dnepr0mike small arms

TABLE OF CONTENT (click to jump to specific section)

About this project
- Preamble
- Tools and supplies used
- Conversion parts
- Legal compliance
- Information sources and references used
Mechanical modifications
Step 1: partial disassembly - external parts
Step 2: partial disassembly - internal parts
Step 3: trigger plate/guard removal
Step 4 (optional): factory FCG diassembly for disconnector spring retrieval
Step 5 (optional): receiver notching for double hook trigger
Step 6: new FCG fitting and installation
Step 7: trigger guard installation
Furniture Installation
= = = =Overview of K-Var/Arsenal furniture set for stamped receivers
Step 8. Upper handguard gas tube installation
= = = =Lower handguard and handguard retainer conversion problem
Step 9. Installation of Saiga-AK retainer: cutting barrel notch
Step 10. Pistol grip
Step 11. Butt stock
Refinishing: surface preparation
Chemical paint stripping
Sandblaster paint stripping
Refinishing: proccess
Introduction to chemical metal refinishing
Bluing - Black Iron Oxide
Parkerizing - Zinc or Manganese Phoshate
Pros and Cons of each method
Tricks & Tips
Health hazards
Content of this website is a reflection on my experience in building an AK rifle from Saiga and how it all has BeGun.

One day I decided that I want an AK74. Buying one of those $350 Century built Bulgarian AK74s was out of the question due to AWB (re-adopted on the state level). Making situation worse was fact that majority of AKs sold state wide are AK47(7.62x39), old, beat-up, pre-ban. Being pre-ban those were not cheap either. So my choices were:
1. Keep looking for AK74, driving around the state hoping to catch one and then shell out around $1k for it
2. Get a parts kit and build it myself on the budget (without prior experience, special tools... hmm, skeptical)
3. Get Saiga 5.45 sporting rifle and converted into AK74 configuration.
While price-wise this is not always more advantageous than the parts kit, but it has certain number of PROS that you don't get with the parts kit:

+ Saiga is brand new rifle, not 'G to VG' or 'VG to EXC' service rifle meaning: No anxiety about condition of parts in the kit. Not a small deal from what I've heard
+ When put together price of the parts kit, barrel, receiver you will likely get a number above $400 (assuming: $100 for a receiver, $100 for a barrel, $150 for a kit and who knows how much in complience parts. Add shipping costs that could be as little as $50 and up to a $100 or sometimes even more). Saigas on other hand are sold ~$350 (as of Dec. 2010)
+ Saiga is complete, fully functional rifle 'chassis'. Barrel, trunnion, sights and receiver all factory put together, head spaced, sighted and test-fired. All done by same guys that currently manufacture AK100 series - Izhmash. Most difficult work is done for you already
+ Saiga comes with chrome lined, hammer forged barrel. Although there are chrome lined barrels out there to use with kits, but too few and far in between (usually selling for extra $$). If you are cost-conscious and/or want to take advantage of cheap surplus ammo and shoot anxiety-free this should matter to you
+ Side-mounted optics rail that's installed already - one less thing for you to buy and mess with
+ Last but not least - true Russian AK vs copycat. Definitely something to brag about at the range ;-)

Such was my reckoning when I decided in favor of Saiga.
Toold and supplies used
There is an absolute minimum of tools needed to acomplish certain level of conversion. It was always a trade off between do it faster and easier vs. slower and perhaps with certain degree of difficulty.

