Knife Making Log, Advanced Class 203: Fluxes and billets

[Steve Sells]

steve sells
This is our third edition for the advances class 200 series, next week we will be returning to the 100 series for beginning knife makers
 
.. Those iof you who are just joining us, this is the advnaced class for knife chat, for one hour we take over this chat room to talk blades,  So far we covered some steels to start using, later we will get into some strangs mixes, for now I would like to alk about various fluxes used, and some NOT to use and why. Some use Wasps nests and also sand is used, becaue they were available, also burned straw ash these can work, but are not the easiest to use, Borax is common in many places, and works well, There are also commercial fluxes available, and some of them are no good for pattern welding,  the addition of iron filings in some will leave strage things in the visable weld lines and in some case can ruin the looks fo your blade. IF you wish to try thesethat is up to you of course. but I am attempting to get people started, after the start we expect people to experiment and learn new things I do not have all the answers, only have answers to questions I have asked myself, and in some cases theyr are other answers I have not found. please read all you can.

20 mule team borax is about $4 a 2# box so its cheap, at room temps its used as a mild washing aid, but at forge welding temps it turns liquid and has a PH of -2.2  this is extermily currosive so take precautions of splatter becasue it isnt only heat you have to worry about, also it will stick to you like honey and will not flick off too well. the stuff I get in the grociery store does had water bound up in it, some people prefer to cook this off prior to using as a welding fluc, thats fine, do it if you feel it works better for you. One thing is Flux is used to protect frpom, Oxygen to prevent scale. it also as a currosive cleans the weld jkoint for us to get a nicer weld scale is cause by oxidation, and scale melts at about 5,000F meaning if we have scale we cant get a good if any weld. if there is scale it will show normally as a black line that likes to rust, if you have it only way to fix is to grind that out and try welding closed again.

Using sand.
Not all sand is created equal, where I gre up on lake MIchigan we has white silica sand thats great for glass making and for flux. but here in Indiana its red clay that dont work too well. so try a test melt in your forge before you decide to use a billet with the sand  I have never used wasp nests, I am assuming its the sand form the mud dauber they use I dont know so I cant comment on it,  please feel free to post it as a question in the forum. I use borax for most all my welds, Having said that Its not enough fro some alloys HIGH CHROME needs more that plain borax most the time Stainless steels can be forge welded, and in a coal forge, I have done it. and I know others that have also The thing that ake it stainless is becasue it has more tha 13% free chrome, notice I said free chrome, D2 has 12.5% chrome but is not a stainless because most is bound up ion carbides, but that is left to another class.  the pioint is Its stainless nae,k come  from the resistance to currosion.  that is beacuse the chroms formes a microscopic layer of chrome oxides that protects the steel that same chrome layer formes with any thing that includes chroms in the alloy to a point and this can effect welding so to aid in this problem, we add a few other things to our flux some thing that is not published because it is very toxic and I just happen to be alergic to it, so while its good for all to wear a resperator, I have to for the Flourine compound that is added to the borax to eat at the chrome layer to allow a clean forge weld.
 
In low chrome alloys like 52100 and such the addition of Borix acid will help a l;little and if you clean well before the weld should be enough to get that to weld for you. also watch your tempts the higher we go, the saster the oxid layer can form,

oldtimer
Is it possible to weld without flux?

steve sells
Yes it is, a lot of people weld steels with out flux, but I still recomend when learning to make your job easier and use it, but after you get good at it, feel free to try.  I doubt high chrome steel can be with out flux but I have been wrong before that is all I have for tonight,

Rich Hale

This week we will show a little of the shop work for the billets we talked about last week.  It would be real good if you review last week’s lesson after this one to get this clear in your mind on how these go together. Printing copies for a shop folder of all of these tutorials would be a great way to keep steps inline.  We will show steps in two billets. One will be the 1084 and 15 N 20, It has 11 layers and has had first weld done. It has also been drawn out to 24” long and is ready to cut, grind, stack and reweld. As many times as we need to get the layer count we are looking for. How many layers do you want? My thoughts are simple. What I have in mind for the blade I will make will determine the layer count,,as well as the size of the blade and the handle material. I make some slip joint pocket folders, I
want a higher layer count for these and a nice clean tight pattern. For a Bowie style blade I can do a lower layer count for a kind of rough look, or a high layer count for a refined appearance. Wot is high and wot is low?  This first billet is 11 layers at first weld. That is too few for almost any blade I can think of. However it will be enough if you are hand hammering and want to make a first pattern welded blade. I like a minimum of 50 layers for a twist. 100 looks better to me. How tight you twist will change the look also. A 12” long bar will loog one way if twisted three turns and a lot different if twisted ten turns. This would be a good time to layer some modeling clay with at least two layers and twis and see wot you like.

