gray iron vrs ductile iron for mortar?

[entsminger]

I'm considering buying a 8 inch 1861 siege mortar to shoot and am wondering about the benifits of ductile iron vrs gray iron? One manufacturer sells a 8 inch mortar made of standard gray iron. Possibly another sells theirs of ductile iron. These will have no barrel liner as I don't know of any manufacturer who puts liners in big mortars like these. I hear that ductile iron is weldable thus it can be repaired. I don't know if gray iron can be repaired? Ductile iron is said to be stronger? Is it important to have a 8 inch mortar barrel made of ductile over standard gray iron or is the standard gray iron 8 inch barrel strong and safe enough to shoot typical zinc balls ?

  Scott Springston

[GGaskill]

Ductile iron would be better as it is less brittle as well as stronger.  But manufacturer experience is at least as important as material.

You will want to cast hollow zinc shells like the original cast iron shells so the weight is about the same as original.  A solid zinc shot would be over weight for a mortar.  (Hollow will be cheaper, too.)

[Double D]

People who should know have told us that Mortars do not require liners, so no issues there.

As to type of Iron, may somebody inthe know like Artilleryman will come along and tell you.

What does Paulsens use? That's what I would go with.

[Cat Whisperer]

Two very good principles here.

1. One material is better than the other - ductile vs. brittle.

2. (Reputable) people that are in the business that would know by experience of what works and what doesn't should be your authority for making a decision.

Theory and practice.  One of the things one learns as an engineer is to figure out how to do things you've never done before - as a way of life.  It is always less costly to let someone else make the mistakes (however reasonable the assumptions were) and learn from them.