The International Hobby Metal Casting ezine.
Brought To You By:
www.myhomefoundry.com
Australia.
Number: 85 - December 2010.
Christmas is nearly upon us once again; it is incredible how it rolls around so quickly each year. I wonder if that's because we are so busy and involved with family - work - hobbies etc, that we don't seem to notice the months ticking by, it really is important to make the most of each day.
But, on the other hand, we all get those days that never seem to go right... your carefully prepared plans are wrecked, things get thrown into disarray... what do you do when that happens?
I guess it really depends on how you can handle stress, if you are the type of person who likes everything to run like clockwork, it can be tough when something comes along to throw everything out of whack, it can be quite upsetting and you end up getting into a bit of a frazzle.
I've had those rotten days also, but a sports exercise workout can help on days like that, yes, there is nothing like a hard physical workout involving your favourite sport to take the anger and anxiety out of the system... my personal favourite is road cycling, been involved with it for many decades, riding a bike is pure freedom, it is a low impact sport, and does wonders for your body & health... swimming has the same benefits.
Exercise also helps to keep the brain alert... and that can be mighty helpful when bogged down with a problem your trying to solve. OK enough of sport, exercise etc, I'm probably making you feel tired.
And as you would realize, this is the last ezine for the year, I hope you have enjoyed the ezine throughout the year... yes we missed a couple of issues... due to....yes, my plans were thrown out of whack!
Anyway maybe you will find the contents of this eazine a springboard to launch your new hobby foundry, or to begin exploring new avenues if you are and old hand at metal casting.
Col.
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Fun With Lost
Foam Casting.
Styrene foam pattern.
Pattern
embedded in the sand.
Shake - Out & The Result Of The Pour.
The Al casting
after
a light polish on the wire buff. The original pattern had
eight foam balls,
the casting only has six well formed balls - What happened? The First correct
answer sent to us will collect a FREE
Pattern Making ebook - Valued at $27.97.
What is your dream?
I'd be willing to put on a dollar bet that everyone involved in hobby metal casting has a dream or vision of something that they would like to create from molten metal. Yes, even I had a dream of casting something in metal several years before I becoming involved in the hobby, but unfortunately the dream never materialised due to the lack of knowledge and techniques required to begin exploring the art of metal casting, that was about twenty years ago, foundry work was relegated only to thoughts in my mind at the time. But then, a couple of years later, something clicked and the learning began in earnest.
The Realization Of Your Dreams Won’t Happen In An Instant!
The world we live in today is an instant coffee world. We are conditioned from Childhood to expect things to just happen with the snap of the fingers, unfortunately when we are forced to take a reality check, we suddenly find that the "instant wish" doesn’t happen, it’s not quite like that in the real world.
Often I get emails from people who have just begun hobby metal casting, they want to know how to cast automotive cylinder heads, or they want to know how to cast a small engine block! Hey, there is nothing wrong with having a dream or vision, without a dream many things wouldn't happen. But a more realistic approach is required; the aim should be to take up the challenge to create simple objects first, lay a solid foundation in the basics, and use those skills to advance you toward your goals and hopefully help to make your future metal casting dreams come true.
Dont be afraid to begin your dream... but conquer the small things first, treat the small things as your base camp where you begin your climb to success, and when the small things have been conquered, you'll be able to quickly move forward and your confidence level will grow enormously; you’ll get to learn many of the skills which you can use to apply in the future to the bigger things (Or the BIG dream) you eventually want to create.
It may even take several months, maybe a year, to build the required skills and confidence to finally take on that project you've set your heart on from the beginning. I can tell you from personal experience that attempting something beyond your skill and knowledge will only lead to disappointment, heartbreak, and deep thoughts of giving the hobby away.
I'm sure this happens to a some people, and yes, problems can rear their ugly head at times, and the sole hobby worker will find it difficult to discover the right answer, (A coach or mentor could be of great value to you)) but often with just a little more practice, trial and error, the answer can be found. And when you do find the answer; make sure that you write down plenty of notes about the method or technique for future reference, so that you can repeat the particular process or technique again at a later date.
Keep the dream alive by constantly working towards your goal, remember; that each little step you take will lead to bigger steps, bigger successes, and that of your future success, it is never too far away. And that about sums up hobby foundry journey! I hope you can keep your dream project alive.
Fire Brick For Furnace Use.
A Firebrick or refractory brick is a block of ceramic material used in the lining of furnaces and kilns. A refractory brick is built primarily to withstand high temperature.
This does not usually accompany resistance to heat flow; in fact, most refractory bricks usually have the highest thermal conductivities. This is logical, as thermally related fractures are caused by tensions within the mass of the material. In turn, these fractures are caused by different degrees of dilation within the mass; these varying degrees are caused by different degrees of heat being absorbed by thermally non-conductive materials.
Using a thermally conductive material negates the whole causality chain presented here by allowing the material to absorb heat uniformly, thus dilating uniformly and avoiding the internal tensions, which lead to fracture.
