In the white?

[George Stringer]

A customer brought in a Remington 552 yesterday that he had cleaned. His receiver and triggerguard were white. I already know what happened to it but I thought I might throw this out and see if anyone else might have an idea. George

[Rob Pincus]

He was trying to recreate that scene at the end of the big gun fight in Hard Boiled and he forgot to wipe the flour off the gun.

[Morgan]

Obviously, he used something evil to clean it with. I've no idea what. I also assume it has something to do with the metal or treatment/coating of the metal of the receiver and trigger guard, as the barrell was unaffected. Now I'm curious!

[GLV]

Paint sure comes off easy don't it?

[Bushwhacker]

Used spray on carb cleaner?

[Rich Lucibella]

You're killin' me with the suspense, George. My best guess runs along the lines of Flyer's carb cleaner assumption.
Can you give us a hint in terms of the chemical reaction that causes this?
Rich

[Rob Pincus]

I'll send a firearms related piece of clothing (hat, T-shirt, something from the stash) to the first one who guesses correctly. With Rich's Permission and George's judgement on who wins.

------------------
-Essayons

[jer]

How about vinegar.

[sskraft]

Sounds like he used an ultra-sound cleaner.

[Walt Welch]

Hmmmm. As I recall, some Remington .22's of that era had Al receivers and trigger guards. Since Al is a more reactive metal than Fe, and anodizing the most common method of coloring Al, I suspect that he used some method that caused or utilized an electric current, which would strip the Al much faster.

An acid bath, as suggested above, using vinegar, would be a possibility. One other possibility occurs to me. There is the Outers' lead and Cu removal (from the bore) system which uses an electrical current. Could a misapplication of this method be the culprit? Walt

[Doc Lisenby]

Two guesses; he tried to use aluminum black on paint or soaked it sulfuric acid to remove rust. He certainly didn't try to cryo treat with dry ice? Naw, rocket scientists don't do that. Sand blasted the stock with the recv'r installed? Baked Teflon finish over the paint? I give up George, keep the prizes. Doc

[George Stringer]

Guys, I'm going to let this one go another day and see if we get any more responses. Here's a hint. Walt was on the right track with the anodized aluminum. George

[4V50 Gary]

He couldn't have been bead blasting it unless he wanted it white to begin with. A good dunk in the caustic (hot) blue bath will remove the finish (and if long enough, dissolve the part).

[George Stringer]

Well, guys, everybody pretty much guessed along the same lines but nobody actually came up with the correct answer. My customer and some of his shooting buddies went in together and bought a bluing tank and some Dicro-Clean 909. While Dicro-Clean under normal circumstances shouldn't harm anything it is slightly alkali. If (as in this case) the anodizing is weak in areas from wear the alkali will get under the finish and remove it. What really shook him up was that they had cleaned several guns with anodized parts and this was the only one that turned. It was also the oldes and had seen the most use. I didn't expect anyone really to come up with Dicro-Clean in particular. The alkali was the key. George

[Rich Lucibella]

Rob-
Thanks for the T-Shirt offer. Go for it.

Walter Welch-
Curse you, Red Baron!

OK. Let's think about this. It had to be something that was either sprayed on, dipped or, as Walter says, elecrolysed.
Rich

[Rob Pincus]

seems you boht posted in the same minute, but without the benefit of each other's posts.

So, no winner?

[Walt Welch]

Y tu madre tambien, Rob; no winners my tuchas. TWO winners is the way I see it!!

Actually, I am somewhat confused as to why alkali would strip anodizing from Al.

Just to make sure I understand the problem: the parts stripped (receiver and trigger guard) WERE Al?? The bbl. ( probably steel, but remember Rem. had some .22's with Al sleeved steel bbl's; Al over steel) around that time, was indeed steel, and unaffected?

What, specifically is Dicro-Clean 909?? It sounds like a detergent cleaner, which would make it more probably very, rather than slightly, alkaline. Since acidic solutions are usually the ones associated with attacking metal, but some notable exceptions exist ( warm alkaline spring water dissolved stainless steel grid used in archeological exploration; some chemist explained why simple galvanized steel would have lasted); what was going on here??

A more technical elucidation seems warranted.

Walt

[George Stringer]

Dicro-Clean is a detergent type cleaner that is used by gunsmiths when preparing a gun for rebluing. Gun parts are suspended in the cleaner mixed with water for 15-20 minutes at 180 degrees. The actual alkali content, I couldn't say. Slightly alkali is the manufacturer's description of their product. Not being a chemist I can't really say why the alkali reacted like this other than to say that where there are weakened areas it will get under the finish and remove it. It's sort of like Alka-Seltzer. I don't know why it fizzes and disolves in water; just that it does. BTW, the barrel was steel and unaffected. Winners? I don't really see any, but since Rob volunteered the prizes I'll let him be judge on this one. This was sort of a "trick" question I guess. I didn't really mean it to be. Anyway, the moral of the story is know what you are using on your guns. George

[Rob Pincus]

Awwww, geeez, George.... I said you had to be the judge.

I didn't see anyone mention "alkali" and certianly no one said "dicro-clean"

I guess I'll let the prize(s) roll over to the next "Gun Smithing Trivia Question" you come up with.

(just out of curosity, who were the two winners you were thinking of and why, Walt?)

