Resin long gun barrels

[smtk]

I have a question about casting long gun barrels.

I was hoping to save time by casting them. The most delicate is 3.2mm by 60mm the resin copies just seem way to fragile they break taking them out the split moulds.

I just wonder if you guys had any tips for making them stronger and mould produce more reliable casts?

[mangozac]

The only down side is that gun barrels show up the slightest mould slip quite easily. Although if they're designed the right way they can be done with a split mould that has a very "shallow" split.

3.6mm is a decent diameter - I could understand breaking 1mm, but not anything bigger than 2mm. What about demoulding them much sooner before the resin has hardened to the point of brittleness? Otherwise you might need a less brittle resin...

[Fleafa]

You could always insert a wire down the length of the mould before pouring?

[Anvils Hammer]

A steel rod would split the resin as it contracts (possibly)

A lenght of copper wire could work well..

Also strands from fibreglass chopped strand matt would make the barrles almost indestructible!

My plan when I get to gun barrels, is to cast the gun, the barrel end, and supply the kit with a plastic/metal rod cut to the right lenght, much stronger and no warping/mold line. Is this somthing you could consider?

AH

[smtk]

I use styrene rods at the moment because they can take a few knocks but I was hoping to cast them so it saves making the barrels (which have a gusseted look at the base made from larger styrene tube and greenstuff) just for /lazy pour build.

I like the fibre glass idea (although fibre glass is nasty itchy stuff). I'll have a try without any talc and at 60psi to see if that helps if not then add some small slits.

[mangozac]

I like Joel's idea best, and indeed many aftermarket military conversion manufacturers sell kits to replace injection moulded barrels with metal ones (and resin its for the muzzle, etc). You could get away with both metal or styrene tubing.

Otherwise go for a split mould and only cut the split down just enough to clear the rear end of the barrel. Then you can just yank them out and there will be no mould lines at all.