The top billet in this pic is the one we spoke of above.

This is that billet cut into four pieces an all welding surfaces ground and ready to assemble.

Tacked and wired ready for forge. I will heat til it just starts to show color and tap to eliminate the spaces between layers,,then flux and back in fire. At the end of this weld I will have 44 layers. I can use it at that count or draw, cut grind stack for any count I wish. Cut once and reweld for 88. Cut into three pieces for 132 four pieces for 176 etc. If you are working more than one billet is is easy to keep track on work bench with a cahilk mark for layer count on each…also a note about wot metal is in each. In the first pic I also showed the canned billet ready for first weld.

Here it is after that weld and I have reduced its thickness by about one third. That assures me that as long as I have prepared every layer of the metal for welding, I have made sure to eliminate oxygen from the can by the paper insert and an airtight can, I will have a solid billet inside. I will flatten the billet out and remove the can. I use a four inch side grinder for billet work a lot. I use it to cut a drawn billet and to remove scale before restacking for next weld. I could use a a belt grinder but I seldom wait for the billet to cool and I am not going to take a chance on quenching these steel in water so I can hand hold. Stick in the vice and cut or grind. You can clamp billet and grind the welds off and see if the can will peal,,,if it is welded to billet you can grind entire can off. Or for those of us with a
milling machine with a carbide tipped cutter can do this nice and clean. I clean all billets up in the milling machine and make all sides and thickness’ parallel.

This is about 100 layers of nickel and 1095 in ladder pattern. It will be a folder and the spring and blade from this piece. It was welded in a can like the one above.  The patterns really come to life after heat treat and with pure nickel in them they look even better if hot gun blued. Keep in mind that nickel will not bond with nickel. When I open that can I must not grind the thin layer of 1095 so that the nickel shows, When it mates with another piece for another weld, if that piece also has nickel exposed in the same place it will not weld. In these pics you can see that I did not spend a ton of time getting all pieces of billets exactly the same thickness or width. When all welds are completed and layer count is correct I will use a kiss block and flat dies the power hammer to make it right for thickness while eyeballing for width. For twisted I will make a square which I will knock the corners down into a rough eight side before twist. A one inch sq is a good place to begin. After twist will use kiss blocks.  I like about a 3/8” thickness for a knife blade billet before I remove scale and profile and rough grind for blade. Thinner for billets for folders. about ¼”  I feel that with all of the work I put into developing patterns in a billet, I do not forge to profile or bevels. It distorts the pattern. However many folks do and it certainly make an interesting pattern. Use wot you wish. This session will be the last in a three part series of advanced knife making for a while. I will now move back to knife making for those working up from our basic series.   For the advanced we will get back here in the future.

[Rich Hale]

I know this is an advanced class in knife making. That said I will not personally  address any of the flux compounds required for SS as they can instantly cause irrepperable damage to lungs and other airway tissues. Remember this text reaches a lot of folks that may not have access to necessary protection from these hazards. As Steve mentioned above, even the borax has hazards.

[Steve Sells]

Not to be rude about it, but in a word: NO

I will not publish the chemicals name on the open forum. its too dangerous for an internet forum, people can die.  Like building a nucular weapon, the informations is out there if you look for it, but I wont discuss it more than I already have for safety and for my conscience.  I mentioned it only becasue  I needed to let people know pattern welding stainless steels as well as D-series and other higher alloy series of steels is possable, but there are risks involded, this is for high level smithing, not for beginner experiments.  As I was told by my teacher Bill Wyant:  when you are ready you will know grasshopper.

[Gunnie7]

Good stuff guys. I've been smithing since 1988 and I still learned from this post.

[Shamus Blargostadt]

wish the pics were there... "...worth a 1,000 words."

 

[LastRonin]

wish the pics were there... "...worth a 1,000 words."

 

​buy the book... I did. And I am glad I did   http://www.iforgeiron.com/topic/40865-introduction-to-knifemaking/