abrasive grit for sandblasting

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patrolman

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hi y'all,

getting ready to try my hand at a spray-on finish for my 1911, as it is currently devoid of any finish. after reading through some threads on here, it appears that I'm going to need to sandblast the parts prior to degreasing and spraying. I have two questions about sandblasting the parts:

1- What abrasive grit am I going to need? The parts are all bare carbon steel.

2- Do I need to tape off the slide rails and frame rails? I lapped the frame and slide rails together and it is a tight fit. Will blasting the slide and frame rails loosen the fit, or should I not be concerned about it?

Any help is always much appreciated.
 
I have a blast cabinet, and there's no way I'd blast one of my 1911's myself. I'd definitely take it to a smith first. If I DID do it myself, I wouldn't use anything harsher than glass beads.
 
Given that the rails are going to show wear, I would just tape them off.... as well as any sensitive areas that are not going to show during normal usage.

What kind of finish are you going to use?
 
Blasting

Don't use glass bead, it will not provide enough bite for the coating to hold. I use 120 grit Aluminum Oxide. It's your choice if you want to tape off the rails, also depends on what product you use. Gunkote will have little effect on the rails because it is a very thin coating and can be used on roll pins and triggers, Dura coat is a little heavier and if the gun is very tight it would pay off to tape off the rails. Also Dura coat has no lubricity properties where as GunKote does. Cerrecoat is good too.
I do a lot of coating of all the above mentioned coatings. I generally find out how/who is going to use the firearm and then make a recommendation on what type of coating would be best.
If it's a LEO rifle, being an M4,MP5 or UMP I recommend GunKote because of it's heat displacement abilities. Dura coat for sexed up camo jobs on bolt actions and any one of the three for pistol and revolvers. All three are good products and have different applications.
Hint: set the frame and slide on a jig that will allow you to take it from the blast cabinet to the cleaning tank and spray booth to the oven with out having to touch the metal.

Semper Fi
Guns - out
 
If your glass bead is not giving enough bite your pressure is too low. HF blasting cabinet says something like up to 100 or 110 Lbs or air. Run mine up to 120+ to get good bite into metal. I use glass bead from the streets dept, they use it in paint to make the road lines all sparkly.
 
I am looking for a durable, utilitarian spray-on finish. I am leaning towards GunKote, and it seems that a thin finish would be preferable for this pistol. So, looks like I'm gonna need 120 grit alox or glass beads at 120 psi or above. Anything else I need to consider?

Thanks for the replies, as always.
 
The manufacturers of the coatings SPECIFICALLY state:
"Do Not Use Glass Beads".

As for masking the rails, that would depend on just how tight your fit is.
Properly applied, the coatings will build up less than .001".
 
thanks, chuck.
will go with the alox abrasive.
I know you do a lot of finishing/refinishing. I have about .002 clearance between the rails, according to my feelers. Do you think GunKoting the rails will present a potential problem?
 
patrolman,
You mentioned most likely using Gunkote.
It is superior to Duracoat.
Proper application will build-up approximately .0005" per surface.
Use an airbrush. The aerosol cans leave a lot to be desired.
If necessary you can re-lap the fit. I usually find that a good oil and some grunt work will restore smooth function.
On occasion I will use a JB Bore Cleaner/oil mix.
Have fun!
:)
 
10-4 there, chuck.
will go ahead and re-lap the fit after coating the rails. I used some 600 grit abrasive paste to lap the first time. think this will be okay to use to re-lap after the GunKote?

By the way, any validity to this "tack-coating" stuff? I've read articles and posts on "tack-coating" the surface with very small amounts of finish before full-on coating as a way to obtain a smoother and more durable finish. Worthwhile?

thanks again for the advice. awesome to get it from professionals.
 
I would not use conventional lapping compound as it will embed in the coating and continue to lap even after it has been removed.
Toothpaste, JB Bore Cleaner or Simichrome will not.
Several, as in 4 or more, light coats is best.
I hope this helps.
 
thanks, chuck.
I have some simichrome laying around, so I'll give that a go after coating.

thanks, havoc.
Will dial in for 55-65 psi.

Again, thanks all for the help. Will report with the final results.
 
Brownell's has some videos on line abut applying Gun Kote. The links to them are on this page.

