[TheForge] TheForge Digest, Vol 87, Issue 7

Mon Apr 4 16:08:41 EDT 2011

Thanks Steve, a great post and a keeper.  I have added to my files.

What kind of rolling mill do you have?  Home made, based on the down under 
(Australian) design or something of your own?

Dave

--------------------------------------------------
From: <doveknives at aol.com>
Sent: Monday, April 04, 2011 1:08 PM
To: <theforge at mailman.qth.net>
Subject: Re: [TheForge] TheForge Digest, Vol 87, Issue 7

>
> Gents,
>  I will try to answer the questions if I can.  Change in font size to make 
> easier reading, not yelling.  :  )
>
> By "dry welding" do you mean without flux?
>
>  As mentioned by another post, Yes this means no flux.  By eliminating the 
> flux I eliminate the attack of the flux
> on the forge lining, the flux splash around  the shop and on me.  As well 
> as the concern raised by the fine layer
> of flux found by those who have done electron microscope exams of many 
> different makers whose welds
> appeared to completely clean.
>
>  What thickness material do  you use in your billets?
>
>    .05 for both types of steel, 1095 & 15N20, both new bought in coil. 
> Average  billet size depends on intended pattern,
>  Can double up layers of the same material for pattern definition.  Start 
> my students on a stack of 30 layers cut 2" x 4".
>  I buy the coils slit to 4" to begin with.  Now anyone who has tried to 
> stack thin stock and forge weld it will tell you that
>  it will expand unevenly and open up allowing scale to form between 
> layers.
>    The way to stick a dry weld is to do the job of flux for yourself. 
> That means keeping O2 out of between your layers.
> Many have done the forge welding in a box with some kerosene in it to 
> consume O2, This is called "hydrocarbon welding".
> I am basically lazy and did not like building the boxes.  So to eliminate 
> the afore  Mentioned uneven expansion of layers
> under control  I used Mr. Binnions (spelling might be wrong, sorry James) 
> trick for setting the fusion of Mokume.  In my first
> stack I place a fusion barrier, in this case some oxided SS foil on top 
> and on the bottom of the billet, this keeps the billet
> from sticking to the pressure plates .  The pressure plates are 1/2x 2x4 
> mild steel and placed on the top and bottom of the
> billet.  I run a cold MIG bead down each corner of the billet to hold it 
> all together.  I then weld a handle onto one end of the
> billet.
>
>   Using the pressure plates keeps the billet from expanding and allowing 
> O2 in.  The billet heats very evenly using this
> technique.  Just be certain to allow the heat enough time to completely 
> penetrate the billet.  I view the billet in the fire using
> foundry glasses that clip onto my ball cap brim.  I usually set my weld at 
> just below 2000 degrees F  in a 30 ton forging
> press only reducing the height of the billet by 1/2".  I then go to the 
> welding table, using a side grinder I cut the two welds
> on the end of the billet at the pressure plate and peel the plates off the 
> billet. The all that is left is to draw the billet out to
> .75 thick, 1.125 wide and however long it wants to go.  I use a 
> combination of my power hammer and a rolling mill.
>
>  To gain pattern density I generally cut this bar into four or five equal 
> pieces and surface grind both sides to 400 gt.  Now
> I can hear someone say "I don't have a surface grinder".  Don't let this 
> stop you, use a belt or disc grinder, start with 50 grit
> and go to progressively finer grits, I use 220 then 400.  It is during the 
> traditional cut and fold technique where many problems
> occur.  This is one step I was glad to eliminate, and one that benefited 
> me perhaps the most.  By investing the time in
> polishing the mating surfaces I increased the surface area that is in 
> contact and eliminated the air gaps that can allow scale
> to form between layers.
>
>  I next lay up the stack and button weld (read as round puddle tack weld) 
> the stack together placing the button welds only on
> the ends of the billet.  Anytime you are arc welding on your billet, only 
> weld on the ends, these are cut off along with about
> 1/2 inch of stock between the first weld and re-stack as well at the end 
> of the finished billet to eliminate any chance of the arc
> weld showing in the finished billet.
>
>
> Do you use an induced-draft forge or a blown-air forge?  Do you do 
> anything special
> to adjust your flame conditions?
>
>  I have used both with great success.  When designing your forge remember 
> that propane needs 18 inches of extension for
> optimum performance, this is what works for me, I know there are those 
> that will disagree, but this is what works for me.
>  Currently I am using a forced air gas forge that is a slightly modified 
> Don Fogg design.  The forge body is a12" tall 12" dia.
> .1 wall thickness black iron pipe that we split down the length and welded 
> in 6" of .1 thick strap that makes the fire chamber
> an oval shape.  Burner is injected at a tangent at the bottom rear.  We 
> lined the forge w/2" of Fiberfax in 1" layers doubled
> to allow us to wrap the wool out the door to cover the pipe at the door 
> edges to protect from burning the steel away over time.
> The doors are side sliding fire brick slit on the edge to allow for 
> guiding on an angle iron frame.  We are using about half the
> fuel as with the aspirated forge and welding muck larger billets, largest 
> is averaging 4x5x4 inches.
>
> I've heard arguments on both sides of the debate, and am curious.
>
>  I don't pay attention to the arguments, try both theory's and use what 
> works.
>
> Gas forges are notorious for producing scale.
>
> The point made by another post is true, the mix is critical.  I used a 
> .035 mig contact tip in the aspirated forge burners.  On the
> current forge we are using a blower but we have the gate valve almost shut 
> and we are using a flow meter, the type with a little ball in it to 
> regulate
> the propane.  Used to run at about 60 on the meter, have tuned all the way 
> down to 24 and still making welds perfectly.
>
>  My shop is at 5000 feet elev. The greatest difference in my production 
> made by switching to dry welding is hard to say.  I will name the most
> notable ones being, my forge lining is lasting for 2-3 years between 
> relines, My weld failure rate has dropped to 2  in 7 years, yes, that is 
> only
> 2 in 7 years, one of which happened last year at the RMS conference in 
> front of about 50 blacksmiths, over worked it in an unfamiliar press.
> Boy was my face red!!!   Weld was able to be cleaned w/ acid and reset w/o 
> problem.  The other was not letting the billet soak long enough to get
> to welding temp all the way through.  None of this is said as a means of 
> bragging.  It is to say that using clean stock, proper heat, cleaning well
> between welds, yields predictable, controllable results that even a 
> bumbling fool as myself can achieve good forge welded Damascus.
>
>
>
> Trusting HIM,
> Steve Rollert
> keenedgeknives.com
> doveknives.com
>
>
>
>
> -
> ______________________________________________________________
> TheForge mailing list
> Home: http://mailman.qth.net/mailman/listinfo/theforge
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:TheForge at mailman.qth.net
>
> TheForge mail list group photo site is
> http://www.photoworks.com
> Login: blacksmithblacksmith at hotmail.com
> Password: anvil
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> 