The phenomenon we note in blued Rugers known as "plum" coloration has been the subject of considerable discussion over the years. This is usually explained as being the result of certain elements in the investment-cast steel Ruger uses for certain parts reacting with the bluing bath. We know that Ruger offered to re-blue guns in the early days if the customer wished, but did not guarantee any different results than seen on the original finish. Whether you like this deviant color is pretty much a personal thing, with some liking it almost as a "variation" and others disliking it as a manufacturing failure.
The matter came up on RugerForum dot net, and IOWEGAN addressed it from his position as a gunsmith with considerable experience in re-bluing Rugers as well as other guns with similar "problems". With his permission, I offer up his commentary for our edification and information . . .
"There are six reasons for guns to turn "plum". First is the temperature of the bluing salts, which must be maintained at exactly 292 deg F. If the temperature is lower, bluing won't take properly. If the temperature is just a few degrees too high, parts will turn plum. Second is the concentration of the salts. Because water boils off, the salts tend to get too concentrated so bluing tanks must be equipped with a water replenishment system to keep the salts to water ratio at 10:1 (10 parts water for one part salts by weight). If the mixture gets too concentrated, parts will turn plum. Next is "time in the tank". If parts are left in the bluing tank too long, they will turn plum (1/2 hour is normal). Bluing salts do "wear out" so they must be replaced fairly often. When salts start aging, gun parts turn plum. Last is the alloy. Some alloys require special additives to the bluing salts or the parts will turn plum no matter how well you maintain the tanks. In most cases, parts will turn plum right out of the bluing tank. When alloys are the cause, it may take several years for the plum color to show up. I can't fault Ruger for alloy issues during the first few years of production but after that, there's no excuse. Several years ago, it was common to see a brand new Ruger SA with plum parts ... so the alloy was not their only problem. I think Ruger was "guilty" of several of the above issues but they are doing much better now (same alloys).
"Back when I had my shop, I had a very nice bluing tank setup. I blued hundreds of guns but always had problems with Ruger SA cylinders, loading gates, sometimes frames, but never barrels turning plum ..... despite my best efforts to maintain temperature and a proper mix ratio. I also had problems with Winchester '94 receivers and any other gun with cast parts. One day I called Brownell's (I used their Oxynate #7 salts) and asked if there was anything I could do to prevent "plum". The answer was a resounding "yes .... buy an additive called Oxynate "S" and your problems will go away." I did just that and my first "test gun" was my own Ruger Liberty Blackhawk. It had a very plum loading gate and cylinder plus the cylinder frame showed some plum too. Besides, I carried this gun while deer hunting so it had considerable holster burn on the barrel. Guess what? When I took the parts out of the tank, they were blacker than a whore's heart. I still have the Liberty and it is still black with no signs of plum and that bluing job was done 30 years ago. For a handgun sized bluing tank (2 gallons), it takes about two ounces of Oxynate "S", which is now about $2/oz. I don't know how this stuff works but it indeed it does work on Rugers, Winchesters, and any other cast gun parts."
I think this is great information to be added to our treasure trove of Rugerdata, and thank IOWEGAN for his commentary.
The matter came up on RugerForum dot net, and IOWEGAN addressed it from his position as a gunsmith with considerable experience in re-bluing Rugers as well as other guns with similar "problems". With his permission, I offer up his commentary for our edification and information . . .
"There are six reasons for guns to turn "plum". First is the temperature of the bluing salts, which must be maintained at exactly 292 deg F. If the temperature is lower, bluing won't take properly. If the temperature is just a few degrees too high, parts will turn plum. Second is the concentration of the salts. Because water boils off, the salts tend to get too concentrated so bluing tanks must be equipped with a water replenishment system to keep the salts to water ratio at 10:1 (10 parts water for one part salts by weight). If the mixture gets too concentrated, parts will turn plum. Next is "time in the tank". If parts are left in the bluing tank too long, they will turn plum (1/2 hour is normal). Bluing salts do "wear out" so they must be replaced fairly often. When salts start aging, gun parts turn plum. Last is the alloy. Some alloys require special additives to the bluing salts or the parts will turn plum no matter how well you maintain the tanks. In most cases, parts will turn plum right out of the bluing tank. When alloys are the cause, it may take several years for the plum color to show up. I can't fault Ruger for alloy issues during the first few years of production but after that, there's no excuse. Several years ago, it was common to see a brand new Ruger SA with plum parts ... so the alloy was not their only problem. I think Ruger was "guilty" of several of the above issues but they are doing much better now (same alloys).
"Back when I had my shop, I had a very nice bluing tank setup. I blued hundreds of guns but always had problems with Ruger SA cylinders, loading gates, sometimes frames, but never barrels turning plum ..... despite my best efforts to maintain temperature and a proper mix ratio. I also had problems with Winchester '94 receivers and any other gun with cast parts. One day I called Brownell's (I used their Oxynate #7 salts) and asked if there was anything I could do to prevent "plum". The answer was a resounding "yes .... buy an additive called Oxynate "S" and your problems will go away." I did just that and my first "test gun" was my own Ruger Liberty Blackhawk. It had a very plum loading gate and cylinder plus the cylinder frame showed some plum too. Besides, I carried this gun while deer hunting so it had considerable holster burn on the barrel. Guess what? When I took the parts out of the tank, they were blacker than a whore's heart. I still have the Liberty and it is still black with no signs of plum and that bluing job was done 30 years ago. For a handgun sized bluing tank (2 gallons), it takes about two ounces of Oxynate "S", which is now about $2/oz. I don't know how this stuff works but it indeed it does work on Rugers, Winchesters, and any other cast gun parts."
I think this is great information to be added to our treasure trove of Rugerdata, and thank IOWEGAN for his commentary.