Minimum of tools used so far:
1. Rotary tool (a.k.a. Dremel) with a set of grinding wheels, diamond burrs and cutting disks
2. Plyers
3. Flat head screwdriver
4. Set of mini-files
5. Rifle rest (gun vise) or set of benchrest bags (seen in some of my pictures)
Once you decide to take-on more advanced work like adding compensator, swapping out gas or front sight blocks, blue/parkerize, list of equipment and associated expences continues to grow.
Additional tools:
1. Bench vise (nicer and comfier than work in your own lap)
2. Drill press (for more advanced work like swaping out gas/sight blocks)
3. Muzzle threading kit (die, die holder, TAT-Threading Alignment Tool, pipe cutter-to remove muzzle sleeve)
4. Sand blaster and abrasive media (Only needed if you planning to refinish your rifle completely with either 'Spray-n-Bake' stuff, Black Oxide or Phosphate)
5. Compressor setup w/desiccant filter (needed for sandblasting and blow drying after bluing/parkerizing)
6. Sandblasting cabinet (you can either make one or splurge on store-bought)
7. Bluing/Parkerizing setup (at least 2 tanks, heaters, stainless mesh basket, spool of wire)
8. Bluing/Parkerizing chemicals (as well as lots of WD20 for re-oiling)
Conversion parts
For basic conversion:
1. Furniture set: both handguards, buttstock, pistol grip (although set is 4pc. it counts as 3(three) 922r complience parts)
2. Pistol Grip mounting bolt and nut
3. Fire Control Group (a.k.a. FCG or Trigger Group. Consists of trigger, hammer, disconnector - another 3 complience parts)
4. Retaining plate for your FCG
5. Saiga-AK Lower Handguard Retainer (great for basic or even advanced if you don't want to mess with pressing-off gas and sight blocks)
6. Standard AK47/AK74 Gas Tube (Saiga gas tube has no provisions for Upper Handguard)
From my online research according to Title 18 Chapter 44 Section 922(r) of the United States Code, defined further by Title 27 Part 478.39 of the Code of Federal Regulation (CFR)
I CAN NOT make an AK out of my Saiga, UNLESS I use no more than ten (10) imported (original Saiga or surplus) parts during my conversion.

To achieve ten (10) imported parts count I could just replace original Saiga FCG and furniture with 3pc US-made FCG AND 3pc US-made Furniture.

Turns out that AK-family rifles consist only 16 parts out of 20 defined by BATFE in their complieance list.
Therefore replacing those imported parts with 6 US-made would bring down imported parts count to legal 10.
Worth mentioning that by installing only those 6 US parts I will be still 'in the clear' to outfit my Saiga with 'muzzle attachement' and allow me to retain/use original/imported mags.
Information sources and references used
Mechanical modifications
Step 1: partial disassembly - external parts
Field strip and inspect.

If haven't done it already, take gas tube off now, then sporting furniture.
Gas tube release lever might be too tight to do by-hand. In that case use cleaning kit tube and a slot cut into it's side just for this purpose.
There are three butt stock screws, two of those would come handy for attaching new butt stock, so loosing them would be a real bummer.
My rifle came with 'passport' with Quality Inspection stamps, and inspector's name/signature. According to it rifle has produced maximum spread of 133mm (5-1/4") @ 100m. 133 is written-in by hand.
saiga_field_stripped saiga_furniture_off saiga_furniture_off
Step 2: partial disassembly - internal parts
Saiga 5.45 pivot pins removal Saiga 5.45 FCG (incomplete). Remove rivets that hold sporting trigger and trigger linkage. I tried drilling as many people suggest, but rivet started turning with the drill bit.
Using rotary tool equipped with diamond burr (ball shaped)instead solved the problem. Angled ~45 degrees off the rivet axis it removes material quickly without turning the rivet itself.
After half-hour messing with various drill speeds and bits it took me, maybe, a minute or two per rivet. Then I just knocked them out with a punch and a hammer and rest of the sporting FCG spilled-out from the receiver.

Saiga 5pc sporting FCG will need to be replaced with 3pc standard AK FCG that also US made for 922r compliance.

1. sporting trigger: discard
2. Y-shaped trigger linkage and spring: discard
3 and 4. hammer catch and disconnector: discard
5. hammer spring: KEEP
You also need to keep selector lever, BHO and BHO-spring (not pictured), two pivot pins.
Step 3: trigger plate/guard removal
To remove sporting trigger plate I had to grind-off three rivets (pictured) using rotary tool (a.k.a. Dremel). Then I attempted knocking them out with a punch, but during riveting process rivets expanded under the plate also. I was not wiling to risk receiver damage or deformation because they are really don't want to come out that way. Instead by just twisting and turning sporting plate I was able to pop it off also with help of a large screwdriver, jammed under the plate and turn/force it deeper. Just be mindful of damage and possible paint chips.

