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[ARCHIVED THREAD] - Can this SP 1 lower be repaired? (Page 1 of 2)
Posted: 7/4/2020 11:04:55 AM EDT
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While searching "Colt SP1" on GB, I came upon this lower. What caused the damage and can it be repaired? https://www.gunbroker.com/item/873113490 |
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If anyone can it’s John Norrell, he’s known these days more for his Moly Resin but he’s who I’d call. Truthfully at the price why bother? You’ll end up with over a grand in just a lower receiver in no time. https://molyresin.com/ Good luck |
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Quoted: Looks like it had been in a fire. Most likely the temper is gone from the aluminum. Looks more like saltwater damage. Probably in someones fishing boat and then used some kind of paint (after cleaning) to pretty it up. Receivers melt if they're in a fire, not flake. I've seen it. I wouldn't touch that with a 10' pole. |
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The same lower was on the EE along with matching upper, but the ad is now closed. https://www.ar15.com/forums/equipment-exchange/Pre-Ban-1966-Colt-SP1-Matching-Lower-Upper-SN-05849-/158-2015014/ |
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After looking at the pictures on our EE, which show a pitted steel ejection port door, I tend to suspect that this could be the result of saltwater corrosion. I suppose it instead could be the result of something rather gory, but I don’t know how that would affect 6061 aluminum. The fact that some areas are extremely corroded while others are not corroded at all, make me think it wasn’t the result of a uniform environmental factor. A 1966 Colt would most likely be made from 6061 aluminum, which didn’t hold up too well in the jungles of Vietnam. The corrosion and sloughing-off of the aluminum on that SP1 receiver looks just like the white powdery corrosion shown in pictures of early XM16E1 rifles, and their chopped magazine wells as currently sold on Gunbroker. That receiver could be prettied-up by bead blasting off the corrosion and anodizing, spreading some putty like JB Weld into the corroded areas, smoothing out the surface, and spraying on some Norrell’s or Cerakote. The juice wouldn’t be worth the squeeze, as was mentioned before. |
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Quoted: Someone used simple green or some other type of non friendly to aluminum cleaner on it. Seems to be pretty high for a chewed up lower, even if it is a SP1. That isn't that much lower then the last complete SP1 I bought that was in damn nice shape. They would have had to leave it in SG, undiluted, for a long time (like over a month). We used to use SG to clean our a/c and I've used it to clean Al engine blocks and have never seen damage like that because of SG. |
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Quoted: I have seen blood etching on guns look llike that. Can never get get rid of it, blood is extreamly corrosive.. The pH of blood is ~7.4 which is fairly neutral. It doesn't rust steel because it's corrosive, it rusts steel because it's loaded with oxygen and that causes oxidation. The damage on that receiver looks like galvanic corrosion, especially since we know it was originally Type 3 anodized. ETA- First, it looks to me that it was painted/coated post corrosion. Second, with the amount of aluminum lost on the pistol grip area of the receiver (Gunbroker pics), it was obviously subjected to wet storage in a dissimilar metal container, probably steel. That would explain why the aluminum lost so much metal, but the parkerized steel parts didn't. The light cad plated steel grip screw exacerbated the corrosion being in direct contact with the receiver. Of course, if it were in saltwater that would accelerate the corrosion. |
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Quoted: I have seen blood etching on guns look llike that. Can never get get rid of it, blood is extreamly corrosive.. No it's not. If it was it would kill you and it doesn't take you being very much out of range to really mess someone up either being acidotic or alkolodic. 7.35-7.45 is what your body tries to maintain. |
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Quoted: No it's not. If it was it would kill you and it doesn't take you being very much out of range to really mess someone up either being acidotic or alkolodic. 7.35-7.45 is what your body tries to maintain. Ask me about my patients with pHs of 7 that lived, I’ve actually had a few and at least one I remember being 6.8!  Back to op: It’s a 4 digit and there’s not much structurally going on with a lower other than keeping all the pieces and parts in proper placement and alignment. I shot a registered transferable M16 yesterday that had been made prior to ‘86 from the front half and a rear half of a saw cut demil being welded together. If I got it cheap enough I would try and fix it up. I have used JB Weld to fill logo roll marks on lowers, sand it smooth and then moly resin over it without issue. My biggest concern would be the serial number and is it “obliterated” by ATF standards as I’m looking at it on my phone and hard to tell how bad that last digit is. A more talented person than me could probably fill the heavier putting with weld and then smooth it out. I’m a cave man though without skills so JB Weld would be my option. Either way, I wouldn’t be interested in it for anything more than 1/3 of that price and even that would be hard to justify and would really want to see it in person or some really detailed pics. Would be a fun challenging project for cheap but short of that, nope. |
