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View Full Version : Rails - to blast or not to blast


briang2ad
July 1, 2005, 07:21 AM
In refinishing my CZ 75 (PreB) should I blast the rails with 120 MESH Al Oxide, and KG Gun-Kote them (like the rest of the gun? I'll probably do a portion of them anyway, and my slide/rail fit is now a little loose. KG is also sending me a little rubbing compound meant to smooth them after 'painting'.

Also, are there other places on the slides or rails to avoid blasting, etc.?

Dave Sample
July 1, 2005, 12:27 PM
We tape off the rails and the entire inside of the lower end. We do not want to blast areas that need to remain smooth for function.

briang2ad
July 1, 2005, 01:42 PM
What do you tape off on the frame? (Or do you mean the enter inside of the frame?)

Also, do you use standard blasting tape. I checked and the blasting co has that avaliable for me.

Thanks.

Wildalaska
July 1, 2005, 01:50 PM
We use electrical tape. Light blasting the rails with fine beads should not hurt

WildglassAlaska

Dave Sample
July 1, 2005, 09:00 PM
It would hurt our guns, Oh Wild One! Our rails shine like a diamond in a goats butt! I use a special brown target tape that I get many rolls at a time from a shooting pal. I also use Blue Masking tape for soime things. We do two media blasting so we have to have really good tape. I go through a lot of tape but tape is cheap compared to polishing time. I prep and then have Gunsite blue all of our class 1911's and they come out nice. We do the top rounds of the slide with a rougher blast that the rest of the gun. Gives them that Old time Colt look that we like on a fighting handgun.

http://pic11.picturetrail.com/VOL368/953404/7728367/101700069.jpg

http://pic11.picturetrail.com/VOL368/953404/7728367/101700075.jpg

http://pic11.picturetrail.com/VOL368/953404/7728367/101700198.jpg

This is an old basket case '70 Series Colt that we just shipped back to it's rightful owner after cleaning it up and making it run again.

Wildalaska
July 2, 2005, 12:30 AM
Sigh.......

Blasting dint hurt this one:

Ferget it too many pics...see www.wildwestguns.com/pistolsmithing (http://www.wildwestguns.com/Pistolsmithing/body_pistolsmithing.html)

WilddifferenttechniquesmaketheworldgorounDaLASKA

Jim Watson
July 2, 2005, 06:00 AM
I agree with Dave this time.
I had a gun fitted up pretty much out of spare and junk box parts but it shot well so I had it refinished to match all over. The klutz blasted the rails, the gun wouldn't function, and the slide had to be refitted and re-lapped. So now the rails are rubbed bright and the gun looks like it has shot a zillion rounds if you see it stripped.
Cover 'em up.

Handy
July 2, 2005, 10:05 AM
In the case of the CZ, the rails are currently coated. Is there no way of recoating them, since the coating only sticks to a blasted surface?


Just thinking about it, if the gun comes coated, why blast it at all. The surface is probably already rough if the old finish is removed chemically.

Unclenick
July 2, 2005, 11:47 AM
Handy, you generally need to freshly activate the surface for best finish adhesion and to resurface any burnished places to make them match.

Dave's guns are all precision fitted by hand and by lapping. You don't want even the extra few ten thousands that Parkerizing would add to the surface of the rails of a nice gun like that. Not to mention the lubricity differences.

As to an unfitted CZ or any loose military fit gun, finishing the rails won't make it noticeably worse, in my opinion, and may even tighten it a little. Odd things can happen though. If, for some reason, you got bad adhesion on sliding surfaces, you might have a problem with the finish coming off and balling up and jamming the works at an inconvenient moment. If the adhesion is good and the product well proven in gun actions, it shouldn't be an issue. Certainly finishes developed for the military to control salt corrosion (i.e., Tenring Enterprises' TR Gun Kote for Navy SEAL weapons) are intended to cover the gun completely, except for the chamber and bore.

If Dave says the blue masking tape holds up, then I'm sure it will. This surprises me, but I haven't tried it. I've just had bad experience with plain manilla-colored masking tape being eaten through by blast media. I like the elastomerized high voltage electrical tape. It is rubber-like and stretches way out and melds with surfaces well, but I will try the blue stuff and see how it does? Way cheaper.

Nick

Dave Sample
July 2, 2005, 05:08 PM
I have to clear something up here. I use a lot of the blue tape for slide protection while I am installing sights, etc. I also use it for blasting barrel bushings where I insert fuel line hose through the bushing and then tape it off so that the front part is all that get blasted.
The hose keeps the stuff away from the inside of the bushings which are tightly fitted.
The brown target tape is just right for the sides of the slides as I tape off the sides when I blast the top round with the black stuff. Most of what I do building these 1911's is a pain in the butt, but I love the end result.
I will try to get a couple of pictures for you someday of how we do these things here in the tiny shop.

spacemanspiff
July 3, 2005, 12:34 AM
Our rails shine like a diamond in a goats butt
isnt that illegal in most states?

briang2ad
July 3, 2005, 03:09 AM
OK - if you are refinishing a CZ in Gun-Kote (or similar product), you must blast and refinish at least the front part of the rails on the slide. (Otherwise it would look stupid - the rails on the slide front are exposed).

Should you just go ahead and blast (120 AO) the whole rail on the slide anyway? I think this is standard, because KG is sending me some KG2 rubbing compound for this purpose. There is 'plenty' of play in the slide.


