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Posted by Terry Mayhugh on March 18, 2006, 3:34 am
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I'm in the middle of creating a pretty complex pattern that I intend to
green sand (Petro Bond) cast in aluminum. I chose basswood for the pattern
because there is a lot of carving to do to create the organic pattern I am
making, and this is my first significant woodcarving project. Basswood seems
to be a dream to shape because it turns, carves, and sands so easily; and
there is very little grain in the wood for an excellent surface finish. Now
that I'm some 20 hours into the job it occurs to me that it might be too
soft to withstand the ramming process without being damaged, and I would
like to get at least 5 or 6 good castings from it. Now I'm wondering if I
chose the wrong material. Has anyone else any experience with basswood in
this application? I was planning to spray it with polyurethane before using
it but I'm not sure that will add enough hardness. Would an epoxy paint make
any significant difference? Any thoughts out there before I put another 20
hours into it?
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Posted by Trevor Jones on March 18, 2006, 9:22 am
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Terry Mayhugh wrote:
>
> I'm in the middle of creating a pretty complex pattern that I intend to
> green sand (Petro Bond) cast in aluminum. I chose basswood for the pattern
> because there is a lot of carving to do to create the organic pattern I am
> making, and this is my first significant woodcarving project. Basswood seems
> to be a dream to shape because it turns, carves, and sands so easily; and
> there is very little grain in the wood for an excellent surface finish. Now
> that I'm some 20 hours into the job it occurs to me that it might be too
> soft to withstand the ramming process without being damaged, and I would
> like to get at least 5 or 6 good castings from it. Now I'm wondering if I
> chose the wrong material. Has anyone else any experience with basswood in
> this application? I was planning to spray it with polyurethane before using
> it but I'm not sure that will add enough hardness. Would an epoxy paint make
> any significant difference? Any thoughts out there before I put another 20
> hours into it?
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
Terry Mayhugh wrote:
>
> I'm in the middle of creating a pretty complex pattern that I intend to
> green sand (Petro Bond) cast in aluminum. I chose basswood for the pattern
> because there is a lot of carving to do to create the organic pattern I am
> making, and this is my first significant woodcarving project. Basswood seems
> to be a dream to shape because it turns, carves, and sands so easily; and
> there is very little grain in the wood for an excellent surface finish. Now
> that I'm some 20 hours into the job it occurs to me that it might be too
> soft to withstand the ramming process without being damaged, and I would
> like to get at least 5 or 6 good castings from it. Now I'm wondering if I
> chose the wrong material. Has anyone else any experience with basswood in
> this application? I was planning to spray it with polyurethane before using
> it but I'm not sure that will add enough hardness. Would an epoxy paint make
> any significant difference? Any thoughts out there before I put another 20
> hours into it?
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
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Posted by Roy on March 18, 2006, 9:56 am
Please log in for more thread options It should hold up perfectly fine under whjat its going to endure
durjing raming. If your after a lot of detail go with petrobond.
--
\|///
( @ @ )
-----------oOOo(_)oOOo---------------
oooO
---------( )----Oooo----------------
( ( )
_) ) /
(_/
The original frugal ponder ! Koi-ahoi mates....
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Posted by Terry Mayhugh on March 18, 2006, 11:35 am
Please log in for more thread options I'm using Petro Bond and I will be casting the parts myself. Thanks for the
encouragement.
> It should hold up perfectly fine under whjat its going to endure
> durjing raming. If your after a lot of detail go with petrobond.
> --
> \|///
> ( @ @ )
> -----------oOOo(_)oOOo---------------
>
>
> oooO
> ---------( )----Oooo----------------
> ( ( )
> _) ) /
> (_/
> The original frugal ponder ! Koi-ahoi mates....
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Posted by on March 18, 2006, 3:39 pm
Please log in for more thread options 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:
> I'm in the middle of creating a pretty complex pattern that I intend to
> green sand (Petro Bond) cast in aluminum. I chose basswood for the pattern
> because there is a lot of carving to do to create the organic pattern I am
> making, and this is my first significant woodcarving project. Basswood seems
> to be a dream to shape because it turns, carves, and sands so easily; and
> there is very little grain in the wood for an excellent surface finish. Now
> that I'm some 20 hours into the job it occurs to me that it might be too
> soft to withstand the ramming process without being damaged, and I would
> like to get at least 5 or 6 good castings from it. Now I'm wondering if I
> chose the wrong material. Has anyone else any experience with basswood in
> this application? I was planning to spray it with polyurethane before using
> it but I'm not sure that will add enough hardness. Would an epoxy paint make
> any significant difference? Any thoughts out there before I put another 20
> hours into it?
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> I'm in the middle of creating a pretty complex pattern that I intend to
> green sand (Petro Bond) cast in aluminum. I chose basswood for the pattern
> because there is a lot of carving to do to create the organic pattern I am
> making, and this is my first significant woodcarving project. Basswood seems
> to be a dream to shape because it turns, carves, and sands so easily; and
> there is very little grain in the wood for an excellent surface finish. Now
> that I'm some 20 hours into the job it occurs to me that it might be too
> soft to withstand the ramming process without being damaged, and I would
> like to get at least 5 or 6 good castings from it. Now I'm wondering if I
> chose the wrong material. Has anyone else any experience with basswood in
> this application? I was planning to spray it with polyurethane before using
> it but I'm not sure that will add enough hardness. Would an epoxy paint make
> any significant difference? Any thoughts out there before I put another 20
> hours into it?