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Quoted: Grip screws I have seen are a type of stainless. Looks like the edge of the threads on the corroded side of the grip and maybe some corrosion at one of the hammer pin holes. You may be right. I believe that there was a cad plated screw but perhaps not. I have no idea what was being used in '66. Either way, stainless or not, the screw reacted and the corrosion ensued. The reason it corroded in certain parts are not others is that the anodizing was breached in those locations and it left the aluminum unprotected. |
| Say blood is not corrosive, maybe not to us as in our body, i had a new smith model 59 that was used in a suicide attempt, no not me, but when i got that pistol back from the police 1 year later it was junk, the slide and barrel were fused together, i did manage to get it apart but never was usable. As i said junk. |
This thread has the ADD/ADHD of GD. pH levels of blood......  Anyway, these are mine that are for sale. I didn't get any bites in the EE and would like to move them so tossed them on GB. Was hoping to get someone in a ban state a fully functional lower for less than the 1k all the others go for, I have the matching upper as seen in the EE ad. Like the others have mentioned, it's certainly not worth my time repairing and if you're outside of MA or CT, it's probably not worth yours either unless you're putting together a lessons of Vietnam gun. If you're interested, hit me up, I'm not married to those prices I posted but I did have to decline the $200 offer. Also, the last digit/full SN is clear as day, just a little raised. If it's a worthless brick, I might go the jb weld molyresin route for something to do. Again, would rather get it into a ban states persons hands for a fraction of other prebans but we shall see. |
| I thought the corrosion was acid when I first found the GB auction. Wat else could do that kind of damage? Unless it was at the bottom of the South China sea for fifty years or more. I bought M14 mags dredged up from the California coast. New Park job and spring, good as new. |
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Quoted: I thought the corrosion was acid when I first found the GB auction. Wat else could do that kind of damage? Unless it was at the bottom of the South China sea for fifty years or more. I bought M14 mags dredged up from the California coast. New Park job and spring, good as new. Something like so? Attached File |
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Quoted: I thought the corrosion was acid when I first found the GB auction. Wat else could do that kind of damage? Unless it was at the bottom of the South China sea for fifty years or more. I bought M14 mags dredged up from the California coast. New Park job and spring, good as new. Galvanic corrosion. Didn't you read the thread? It's the reason that the aluminum on this gun is ravaged and the steel parts are relatively undamaged. Attached File |
| Looks like it was exposed to some type of caustic substance or acid. The damage pattern appears to support the idea that it was probably covered with the substance by accident like a spill or splatter. We used some industrial metal cleaning solutions / acids that were heated to the boiling point During the cleaning process of automotive parts. The one solution tank would literally turn aluminum to a gray foamy mess while dissolving it. This process definitely changed the part tolerances. |
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Quoted: Something like so? https://www.AR15.Com/media/mediaFiles/416992/FA58E83B-D133-4CA2-8D7D-4FE99A035916_jpe-1491515.JPG Off topic, but I'd love to hear the story on this gun. |
