I was around at Pete's Foundry today and was able to get hold of a second set of photos of the sacred sword castings. These are the original three candle job and the patterns are made of MDF by the customer after a failed attempt in styrofoam and after lots of coaching to get a decent pattern with enough draft to remove the resin sand. "Lee" was the customer and they went to a new Hmong temple in the town of Atherton, South-west of Cairns. If you look at where the runner was cut off you can see small hole which is the only sign of shrinkage, I think Lee said he'd set a gemstone into the hole and apart from that tiny defect the casting was flawless. Considering how far the bronze had to flow it was a miracle it filled the mould, further reinforcing the belief in having three candles lit for the difficult jobs. Lee the customer who hand made the MDF sword patterns with a bit of coaching. You can see Peter gluing the sand pouring spout into position after drilling a hole into the mould and contouring it with a round file. The resin sand is strong enough to take the weight of the lead ingots without a flask around it. MDF sword pattern after spraying with the aluminium powder release agent, it's good for about 30 moulds before needing a new coat. Here Pete has filled one half of the pattern with resin bonded sand that takes about two minutes to cure and is using the leftover sand to make some precast pouring cups/sprues. Breaking the tip off the sand mould to see if the bronze made it all the way to the end... success!!! Checking the rest of the casting, note the bronze in the pouring spout is still dull red, we were that impatient.
Here's some more photos of one of the two swords after a bit of a cleanup with a grinder. My hand gives some idea of scale, these things are heavy!. Loading the blessed/much prayed over bronze ingots into the furnace
Do you know what type of bronze they were casting, besides blessed? Thanks for the photos, would like to see the finished swords!
Sorry I have no idea which bronze alloy it was, Peter mentioned that he had some ingots squirrelled away of a hard bronze suitable for swords and axes, it was almost impossible to machine and had to be ground to shape. I'd love to see the finished swords too, I think they are locked away in the temple these days. Jason, that begs the question that has dogged us ever since: odd number of candles or an even number of candles?.
That is a very long run away from that sprue. I have had stuff go cold in 1/3 of that length. Looks like a great casting session.
Amazing. I'd read that it's very difficult to cast a sword in a sand mold. Looks like it came out great though, congrats! Is your friend Pete on any of the forum sites? Jeff
Peter's not on any online sites, he tells me he's too busy making a living to get online much past using email, that said he's never held back in teaching me stuff in any way. He's more than happy for me to post some of this stuff online for other people to see. If you want to get an idea of what he's like as a person, my nephew tells me he's just like the "Sniper" from Team Fortress 2 which I found hilarious but accurate in view of his competitive target shooting skills. We did pour those swords hot and fast with a crucible that could retain some heat compared to smaller sizes. His furnace design looks conventional enough, but has a phenomenal rate of burn and will get an A20 with 64 lbs of bronze ready to pour in 20 minutes from a cold start and in 15 minutes after the first pot has preheated it. It will get bronze hot enough to boil if he's not careful to throttle it back a bit and it uses gas at a rate that make a 450lbs gas cylinder cold enough to freeze condensation on the outside on a hot summer day. The furnace is very inefficient, about 3% according to one estimate from a gas expert, It has two things going for it: the 3" opening at the top combined with the high pressure centrifugal blower allow 1-3 PSI of positive pressure and that combined with the high volume gas regulator intended for pottery kilns allows a high rate of combustion. Edit: Jeff would you like his email address?.