Type of Wood for Pattern Making
- Thread starter Terryt
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HI Terry
Im new to this myself but personally I think the best wood would be Butternut or Basswood. Unfortunately they tend to be on the expensive side. The most common woods used in foundry pattern making are Mahogany and Pine. Both are easy to work with available everywhere but the cost of pine is much lower. Another advantage with pine and mahogany is when it comes time to do the pour its easy to calculate how much metal to melt. With the small stuff Im messing with this doesnt really come into play but no one wants a short pour.
From the US Navy Department Foundry Manual. http://www.hnsa.org/resources/manuals-documents/single-topic/foundry-manual/ A riveting bed side read.
"CALCULATION OF CASTING WEIGHT"
Another simple method that can be used in cases where a small pattern of solid wood construction with no cores is to be used consists in weighing the patterns and multiplying this figure by the following:
For steel 17.0
For cast iron 16.5
For bronze 18.5
For aluminum 5.0
For lost foam you basically have 2 choices. The white stuff thats made up of little beads and used to pack everything, and the blue or pink ridged foam thats used for insulation.
The white stuff burns out ease but you get an impression of the beads on the casting. Ive read that you can improve the finish by giving your pattern a wash with thinned down drywall compound but Ive never tried it. As for where to get it, well they use it to pack everything. Your thinking of how much youve thrown out aren't you . . . me to.
You can probably buy it in sheets but remember this is a waste product. If you ask around at home electronic shops and the like they will probably have some.
The pink and blue ridged insolation can be bought at any home improvement store but a little pricey (24 x 96 x 1.5. $32.09 Home Depot). If you don't want that much or would like some for free, go around areas where they are building new houses. They will always have cut offs around and some municipalities actually charge more for it if they have to take it to the dump. If you hanging around constructions sites anyhow how about some of that scrap wood?
Have fun and be careful
Im new to this myself but personally I think the best wood would be Butternut or Basswood. Unfortunately they tend to be on the expensive side. The most common woods used in foundry pattern making are Mahogany and Pine. Both are easy to work with available everywhere but the cost of pine is much lower. Another advantage with pine and mahogany is when it comes time to do the pour its easy to calculate how much metal to melt. With the small stuff Im messing with this doesnt really come into play but no one wants a short pour.
From the US Navy Department Foundry Manual. http://www.hnsa.org/resources/manuals-documents/single-topic/foundry-manual/ A riveting bed side read.
"CALCULATION OF CASTING WEIGHT"
Another simple method that can be used in cases where a small pattern of solid wood construction with no cores is to be used consists in weighing the patterns and multiplying this figure by the following:
For steel 17.0
For cast iron 16.5
For bronze 18.5
For aluminum 5.0
For lost foam you basically have 2 choices. The white stuff thats made up of little beads and used to pack everything, and the blue or pink ridged foam thats used for insulation.
The white stuff burns out ease but you get an impression of the beads on the casting. Ive read that you can improve the finish by giving your pattern a wash with thinned down drywall compound but Ive never tried it. As for where to get it, well they use it to pack everything. Your thinking of how much youve thrown out aren't you . . . me to.
You can probably buy it in sheets but remember this is a waste product. If you ask around at home electronic shops and the like they will probably have some.
The pink and blue ridged insolation can be bought at any home improvement store but a little pricey (24 x 96 x 1.5. $32.09 Home Depot). If you don't want that much or would like some for free, go around areas where they are building new houses. They will always have cut offs around and some municipalities actually charge more for it if they have to take it to the dump. If you hanging around constructions sites anyhow how about some of that scrap wood?
Have fun and be careful
Important criteria are: cost, stability (low seasonal movement), ease of working to fine limits (requiring a straight, fine grain and not being too hard), and, for large patterns, low density.
Durability is important in terms standing up to handling, but resistance to bugs and fungi is less important as the finished pattern will tend to be kept dry.
White pine and mahogany are traditional, and jelutong is also very good, as it is quite soft and has a very homogeneous structure, and is light. Good quality ply is useful as is MDF, but that can be too woolly in the middle of thicker sheets.
An example of woods you would not want to use is oak. It is relatively coarse (and sometimes wild) grained, heavy, hard, and moves a lot.
Durability is important in terms standing up to handling, but resistance to bugs and fungi is less important as the finished pattern will tend to be kept dry.
White pine and mahogany are traditional, and jelutong is also very good, as it is quite soft and has a very homogeneous structure, and is light. Good quality ply is useful as is MDF, but that can be too woolly in the middle of thicker sheets.
An example of woods you would not want to use is oak. It is relatively coarse (and sometimes wild) grained, heavy, hard, and moves a lot.
imagineering
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You might like to check out the Synthetics designed for Pattern Making, Cibatool & Renshape are two names that come to mind.
