Hello all.  After finishing my mushroom knife, I'm afraid I've come down with a severe case of damasc-itis, and maybe my Smithing focus is shifting.  As I wait for my 15N20 and 1095 to arrive, I found some old saw blades I've had around and cut them up and started 5  four to six inch billets; 3 with 11 layers and 2 with 13. 

 

Is there a minimum number of layers needed to ensure that the blade will hold an edge? 

 

I'm thinking this may be a good chance to experiment with different layer counts and see what the difference in the patterns are, but I do want each blade to be useful.

 

Thanks in advance.

Edge holding is determined by the type of steel and the heat treat you put it through. It has nothing to do with layers. Both steels you have ordered are adequate knife steels so any number of layers will be fine. I personally would not waste time forting billets of mystery steel, it is a lot of work for something that may not harden or contrast. 

Thanks for the reply.  I'm playing with mystery steel that I had on hand while I wait.  May as well learn on free material, no?  I used 7 layers of saw blade at ~ .090 and 6 layers of .125 mild steel.  The blade that gave me this disease was basically the same materials (7 initial layers folded 4 times for approx. 98 layers) that hardened fine.  Again, this is playing/learning so may as well learn how manipulating layers changes the pattern.

 

Thanks again.

Since you are doing a Hi/Low billet decarborization will be an issue.  On your next attempt, if you have an old file substitute them for the mild steel.  You'll end up with a better billet. 

Ive found lower layers counts (60-100) give wider more contrasting layers while higer layer counts (>150) give finer lines of contrast.  I personally prefer the end layer count in the 70-120 range = Good balance.

layer counts are rather meaningless without a "per inch" involved as you could have a 10 layer billet with each layer 1/4" or a 10 layer billet with each layer 1/100"

 

What I more go by is the old "Damascus Research Group's" finding that with reasonable sized layers and no carbon migration blockers a billet will generally be close to an even carbon content after about 4 times to welding heat.  So that's my starting goal.

 

 

 

it has been proven its 80% at only 2, and full at 3x,  you may have missed that report

And what the the FINISHED size????? Starting size of the billet has only a bit of control over the finished size.

Thomas - Gotcha.  Final/finished blade size will be approx. 4" x 1/2"

1/2" thick???? (did you mean billet and not blade?)

Sorry if I haven't been clear.  The blade size I'm looking for is about 4" long, 1/2 in wide and ~ 1/8" thick at the spine.

 

 

 

A little aside:  As I was making my folds on a few of the 5 billets I made out of the saw blades last night, this was the last one, and I was kind of excited because this was the billet with the longest pieces from the middle of the blade and I was anticipating getting at least a foot of 1/2" square to twist and play with.  The billet after the first weld was 11" long and when I went to cold chisel the line where to make the split, my math told me that 1/2 of 11 inches is 6.5, (remember, this was the end of the night and the last weld and it was at leas an hour after bedtime....and I'm getting older....) which is where I marked, cut, and imagine my surprise when I folded the billet and had an inch sticking out.....

 

So here's what I came up with today.  My patient load has been a bit slow (typical this time of year) and I forged/twisted/filed/sanded and quickly etched for 15 min this prototype from the one inch +/- stub of 11 layers that you can see I cut off the billet in the pictures (shows up really good in the first picture where you can see the flux line on the handle.) 

(The little biscuit was approximately 1 3/8 square by 1/2" thick)

 

Not sure if I'll do more work on this and try to turn this into a folder...