I would not blast/refinish the rails on the frame - they are not exposed.

None of this is an issue on a 1911 - rails are not exposed.

Thanks.

Dave Sample
July 3, 2005, 02:18 PM
It is legal here in Arizona. We are still part of the U.S.

Don't try this at home, the goats do not like it at all!

It has been a long time since one ate a diamond ring of mine and I recovered it and licked it off. Yuk!

Unclenick
July 5, 2005, 09:01 AM
Thanks, Dave. That makes sense. . . your prior comment, not the last one ( :barf: ).

Nick

Non-member AHGHA (American Humane Goat Husbandry Association).

Dave Sample
July 5, 2005, 01:59 PM
Uncle Nick knows I was just woofin'. I let the goat lick it off!

"This could be the start of a beautiful friendship, Louie........................................."

Mac's!
July 7, 2005, 09:04 PM
Hello All.....Well...We DO blast the rails when we do a Tuff-Gun re-finish job on a semi pistol! Now, having made that statement, there are several items that must be mentioned.
We do not use silica sand for our abrasive blasting media. It's too rough and will eat metal if the pressure is high enough or allowed to blast on one spot. Glass beads don't work well either since they tend to polish the metal. We use a product called Black Beauty which does an excellent job of old finish removal and surface preparation but without being too aggressive. It's a little more expensive but worth it.
Alloy frames are just given the "quicky" treatment to remove the gloss but not damage the Anodizing. All alloy parts are given a Mil-Spec chemical bath to harden any areas that had the Anodizing worn thin and to prepare the surface for the new finish.
Steel is blasted right down to bare metal and Parkerized, including the slide rails.
We use only Gunkote that's molly based (Mollybdenum Disulfide) because it burnishes with use to a fit that is slicker than original. A note on so called "Molly finishes". Many of them have no Mollybdenum Disulfide at all!
Certain areas, like slide rails, get the Gunkote applied heavier than others. How thick depends on how loose it was to start with and the base metal. All steel = heavier..Alloy = thinner, etc.
Then the slide rails are hand lapped but no lapping compound is used! It's a polishing compound that will not embed into the metal and gives a very smooth final finish.
Ok, now that we're to the subject of hand lapping (Finally!) there are some special considerations that must be taken into account. Slide rails are machined into the surface of the metal. Most manufacturers make a compromose between speed and quality. That means that operating clearances may be a "bit on the loose side".
If you were to look at a brand new slide rail under a microscope, you would see that the surface is not smooth or flat. It has bumps, lines and dips. It is NOT smooth like a piece of glass. Many times, you can see this without a microscope!
The idea is to apply more molly-resin Gunkote than needed and then hand lap off most of the excess. The final fit is acheived by actual firing to burnish the rails to match each other. Yes, sometimes the finish may be polished thin in some spots but those are the high spots that were always carrying the load. The difference is that now, the low spots are doing some work too. The result is a reduced friction coefficient that you can feel.
Yes, there are shooters who may disagree with me on this. But please consider this: It's a metal on metal contact that takes a lot of pounding. It's a bearing surface but it is NOT a bearing. There will always be wear marks on the finish. The idea is to get as much of that bearing surface as possible to take the load.
Keep Yer Powder Dry, Mac
Mac's Shootin' Irons (http://www.shootiniron.com)
Tuff-Gun Finishes. The Name Says It All.

briang2ad
July 8, 2005, 08:02 AM
Mac:

I contacted a local blaster who uses "Black Beauty" for other things, and he sells it cheap. I could buy the stuff from him and do it myself (friend's blast gun). His is called "30-60" if I can recall - what does that mean and which one do you use?

My other option is to have another local professional blaster do it with 120 MESH Al Oxide (as per KG specs).

What instructions would you give to them when doing it? ( I am doing a Mak and a PreB cz 75).

Thanks.

Dave Sample
July 8, 2005, 08:35 PM
I know absoultely nothing about painting guns. I loved Mac's very interesting post, however.
My rails are steel to steel and are not perfect by any means. Just good enough to do 3/4 of an inch at 25 yards with a man or woman who can shoot a 1911 standing on their hind legs. I like to have 0 play in any direction except back and forth and this is a 10-15 hour job for our Online 1911 Students. It is just part of the Hell I put them through for 12 weeks. We use JB Bore Compound because it is a non imbedding stuff that can be washed away when done. The end justifies the means when they fire that first shot and have that "Platinum Moment" as one student descibed it. These are nice guns when done.
I will always use lot's of tape. It is part of the Art of the 1911. I love the idea of "Black Beauty" instead of "the Black s**t from Ajo."

Wildalaska
July 9, 2005, 12:26 PM
Dave Im gonna take my rail blasted defender off to the range tomorrow and shoot for accuracy

Ill have Spiffy witness

Wont be at 25 yards though since I cant see that far

WildbatAlaska

Bill Z
July 9, 2005, 02:03 PM
Ken, your not going top make Spiff stand next to the target while you are shooting again, are you? I'd think he'd be getting tired of that by now.

Wildalaska
July 9, 2005, 02:41 PM
He holds the target :)

WildwilliamtellAlaska

Dave Sample
July 9, 2005, 02:51 PM
Hey Wild One! I gues the William Tell thing is out now with you with an apple on your head and me shooting EAGLE 1 and hitting it on the first shot and then have apple juice in your eyes, HUH? Man ! That would be fun....................................for me!