It is important for refractory brick to have a high resistance to erosion by ash-laden gases and to the fluxing action of molten slag; it should not spall badly under rapid temperature change, and its structural strength should hold up well under rapid temperature changes.
Fireclay is baked in the kiln until it is partly vitrified, and for special purposes may also be glazed. Firebricks usually contain 30-40% aluminium oxide or alumina and 50% silicon dioxide or silica.
For bricks of extreme refractory character, the aluminium oxide content can be as high as 50-80% (with correspondingly less silica), and silicon carbide may also be present. The standard size of firebrick is 9 x 4.5 x 2.5 in. (228mm x 115mm x 64mm).
Metal Art.
Metal Art can take many forms, some of the most imaginative is what's known as Found Metal Art, IE, taking scrape metal as it is found and using your imagination to make something symbolic from your found metal, most art galleries have examples on display, it never ceases to amaze me the things that metal artists create.
Another type of popular metal art takes the form of laser or plasma cuttting of plate steel into all kinds of different shapes & objects, this art form is a very popular and sought after art form.
Many hobby foundry people are also now exploring the field of metal art, and I would encourage you to begin exploring the beautiful natural shapes that can be formed by pouring molten metal into various shaped cavities in sand, the more you experiment the more things you will come up with, let your imagination run wild. To give you a few different slants on the idea (Do not copy) visit the web sites below:
http://www.artisanmetalshop.com/
http://www.americanmetalartsstudios.com/
http://www.ironaccents.com/
What Is A Good Crucible?
Melting of metals is serious business for the backyard metal caster, your personal safety & well-being could be in jeopardy if you choose to use poorly made crucibles.
Not everyone involved in foundry work, possesses the necessary welding skills to enable the fabrication of reliable steel crucibles. In the beginning the novice hobby foundry operator often chooses steel crucibles mostly out of financial necessity, or perhaps they have seen pictures of makeshift crucibles made by others.... steel crucibles can be quite OK if they are constructed and skilfully welded together, a good-sized melting pot can be easily made in the home workshop for next to nothing.
But there are shortcomings with steel crucibles.
The fierce heat & hostile environment of the gas-fired furnace promotes the destruction through corrosion of a mild steel crucible, I know this from experience, having used a steel crucible during the start up phase of metal casting, the steel melting pot was certainly an attractive proposition financially and also due to the ease of which one can be quickly obtained. But, the shortcomings were soon apparent.
The biggest drawback with mild steel crucibles is that of corrosion, which happens naturally when steel is heated to a high heat and allowed to cool, flakes of rust or iron oxide will peel off the internal & exterior walls of the crucible every time it is placed in the furnace for a melting session.
Rust and scale can be removed from a cold crucible if it is hit sharply with a hammer, or a short length of steel rod, the scale will fall away, but a small quantity will remain and it will most likely dislodge during the melting session and fall into the melt.
At the end of the session it is put aside to cool & corrode.Any rust flakes that end up captured in the molten metal (Slag inclusions) and subsequent castings will make the machining operation almost impossible to carry out.
The time that a steel crucible is idle between melting sessions could be be anywhere between one to four weeks duration, this standing period is the time when heavy corrosion takes it's toll on a steel melting pot.
Graphite/zircon coatings can be applied to the inside of the crucible to helpreduce corrosion, but it will continue to be a problem for the simple fact that corrosion is a natural oxidation reaction of iron & steel when exposed to the atmosphere & also to the furnace atmosphere.
Over a period of time small pinholes will begin to appear in the walls or the base of the crucible (if the base is of a thin section), this pin holing action is potentially dangerous to the user, a pot full of molten metal that
suddenly begins to leak while transferring from the furnace to the pouring shanks, could easily spill onto your legs & feet, inflicting serious personal injury. This is not the kind of thing you want to have happen on a weekend, or at any time for that matter.
Personal safety does NOT have a price. there are no compromises. Silicon carbide crucibles are not cheap, but with proper care they will last for many years, perhaps as much as seven years.
Crucible longevity will more than repay you with safe melting practices and an assurance that your foundry melting session is not marred with accidents & interrupted due to faulty or improperly constructed equipment.
It is a difficult decision for the hobby foundry worker who is generally on a tight budget and is always anxious to get the new foundry up and running sometimes even before all of the proper tools & equipment have been acquired or built.
.
My advice to any one keen to start hobby foundry work is not to be too impatient, take your time to build the best equipment, tools, etc that you can, and concentrate on getting everything set up, do some experimenting and carry out a practice session before you choose to carry out a full melt session.
Hobby metal casting is a highly rewarding metal craft, the simplicity of the art quite often just amazes onlookers as they watch an experienced operator convert chunks of worthless scrap into valuable metal items which are created by pouring molten metal into simple green sand moulds... the things that can be created with the art of foundry are limited only by your acquired skills & imagination.
Now, go enjoy your foundry over the Christmas New Year Holiday.
But keep it safe.
Merry Christmas & a Prosperous, Healthy, New Year To You.
Thank you so much for your support over the past year.
Col Croucher.