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Quoted: Looks like it was exposed to some type of caustic substance or acid. If that were the case the steel components would have been affected also. Q: Why does corrosion occur between anodized aluminum and steel? A: Aluminum is a reactive metal (unnoble) which should have a low corrosion resistance, according to thermodynamics. The high corrosion resistance found on aluminum, nevertheless, is due to the presence of a thin, compact film of adherent aluminum oxide on the surface. Whenever a fresh aluminum surface is created and exposed to either air or water, a surface film of aluminum oxide forms at once. This aluminum oxide dissolves in some chemicals, notably strong acids and alkaline solutions. When the oxide film is removed, the metal corrodes rapidly by uniform dissolution. In general, the oxide film is stable over a pH range of about 4.0 to 9.0, but there are exceptions. One of these exceptions is in environments where the surface film is insoluble, but weak spots in the oxide film lead to localized corrosion. Local corrosion can only be found when aluminum is passive, covered by an oxide layer as the one formed by anodizing. Localized corrosion has an electrochemical nature and is caused by a difference in corrosion potential in a local cell formed by differences in or on the metal surface. Galvanic corrosion is due to an electrical contact with a more noble metal or a nonmetallic conductor in a conductive environment. The galvanic corrosion is very dependent on the cathode reaction and which metals are in contact with each other. The efficiency of this cathodic reaction will determine the corrosion rate. The most common examples of galvanic corrosion of aluminum alloys are when they are joined to steel or copper and exposed to a wet saline environment. The galvanic corrosion of aluminum is usually mild, except in highly conductive media such as slated slush from road deicing salts, sea water and other salty electrolytes. The contact area must be wetted by an aqueous liquid or humidity in order to ensure ionic conduction. Otherwise, there will be no possibility of galvanic corrosion. The galvanic series for metals show that aluminum will be the anode of the galvanic cell in contact with almost all other metals and, hence, the one which suffers from galvanic corrosion. Galvanic corrosion article |
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Quoted: Galvanic corrosion. Didn't you read the thread? It's the reason that the aluminum on this gun is ravaged and the steel parts are relatively undamaged. https://www.ar15.com/media/mediaFiles/416992/FA58E83B-D133-4CA2-8D7D-4FE99A035916_jpe-1491515.JPG Huh, I like to learn something everyday. Now I've learned about galvanic corrosion. Thanks! |
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Quoted: I'm not married to those prices I posted but I did have to decline the $200 offer. Also, the last digit/full SN is clear as day, just a little raised. If you’re considering when I said “I wouldn’t be interested in it for anything more than 1/3 of that price and even that would be hard to justify” an offer it wasn’t And my concern with that last digit would remain in that if it”s raised as you say then that means there’s corrosion going on there too. That corrosion will need to be addressed or else it will most likely continue. The big question is can you address it and repair it without obliterating that digit? I don’t know off hand but I personally wouldn’t spend anything more than I would be willing to lose on it without knowing or at least seeing it in person. My personal level of comfort in potentially throwing money away in a dumpster fire is somewhere between the sellers asking price and $50 but much closer to that low end. Just being honest and not stomping your price at all as it’s listed on gunbroker and not the EE. |
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Quoted: If you’re considering when I said “I wouldn’t be interested in it for anything more than 1/3 of that price and even that would be hard to justify” an offer it wasn’t And my concern with that last digit would remain in that if it”s raised as you say then that means there’s corrosion going on there too. That corrosion will need to be addressed or else it will most likely continue. The big question is can you address it and repair it without obliterating that digit? I don’t know off hand but I personally wouldn’t spend anything more than I would be willing to lose on it without knowing or at least seeing it in person. My personal level of comfort in potentially throwing money away in a dumpster fire is somewhere between the sellers asking price and $50 but much closer to that low end. Just being honest and not stomping your price at all as it’s listed on gunbroker and not the EE. Nah, was an offer while in the EE, however you have flattered me regardless, so I appreciate that!  You don’t have to disclaimer yourself with me stranger, I’m with you 100%. |
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Pull parts Send to Braceman Braceman strips anodizing Welds 6061 aluminum to repair corrosion Lay down buffer tube boss reinforcement and mag release fence Convert to modern pivot pin Machines to modern M4 spec w/ pre-94 SN Reanodizes Sell in Massachusetts or Connecticut Profit? Anyone remember the thread of the Glock & SIG P228 stored together in a foamy case that got wet while the ARFCOMer was deployed? That SIG frame was flaking apart. You can charge your phone anywhere in the world with this one simple trick!
