Wax finnish with no retempering when restoring old heads

[salix_caprea]

Dear smiths,

I recently started a small forge and I am learning lots. I have a few old looking finnish and scandinavian axes that I am restoring. I have polished, reground and removed knicks and bits in some of them. As a result of that, some heads are left with new shiny and original dark patina on them.

I would like to take care of that by either retempering some of the heads (which needs to be done anyway in some cases) and/or finnishing the heads with beeswax to achieve a more homogenous black look. Now here’s my question:

Because the steel needs to be rather hot (100 ºC - 150 ºC) for the beeswax finnish to soak in, would you say that could negatively affect the current temper of the tool?

For heads that don’t need to be retempered, I was thinking about heating them in the oven until them reaching 100ºC or so, and then coating with wax. What do some of the more experienced smiths think about this approach?

Hope this question is interesting to some of you!

 

[jake pogg]

It sounds like an interesting project,lets try to make sure that we all understand What,exactly,you're trying to do,and Why,but very importantly-that we're on the same page in regards to what the Terms mean.

Tempering is the second part of a two-part process that is used to strengthen steel tools after initial forging,usually referred to as Heat-Treating.
Without re-doing the first part,Quenching,it is rather a pointless exercise .

So the first question:Are you sure that you mean "Tempering",or is it possible that you mean that some of your axes are(for whatever reason) in need of being re-Heat-Treated?

100C is fairly well below what a normal T for tempering of an axe involves;meaning that you can heat to 100C without worrying about HT.

Second question:Heating to 100C,is that something that some chemical process(bluing et c.)calls for?
Or are you hoping to achieve a so-called "forged" finish?
Just in case i'm right,"Forged" finish involves Vastly higher temperatures(in excess of 800-1000C),and will Definitely screw up any and all existing HT of your axes,forcing you to re-do it.

Another thing you may be thinking of is when a forging gets oiled,and oil polymerized by burning it...?
Such method is not really great for your application either,it really only works on deeply oxidised(by forging) surfaces.On shiny new steel burned oil will look patchy and yellow-brown,not at all aesthetically pleasing.

 

[salix_caprea]

Thank you for your message! Yes, sorry for the wrong terms. By re-tempering I mean re-heat-treating the heads. As I said, some of them just don't need to be re-heat-treated as they are in relatively good condition.

But if I want to achieve a more homogenous look (I was thinking about the nice black given by rubbing a block of beeswax on the still hot steel), I will just get the heads warm up to 100ºC so that the wax can melt and soak on the surface of the tool. Do you think I will get a nice finnish that way?

I will keep what you call a "forged" finnish on axes that need to be re-heat-treated anyways.

Thank you for your time

 

[jake pogg]

By re-tempering I mean re-heat-treating the heads. As I said, some of them just don't need to be re-heat-treated as they are in relatively good condition.

Ok,well,if you're sure that some of your heads Need to be re-HT'd...(it's quite unusual;commonly only necessary if the head has been in a house-fire,or for whatever other reason subjected to T above that of 200C or so).
It isn't rocket science,but will take some time,and fuel,and following a fairly strict regimen.

You'll need to Normalize the head prior,in order to achieve the fine(-er) rain structure.It involves bringing the head to about 830C+,and doing so 3 times,allowing it to cool each time after heating "in still air"(just being set down and left alone,untill you can no longer see any glowing of heated steel(in darkened conditions).
When you bring head to heat you may want to heat only the first couple inches of blade,the rest of the head must remain soft anyway.But,you can't just stick it in the forge edge first,or the very thin part of it will overheat.So try to start heating the head somewhere back from the edge,running the heat towards edge,attempting to have it all come to T evenly and at the same time.That will depend on the type of heating available...Is your forge solid-fuel or gas?
(nothing like Normalizing for some good solid Practice of heating a forging.
Unless your forge is equipped with a thermocouple you'll have to judge your T by using a magnet.
Heating slowly and gradually,attempting to heat only the areas you need heated,under low light conditions you keep on checking the surface with the magnet.Once steel looses magnetism,you'll know you're somewhere above 800C.You'll then have to continue and get it just a little hotter,not much but just a bit.That,roughly 830-850C, is so called Critical,or Austenising T,and it's what you'll want to have when you go to the second stage,the Quenching.
So again,to normalize,bring that head to heat 3 times-first to a bit Above Crit.,second time try for just At Crit.T.,and the third just a touch below Critical t.Each time allow the forging to cool on it's own in still air.

Next stage will be Quenching,and it'll have it's own particulars,and eventually,to finish the process,Tempering...I can keep on going on like this ,but once again-are you quite sure those heads require re-HT'-ing?

But if I want to achieve a more homogenous look (I was thinking about the nice black given by rubbing a block of beeswax on the still hot steel), I will just get the heads warm up to 100ºC so that the wax can melt and soak on the surface of the tool. Do you think I will get a nice finnish that way?

No.Unfortunately,if shiny steel is brought only to a low T like 100C or so,and then coated in wax or oil,it'll not turn that nice black of a Real hot-forged steel.
Oil will pyrolize somewhat,and become sticky(and brownish-yellow).Wax will probably remain transparent.
To achieve a nice even black color without heating to higher ranges(forming an oxide layer) you'll have to induce oxidation by one of the chemical oxidation methods(so-called "cold-bluing" or the like).
It is that film of oxide that looks black,by either being black itself,or retaining oil/wax/color/whatever to appear black...

 

[muleman77]

One of the things that makes vintage axes desirable is the quality of the steel, and heat treat. I've retreated some heads that needed it, but to do so for cosmetic reasons is foolish IMO.

Many vintage axes were not forge finished, but rather shiny, and often painted. Time and weather have given many of these a patina that looks "forge finished".

Cold blue gives a nice look to shiny steel with no risk. It can blend in shiny areas from grinding or filing off mushrooming etc very well.

No way to really know what you have going on with yours without a few pictures though.

 

[Square_peg]

I think that you just want to burn some wax onto your axe to give it a black look similar to seasoned cast iron. To do that you don't need to re-heat treat your axe, you just need to bring the axe up to the smoking point of whatever you're coating it with.

I don't know the smoking point of parrafin and a quick web search didn't provide an answer. But there are several cooking oils which reach their smoking point at a temperature that's unlikely to change the temper of your axe. Many high carbon steels will need to tempered close to 500*F to achieve normal RC hardness for an axe - in the mid-50's HRC. Almost any high carbon steel which has been fully hardened will not drop below mid-50's HRC at 400*F. This is also my experience from heating a few fully hardened axes in my oven at increasingly higher tempertures until they became file-able.

So if you pick an oil that has a smoke point under 400*F and apply it to a 400*F heated axe you should get the result you're looking for. Extra virgin olive oil and coconut oil are examples of such low-smoke-point oils. Parrafin may be as well, I don't know.

You could test parrafin on a piece of steel heated to 400*F in your oven. Be sure to first test your oven temperature with a good oven thermometer. You might try a test run on a piece of scrap steel. You could even test lower smoking points to see if you get the parrafin to smoke. My sense is that parrafin will have a low smoking point, under 500*F. But that's just from recalling instances where I spilled wax on a hot stove burner.

If you try any tests please let us know what you find.

 

[A17]

I hot-waxed a tomahawk using the redneck method. I rubbed it down with wax before I took a mini torch and melted the wax all over it. So far the finish has held and looks pretty decent.