[Doc Lisenby]

I learned that the coating on the aluminum alloy on these receivers was anodizing rather than paint. I know that aircraft are painted and primed with zinc chromate, so I just assumed that this was a fancy black form of the same type of paint. Anodized aluminum that I knew was anodized appeared granular, like a "French Gray" sandblasted finish. Learn something new everyday. I thought the Dicro-Clean #909 had either KOH or NaOH (lye) in it, as a lot of de-greasers have, but Brownell says it is non-caustic. And "caustic" is another name for lye so it must be something I've never heard of or else it is lye with a buffer which only allows it to become caustic at 180 degs. What do you say Walt? My med school chemistry prof has been dead twenty years so I'm a little rusty on the subject. I do know that anodizing is kinda like electroplating and there must be some electrolytic action occurring to remove it as happened here. The way I understand the anodizing process is that the bare Al is oxidized electrically (the Al is the anode-negative plate) and then dyed and pickled. Maybe the oxidation layer is still there "in the white" and only the dye is removed chemically. Doc (Class of '69)

[Walt Welch]

Well, even though I worked as a biochemist, and graduated in the Class of 1976 at the University of Nebraska (GO BIG RED), I decided to post this question to a man who plates and strips firearms for a living, and who has probably forgotten more about the subject than I will ever know.

I am doing this, of course, out of a pure search for the truth, not because some weasel is trying to squirm out of giving out prizes.

Here is the answer:


Well, Walter, it isn't any mystery. Lye,(sodium hydroxide), or washing
soda, which is sodiun carbonate(not bicarb)or TSP, (Tri-Sodium
Phosphate),
are the most commonly used degreasers. The sodium saponifies(turns to
soap) the oils and fats present so that they will wash away.
Unfortunately, it also attacks aluminum and magnesium alloys just as
quickly and washes them away.heh heh. Not a smart move. Jack F

The greatest obstacle to true education in this country
is the worship of "credentials" rather than knowledge.
<http://www.jack.fuselier.com>
*****************************

I then asked him about the wearing of the anodized layer may have affected the process:

*********************************
Right, Walt,
I'm sure the anodizing/dye combination does protect the metal for a
short time, probably long enough in the case of some alloy frames
to save them. It's possible that this gun was not anodized at all,
there is no rule that says it must be. Aluminum oxidizes and
protects itself against corrosion anyway and anodizing is just an
artificial extension of the same process. Not all anodizes are the
the same anyway, the voltage level used, the electrolyte used, and
the dye and the curing process all make a difference. Additionally
a powdercoat of clear lacquer is sometimes baked on. I use powdercoat
myself on some things. I don't trust the anodize completely just
because of incidents like that one. A good anodize/dye job is a thing
of beauty, as much trouble as bluing, and you don't want it ruined by
a can of oven cleaner. Jack F
***********************
Eagerly anticipating the arrival of my prize, along with the simultaneous poster who answer was as valid as mine, I remain, Respectfully yours, Walt Welch

[Rob Pincus]

Send me Jack F.'s address and I'll send him a prize.

[Doc Lisenby]

Thanks a million, Walt, I like to learn a few things from real experts. Keeps me from getting too pompous. I disagree with Jack about the hinderance to education tho'. I prefer: "We think we know everything, therefore we can't learn sh--."
I just got volunteered to teach Anatomy and Physiology to a class of surgical nurses next semester 'cause they can't find anyone to teach it. I'm having to drive 23 miles thru the swamp (one way at night) so they can pull down $30 an hour at my Medicare expense.
When am I gonna fix these boys' Walmart guns?
George, can we find out whether these rec'rs are anodized or not? Let's get another question going. How about whether corollary forces causes the commode water to swirl clockwise in the Northern Hemisphere and does it cause a bullet to drift to the right or left? My opinion; nope and to the right with a right hand twist. Doc

[4V50 Gary]

Hey Doc!

A lass from Down-Under told me that the water swirls counterclockwise there. So long as it goes away, I'm a happy camper.

Gary

[Walt Welch]

Doc; you nearly gave me a coronary looking up corollary. As I thought, a corollary is a proposition which follows from one previously proven.

You probably mean the Coriolis effect. This is simply a corollary <g> of the fact that the earth is rotating, and objects traveling above it tend to appear to move, as the earth is rotating below the object: here is a better explanation:
http://www.media.uwe.ac.uk/~masoud/projects/water/coriolis.htm

Think about a particle of water moving over the earth's surface in a northerly direction, in the northern hemisphere say. It has, in its new position, an eastward velocity greater than the ground beneath. Relative to the earth it appears to be swinging to the right.

Again, if water or air moves eastwards, its velocity relative to the axis of the earth is greater than the ground beneath it, so it tends to move "uphill" to the south, where the earth's velocity is greater. Hence it appears to veer to the right. It will be found that free initial movement in any direction invariably produces a rightward swing, in the northern hemisphere.

This apparent desire for moving water to swerve to the right means that it tends to form a vortex, running counter-clockwise, the so-called "Coriolis" effect. The same reasoning applied in the southern hemisphere produces a clockwise vortex. Sections through such swirls are trumpet-shaped. They are called "free" vortices, or whirlpools, and the fluid flows in towards the centre, following a spiral path.
*************************

However, Doc, the Coriolis effect is extremely small, requiring something like a Foucalt pendulum to demonstrate it. So, while large masses of air follow this rule of curvature, small masses of air, or water, as in a bathtub, do not necessarily do so. The Coriolis effect is easily overwhelmed by local forces.

Now about having to teach A&P to a bunch of nursing students; why, there was a day when I would PAY for the honor of doing so <bweg>
Yours in science. Walt