Time to remove trigger guard from sporting plate. There is a spot-weld holding both together as seen on the picture. I tried drilling it from trigger guard side and grinding from unpainted (back) side. After much fuss and two dull drill bits, finally managed to do inflict enough damage to the spot-weld, so it could be ripped off trigger guard by hand. That was a tough nut to crack. Once trigger guard was removed, I cut-off excess length as pictured and round/smooth corners and face of the cut. Put it away for now.
saiga_trigger_plae_rivets Spot weld joining trigger guard and sporting plate
Step 4 (optional): factory FCG diassembly for disconnector spring retrieval
Saiga FCG disassembly This step was not optional for me because I did not purchase disconnector spring and Tapco G2 FCG comes without one. So I *had to* take apart original Saiga FCG.
Although seemingly simple, it did take a bit more time than one could anticipate, and then some.
First I determined on which side retaining sleeve protrudes out more and could be worked with. Then using pliers squeezed flared-out edges back together, but just enough to return them to normal diameter.
I had to squeeze a little at the time and also move pliers around, since I did not want to destroy it. Who knows maybe it'll come handy some day as a replacement part.
Using punch-like tool of proper diameter I knocked out sleeve enough, so it could be pulled with pliers. Alternatively, knocking it until disconnector spring is free would have aso worked. Objective is to get the spring, there is no need to completely remove retaining sleeve and taking apart entire assembly.
Using retrieved disconnector spring putting together US made trigger, disconnector and retaining sleeve was a breeze.
Although Tapco G2 FCG rated 3-4 lb of pull, I'd like mine to be also as smooth as possible.
Perfecting trigger function by polishing contact surfaces now while all 'guts' are still out, rather than doing it later wasn't a bad idea either.
Tapco G2 FCG overview
Here how (pictured) 3pc Taco G2 Intrafuse FCG compares to original Izhmash sporting FCG. Note that original parts are machined that clearly visible from milling marks on some surfaces. In contrast Tapco makes FCG parts by injection molding using 4140 tool-grade carbon steel. Tapco website also warns that G2 FCG is not compatible with NDS-3/NDS-65 receivers and Saiga platform. Using their product may cause double-firing (not sure if that's such a big disadvantage).

Anyway, double firing and trigger slap can be easily fixed by removing tiny bit of material as per this great thread by PA Rifleman.
Some people are badmouthing Tapco products, but for the price you really can't go wrong! Especially if you are on the small budget.
Sure, I would rather use fully adjustable Red Star AK FCG, but price difference $80 vs $25(for Tapco) makes for a very good incentive.
I've seen many satisfied Tapco G2 customers that are very happy with their choice.
There were claims made that Arsenal FCG is superior to Tapco G2 but my online 'gun boards' research actually indicated opposite.

It is also worth mentioning that Tapco G2 is a single-stage while Saiga original trigger is a double-stage (more on trigger types by Chuk Hawks). Keep this in mind if you are proponent of a specific kind.
saiga FCG vs Tapco G2 FCG saiga FCG vs Tapco G2 FCG
Step 5 (optional): receiver notching for double hook trigger
receiver notching For some reason I have decided to use double-hook trigger basing my decision on claims of higher weapon reliability (case when one of the hooks breaks off). Something along the lines: benefit of extra reliability out-ways trouble moding the receiver.

Now in retrospective, after all things are done, I conclude that it is not necessary step to take, nor justified for a casual shooter. I can certainly see the potential benefit if rifle used as a 'weapon of war', otherwise it's just 'extra trouble for a double' with return little to none.
For all DIY-ers out there, I advise not to fall for the same questionable 'benefit' as I did. Guys at Izhmash use single-hook and everyone agrees, that they know what they're doing.

So with double-hook trigger in my hands I had to make a cut-out in the receiver to accommodate for a double hook Tapco G2 trigger, since Izhmash original trigger was single-hook. I used rotary tool equipped with beloved ball-shaped diamond burr to cut a none-through groove and then cylindrical burr to finish off through all the way. It took quite some time, since my burrs were already worn and receiver steel is pretty hard. Drilling a hole and then connecting it with trigger opening would be an easier way, I would think.
Step 6: new FCG fitting and installation
It's about time to test-fit new FCG and see if there are any modification needed to be done.This was by far the easiest step in the entire project, except for mounting a pistol grip.

After quick assembly it became apparent that trigger's lip is hitting front edge of the receiver's trigger opening, as seen on the picture.

Quick Tip: Test-fitting without hammer spring attached makes for a far easier task.

Trigger needed to be modified as pictured. Cylindrical diamond burr did the job perfectly and quickly too.

Alternatively fixing trigger in a bench vise and taking file to it would be even easier. Few quick swooshes are better than a 'dancing' burr.

