Found Dreaming

Here is a reference for Gating Aluminum, steel and Cast iron. it is pretty good, but probably the best thing about it, is it lists many of the exceptions to best practice, which mostly apply to small castings, which is waht most of us are hard at

http://teacher.buet.ac.bd/bazlurrashid/ ... _guide.pdf


V/r HT1

There is a whole lot in those few pages. I need to read it through but skimming I saw several things I want to look into more. I do have to say though that it is very formal with the rules based path to particular results and while that is probably the way it is done in much of industry I think there is a lot of feel to real world practice especially for those of us self taught folks. Still great reading a reference, thanks.

Harry wrote:I think there is a lot of feel to real world practice.

When I went through Pattern maker molder Journeyman school... 20 years ago. we did several castiing design projects. we where given a blue print, and told to do all the design, determine the parting, add machining allowances, draft, then formulate and design a gating system. and draw it all out ready to go to the pattern shop. But before we actually did the math for the gating systems we all had to do a "best practice gating system, meaning with no math we designed a gating system as if the pattern shop had sent us a loose pattern with no gating system that we would have to hand cut into the sand. everytime we compaired our informal gating design with the formal design. they where always as close as foundry hand tools would allow.

What this means, is that a basic schooling in sound gating principles will mimic the formalized AFS gating formulas.

But as I mentioned very small parts can act different. the plaques I do so many of are a bigg example of that , they HAVE to be filled extremely fast, so you dont get cold shuts, so the gating systems are all WAY too big to get the hot metal into the mold quickly without having to superheat the metal .

P.S. in the foundry 5 LBS of brass is pretty small

so I guess the 9kg (19.8 lb) cannon that I am trying to do is an ok size then (Im having problems with the core floting and a bit of shrink) but I'm getting there.

Nudge pour it verticle like they did a couple hundred years ago with a big shrink head on the end.

I will give that a go, Thanks

Nudge;
I'm home now I will get the book out that I read on cannon making and scan the pages of how they poured them a couple centurys ago, it also tells how they figured the size or proportions of the barrel from the size of the ball that they wanted to use. actually it was quite interesting reading, althought it did take a spell for me to read it all. what with trying to decypher ancient chemical names and such.

DAvid

Hay, That would be cool if you would do that.
The cannon is one I started for the BYMC contest... I only look at AA about once a week or so now. Things have changed, I haven't I have a lot of problems getting pics and the smilies to work over there

Here is a quick look at the pattern and size

that the pattern for your cannon your trying to pour

well the damn scanner died, along with a lot of other electronic gear, guess its time to start replacing this junk with new junk, wonder if I could cast me a new printer if I used one of the old ones for a pattern.

http://s1222.photobucket.com/albums/dd4 ... n%20files/



The picture you see above is from a 16th century book by Vannoccio Biringuccio titled a Treatise on Metals and Metallurgy. It took me a spell to read it some sections were interesting and others boring, but its amazing that what they did 3 to 4 hundred years ago with no more then what they had, not like today if they wanted say Nitric Acid they made it.

I had planed on scanning the chapter in the book on gun making but as you can guess from the above my scanner is I guess dead. In the picture you can see where they poured vertical and used a large feeding head (his words) to feed the gun for shrinkage this being the last metal poured in so it would stay hot the longest.

They used a iron support on the inner end of the core to hold in it place, this way the gun could be layed at an angle for pouring. I added a couple more photos to the above album that is the part on how they centered the core in the mold, I understand that the guns that are being talking about in this book some of them had bores in the range of 12 inches, and that yours is probably on the order of an inch from the looks of the core support, I hope that this information is of use to you if you need anything else let me know I can take picture of the hole chapter and load them into the album, I don't really have a setup for taking shots of book pages but who knows, these seem to of come out ok.

David