What flux to use?

KenH

Well-Known Member
Hello all, As ya'll know I've done just a tiny bit of forge welding for San Mai which I dry weld by doing a seal weld all around the billet. I would like to try forge welding about 8 or 10 layers for a Damascus billet. That seems a bit thick for a seal weld - what flux would give me the best chance of a good forge weld? Plain old Borax? OR - I've read about commercial flux. Would any of the commercial forge welding flux give better chance of a good forge weld? No more forge welding than I plan, forge damage is not so much of a concern. Remember, I'm using "Arm" power hammer for forging {g}:confused:

Thanks for any insights.

Ken H>
 

GeneK

KNIFE MAKER
All the damascus I have made has been dry welded. The largest billet was 15 layers of 2" X 4" material. Normally, I use 1 1/2" X 4" pieces, all hand hammered. I weld the corners of the billet then weld a handle on. I've been lucky to not have any problems doing it this way.
 

EdCaffreyMS

Forum Owner - Moderator
Anhydrous borax would be my choice. Regular borax is difficult to use, because of it's high moisture content....when you put on hot steel, the boils and falls off...you usually end up with more on the floor than your billet(s). Dry welds have their place too, but if your just starting out, your chances for success go up dramatically with flux such as anhydrous borax.

I buy mine from pottery supply or mining supply outfits. The more you buy, the cheaper it is.....I usually buy in 100lb bags......but you can get it in 5, 10, 15lb bags too.
 

KenH

Well-Known Member
I've got a couple lb of Anhydrous borax made an offer on today. We'll get it - that stuff ain't cheap!! How far does 2 lb go?
 

Daniel Macina

Well-Known Member
Have you looked at soaking your billet in kerosene? From what I hear you have to set your weldin one heat though (not positive on that though). Not sure what equipment you have
 

KenH

Well-Known Member
As I mentioned, the equip is my Arm powered 2-12 lb hammer. Of course a forge and anvil. That's about it for equip. It is a gas forge with a TC for temperature monitoring. I think I'm following Ed's advice and going with Anhydrous borax.
 

Daniel Macina

Well-Known Member
After trying the dry method I have never looked back.
Do you just slice off the welded edges when restacking or finishing the billet? Also wouldn’t it be fairly easy to have a pinhole in your weld that would ruin the billet? Just curious.
 

DanF

Well-Known Member
Do you just slice off the welded edges when restacking or finishing the billet? Also wouldn’t it be fairly easy to have a pinhole in your weld that would ruin the billet? Just curious.
If you are using stainless you weld a solid weld all around. If using high carbon steel (read non-stainless), you do not need a solid weld. A good number of knifemakers will deliberately leave a pinhole (exhaust port) in the stainless (multiple pinholes not good). In both types of steel, the welds are ground off the 4 edges to keep the welding rod material from incorporating into the billet, leaving a spot of unwanted material in the finished damascus.
Both methods (solid welds and tacking) are proven methods, I suspect it becomes a personal choice based on each person's experiences with it.
 
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BossDog

KnifeDogs.com & USAknifemaker.com Owner
I hate flux. It eats your forge lining up. I have used anhydrous borax and mule team. I have found the anhydrous is better like was mentioned earlier in this thread. I keep a box of 20 Mule team in the forge since I don't have any anhydrous on hand. It has gotten used once I think in the last couple years.

Having said that, I never use flux. I will either weld the seams solid if it's a small layer count like a fold or I will wrap bigger billet stacks in heat treat foil.
Wrapping in heat foil will last long enough (usually) to get the weld to stick. It burns off pretty quick so your first weld has to take.
 

Chris Railey

KNIFE MAKER
I forge small Damascus billets by hand and I use 20 Mule Team Borax straight from the grocery. I do find a less is more approach is cleaner for your forge. I put enough to cover the edges and stuff but not handfuls of the stuff. That being said I would do what Ed says or the HT foil trick from Boss is an awesome idea if you ask me. Both of them have done far more damascus than I.
 

springer82

Well-Known Member
I use anhydrous borax myself. It works well. Starting at 8 to 10 layers what end count are you looking for? With hand work you will have more heats. Don't be shy to add more steel as you go to make up for what is on the floor! What will you use? (1080/15n20) Best of luck. Post some photos!
 

KenH

Well-Known Member
I welded up one billet using 6 layers, alternating 1.125" wide by 4" long of 15N20 and 1075 with .003" nickel between layers. That billet I seal welded all the way around just like for San Mai with SS cladding. That wound up being only around 3/4" thick after setting welds good and grinding to clean up sides. I plan to make another small billet of the same with perhaps only 5 layers. Then final weld the two billets together to have a single billet around 1" square x 4" long. Still thinking but would like to put a full twist (or 1/2 twist?) before drawing out billet to something around 1-1/2" wide by how long it works out for a .180" or so thickness. That should give enough to clean up nicely grinding and have enough for a decent blade.

Should I forego the twist? Once I get this all done I'll be sure to post some photos. I've got 2 lb of Anhydrous borax on order, should be here by end of week, or early next week.

Ken H>
 

springer82

Well-Known Member
Ken that sounds like it will work out fine. If you don't do a twist and want something cool there is always raindrop. Got a drill press.
 

KenH

Well-Known Member
Got drill press - 3 of them in fact :) With only 10 or 11 layers will the raindrop pattern work very well?
 

KenH

Well-Known Member
OK for an update on this thread. As mentioned before I ordered 2 lb of anhydrous borax and got it in other day. Today I got the forge out and tried it. I used 7 layers of 15N20 (.074") and 1095 (.-94") with a thin layer (.003") of pure nickel between layers so it would match the first little billet I forged. Once cleaned this are about 1" wide X 3" long. I ground clean both sides of steel, clamped tight in vise and welded the end corners with a rod welded to one end. Soaked stack edge with WD40 (just sounded good), put in forge and heated to a dull red, put small amount of borax on edges to cover good, put back in forge and let soak for a few minutes until it looked really hot (about 2100F per indicator), pulled out and used my "Baking Soda" power to forge. Repeated a couple of times and it's looking pretty good. Just to check I allowed billet to cool some and ground sides smooth. Looking good, no visible delaminations.

Ground one side clean, took previous billet & cleaned one side good. Clamped in vise and welded ends, turned over to spot a weld in center - wound up welding full length so this turned out to be a dry weld. This 2 layer stack is about 1"X1"X3". Put in forge, got hot (around 2100F) with good soak. Set weld, then started drawing billet out. After drawing out some I've got a nice billet about 0.4"X1-1/8"X5". I ground sides clean and it looks good to me. I etched in FC and can see layers nicely, but it was hard to photo. I got a photo of the side sanded with 400 grit and looks pretty good to me.

Here's a view of the side shot with phone.


Now to decide if I wish to draw it out plain, or try something fancy like raindrop or ladder. I understand both those are done the same way, a bar across for ladder or a hole part way thru the billet for raindrop? I expect the side needs to be clean like it was to be welded so the holes/bars will close up without voids?

A question, will the nickel layers weaken the bond between the 15N20 and 1095? Would it be better not to try a twist?
 
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