Gentlemen,

I am having an insert barrel made for my combination gun so it becomes a double rifle. I want to take a chamber cast to send across to the maker in Germany so we can a good fit. Send the gun across is far too complicated and expensive.

I have some good west epoxy resin with fillers. My plan is as follows.

1) oil the bore well, even some spray wax as a release agent.

2) plug the bore 2" beyond the chamber with a tight wad of kitchen towel and the cling film - I know epoxy doesn't stick to that.

3) apply some more oil / wax to the chamber.

4) remove extractor and tape over the other barrel.

5) hold the barrel vertically a poor in epoxy mix - thickened thick putting cream consistency.

6) allow to harden

7) using a sold rod - tap out the plug and send to gunsmith.

Anything I have forgotten.

Epoxy doesn't shrink and gives very good detail.

I would not use epoxy but I am a very conservative gunmaker. Some folks have a higher risk tolerance than myself. You may be one of those people. If it was me, I would invest in some casting compound. It is very reasonable, not much more than epoxy, and it melts in boiling water. The chamber and bore do need to be well oiled. Good luck.
Steve

Cerrosafe shrinks slightly during cooling. After an hour or so it expands to the chamber's original dimension. After cooling about 200 hours the casting will expand .0025" larger than the actual chamber size. Don't know what the expansion/contraction #s are with expoxy. And if the casting becomes stuck for some reason, it's easy to reheat the Cerrosafe and pour it out.

Cerrosafe is actually made just for that purpose. And at $15.00 per pound plus shipping its probably one hell of a lot cheaper than epoxy's with unknown shrink rates and risks.

http://shop.boltonmetalproduct...-4250-2-LB150005.htm

Heym. My thoughts might be to put the gun on a European Firearms Pass and fly over to Germany with it...get them to do the work then fly back and bring gun and inserts back (entered by the Germans on your UK FAC).

Declare the inserts to UK Customs on arrival back in UK.

I can't see a cheap flight being much more than the cost of all the faffing and farting about of sending it.

Norman Clark at Rugby has cerrosafe blocks. Or at least i saw one when there last week. About £15.00 I think it was.

quote:

Originally posted by enfieldspares:
Heym. My thoughts might be to put the gun on a European Firearms Pass and fly over to Germany with it...get them to do the work then fly back and bring gun and inserts back (entered by the Germans on your UK FAC).

Declare the inserts to UK Customs on arrival back in UK.

I can't see a cheap flight being much more than the cost of all the faffing and farting about of sending it.

Norman Clark at Rugby has cerrosafe blocks. Or at least i saw one when there last week. About £15.00 I think it was.

I had looked at this, but the direct flights from Scotland to where the gunsmith is located in Germany is £200 plus, then add another €50 each way for transporting a firearms and then car hire, plus days off work etc its getting expensive. I have done the trip before - From Scotland we seem to pay about double for flights to Europe than you would from Southern or Central England - not sure why.

I think I remember some epoxies with cure shrinkage, the dimensions may not be right. I'd worry all night about epoxy getting stuck, too. I'd use Cerrocast.

By the time the Cerrosafe gets to Germany it will have expanded to be larger than the bore.

Would a fired, brass shell give them the dimensions they need?

How much does it cost to send just the barrels?

quote:

Originally posted by Recoil Rob:
By the time the Cerrosafe gets to Germany it will have expanded to be larger than the bore.

Would a fired, brass shell give them the dimensions they need?

How much does it cost to send just the barrels?

200 hrs/24 hrs = 8 days. There are ways, I'm sure, to get something from Scotland to Germany in less than 8 days.

I have some cerrosafe casting that are pretty old and still in specs? Where did you get that information..perhaps the mix?

quote:

Originally posted by Atkinson:
I have some cerrosafe casting that are pretty old and still in specs? Where did you get that information..perhaps the mix?

CS Alloys Cerrosafe data:

http://www.csalloys.com/products-cerrosafe-alloy.html

Cerrosafe is used because it is a universally consistently mixed all metal alloy and has a predictable expansion rate of .0025 inches per inch after normalizing. This is the rate from Boltons advertisement. To work it out you measure your casting after it has normalized and divide the measurement by 1.0025 and it will give you the true measurement of the chamber that was cast. Once normalized, the casting should hold it's final dimensions forever. There are no solvents to evaporate and cause shrinkage as in plastics and it won't break down and shrink with water vapor in the air like sulfur does.



Non-Eutectic Alloy

Melting Temperature 160-190º F or 71.7-87.8º C

Density .341 lbs./In3 9.4 g/cc

Shrinks initially, grows to .0000” in 1 hour and continues to grow to .0025”.

Originally made for toy soldier casting. Principal uses are in proof casting cavities (threads, dies, molds, blind holes, gun barrels); Duplicate patterns in foundry match plate making: supporting work pieces while machining; pray coating wood patterns. Dental lab techniques (swaging, jacket crowns); Masks for electroplating and spray.

Oh I think I see the confusion now! Cerrosafe doesn't keep growing forever. After it has normalized, a 1 inch cube of cerrosafe will grow to exactly 1.0025 inch FINAL size. A half inch cube would grow to .50125 final size and a two inch cube would grow to 2.005 inch final size. Then it will stay that size forever. The rate of expansion however is very predictable so no matter what size your casting is, you can compute the actual size of the chamber.