The International Hobby Metal Casting ezine.
Brought To You By:
Col Croucher, administrator of: www.myhomefoundry.com
Australia.
Number: 63. January 2009.
Hello Fellow Metal Caster.
Welcome to the many new ezine subscribers over the past few weeks, I hope you hang around for awhile to learn some interesting basic foundry knowledge.
To all of the Aussie subscribers, hope you enjoy your Australia Day Holiday, (Monday Jan 26th) whether you are BBQing, boating, driving in the Alps, lazing in the pool, still on holidays, watching the cricket or tennis, whatever, avagoodweekend!
I had a sudden jolt into action yesterday day when I looked at the calendar, geez I said, it's the 24th of January... already, what the hell am I going to write about for this month’s ezine I thought, well I guess I better think of something because no one else is going to do it for me, the hols and the festive season really plays havoc with deadlines and "must do" things! I just have to get in the groove again.
There's one thing I will say, and that is congratulations to the enthusiastic people who are just starting out on their metal casting journey, I am sure we will see some great things from these people later in the year when they have their mini foundries all set up and ready to go.
It is a fair while since I have had the foundry going, (Too hot in the Summer Time) I might even have to do a refresher course?? I 'm kidding you of course, it is true, that once you become thoroughly familiar with foundry work, it is like riding a bike, once you learn the required steps & methods it all becomes automatic, and if you happen to forget something important it will truly show in the castings you produce.
If you are into building special projects, or into restoration of all kinds of old things, then being able to produce your own quality castings right now is even more important, what I mean by that is that if you have to pay for things in these lean recessionary times you will be shelling out hard earned cash for things that you can really produce for a very low cost from scrap metal in your own backyard foundry.
Now there's another point I just thought of.... have you been into any scrappie yards (Scrap metal dealer) lately, do you remember not all that long ago, when they were pushing the price of scrap metal though the roof to feed the hungry furnaces in China, well things have changed since then, a lot of dealers have virtually stopped buying metal, and the bottom has just dropped out of the market.
So if you want to stockpile some scrap Aluminium or Bronze, it might be wise to start collecting & hording now, I stockpiled about 300KG some years ago, and still manage to add to the pile from time to time.
It seems our web site has even reached people in Bolivia, Ecuador etc, and other small countries, many of these people want to purchase the hobby foundry ebook package but don't have credit cards, a few have used Western Union but the fees are really too high.
If you have purchased the package but not set up your free membership subscription yet, then you better flick an email to me (Include your Pay Pal or Clickbank order number) and I will send you the sign up link.
Just the other day a new customer got a little excited and accused me of charging his credit card for the membership subscription, but we quickly put him at ease, it appears the word "subscription" immediately said (In his mind) payment deducted from credit card... he did not read the word FREE, so if you have been fooled by the same thing, fear not, you wont be charged for your MHF membership.
Huh, you want to now how to set up your membership? Learn More Here.
OK that's about it for my three-minute prattle. So what have you been up to lately, if you have some nice castings, or a foundry project you want to share, get in touch with us soon.
Col.
The woods would be very silent if no birds sang there except those that sang best.
Think About It.
Then Go Here.
Or if you are into bulk ebook deals this may be just what you are looking for:
Monster Pack.
Having Fun With Lost Foam
Casting.
Foam balls
glued together.
Foam pattern embedded in dry
sand
Casting Shake Out From Dry
Sand.
Completed
Aluminium DNA Tree Casting.
Occasionally an email arrives at the foundry inbox with someone asking about lost foam casting, this method of producing foam patterns for castings is widespread in the foundry industry. so it is only natural for the home hobby foundry worker to adopt the method also. I can’t say that I am a great fan of the process, but I also know that there are plenty of least foam enthusiasts who wouldn’t cast any other way.
The photos you see on this page were taken in the foundry one-day way back in 2007, crikey that's just so long ago, or is it?