Tapco G2 trigger hitting edge of Saiga 5.45 receiver openning. Tapco trigger mod
Step 7: trigger guard installation
This is also an easy step and there is not much to tell about it. Once trigger guard is trimmed as described in Step 3, it also needs to be squeezed slightly in the bench vise (or with a C-clamp) for mounting hole to align properly.
Quick Tip: squeeze little-by-little and test-fit often, so there is some tension left in it. Since non-bolted side will be just tucked-in and under mag-release bracket, some pressure will help it stay put and not wiggle around.
Have a 4mm (or inch equivalent) bolt and nut handy, but make sure that bolt is no longer than 12mm otherwise fire-safety selector won't be able to clear it. Self-locking nut, locking washer or non-permanent 'Loc-Tite' wouldn't be a bad idea either.
Furniture Installation
Overview of K-Var/Arsenal furniture set for stamped receivers
I decided to go with pricier, more historically accurate furniture by K-Var/Arsenal. It is also claimed to be manufactured to current Russian mil-spec standards.

Unlike Tapco it has trap-door compartment for cleaning kit and that feature alone tipped the scale for me.

Stainless heat shield was an added bonus. Although for casual semi-auto shooter it's not as crucial as for full-auto high-volume shooter.
I have heared reports that putting more than 120-150 rounds of contiguous fire through the barrel without 'cool-down' intervals, will cause unshielded handguards to start melting. There is even a picture floating around.
For the rest of us folks out there it is no more than historic accuracy factor.

k-var/arsenal furniture set from dinzag k-var furniture set close-up
Step 8: upper handguard gas tube installation
East German upper hand guard vs. K-Var

How to twist-on AK polymer hand guard onto a gas tube
Installing upper handguard onto a gas tube was one hell of a task. As you can see from the photos, K-Var has quite a bit more of material in highlighted areas compared to E.German. In order for you to be able to twist hand guard onto gas tube some of the polymer would need to be removed (see next photo in gallery mode). Basically edges need to be round off enough so you won't have to try to put a 'square peg into the round hole'.

E.German handguard that came with gas tube, was very easily removed and re-installed. Because of how much material was not there. You might want to file-off your K-Var handguard just enough to make it 'little tight'. I filed-off corners just too little (see photos) and twisting it on was w-a-y too hard. Almost took the skin off my palms before I was able to get it on. Don't make same mistake and file the hell out of it, do yourself and your hands a favor.

Alternatively, if handguard could be fixed into a bench vise vertically, where you don't have to hold it by hand, you might not need to file-off corners at all, but only if you have a vise.

There is a video 'how-to' on handguard installation available here.
Lower handguard and handguard installation problem
Lower handguard is easy to put on and there is not much to add there other than it might need to be filed depending on tolerances of your receiver. Mine slided right in and required no trimming whatsoever. It does though, require a handguard retainer to be installed onto your barrel. In case of an AK this is normally done prior to pressing-on gas block and FSB, so then it always stays on to prevent being lost.

In case of Saigas this step is skipped, since completely different style 1-pc. handguard being used. Anyone who converted Saigas before, knows that there is very few solutions to this problem exist.

1. you can un-pin your FSB and gas block and install surplus retainer, that is if you have proper equipment to press-off your factory FSB and gas block, then drill and pin gas block and FSB and press back onto your barrel. This requires hydraulic shop press, drill press and some AK building know-how. Not your average garage hobbits job. Nor it is cheap if you decide to take this route and have to buy equipment.

2. buy a bolt-on clamp-like handguard from dinzag's or elsewhere for about $50-70+S&H. Cheaper? Perhaps. Easier? Of course! But, not my cup of tea. Mainly because of the quite hefty price (for a budget builder) and also cumbersome visual appearance.

3. get a surplus retainer and modify as pictured below and then use in conjunction with notched bolt and nut. I chose this way thinking as cheapest and easiest of three. results could be seen in the photos. Now in retrospective, I wish there would be a 4-th option, since I didn't like how 3-rd option came out. Also how fairly difficult it was to achieve (with limited tooling) this less than spectacular result.
AK47/AKM lower hand guard retainer AK47/AKM lower hand guard retainer and cut lines
AK47/AKM lower hand guard retainer cutting center section AK47/AKM lower hand guard retainer handy spreader solution AK47/AKM lower hand guard retainer cut and installed
4. At the time when above paragraphs were written there was no option number 4. Until now. Unsatisfied by what I had in my disposal I spent some time to create my own option, that will IMHO work great for Saiga rifle conversions.

Modeled after AK74/100-series Lower Handguard Retainer an improved version of older AK47 style. Featuring top side lip extension that prevents handguard from moving up-down and holds it more secure. Although original handguard retainer is injection molded to ease of massproduction, my on other hand, is precision CNC machined from solid steel stock to 1/100 of a millimeter and designed to match Saiga barrel dimensions.

