brass/ bronze

[Frank Rathmell]

I want to make another golf ball or pop can mortar as a gift. It would be for my boss in appriciation for him letting me use the lathe/mill and shop for private projects.
 
I would like to build in brass/bronze. I would like to know what alloy to use. also sould it be built to the same dimentions that would be used for steel.  I would be using a plan that was posted by     CU CANNON.
 
Thanks in advance
 
Frank

[seacoastartillery]

     If it were me, Frank, I would pick one of the bronzes which are known for their strength.  If you look at the bronze types available on the onlinemetals site, you can compare the ultimate tensile strength PSI numbers, the Yield Strength PSI numbers and the Elongation figures too.  We like silicon bronze which has numbers similar to low carbon steel which is the preferred material for cannon making.  Take a look at their site and make up your own mind:   http://www.onlinemetals.com/bronzeguide.cfm

     By the way, you could do a lot worse than selecting a CU Cannon design for your mortar.  Mike and I were so impressed with how well his first pop can mortar, a coehorn design, came out that We Bought IT !  It has excellent proportions, very close to an original and, even in steel, it looks good!  Much better in Bronze, we are sure.

     Good luck with this project and post some in-process pics if you can.

Tracy and Mike

[GGaskill]

Brass/bronze is generally about 2/3 the strength of steel although there are some really strong bronzes available. 
Silicon bronze (trade name Everdur) is a good choice.

[Victor3]

Brass/bronze is generally about 2/3 the strength of steel although there are some really strong bronzes available. 
Silicon bronze (trade name Everdur) is a good choice.

 I don't think Everdur is available as round stock though, is it? 


 Some like to use naval "bronze" (464 brass) but IIRC it's not all that good as far as the numbers go compared to some real bronze alloys.

[RocklockI]

Frank, everdur is good . But honestly if you follow the three to one rule I don't believe you'll have any trouble with any decent bronze or brass .
 
With the reduced chamber that is used on a mortar ,and small amount of powder 20-30 grians, you'll be ok.
 
At 60 grains the ball will not be seen leaving the muzzle and your GB will be GONE .
 
IF you EVER intend to launch steel fox balls (see sticky note) then you'll have to experiment starting low and increasing untill you are happy OR your mortar begining to flip over !
 
My 2cents worth
Gary
Now if you ever want a cast bronze mortar .......