Metal Casting Pattern Question

Are you using green sand, or are you using petrobond? They are different. Green sand is sand, clay, and water. Petrobond is sand and a petroleum binder.
Are you doing the castings yourself or farming them out to a foundry? Fragility may be an issue if you are handing your pattern to a foundry, but likely will not if you are the one ramming up the molds. As long as you have the pattern well supported while ramming up, it will endure more than you will be willing to put to it. On the other hand, I have seen what can be done to profesionally built patterns in a foundry, and it was pretty brutal.
Petrobond will be easier to get fine detail without having to deal with issues relating to drying of the mold sand. That may or may not be an issue for you.
I have seen guys ramming up patterns for fine detail using only hand pressure to put in the facing layer of sand. Once the later layers are started then the rammer can be applied a bit more vigorously.
For your own use, boxwood should be fine. You will know where the potentially fragile bits are, and you will treat it accordingly. As you only want to get 5 or 6 good castings from it, it may even be overdoing it a bit.
Paint it with whatever you have that will leave a smooth finish to allow easy release from the sand.
Cheers Trevor Jones 222 79799 body Terry Mayhugh wrote: Are you using green sand, or are you using petrobond? They are different. Green sand is sand, clay, and water. Petrobond is sand and a petroleum binder.
Are you doing the castings yourself or farming them out to a foundry? Fragility may be an issue if you are handing your pattern to a foundry, but likely will not if you are the one ramming up the molds. As long as you have the pattern well supported while ramming up, it will endure more than you will be willing to put to it. On the other hand, I have seen what can be done to profesionally built patterns in a foundry, and it was pretty brutal.
Petrobond will be easier to get fine detail without having to deal with issues relating to drying of the mold sand. That may or may not be an issue for you.
I have seen guys ramming up patterns for fine detail using only hand pressure to put in the facing layer of sand. Once the later layers are started then the rammer can be applied a bit more vigorously.
For your own use, boxwood should be fine. You will know where the potentially fragile bits are, and you will treat it accordingly. As you only want to get 5 or 6 good castings from it, it may even be overdoing it a bit.
Paint it with whatever you have that will leave a smooth finish to allow easy release from the sand.
Cheers Trevor Jones

It should hold up perfectly fine under whjat its going to endure durjing raming. If your after a lot of detail go with petrobond.

I'm using Petro Bond and I will be casting the parts myself. Thanks for the encouragement.

Coat your project with silicon rubber and let it dry... Peel the mold off and use it to fill with epoxy mix... Let it dry and you got a tough mold pattern...
Terry Mayhugh wrote:

Coat your project with silicon rubber and let it dry... Peel the mold off and use it to fill with epoxy mix... Let it dry and you got a tough mold pattern...
Terry Mayhugh wrote:

This would be expensive, depending upon the size of the pattern. I don't even have any silicon rubber 'cause I know that I would never be able to justify using it, given its cost. As to epoxy, when I built my stripper canoe 11 years ago, it was $120 a gallon. It's not any cheaper now.
Bob

Sugar Pine was once said to be the most widely used lumber in the pattern industry. It is a very soft wood; it might even be softer than your basswood. So for your limited use I would think the basswood should do fine. Damaged is more likely to be caused by tool banging or other abuse, which would damage hardwoods and soft metals as well.