I don't have as much experience as the other posters and none have mentioned it, but I have had better results with bake on finishes when applying them over fresh pakerizing. At least, you might want to look at KG's pre-treatment: K-Phos
Regards,
Greg
 
Pre Treatment

YES! K Phos is good and that is in the standard package when I do a job. YES! gunkote over parkerizing is also very good and is tough as an M1 tank when it comes to seriously harsh environments. Bake on finish from Brownell's is a good low cost method for the "do it yourself" type. Just follow the instruction to a "T" and you will have a good looking and durable firearm coating.
Good luck and have fun with it.

Semper Fi.
Guns - out
 
What about a parkerized pistol with holster wear....should it be re-parked before coating? Or will the coating wear OK on the spots where the parkerizing wore off? Just blast the whole thing clean?

And can those coatings be removed later if you don't like it?

Not that I'm planning on doing it, but my RIA Compact that I carry every day is getting some shiny spots on her.....
 
Shinny Spots

I don't think there is a coating out there that could prevent shinny spots from holster wear. The finish on glocks (tenefer) is very very good and that even rubs off. The spots that the parker has worn will be a little smoother, hence a slightly different look then the parker parts. Generally, if the parker is 100% I don't blast but give the piece a good scrub with a tooth brush and mineral spirits. And yes you can K-Phos over parker. It makes it that much tougher. I almost for got. Once it's on you can only remove it by blasting. It's not as for giving as Duracoat where it can be quickly wiped off (during the spraying phase) with mineral spirits and resprayed again. Unfortunately you wont know until it's in the middle of the heat curing phase if there was a hiccup, or not.
 
Last edited:
havoc,
I've never understood K-Phos even though I used it a very few times.
I don't believe that it dries leaving no residue at all. And it seems to me that any residue will degrade the adhesion of the coating.
I made up some test blanks both with and without the K-Phos treatment. Scraping the coating with a dime, showed no perceptible difference.
Now I routinely use a true park (manganese phosphate) as a prep on carbon steel parts.
I'm tempted at times to use K-Phos on non-parkable guns, such as stainless and aluminum. But I'm concerned about actually doing more harm than good.
Seems to me a perfectly clean fresh parked or fresh blasted surface would offer more tooth to the coating.
I also don't believe in pre-heating. Pre-heating does make the application easier as it reduces the tendency to run. But that quick dry might also keep the coating from fully microscopically penetrating into the pores of the metal.
All in all, doing a very professional job requires a lot of experience, experimentation, attention to detail, time and of course luck!
It sure is not my most favorite or most profitable task. But it does allow me to be in control over the finishing aspect of building a gun. Over the years of dealing with many different platers, coaters and incompetents, I've been disappointed almost as often as pleased.
:)
 
K- Phos

I use K-phos for gunkote, mostly on pistols and revolvers and have found it to give a little bit more adhesion. But keep in mind that KPhos was made exclusively for gunkote and for those that don't have a parkerizing setup. I whole heartily agree that parkerizing is the best pre-treatment for gunkote or duracoat. All in All, as you stated, these coating will stand on their own with out pretreatment. I'm sure your aware of the "tricks of the trade", and some of these we keep to ourselves. Kphos is very good, but not the save all to pretreatment, but with some experimenting and testing you can have a very good product.

Semper Fi
 
I'll probably leave my Compact as-is. The wear spots give her "character" and credibility as my "duty gun".

That's my excuse, and I'm stickin' to it.
 
K-phos 2

Sorry for being short on my last reply, had frames in the curing oven I had to check on. I've used K-Phos on aluminum and stainless with no problems so far. I won't use gunkote on any poly frame and don't recommend it for any type of plastic, I use duracoat for those. I just hope they don't develop a living coating that grows as it wears...we'll have no work to do.

Rondog, we didn't mean to chase you away with our mumbo gumbo. You can do a good job and it will be fine just follow the instructions.

Semper Fi
 
The finish on glocks (tenefer) is very very good and that even rubs off.
Click to expand...

Actually the tennifer treatment is a metal treatment that penetrates the metal to a certain depth. The black on top is a glock coating. In fact if you stripped all of it off you would still have tennifer underneath. Its practically the same as mellonizing.
 
tennifer

Yes, and tennifer has been used for year in the machining industry for years. I guess what I was trying to say is there really is no finish isn't prone to being rubbed off by a holster.

Semper Fi
 
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