This little story began when I accompanied my lovely wife to Spotlight, a large craft store (group) here in OZ, they stock a gazillion little things, many of which can be adapted to hobby foundry work, while cruising around the shop & just eyeballing things, my mind clicked into gear when I spotted some bags of styrene balls of different diameters, I grabbed a bag to purchase, and the good wife queried my interest, cant tell you right now dear, take too long to explain to you... explanation accepted, and we cruised on over to the check out.
A few days later I stuck the smaller foam balls together with woodwork glue (PVA) and made a longish column, which was then glued to a half round base made from one of the largest foam balls, can you see what I am making here I asked my wife?... No came the answer, what the dickens is it? She asked.
Me with my warped sense of humour said, "some kind of DNA gone wrong", what the... she said, and before she could say anything else I said, "wait till you see the casting" How the heck ya gunna do that? "Show you in a while" I said.
The Simple Process:
First I grabbed a large old steel crucible I had made a long time ago for a pouring job, about an inch of fine DRY foundry sand was placed in the bottom, then the DNA tree was held upside down (By the base) and more dry sand was poured into the steel crucible. Note: A large jam tin or bucket would also do for the container.
The sand was poured in until it almost covered the raw uncoated foam DNA pattern (See photo above), the steel pipe crucible was given a few good sharp raps with a piece of wood to make sure the sand had settled into every nook and cranny, after carefully brushing grains of sand away from the top of the pattern base, it was now ready to accept some molten metal, and set aside while the gas fired furnace was prepared and lit in readiness for the melt.
The amount aluminium metal required for the pour was not a lot so it did not take long to melt; now I don’t do much foam casting for one simple reason.... I hate the bloody smell of the toxic fumes, you need a well ventilated area, or do it outdoors, although your neighbours over the fence might wonder what the blazes you are up to when they get a whiff of the burning foam.
OK, so we have the melt ready to pour, ideally a large collar should be placed around the top to make sure all of the metal is going to go where you want it, but I did not have time to do that,
so the crucible was upended pretty quickly right in top of the foam pattern base, and I just kept on pouring, and the metal just disappeared down the hole... amazing, then suddenly the cavity was filled, the excess of metal was poured from the crucible into the ingot mould, and I adjourned into the kitchen to tell the wife the DNA tree was poured, and she will be able to see the results after we have a cuppa.
There is one great thing about the shake out process with foam casting...there virtually isn’t any, you just up end the container of dry sand and tip it all out and the casting will end up resting on the sand... keep your fingers off, otherwise you will burn them, the metal takes a while to cool down.
So what have we got, (See photo above) a damn near perfect reproduction of the foam DNA gone wrong tree, with a couple of deformed bits on the top, ah well I guess my DNA aint what it used to be. What do you think, do you like my simple art casting? I reckon it is pretty cool.
The most time consuming part of the project was gluing the foam balls together, the preparation of the dry sand mould took only a few minutes. Does this technique have an application in the hobby foundry, you betcha it does, in the future when I want to make a quick one of a kind casting, the foam pattern making gear will come out for sure. And I will just have to put up with the stink!
You might be wondering about the foundry sand employed, this is a normal fine grade washed foundry sand as used in the cold set or Co2 moulding system, I actually bought a small qty from a commercial foundry situated not far from me. Warning: Do NOT USE MOIST SAND with this method.
So if you want to have fun and experiment a little, you can use various coatings on the foam to improve the casting finish, in fact, I believe that a good finish can be achieved that can almost match that of investment casting finishes.
It is also amazing to wonder why the dry sand does not collapse in while the pouring process is happening, my guess is that as the foam melts or vaporizes, a fine sticky substance is left on the grains of sand which binds the sand long enough for the metal to enter the mould and space and not go out of shape, in other words the metal will support the sand, imagine if you could video the process as it happens in slow motion.
Enjoy the fun but be careful next time you are in the foundry.
Col.
Trust the comming year will be both productive and satisfying for you, regardless of the doom & gloom that has descended upon the globe. There is one great thing in your favor, you can still build, repair and keep the wheels turning with your practical skills, perhaps even use your skills to create some ready cash, don't be drawn into the negative attitudes that most people have adopted, no matter what happens in the world, there is always an opportunity.