Saw blade questions

[Will W.]

Hello everyone. 

I am pretty new to smithing, and this is my first time posting anything on this site, so go easy on me. Ive made tools and knives and such, but I just attempted my first forge weld yesterday. Nothing special, just some mild steel bar stock. It went way better than expected, they actually stuck very well, so I want to keep going. I have a LOT of old reciprocating saw blades (sawzall blades) and I want to try to weld a few, and if all goes well, I may try to make a knife out of it. My question is, what kind of steel are these saw blades likely made of? Will they make a useful knife, or are they low carbon? I don't know many specifics about them, as they've been floating around the shop for many years. I have blades for cutting wood, metal, and concrete. Im not sure if that makes a difference. Any help would be very appreciated.  

Will

[swedefiddle]

Good Morning and Welcome to this Land,

If you put your location in your Avatar, you may find someone close to you who can answer your query. Yes it is quite interesting, starting out with a Forge Weld and wanting to make a complex knife. Some people start out wanting a Sword, not just any sword, but one from the Stone.

There are an awful lot of knowledgeable people on here and there are some who make good shadows. Do not rely on the answers until you get used to who can be relied on. Find your local Blacksmith Association, show up and learn with your eyes and ears, not your mouth. Take an old fashioned NoteBook and a Pencil, make a bunch of marks that you can read and understand in 5 years. Use a camera or phone to record things you don't want to forget.

Enjoy the Journey, there is no finish line.

Neil

[Latticino]

Sounds like the OP has already made a couple of knives, so I certainly don't see why he shouldn't try for a forge welded patterned blade.  Takes some boldness, but others have succeeded with forging up a successful billet the first time.  Keeping clean surfaces, forge temperature and atmosphere control, and careful tacking before any major deformation is the key in my book.  I know some don't use flux, but for a first billet I would recommend using it.  Weld from the center section of the billet to the outside though to try to push the flux out and avoid inclusions.

Before you go for a large billet it might be prudent to test your materials on a smaller one, with relatively low layering, just to see how hard they are to weld together and whether the stack hardens successfully.  I would expect decent saws-all blades to be high carbon steel, but avoid any that have imbedded carbide teeth.  In fact you might want to grind the teeth off altogether.  For patterning you may want to include something with a bit of nickel in it as well as the saw blades, to get contrast.  I think folks who are trying pattern welding on a budget often mix saw blades with pallet strapping material and truck leaf spring to get some nice contrast.

Good luck

[Will W.]

I have made a few knives. Nothing incredibly special, but they are sharp and hold an edge well. I planned on testing the hardenability and weldability of these blades before going for the actual billet, but I figured I would try to obtain some more knowledge first. I do use flux though, and planned to grind the teeth and shank off. I had not thought to weld from the center out, that makes a lot of sense though. I thank you for your time and knowledge. 

Will

[Latticino]

2 hours ago, Will W. said:

I had not thought to weld from the center out, that makes a lot of sense though. I thank you for your time and knowledge. 

Will

Hope I was clear with that comment.  It is hard to describe in text, but a picture would do much better.  I meant that the material should touch down initially in the center of the width of the billet, then be worked towards the outer edges.  Some folks slightly crown their layers to assist with this.  I was not referring to where to start welding along the length of the billet.  The key is to get any flux or slag to migrate to the outside before the outer edges are welded.

Good luck.

[Frosty]

Welcome aboard Will, glad to have you. Bimetal saw blades are typically much lower carbon than monometal saw blades they have a higher % of nickle for flexibility though. I've gotten good results with mono-metal, metal cutting band saw blades, they harden up well and the nickle content makes for good contrast in the pattern.

The hammer pattern I've had the best luck with starts at the closed end of the billet if it's folded or has a handle welded on. Starting at the fold or handle helps drive inclusions out and away from you. Not being splashed with molten borax is a plus. I start at the fold and run an overlapping series of blows up the center of the billet then come back to the fold/handle and make overlapping blows up each side alternating side to side to keep the billet straight. If the billet is wide enough 3 rows won't cover it strike more rows from the center out to the edges.

I'm not a heavy flux guy I clean the joint surfaces as clean as possible, the shinier the better and I flux lightly at a lower temperature just warm enough the flux sticks then I close the joint. My aim is to prevent oxidization forming as well as I can. More "traditional" folk close their joins bring the billet to orange heat, brush the edges and flux the edges before returning to the forge to bring to welding temp. It's a long time used and proven technique.