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Quoted: Huh, I like to learn something everyday. Now I've learned about galvanic corrosion. Thanks! Quoted: Quoted: Galvanic corrosion. Didn't you read the thread? It's the reason that the aluminum on this gun is ravaged and the steel parts are relatively undamaged. https://www.ar15.com/media/mediaFiles/416992/FA58E83B-D133-4CA2-8D7D-4FE99A035916_jpe-1491515.JPG Huh, I like to learn something everyday. Now I've learned about galvanic corrosion. Thanks! Your welcome. At least someone read and understood what I posted. BTW- Google "lasagna cell". Not only are your AR15's at peril, your Italian entrees are too! |
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Quoted: Off topic, but I'd love to hear the story on this gun. Quoted: Quoted: Something like so? https://www.AR15.Com/media/mediaFiles/416992/FA58E83B-D133-4CA2-8D7D-4FE99A035916_jpe-1491515.JPG Off topic, but I'd love to hear the story on this gun. Posted here not too long ago, no info was given. Crazy shit though. |
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The only way that'd be worth it is if you lived in a ban state. Because if I lived in a ban state, and it were worth it, I'd buy it just to have FFL transfer paperwork and permits that says I own a legit preban lower with that serial number. ... You can figure out what I would want to do after that by learning all you can in the DIY Forum. Boy, that engraving looks pretty jacked up, you might have to find an engraver who will do ColtTM markings. I'd definitely get it refinished too with a good coat of anodize. I could see "refurbishment" running about $195 not including various shipping costs and transfer fees. |
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Quoted: Someone with more retro knowledge than I will need to answer that. I cannot see Colt using separate materials after the TDP was updated. But I've been wrong plenty. Knowing the way Colt operates, I can EASILY see them using up the older (inferior) castings on the SP1, while using the newer (superior) castings for the military. |
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If it's 6061, it can be made better than new w/ the original SN. If it's 7075, then the cosmetic issues can be fixed, but perhaps more easily w/ epoxy and Duracoat than welding 7075, machining, & Cerakote. Any 6061 lower should be able to be stripped, rewelded, & remachined to modern M4 reinforced profile w/ the original SN. |
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Quoted: Knowing the way Colt operates, I can EASILY see them using up the older (inferior) castings on the SP1, while using the newer (superior) castings for the military. Quoted: Quoted: Someone with more retro knowledge than I will need to answer that. I cannot see Colt using separate materials after the TDP was updated. But I've been wrong plenty. Knowing the way Colt operates, I can EASILY see them using up the older (inferior) castings on the SP1, while using the newer (superior) castings for the military. They were forgings, not castings, but I would agree that Colt would use them up before replacing them with 7075. |
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Quoted: Knowing the way Colt operates, I can EASILY see them using up the older (inferior) castings on the SP1, while using the newer (superior) castings for the military. Quoted: Quoted: Someone with more retro knowledge than I will need to answer that. I cannot see Colt using separate materials after the TDP was updated. But I've been wrong plenty. Knowing the way Colt operates, I can EASILY see them using up the older (inferior) castings on the SP1, while using the newer (superior) castings for the military. It's quite possible, in an effort to recoup the investment in the forgings. I'd rather not speculate though. |
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Obviously not many boat owners on here. Those lowers reacted just like the sacrificial zinc anodes on every outboard boat motor. They sacrificed themselves to the Galvanic Process to save the "important" metal parts! Dissimilar metals are not good playmates and chemistry is weird and everywhere. OP Buy it CHEAP as a beater rifle project truck gun swamp peashooter. It would never be your favorite rifle but you would spend time shooting it because you never have to worry about scratching it! Talk about the BFPU look! 
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Quoted: Obviously not many boat owners on here. Those lowers reacted just like the sacrificial zinc anodes on every outboard boat motor. They sacrificed themselves to the Galvanic Process to save the "important" metal parts! Dissimilar metals are not good playmates and chemistry is weird and everywhere. OP Buy it CHEAP as a beater rifle project truck gun swamp peashooter. It would never be your favorite rifle but you would spend time shooting it because you never have to worry about scratching it! Talk about the BFPU look! At the $600 current bid, cheap is out.
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Quoted: The big clue to me is the SP-01 didn't get a magazine fence til the 1980's. Colt was likely using the original set of forgings (thus 6061) from the early 60's into the early 80's when they finally introduced the A2 sight. I don't think so, before there was serious competition in the AR market when Colt was basically the only game in town; Colt was big on differentiating between the AR15 & M16, they used to bend over backwards to make sure the rifles used different parts just to show everyone that the AR15 was not a machine gun. Way back in the late 80's I remember seeing a video of AR15 production where they were machining the fences off of the forgings to make AR15's, Weird but true. |
[ARCHIVED THREAD] - Can this SP 1 lower be repaired? (Page 1 of 2)
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