Casting with steel

[Titus]

Hi guys, I understand the basic concept of first turning a prototype barrel out of wood and then making a mold and pouring molten steel inside. I do however have a few questions, regarding casting barrels which I hope you can answer.

Firstly, what types of materials can be used to make the mold from except for casting sand? DoubleD, I will appreciate your input in this regard as to where I might find casting materials in South Africa. I do a have a metallurgist friend who is working at Scaw Metals and he can find me refractory materials

Secondly, how was cannon barrels bored in the old days? I am considering investment casting, but I understand this can only be done with the right materials for the mold and not with the prototype barrel already bored.

Thirdly, can a negative of the mold be made from wax, already bored, then made into a cast, left inside the mold, and the molten steel poured in. Will it replace the wax by burning it off, or will it cause impurities/weak spots inside the steel?

Fourthly, does anyone have a link to a source which describes how to build a foundry?

[Cat Whisperer]

Casting in steel is in another league from casting in aluminum or bronze.  The temps are MUCH hotter.

Green sand is typically used, split patterns rammed in the flask (cope is the top, drag is the bottom).  Sprues and risers used to get the iron to the cavity.  (That should give you a few terms for searching.)  Patterns are frequently made of wood.

Core pieces are made from another type of sand and binding agent, generally baked.

There are many text books on foundry practices - some at HS or technical school levels - and often available very cheaply second hand.

[KABAR2]

I have cast in brass, bronze and other non ferrous metals,  moving up to cast iron requires more heat and when you get to the point of casting steel I believe you need to be taking it to a foundry, I think this is beyond most hobby/foundry ability. you would want to cast solid rather than cored for several reasons.

1) sand casting with a core requires something to hold the core centered, made of a like material as the casting these are called chaplets, in theory they "meld" into the casting,
there have been articles written about accidents where over charged or abused cannon had the chaplets blown out the side of the barrel. one would be The Muzzleloading Artilleryman (Vol. 4 No 4. fall 1983)

2) Use of pipe core which then is your actual bore, issues can arise with this method as the core some times floats off center and may leave the breech thin on one side there have been cases of separation between the casting and the core sleeve. Two articles  The Muzzeloading Artilleryman (vol5 no.3 summer 1984) and The Artilleryman (Vol. 7 No. 2 spring 1986)

the best method is to cast solid and bore and sleeve afterward.  weather casting in sand or wax this would be the recommended method  leaving a void that may become the bore leaves allot to chance.

your main enemy in casting with a core is gas bubbles that could be trapped in the pores of the metal as it cools
any of these near the surface of the cast bore these voids would cause you trouble.

In the old days 18th Century the barrel was stood on end and they were bored down into the barrel,
as equipment improved with the advent of steam power lathes and boring machines which would
hold the piece horizontal became the norm.

A good book to start with is THE METAL CASTER'S BIBLE a complete and practical guide to metalcasting! by C.W.AMMEN  library of Congress number ISBN 0-8306-1173-8

Hope this helps,

Allen <><

[jeeper1]

I have this picture of how cannons used to be bored.

[GGaskill]

Always thought if they had rotated the barrel instead of the drill, that would have been a good machine.  Gravity feed and gravity chip removal.

[Titus]

Thanks for the replies so far.  It really helps me alot so far.

[Titus]

Well guys, I have some feedback.

I am going to build my own pattern for the mold. Got some value able info on gun founding. For those who would like to read up on it, the links to the sources follows at the bottom.

So I will make a pattern in the same way they did in a 18th century foundry and then take the pattern to a foundry to do the casting for me. While I am busy I, I am going to include some embellishments like a Monogram on the breech of King George (I am planning a Blomefield pattern) and some astragals and fillets. Maybe some other intricate embossing aswell. Will give feedback as I progress.

 

http://home.europa.com/~bessel/Naval/Forge.html

http://riv.co.nz/rnza/hist/gun/found.htm

[dan610324]

try to google for an site called backyard casting , there you will find tons of info .

at yahoo.com they have something called yahoo groups , search there for cannons and casting
I know there is at least one grope for each of those topics .

BUT IF YOU NEED INSPIRATION THERE IS AN NORWEGIAN RENACTMENT SITE THAT GOT TONS OF DRAWINGS FROM 1680 TO MID 1800

                                  WWW.ARKELIET.NET 

I attach a few samples here

when you say steel , do you then mean real steel or cast iron ??
if you mean real cast steel you will have problems doing it yourself , but if you talk grey cast iron its possible to do it without any big problems in your backyard . check the backyard casting forum and yahoo .

but I would recommend you to use bronze by two reasons , first safety and of course for its beauty  ;-))

an cast iron black painted barrel aint so fun to look at .

when it comes to the casting process I would recommend to use the lost wax method , then you relatively easy can attach dolphins and patterns to your design . the surface will be perfect and need minimum of after casting work to be finished .

try to find some wax , anything will do , old candles , bees wax or whatever you can find .
remelt it and cast it into an pipe with polished inside , just spray the inside first with some teflon lubricant .
when it cooled down you just press it out , then you have the perfect material to put up in an lathe and shape it to your decided design .

when its finished you can attach anything to it such as dolphins , achantus leafs and other symbols or writing also made from wax .
then you can leave that wax cannon to an bronze founder and he will finish the investment mould and do the casting for you .

it will be cheaper for you if you will bring your own copper , but only use elecrolyt copper , not pipes .
pipes are made from an copper alloy . you should use only copper and tin in your bronze alloy , 90 / 10  copper / tin .

[dan610324]

more

[Titus]

thanks dan. I am going to cast with a steel. Not iron. I found a steel stronger than SG42. cant remember the classification, but extremely strong.

[dan610324]

ok , but I still hope you will use the lost wax method .
its easy and its amazing to see what you can do with just a few scalpels .

[GGaskill]

The primary problem with casting in steel is the melt is not real fluid so it doesn't fill in details well.  If you have to use steel, make your pattern simple without a lot of fine detail.