Hi all, thought some of you might be interested to see the next patterns for the 5" gauge "Castle/King" castings I am making for a client. I will be tackling the inside and outside guide bar brackets next.
the Outside frames are straight forward and I have designed the pattern so that both the L/H and R/H versions are accomodated. This saves the expense of two patterns and two silicone rubber moulds.
The inside frame is more complex , although smaller than the inside motion frame , which I already made , it also supports the front bogie. Removing an intact wax from the mould will be challenging.
I also have a personal job that I would like to get done!
The handles on some of my machines are a bit tatty so I want to cast a few of these in nickel silver. They should look as good as chrome after polishing. Dan.
Thanks for sharing your fascinating work. I should have thought that nickel silver was prohibitively costly, and its beautiful polish would need regular attention. That is not intended to be critical - as a woodwind repairer I'm familiar with the material and interested in your choice.
Don , nickel silver was used for such items as stirrups , horse bits and other bridle fittings before the invention of stainless steel. It was also used for cutlery of course , usually with a silver plated finish , it keeps it lustre and requires only an occasional polish. As for cost , a visit to almost any car boot sale will provide large quantities of old forks and spoons very cheaply , farm sales are a good source for old horse bridle. I have at least 20 kg in stock and make some of my G1 fittings from it. Dan.
There is a very wide range of cupro-nickel alloys and a wide range of melting points. The metal that I have in stock came from a "horse furniture " factory in Walsall which closed in the 1960's, it has a melting point of around 1100°C and a pouring temperature of 1200°C. This alloy is excellent for sand castings but is pretty much near to the limit for gypsum based investment cements. There are alloys with melting points as low as 1000°C. Dan.
Thanks for that information, I have been doing bit of aluminum casting, nearly always using expanded foam which I find excelent for complicated shapes, but now I would like to have a go with other metals. being able to make castings has opened up a completely new door for me in engineeing.