wardy]

Re: Sandblast prep...

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Hired Gun</div><div class="ubbcode-body">No, glass beads will not work. Beside smoothing the surface they leave glass residue everywhere that will not simply blow off. It has to be rubbed off. Alumium oxide blast anywhere you want the coating to stick.</div></div>

I was afraid of that, guess i'll have to drop back and re-group. I want it done right....and the glass was very readily available so thats the direction I was leaning.

Thanks for the help

 

[CS223]

Re: Sandblast prep...

I use the aluminum foil duct board tape to mask & protect areas from the abrasive. Rubber stoppers where necessary.

 

[1snowcat]

Re: Sandblast prep...

How long do you use Aluminum Oxide before its worn out???

Just approx... not sure what to expect for durability blasting barreled actions...???

 

[Mark Housel]

Re: Sandblast prep...

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 1snowcat</div><div class="ubbcode-body">How long do you use Aluminum Oxide before its worn out???

Just approx... not sure what to expect for durability blasting barreled actions...??? </div></div>
I've blasted a couple hundred Glock slides with the 120 grit AO in my cabinet.
Still seems to be working same as ever. I run about 50-60PSI.

I saw posted somewhere that above a certain pressure (80, 100 PSI??) that it breaks down much more quickly.

Actually, that brings up the question.... How <span style="font-weight: bold">do you tell</span> when the media is worn out?

 

[Straight Shooter]

Re: Sandblast prep...

It's worn out when it turns to powder or dust. My evac system pulls out the dust so I just add a little when ever it gets low and I never have to worry about it. As longs as it feels gritty like sand it's good. Going this way in a sealed system it takes a long time to run out.

 

[Nocalphoenix]

Re: Sandblast prep...

Ok flame suit on if necessary....Alum Oxide was almost impossible for me to find and getting it shipped was cost prohibitive. I used 100 grit paver sand, the sand that is used to seal the joints. joints, cost about $7 for 50pounds and can be found at Home Depot etc. I ran it at 80psi and it did what I needed. It left a rougher finish than AO and I probably would not use it inside the action. I consider it a once and done proposition but for the cost it works for me.

 

[m1k3]

Re: Sandblast prep...

Was the paver sand consistent in texture/grit? I thought about just using plain sand too for testing different grits and finishes but when you look at it closely, its no where near uniform.

I've settled on the 70 grit if you want a true flat finish. 120 for just about everything else.

Mike

 

[Bloody_Tailgate]

Re: Sandblast prep...

Since the OPs thread has derailed I'll add to the mess...I just got my sandblasting cabinet and some 100 grit AO media and everything I blast has an aluminum color to it. Is that supposed to happen with AO?

 

[patriotoutlaw]

Re: Sandblast prep...

I am no expert on this subject. however, I have recently been going thru the same thing. The question was answered in my mind by reading Cerakote's instructions, that are enclosed in the package. 120 grit aluminum oxide.

 

[Nocalphoenix]

Re: Sandblast prep...

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: m1k3</div><div class="ubbcode-body">Was the paver sand consistent in texture/grit? I thought about just using plain sand too for testing different grits and finishes but when you look at it closely, its no where near uniform.

I've settled on the 70 grit if you want a true flat finish. 120 for just about everything else.

Mike</div></div>

Stay away from playsand, its very erratic, I tried to find a link at home depot but all I found was the polymetric paver sand by quickcrete. Anything labeled paver sand will be much finer and more consistent than anything else. I use a $20 gun from Harbor Freight and do not even try to use it in a cabinet, I literally stand in the middle of the lawn or sideyard and blast away. Obviously small parts are a bitch but its doable. For screw heads I have a piece of steel with a variety of thread sizes, I just run the screw flush with that and nothing gets lost and its been a very uniform finish. I have not had any problems with any gunsteel at 80-100 psi but if I do aluminum I back it down to about 40. The sand is to soft to blast knife blades or any tool steel past about 50rc but its great for other stuff. Even blasted a rollbar for a truck in the driveway. After blasting I wash it down with simple green and then MEK or another solvent that is compatible with the paint being used.

I just picked up a Rossi 92 Stainless lever gun. It has a glossy stainless finish that shows scratches very easy and its gonna get blasted real soon. I will post some before and after photos.

 

[cap2031]

Re: Sandblast prep...

It all depends on your process and your equipment. If you equipment can pull out the dust (broken down media) you just have to add fresh media to it.

Now for the more important question, embedding impurities. It helps if you are blading the same kinds of materials (generally clean SS parts or whatever). If you are blading really dirty stuff you could be embedding impurities into your metals, and if all the conditions are perfect and the materials and impurities don't jive then you could create problems like chemical corrosion cracking or other problems. It usually has to be be pretty bad to do this. Aluminum and Ti parts are more susceptible to this, S.S. is pretty tough and resistant.

So in Mfg we usually clean it periodically just to have good clean media that is not going to experience a build up of all the junk.

We are talking 1,000 parts though (again it depends on what your blasting, if its really dirty you may want to change every 50 uses, but it would have to be pretty bad or you are blasting off really corrosive caked on trash).

For general gunsmithing uses I could see this being changed every 2 - 5 yrs (if you equipment can pull out the broken down (dust) media).