| Success or otherwise in your hobby foundry will | | | | is jelutong, this timber comes from the Philippines, I |
| depend to a large degree on your skills & ability to | | | | don't know whether it is from plantation timber, or |
| create simple patterns, i.e. | | | | old growth forests, but it is great to turn on a lathe, |
| Patterns that are easy to mould, lift or separate | | | | or shape and carve with sharp hand tools.Some of |
| from the sand | | | | the other pattern timbers in use are cherry wood, |
| mould after a gentle rap.A pattern that has incorrect | | | | mahogany, maple, white pine, and many others.Quite |
| draft on vertical surfaces, badly finished corner fillets, | | | | often a master pattern can be made from timber, |
| or a pattern that has not been finished to an ultra | | | | and then a replica mould is made using RTV 585 |
| smooth finish will be difficult to work with.Pattern | | | | silicone, this is a quick method to remake replica |
| making is an art in itself, pattern making | | | | production patterns.The replica patterns can then be |
| apprenticeships take around three or four years to | | | | mounted onto a match plate along with the runners |
| complete, before you are given your "Trade | | | | & gates, this method will enable you to mould & cast |
| Ticket".The average hobby foundry worker most | | | | multiple parts at the same time.With a little practise |
| likely won't have the time, or the patience to get | | | | you will soon know enough to make reasonable |
| involved with the art of pattern making to that | | | | quality patterns that create good sand moulds.There |
| extent.But the basic skills are worth the effort to | | | | is one important pattern making tool that will make |
| learn, because | | | | you wince when you purchase, but it is an important |
| without them you wont get far with your hobby | | | | tool to have if you want to make accurate patterns |
| foundrywork, unless you PAY to have all of your | | | | where shrinkage rates are concerned.The tool is the |
| patterns made for you, but that would take all of | | | | "Pattern Makers Rule", this is a ruler about 500mm |
| the fun out of it, and also cost you a sizeable | | | | (20")long. Made by Rabone Of England. No B5. And |
| amount of money.Construction costs of professional | | | | the graduations are marked as: 1/30-1/40-1/60-1 |
| pattern making can vary from a few hundred dollars | | | | 80,The graduations represent the amount of |
| for simple patterns, up to several thousand dollars for | | | | shrinkage allowance for different types of metals. |
| complicated pattern designs.I happen to a know a | | | | The pattern makers ruler provides a built in shrinkage |
| pattern maker who designs and builds patterns & | | | | percentage, which means you don't have to calculate |
| core boxes to make alloy & cast iron cylinder heads, | | | | the final measurement or size of your pattern, you |
| it is not unusual for pattern & core costs to be | | | | simply take your measurement from your shrink rule, |
| around $20,000.00 AU before you even think about | | | | and transfer the measurement to the pattern being |
| melting & pouring any metal.If you are a legacy of | | | | made.The system is quite clever in the way it's all |
| the old tech school system of the sixties | | | | been calculated.For a quick example, the 1/30 scale |
| & seventies, there is a good chance that you still | | | | measurement seems to give |
| remember how to skilfully use woodwork hand | | | | the correct result with patterns used for cast |
| tools.Some of the finest foundry patterns were | | | | aluminium items.Machining allowance on specific parts |
| made using basic hand tools. More than likely you still | | | | of a given pattern may also need to be considered, |
| have a chisel set tucked away in a drawer, or a | | | | generally your own judgement can be used to judge |
| spoke shave, wood plane & handsaw, plus | | | | that.Pattern making can be quite a challenge for the |
| a host of other tools that could be used to make | | | | hobby foundry worker, but once you learn the basics |
| excellent patterns in the home hobby shop.And if | | | | and develop your skills, with a little practice your |
| they happen to be a bit rusty, then get them out | | | | patterns will get better and so will the overall casting |
| again and bring them back to life, re-grind the cutting | | | | quality.If you intend on making lots of patterns, the |
| edges and hone | | | | investment in a shrink rule is well worth the |
| them with an oil stone.Remember what your trade | | | | money.And while you're at it buy a good book on |
| teacher always told you; "sharp tools | | | | pattern making, it deserves a study all on it's own, |
| give the best results."Do the same with the wood | | | | but it forms an integral part of foundry work, and |
| plane and any other tools, such as a small set of | | | | because you're the boss of your own workshop, you |
| carving chisels you could use to carve intricate | | | | have to learn to wear the hat of the pattern maker |
| shapes in wood.You'll need some good pattern timber | | | | & that of the sand moulder & founder.Sounds like a |
| or lumber as it's called in the states... doesn't matter, | | | | whole lot of work doesn't it, but you'll soon learn |
| it's all wood isn't it. There are many types of timber | | | | what will work best for you. Spend the time to learn |
| suitable for pattern making, but, you'll probably be | | | | all you can, and you'll be rewarded with encouraging |
| limited to what's available in your area or region. | | | | results.Col Croucher.To find out more about hobby |
| Quality pattern timber is expensive to buy, so ask | | | | metal crafts and how you can employ |
| for off cuts at the local timber merchant, which you | | | | the methods & techniques to build & create your |
| may get for a considerable discountYou'll be looking | | | | own unique projects, visit our web site to download |
| for a soft timber that doesn't splinter, has a straight | | | | a free ebook to begin your understanding of foundry |
| grain, is easy to work or carve, and finishes to an | | | | metal craft. This article is available for ezine publishing |
| ultra smooth finish.One of the easiest timbers to use | | | | as long as reference is given to the source. |