For the best results it's intended to be mounted by meanse of a barrel notch (same as all Kalashnikov-family of rifles) and a spring-pin or sex-bolt in place of locking lever. Pin hole/oppening location is identical to that of standard retainer and therefore should be interchangable with most variations of AK rifles and not limited to Saiga only. I heard that Chinese variations come with a thicker barrels, so there might be potential for missfit as my 'saiga-ak retainer' is designed for 17mm barrel diameter. Minor fitting might be needed though, as dimmensions of AK parts might vary sligtly depending on origin.

Alternatively it could be mounted with notched bolt and nut (not prettiest but certainly easiest solution for Saigas, since barrels themselves are not factory notched)
AK74 lower handguard retainer Evolution of AK Handguard retainer. Courtesy of my762buzz.
Step 9. Notching Saiga rifle barrel to accept Saiga-AK lower handguard retainer
There are few step and just 2-3 files need to achieve handguard outperforming any other Saiga conversion retainer out there and equal only to original AK retainer. Tools needed: Diamond needle mini-file, 5/32 and 3/16 round chainsaw files. Sets of mini-files and chainsaw files are available at Harborfreight for about $5-6 each.
1. mount handguard and retainer onto your Saiga rifle. This step assumes that handguard is already fitted to a receiver and retainer is fitted to handguard.
2. making sure that handguard and retainer are pushed back as tight as possible, mark a spot on the barrel for a notch.
3. remove handguard and retainer and cut guide groove into the barrel with diamond mini-file about 0.5-1mm deep. Stay perpendicular to the bore.
4. now using groove as guide, widen future notch with 5/32 file. try not to deepen groove any further.
5. switch to 3/16 file widen and deepen grove to ~1.5mm checking fit often. BUT DO NOT CUT DEEPER THAN 1.75mm! Congrats, you are now proud owner of your very own barrel notch.

Needless to say that when cutting you must maintain direction perpendicular to the axis of the barrel/bore. Test groove often by mounting handguard and retainer and inserting 3/16 file as representative of a future roll pin or bolt. If 1.5 mm depth is already achieved but file still doesn't quite fit. then you may elongate upward retainer's pin hole. Unless you will use bolt and nut make notch tight.
Step 10: pistol grip
Installing pistol grip is really 'no instructions needed' type of affair. It's worth to mention a trick on how to hold grip nut in place, while trying to thread bolt into it through the grip itself. I found very useful to shim it tightly with a block of wood of compatible size. Block can be inserted into receiver through butt stock opening. Alternatively tightly wound wad of paper will work too.
Step 11: butt stock
Despite being highly praised and admired by some folks for quality and toughness I, personally, was somewhat disappointed, especially taking into account premium price. Don't get me wrong, it's good! ...but not without own problems:
- fit and finish - acceptable although not great (see picture close-ups). Note metal butt plate not fitted well if you can even call IT a 'fit'.
- trap-door cleaning kit compartment is a 'death trap' for your cleaning kit. Once you put it in there there is no way you getting it out without removing butt plate itself.
I had to grind and file butt stock internal ribs, so kit could actually come out under spring pressure instead of getting stuck in there. After internal ribs are filed/ground and otherwise roughed-up, I greased them with petroleum jelly( a.k.a. Vaseline) would ensure minimal friction. Maybe it's just my cleaning kit (came with the rifle) newer and larger than old style? Who knows. I don't have older one to compare.
While both are minor flaws that are easily fixed, but nevertheless took time to make it work.
Also worth mentioning that part of the butt stock designed to slip into receiver wouldn't really fit past first third of the length, even with help of the mallet.
I had to grind some off with file and rotary tool to achieve nice snug fit.
To make metal butt plate sit snug I had to grind off some material on the ribs and injection molding overflow under butt plate itself.
If you do it also, make sure that there is still enough material left as outlined by red line in the picture. Remove too much and trapdoor pivot will be getting pinched by metal plate to the point that it no longer can swivel. Ask me how I know that ;)

AFTER NOTE: Since section above was written (almost a year ago now) I have used 4 more K-VAR furniture sets and have to say that poor fit is common and prevalent. Only difference being how much fit will be off on the individual set. Out of those four sets in the picture only one had decent fit that I didn't have to fix myself.
saiga 5.45 and k-var butt stock poor fit
Refinishing: Proccess
Chemical paint stripping
Since I have decided to re-blue an entire rifle, I had to face 'paint removing challenge'. In absence of access to sand blasting equipment, I pretty much was left with either sanding by hand or using chemical stripper. I've heard some people used steel wool to strip paint, but I found this method to be too slow and marginally effective. Instead I settled on chemical strip, thinking it'll be not only low cost and fast, but also an easy way to go about it.

