Bluing handsaw blades -- purely cosmetic or functional?

[Mike Allen1010]

Most of the old Atkins, Disston and Simmonds saws I have were quite rusty, even pitted when I got them.

Despite my best efforts with naval jelly, sandpaper, metal polish and buffing I'm never able to get the blades to the bright, mirror finish that you see in some of the "like new" saws that have been well cared for throughout their life.

I have used gun barrel "bluing" (I'm not sure if that's the right term?) on some of my old saw blades as the final step in the blade refinishing process and personally I like the look and it seems like the bluing does help bring out marginal etchs that were previously difficult to see.

My question is is there any functional benefit to "bluing" less-than-perfect saw blades that retains some stains and surface imperfections even after rehabilitation, or is the effect purely cosmetic?

It seems to me that the blued blades feel smoother when I run my fingers over them, than Blades of similar age/quality that I haven't blued, but I'm not sure if: A) I'm just imagining that the bluing makes the blade smoother or B) even if the blue blades are smoother, if it makes them run any smoother in the cut?

I would appreciate any thoughts, opinions or experiences on this question. I know many of you have lots of hands-on practical experience in this area and your feedback would be very helpful.

Thanks, Mike Allen

[Tony Shea]

I would love to see a few pics of your blued blades. I've thought about trying this out myself but more so just on the etching to bring it out a bit. Not sure of the process really of just blueing the etching. Would also like to see some advise on that.

[Jonathan McCullough]

My understanding is that gun blueing like Oxpho Blue or chemical Parkerizing (http://en.wikipedia.org/wiki/Parkerizing) uses Phosphoric acid as its active ingredient. That's the active ingredient in Naval jelly as well. There are three kinds of oxidation of ferrous metals: Red rust, brown rust, and patina or black oxidation. Red rust will eat away and pit ferrous metals, the other two form a sort of protective layer of benevolent oxidation. Bob Smalser's blueing and oiling regimen seems like a good way to keep old saws from rusting in cool, wet conditions. I use naval jelly for about twenty or thirty seconds to raise an old etch, but generally avoid overall treatments like vinegar, electrolysis, naval jelly, etc. What works for me is after cleaning the saw with sandpaper and mineral spirits, I rub a very thin layer of paraffin all along the saw plate and melt it, a protection that has been effective in New England garage conditions for 2+ years. Here's a discussion (http://www.sawmillcreek.org/showthread.php?137251-Pinkie&highlight=) of that treatment.

I don't think there's anything we can do to make an old saw a new saw, but care, cleaning, and sharpening can make an old saw as functional as it was when it was new.

[Jonathan McCullough]

Composed a reply but it blubbed up. Gun blueing uses phosphoric acid I think, which causes protective black oxidation a/k/a "patina." Phosphoric acid is also the active ingredient in naval jelly. I think a surface treated with blueing also retains oils, which may contribute to a smoother-running saw. Pitting doesn't actually affect the performance of a saw as long as it doesn't interfere with your ability to get sharp points on the teeth. I like to use paraffin on saw plates (see here (http://www.sawmillcreek.org/showthread.php?137251-Pinkie&highlight=)) and it's worked for 2+ years in New England garage conditions.

We'll never get old saws looking exactly like new, but cleaning and sharpening will make these great old tools as useful as the day they were made.

[Chris Vandiver]

Would you please repeat that.

[Mike Allen1010]

Jonathan,

Thanks for your explanation about the different types of oxidation and their effects on saw blades, it was very helpful.

I definitely had an "Ah Ha" moment when you mentioned that phosphoric acid was the active ingredient in both naval jelly and gun barrel bluing-- this makes perfect sense to me as I see exactly the same kind of visual effect on the blade in terms of coloration with both products. Maybe I should be reading the ingredients on the products I use!

I am also a big fan of using paraffin on cell blades and plane bottoms, but it never occurred to me to thoroughly coat the saw blade by melting the paraffin as you described in your link. I also appreciated your caveats about melting the paraffin over an open flame as I definitely have "Yosemite Sam" moments on a regular basis!

I have an old Atkins 53 I'm working on right now and I'm going to give your method a try.

[Jonathan McCullough]

Cool. Post your results. I've done a couple of 53's, they're very nice saws. 65s are nice too, but I've never been able to find a 68. The note of caution about heating up the saw with the paraffin is that once it gets hot, it gets very hot.