Required Reading for Foundry Hobbyists

John Campbell is not for the hobbyist, and I have yet to see any hobbyist that could explain his recommended methods, mostly because it heavily depends on computer models that hobbyist have no access to... it's interesting reading, but just the insanely high cope heights should be an indicator that no hobbyist could diligently follow his methods... when someone can explain his methods to me, I might endorse them ...until then.


V/r HT1

P.S. it also really pisses me off that every time i explain something someone comes and snarks that it is not in conformance with John Campbell... or John Campbell would do it better... but no ever offers the John Campbell alternative.
P.P.S I have to have serious doubts about the value of Castings, Second Edition, by John Campbell since in his Preface he even states that it is about grappling with new concepts rather then fact... Rather then fact??? Please

 

Also, that book is like $150, was looking at those titles yesterday. Let us know how the '10 Rules' book is!

 

I have been collecting all those pdf's. Some are really good, some will put you straight to sleep.
Is this something we want to have uploaded here?

This should take you to a fair bit of them. http://www.alloyavenue.com/vb/showthread.php?13584-Books

 

Would be super if we could start with a list, at least. So folks can source stuff from wherever just with the titles.

 

The sources will most likely vanish as time goes by. They would be safer here, but don't want THF to get screwed trying to be the good guys. As the saying goes, "No good deed goes unpunished!"

 

One of the problems I have found with foundry books is that few go into the details of using anything other than water-based green sand molds.
A few touch on petrobond sand, but in my mind, petrobond is just green sand with oil in lieu of water.

All the castings I do use bound sand; either resin-based, or more lately sodium silicate with a hardener.
The typical flasks that you see everywhere are not good for bound sand (because they waste too much sand and binder), and there are no books that detail how to make flasks that minimize the use of non-reusable sand.

And people ask the question "Why not just use renewable sand?", and the answer is that if you want good detail on small parts with very tight accuracy, or want to mold things that can't easily be molded with traditional green sand methods, then bound sand is the way to go.

But basically I do pretty much the opposite of what the books show on mold thicknesses and flask sizes/arrangements, so keep in mind that the "book method" and the method that actually works for your application may be two very different things.
I see too many people that seem to get locked into the "book way", to the exclusion of all else.
There are some really good and accurate methods out there that you will not see in the backyard foundry books, and these methods are well within reach of the backyard guys.
There are several guys who use bound sand around (some here, some elsewhere) to good advantage.

 

I hate to be that "dick", but this is not a molding problem and probably will never be in any foundry book save as a single example of someone saving sand ... your sand should have some recommendation of minimum wall clearance for different metals... based on weight and pouring temp... you will have to design your flasks around those numbers in the best manner you can... I did a casting once of a feed water pump manifold for the USS New Jersey it was about 4 X 4 Feet and L shaped , we had the Patternmakers make us a flask to match it with about 2 inches of sand all around... the L shape made it a pure bitch to lift, and when we poured it, the flask caught fire and burnt completely up... want ta hear the worst part the pattern was wrong, and no one caught it even in the machine shop and it went to the Jersey... our L shaped Manifold was whateve the opposite of an L is :-(


V/r HT1

 

Yep, it is not in the foundry books that I have seen. There are some videos out there that demonstrate bound sand molds pretty well, but not necessarily how to minimize sand usage.
Bound sand can be as thin as perhaps 0.5" thick in some spots, but generally 1" thick minimum overall.

I rip 1 x 4 pine into standard thicknesses, generally 2", 1.5" and 1", and use those to make either the cope or drag, and the spacers that minimize sand usage.
I start with a square or rectangular cope or drag, and fill in the corners and such with spacers on a diagonal, and sometimes fill other areas if they are large.
Sometimes I just tape the spacers in place so I don't have to permanently modify the flasks, which is handy if you just want to try something without making a permanent flask setup.

And another benefit of bound sand is that the flask can be pulled off in a snap-flask fashion, and the two mold halves cemented together with furnace cement.
I never have problems with burned wood flasks since I don't pour with them in place around the mold.