Hence that jug of non-toxic, non-corrosive, gentle paint stripping gel that also smells nice and easily applied with a small brush. Let it sit anywhere from 15 min to 24 hours and then wipe off the paint. That's what instruction said, anyway. I did a quick trial on my trigger guard and it worked exceptionally well. Once I brushed-off black goupe I instantly had very nice bare metal surface that required no additional polishing other than few strokes with fine steel wool. Encouraged I moved on to the rest of the rifle.

I found that it's best to apply very sparingly to avoid goupy residue all over your rifle later. You just need to 'wet the surface'. A little of this stuff goes a long way.
Let it sit 24 hours or even longer or until gel dries completely. Now it's just a matter of going over the surface with a soft steel brush, and that stuff flakes off with paint leaving nice dry almost completely bare metal surface.
Re-apply on missed spots and repeat as per above. Trust me, it's better and much easier to re-apply than use too much. If you over-do it, then it'll never dry. Instead it will turn into sludge-like paste and when scraped, it will leave behind dirty streaks, clog your brush and get stuck in every hole and crevice.
Saiga 5.45: applying paint stripper
Saiga 5.45 chemical paint stripper applied. Undried goupe. Saiga 5.45 chemical paint stripper causing dirty appearance. First photo on the left is a great visual example of common wisdom: 'more not always better'. This is 72 hours since application of the chemical paint stripper. Black sludge-like goupe is covering the surface. It'll probably dry out too if I give it another 72 hours. Which I'm not going to wait that long.

On positive note, one could not notice how well this chemical strip worked on the trigger guard. It's especially favorable looking in this photo.

Second photo on the left documents first strokes of the steel brush. Prepare to get dirty, this stuff goes everywhere and stains. Notice how cleanly paint comes off on the barrel portion where stripper was applied lightly. In contrast rear sight block after brushing has dirty-looking appearance.
Remember how I said earlier cheap and easy? Well, forget it! Maybe cheap, but definitely not easy.
This is several hours of hard brushing two stripper applications later. It is finally start to resemble unfinished metal, but still long-long from perfectly clean, as you can see.
By now I have re-thought my earlier conclusions and this weekend started to invest into sand blasting equipment.

I can brush all I want flat, large surfaces and eventually I will get them to look right. But when it comes to small openings, crevices etc. getting this stuff out is a nightmare! I haven't even touched inside the receiver yet, being so cramped and restrictive in there, I can hardly get to those surfaces with brushes at my disposal.
And when you start looking at the task closer, you start to understand that large, flat surfaces are just small portion of it. It's like, what did I get myself into, really!?
Saiga 5.45 chemical paint stripper after prolonged brushing. Saiga 5.45 chemical paint stripper after prolonged brushing.
Step 2: Sandblaster paint stripping
Saiga 5.45 paint stripped by sandblasting with glass beads. Well, it is three weeks later after I decided not to mess around anymore with a chemical stripper and started building a sandblasting cabinet. I might still use chemical strip on things like safety/selector lever, receiver dust cover, bolt and maybe carrier. Flat surfaces are very easy. Maybe after paint has been broken down I will give it a quick blast with a wallnut shell media and hopefully have same result as with trigger guard.
March 26, 2011: more than a month later and I finaly had a chance to put my home-borne sandblasting cabinet to the test. Using 80 grit glass bead media I went over 80% stripped barreled receiver and also did bolt, carrier and receiver cover. Everything worked great and I couldn't be happier with the results, although it is tough to get certain hard to reach arias of the receiver. Results can be seen in the picture on the left. Click to enlarge.
Refinishing: proccess
Introduction to chemical metal refinishing
Phosphating (a.k.a. parkerizing) and bluing are both chemical passivation proccesses aimed at protecting steel against corrosion/oxidation and improving it's visual and (in certain cases) mechanical properties. Phosphating (a.k.a. parkerizing) is relatively new technology, while bluing has been around for some time in one form or another.
Bluing - Black Iron Oxide
Iron oxide black (a.k.a. gun blue, bluing or 'blueing') is a conversion coating proccess. Meanning - iron in the surface layer of steel is converted to black iron oxide, also know as magnetite. Since magnetite occupies same volume as metallic iron there are no changes in part's dimmension. This is also why there is no destructive 'flaking/scaling' effect as with red iron oxide known as common red/orange rust. Bluing is accomplished by oxidation (or controlled rusting) by meanse of caustic bluing solution. No additional metall is added in this proccess, just converted what's already there into a diferent chemical form. In the sence it's same proccess that protects aluminum from oxidation - thin oxide film formed on the surface of the metal. With aliminium it happens on contact with air and in case of steel takes some caustics.
Parkerizing - Zinc or Manganese Phoshate
Phosphating (a.k.a. Parkerizing), on other hand, is a deposition coating proccess. Meanning - additional material is deposited via chemical reaction onto surface of the part, therefore somewhat increasing dimmensions of the part itself. Phosphating is done by emmersing part into solution of phosphoric acid, zinc and/or manganese with addition of some nitrates, chlorates, copper. When steel goes in contact with the solution chemical reaction takes place on the surface of the part and at this time manganese and/or zinc released out of the solution and deposited onto the surface of the steel. Some might notice that this proccess is simmilar to chrome/nickel plating, although acomplished without help of electric current.
Pros and Cons of each method
Phosphate is thought to be an improvement over Black Oxide finish in protection against corrosion. It forms very porous crystalline coating on the surface of the steel that when saturated with water displacing oil acts as additional barrier against moisture. It's sponge-like nature has higher oil retention ability than Iron Oxide which in turn improves mechanical lubricity. This same property also could be taken advantage of when applying spray-on coatings (Duracoat, Gunkote etc.) which will have easier time adhering to it. Application of the phosphate is also done at lower temperatures (170-210 F) compare to bluing (250-280 F). Lower solution temperature means less likely to do harm to polymer parts. These were advantages.
Disadvantages are as followed. Color variation will vary depending on the age of the chemical bath. At most ideal conditions only dark shades of charcoal-gray can be achieved. With every subsequent use, solution will produce lighter and lighter color until is depleted and have to be discarded. Color variation can be remedied by application of pre-treatment steel blackener prior to phosphating but nothing can be done about solution wearing itself out in rather short period of time.

