Above is the finished replacement of the breach in place.
I had searched for ages on the web to see if anyone had or made replacement breach parts for the 155 mm Britians Gun. and when a odd one became available from a damaged gun on eBay, every collector under the sun was after them. So in the end I gave up hope and I decided to make my own.
The cost of the Silicone rubber mould cost about $60 dollars and if you follow the instructions supplied, then there should be no problem in making replacement parts. I had to put in some spew vents to allow the metal to flow without air blocking the metal flow, after the first couple of pours as the the parts were not complete in form. Plus by using centrifugal rotation spin casting method, thus allowing the metal to be forced into those hard to get cavities. So it took a few goes to get the mould working to produce the desired parts that I required.
Above are the three parts cleaned of slag and spew and ready for assembly. The spring was cut from a larger one and made to fit. The firing lever was made from a pop rivet shank with the rivet removed and bent to shape. You can use these also for axles too, if you like. Just be careful when assembling the breach together or the spring will take off and you can lose the rivet shaped firing pin as well. I found that clamping the breach together with some super glue first before attempting to hone the locking spigots together with a gentle tap tap tap with the hammer until the spigots are flush with the front of the breach. With one of the breaches the spigots didn't protrude enough due to air lock in the molding process. So I drilled out enough for placing small rivet into the outer casing and into the body. Then you all guessed it didn't you, I super glued it into place. This holds the spring and firing pin and actuating firing lever into fixture place allowing to be hammared down.
After the assembly of the breach, it is time to place the mechanism into the breach end of the barrel. There are two brackets on the side of the breach end of the barrel, which you can gently prize apart with a blade screw driver. Make sure you soften the die-cast metal with a heat gun, just enough to allow for the separation of the two parts of the barrel. You can tell by touching the metal and if your fingers don't stick to the metal then you are hot enough, otherwise the metal might just start flowing onto your workbench. Ouch! that was hot.
The screw drive blade is pointing to the gap between the two parts of the barrel. Just above the barrel, near the trail leg of another 155 mm gun is the firing pins which holds the spring around it. Ooh not the screw by itself just to make sure you are looking in the right direction.
You can see the two brackets better here, along side another barrel that had too much of a gap and would not close with heat, so I filled it with my favorite bog and with a bit of paint and that one will be ready for re-assembly.
In the first picture you will see two shiny parts, which are the tandem spring and axle housing which are positioned at the front of the gun carriage turn-table. A while back I had purchased on eBay a couple of wreaks for spare parts and one of those was broken. So that was my first cab of the rank to repair. Again more costs for moulding rubber which was about $50 Australian bucks. I will keep that for another blog I think on how to replace the axles.
Information: The High temperature Silicone moulding rubber two part mix m4470 and was purchased on eBay from Aldaxmoulds. They also have a video clip on how to make your rubber moulds. Thats saves Gunner Jim trying to explain it for you.
Happy hunting collectors.