You can do some neat stuff with bound sand, which is why I use it.
I also generally make small parts, with flasks generally not larger than perhaps 18" square, so it is pretty economical.
Some here have used SS bound sand on a large scale, but I would not want to turn those flasks over without a crane.

Edit:
This video demonstrates bound sand pretty well, but he does not try to minimize sand usage.
It is surprising how thin a bound sand mold can be even when used with cast iron.
The sodium silicate I use is mix with the sand in a mixer, but it could be mixed in a muller too, and one of those mini-mullers would be ideal for this application.

Other benefits of bound sand are that you can cut the sprue and riser holes, runners, gates etc. after the sand has hardened if desired, and this is handy for trying out a runner and gate shape before you make a permanent pattern. A wood rasp bit in a tool and die grinder makes quick work of carving the bound sand.

 

Here is a nice book I found for sale as a reprint on ebay a few minutes ago, about molding machines. I have never seen this book before.
It has some good illustrations in it.
https://archive.org/details/cu31924004586230


And I stumbled across this page while searching for foundry books.
There is a list of foundry books on the left side, and it looks like any of them can be downloaded in pdf form.
This may be a duplicate of some that have already been mentioned above.
https://catalog.hathitrust.org/Record/009577209

One of the books on the link above is the same one that is for sale on ebay, which is "Foundry Molding Machines and Pattern Equipment".
I just downloaded the pdf file from here:
https://babel.hathitrust.org/cgi/pt?id=loc.ark:/13960/t9s18st1j;view=1up;seq=11
The pdf download takes a few minutes, or you can just browse it online.

 

I don't think I have ever seen this foundry book either:
https://babel.hathitrust.org/cgi/pt?id=loc.ark:/13960/t9z03z78p;view=1up;seq=1

 

I agree possibly not for the hobbyist. If you are making aerospace or automotive casting his approach starts to make sense. Parts subject to fatigue and high loads can benefit from reduced oxides.

I own the Handbook and it is really three books merged into one, the same info comes up in different chapters, it is a tough read, no one page summary.

Basically he finds that oxide films in metal harm mechanical properties. I know this as fact from my own tensile testing, low elongations are almost always due to an oxide film or voids associated with a film

Oxides are caused by turbulent flow. The good old AFS gating system we have been all been taught for decades has a high flow rate and creates oxides.

So he favors a thin sprue which chokes off fast to prevent air aspiration (oxides) followed up by a big expansion area to slow the flow rate (water in a stream slows down when it opens up).

It really doesn't even have a name seems to be drifting towards "naturally pressurized" - I call it ribbon gating myself

The he suggests bottom fill to reduce in mold turbulence

So fill the sprue fast, then fill the cavity slow

This can make for a complicated mold for sure, getting the ingates down under the entire casting usually means another mold segment, more time and money, so the payback better be there for the effort

I am converting a series of castings to this idea with really good results - sorry can't share due to NDA

I run a small foundry and don't have access to the computer simulations, but have had good results just from eyeball engineering, I kind of copied what I see in the articles

I am not a slavish disciple, I don't use the vortex or stopper rod ideas (at least not yet), just the smaller sprue and narrower runner has been a massive improvement

Don't read this paper (unless you want to), just look at the gating system in the pictures

file:///C:/Documents%20and%20Settings/foundry/Desktop/2017-3.4%20MMP%20-%20Plunger.pdf




However you are right - for a hobby part (shape) do what's easy/fast - it will be fine, it was for thousands of years - hobbyists are not making Space X castings

Cheers

FoundryJoe

 

Anon's Foundry Tutorial guide can still be found here: http://prometheus-foundry.com/tutorial.html

 

Thanks, I was looking in the wrong place for it. Sorry.

 

I'll look yours up on the Internet Archive and have a look. I just discovered the book called "The Pocket Ref" https://sequoiapublishing.com/ and bought a copy online.