Black Oxide's advantage over phosphate is that when done properly it produces very nice and even blue-back or brown-black color. Unlike phosphate, bluing also does not create heavy grain texture over the base metal. It actually preserves level of polish that was given to base metal prior to bluing. Therefore multiple levels of 'gloss' could be achieved from mat to satin to very high-polish nearly mirror like. This positive property of bluing also has 'other side of the medal'. Minor imperfections like small pitting, scratches, wear, nicks and dangs will not be covered up as if phospate was used. This puts some additional pressure on the task of surface preparation. This and other factors make bluing much more labor intensive affair. It also requires additional setup that not needed when phospahating.

Cold bluing is another form of bluing also known as 'instant bluing'. It is easier and not equipment demanding process that could be done by novice or anyone alike, in the few hours time. Although cold bluing process renders good appearance it is not nearly as wear resistant when comparing to hot bluing. But simplicity and ease of application (carding or even swabbing) insures it's popularity. Also in my experience I found that some cold bluing solutions will cause hi-polish/glossy surface to become more dull, mat-like therefore 'carding' with degreased steel wool, brass wool or even burlap is needed betwin applications and during oiling to somewhat counteract this effect.
Bluing and Parkerizing Chemicals
There is more than one way to obtain chemicals for bluing/parkerizing. In some cases it is more cost-effective to purchase it from places like Brownels or MiwayUSA and in others to make it yourself. All depends on how much money and time you are willing to invest into the proccess. I personally prefer to buy Phosphating concentrate from MidwayUSA since it's most cost effective way to go about it (at least for my operation). And I pefer to make my own bluing salts because it's cheaper than buying it and much esier to prepare as oppose messing around with Phosphating acids.
General process
As with any metall re-finishing process Bluing and Phosphating both follow same basic protocol:
1. Disassemble and clean/degreese all parts.
2. Abrasive blast metal surfaces to remove old finish and/or expose 'virgin' metal layer underneath.
3. Degreese again.
4. Immerse in finishing solution (phos or blue).
5. Rinse and inspect.
6. Oil soak or spray-on finish application.
7. Re-assembly.
Although process doesn't seem complicated it does help to have certain pieces of equipment and know few tricks and caveats of the precess.

Safety Precautions
Breathing protection against inhalation of harmful substances. Both bluing salts and Park acids are corrosive and irritant even when diluted. Bare skin and eye protection is strongly suggested. Special note about SILICOSIS. It's incurable medical condition associated with inhalation of dust containing silica, like the one generated during use of glass beads or sand for blasting.