I hope that was less confusing then helpful.

Frosty The Lucky.

[Will W.]

17 hours ago, Frosty said:

Not being splashed with molten borax is a plus.

I can't help but agree. Haha. That is all very helpful though, thank you. One possible mistake that i noticed with the first weld i mentioned that I made is that i only struck from one side. They stuck together, but you can see where the border of the two pieces was, and the piece i was striking is significantly thinner than the piece that was against my anvil, for obvious reasons. Do you flip the piece 180°, to get even layers, or is it better to only strike one side? I assume even layers would be better, but I honestly don't know. Regarding the blades though, only a few I had were mono metal. I made a stack of 2 mono and 4 bi metal blades. I cut the stack into two pieces after cleaning and tacking, and plan on testing them for weldability and hardenability, before going in blind and trying to make a knife billet. I plan on starting the forge later tonight. I will post my results. As always, any advice or constructive criticism is welcome. Thanks. 

Will

[nkearns]

What were the results? I'm curious to see if it works as I have a ton of blades

[Will W.]

I apologize for the late reply, honestly forgot about it for a while. The actual welding went together very nicely. I used a stack of 8 blades, all bi metal I beleive, with the teeth ground off, and the shank cut off, and ended up with far less metal to work with than I anticipated, though I am new to forge welding and do not rule out user error (maybe I compressed it too much?) I would recommend using a higher count than that to anyone who tries it, but ill leave that to your judgement. Anyways, I went ahead and quenched what I was left with, if for nothing but a little knowledge. All went well and it seemed to harden up pretty well, but not like a high carbon steel. Seemed like a mid carbon steel to me, maybe. Thats just my experience though. 

[ThomasPowers]

For Bandsaw blade and pallet strapping I generally stack them 20 to 25 layers high to start and I don't bother to grind off the teeth before stacking.  I will test the pallet strapping to make sure it hardens before using it.

[Will W.]

I can see how that many would be needed. If I try it again, which I want to do now, I'll have to make a larger stack. Let me know how the pallet strapping goes as well, I have a bunch of that laying around, which I have been meaning to test. 

12 hours ago, ThomasPowers said:

I don't bother to grind off the teeth before stacking

Really?! And that doesn't give you any problems during welding? No delamination issues? 

[ThomasPowers]

No delamination problems the last 25 years of so of doing it that way.  With the multiple folding the scale off of the teeth does some of that.  

How I stack a billet.  1: cut clean BSB and PS to length, (beverly shear or bulldog snips)

2 If welding in a coal forge start with a section of PS then place a piece of BSB on that. PS and then BSB, PS, BSB, PS, usw.  I generally wire them together.  I try to size the billet for the forge as I want to heat the entire billet to welding temp is I have a handle on it and at least more than 1/2 the length if I don't have a handle..

[Will W.]

On 12/3/2016 at 9:12 PM, ThomasPowers said:

I will test the pallet strapping to make sure it hardens before using it.

I just realized I misunderstood you when you said this. Apologies. 

Anyway, that is interesting about the teeth on the saw blades. I did not expect that. How do you go about wiring the billets as well? I've always been curious about that. Tried it once with just some mild steel and it did not go well lol. 

[ThomasPowers]

I use baling wire or rebar tie wire which ever is to hand.  I compress the stack hard in a postvise and then wrap the wire around the bundle tapping it flat against the sides as I go and then cut and twist the ends together tightly and fold it flat onto the side of the stack, then move the stack up a couple of inches and repeat until I reach the other end.  All the twisted ends folded flat are on one side (and on the toothed side as well)

Heating is done slowly in a reducing fire----I like to blow the coal fire strongly to get it very hot and then stick the billet in with NO AIR until it comes up to fluxing temperature.  Flux and replace in the fire and give a slow even reducing blast until ready to forge weld---with my hand crank blower I tend to turn the piece in the fire every X number of cranks to keep it even.  Having a good set of tongs helps keep the pieces from sliding around and getting the billet "set" with the first weld means you can slid off the wires as it will be much smaller after welding.  If they weld to the billet a fast rasping with a worn out farrier's rasp will usually fix that.

[Will W.]

OK. I think the next billet I attempt, I may  try to borrow a few tactics of yours because I was going about this wrong. I never tapped the wire on the sides of the billet to tighten it up. More or less just wrapped it around the billet last time, which in hindsight, what was I thinking? No wonder the pieces were all over the place. Haha. Thank you for the knowledge, and your time.