Grease and oil are first of two reasons why bluing/phosphating might not come out right. I always advice most thorough Degreasing possible. It's worth spending extra time Degreasing than act impatient and have to re-do entire bluing from scratch. Tiny droplet of trapped grease can ruin hours worth of prep and bluing. Usual culprits are riveted holes, gas/sight blocks, trunnion-barrel combo, barrel pin, two flat surfaces joint by spot weld or rivet. These are only few most common examples. See pics.
Good way to make sure that grease in those places is taken care of is to heat your barreled action to about 300F. Metal expanding during heating will squeeze oil from captive areas. Let your action cool-down and then immerse into acetone(or degreaser of your preference). Repeat this process until no more oil can be squeezed out. I usually give rifle a final 24 hour soak in the acetone prior to bluing/parkerizing. See pics.
Temperature control
If you wish to blue on your own you must have a thermometer on hand. I prefer electronic one that goes at least up to 290-300 degrees, that also has one decimal point. I have this one. Decimal point is for estimating how fast solution is gaining or loosing temperature - helpful when pre-heating five gallons and want to know how soon you need to come back to it, since it usually takes 2-3 hours with my hot plate setup.
Large/thick part preheating
Second reason for blotchy blue finish is insufficient heat of the bath. Bluing is done at about 260-280F temperature. 260F (give or take) is lowest end at which solution will produce black finish. Anywhere lower and color starts to vary from chocolate brown to purple plum to tobacco yellow down the scale you go. If you have solution preheated to 275F and then plunge in it your part(s) which are at room temperature what happens? Part starts to draw heat away from the solution quite rapidly. Part itself starts to gain temperature while causing solution temperature to drop. Process continues until both bodies temperature equalized. The bigger/thicker part is - the longer it will take to do that. Unfortunately, chemical reaction occurs within few seconds of metal going in contact with solution. If by then some parts (or section of the receiver/barrel) are below minimal required temperature (~260F) it will produce any color but black, depending on how low it is. Because thicker/heavier parts take longer to 'steal' heat from the solution (than small and thin) things like: barrel, trunnion, sightblocks, gasblock, scope side-rail will be those that affected. See pics.
Volume of the solution to part size ratio is another variable to take into consideration. Once part is submerged solution will loose some of it's temperature and it might in turn also cause same effect.
5 gallons of solution (standard long tank from Brownell's or MidwayUSA) filled to the max capacity and heated to proper temperature won't be enough to retain sufficient heat and properly blue even one AK/Saiga barreled action. That is if you don't pre-heat barreled action first.
Proper rinsing
Sodium Hydroxide (Lye) is a component of bluing solution. This chemical is a potent degreaser and used in soap and detergent making among other things. It is also incredibly hydroscopic and will readily absorb moisture from the air and slowly inch it's way out of any hole or crevice. It will also crawl out of any not tightly sealed container, including your bluing tank if you store solution in it for more than a 2-3 weeks. Since solution itself is more syrup-like then water-like, it requires vigorous rinsing in large amount of hot or even boiling (preferably distilled) water with at least 3 changes of that water, to make sure that you got all lye out from under every rivet and out of every crevice. See pics.
If you don't, it will soon start showing up (around rivets, threads, flat-fitted parts like trunnion and rails) in the form of white-yellow (or red if solution was rusted) powder. Aside from appearance issues it will also can cause localized corrosion spots, especially in parts of the country where humidity is common (even as far North as Canada) or when not cleaned or inspected for weeks on end. Lye itself will slowly breakdown protective oil film and moisture it attracts will cause rust spots. See pics.
Solution rusting
When using non-stainless steel equipment (such as tanks, hang wires etc.). solution 'rusting' is inevitable. Evaporating moisture will cause fine rust to form later on and go into suspension with your bluing solution. What you end up with is fine particles of rust in your bluing bath. Although this will no affect bluing process it will leave very thin, almost dust-like, layer on the surface of blued part. This is not permanent and can be easily wiped-off. Also it will mostly come off during vigorous rinsing. I found that it does not cause any adverse effects it's nevertheless extra step and an inconvenience. Especially when it gets to removing it inside and AK receiver with swabs, toothpicks and brushes. Only remedy to the problem I could come up with is to let bluing solution sit idle until fine particles settled to the bottom and then carefully scoop clear portion into new clean vessel. This will not eliminate 100% of the rust but will cut down on it's amount significantly.

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