Help with a Pattern

[Jammer]

I posted this a while back on AAnother forum, I got some good info but wondered if anyone else has any insight.
I tried to mold this in greensand and had some draft problems around his arm and the crucible. Is there something that I can fill these areas with so I get a clean pull and that I can remove from the original so I can give it back to the owner in the same condition I got it? If I can get a couple good Aluminum casts then I can send some off for pattern exchange to match the belt buckle. The original may have been cast in lost foam. We can remove the "General Casting" and put whatever we want on the front.
This guy says he has a whole box of little crafty castings like this, so maybe I can borrow some others.
I don't know, I've had this one for over a year so he may not lend me anymore.

[Harry]

What we need is for one of us to build a 3d scanner then I could cut patterns like that for passing around. Makes changing the letting easy too. I saw one a long time ago that used milk. You put the object in a dish and pour some milk in and take a picture, little more milk and another picture ect until you get to the top then the software puts them all together into a 3d image.

Then there Davids Laser Scanner and software which uses a bar code scanner and looks awesome.

This sure dont help with your question though does it

I would think caulk though would do the job for you and be easy enough to clean off especially if there is just a little here and there that needs fixing. The other option would be to make a silicon mold and a wax from that. Then you could do whatever you wanted to the wax without hurting the original.

If anyone ever comes across a 3d file for an image like that I would love to have it.

[dallen]

I think that Harry has the right idea of making a mold from silicon so that you would have a master of the original then pour it in wax then make any changes to it that would be needed for casting in sand, from the picture it looks like that one was casted in sand.

[Jammer]

I saw that milk trick a long time ago, not really sure how they trasferred the info to g-code.

I thought of doing a silicone mold and back it with Plaster of Paris, I may try some caulk first though.

[Nudge]

Could you put some wax into the areas that have - draft?.... Then try the green sand and or the silicone
If and when you get it done I would love a copy of it

There are a few programs that do image to gcode out there, I have had a play and found black and white pics work best.

[F.C.]

I posted this a while back on AAnother forum, I got some good info but wondered if anyone else has any insight.
I tried to mold this in greensand and had some draft problems around his arm and the crucible. Is there something that I can fill these areas with so I get a clean pull and that I can remove from the original so I can give it back to the owner in the same condition I got it? If I can get a couple good Aluminum casts then I can send some off for pattern exchange to match the belt buckle. The original may have been cast in lost foam. We can remove the "General Casting" and put whatever we want on the front.
This guy says he has a whole box of little crafty castings like this, so maybe I can borrow some others.
I don't know, I've had this one for over a year so he may not lend me anymore.

Hey Jammer... send me your address and I'll send you some algenate powder... it's what dentists use to make teeth impressions in people's mouths. It's super easy to use... just add water and stir till it gets about the consistancy of pancake batter. Before hand, though, set your object in a small bowl that it will lay flat against the bottom and have minimal space around the exterior. Then mix your batter and pour into the space around your pattern allowing the algenate to flow towards the pattern, engulf it and rise above (this will minimalize any potential for air bubbles to get attached to the pattern). The algenate sets in just a few minutes so don't waste time fuss'n about with the mix. Once it sets, you can flip the bowl over and your algenate mold (with pattern) will plop out. The algenate won't stick to anything. YOu can easily remove your pattern afterward.

Then, to make more patterns with the mold, use wax. First, dab the algenate mold with a paper towel to wick off any seaped moisture that tends to sweat out of the mold. When it's "visually free of moisture" pour in the wax. Just remember to do all your wax replicas within the same hour or two as the algenate will begin to shrink over night. Algenate is awesome accurate in reproducing details and will not harm your original. But you have to work it to produduce your replicas in a couple hours from the time the algenate sets up to ensure all your replicas are exactly the same in dimension.

[Jammer]

I've read about alginate, it's used for doing body molds. I didn't know it would shrink so quickly.
Thanks for the offer, I'll dropou a PM.

[Rocco]

I've used alginate, it's very user friendly, just mix with water and use immediately, no smell, no nasty chemicals. It does a very good job of faithfully reproducing detail, it's big downside and probably the reason its not more widely used is the extremely short storage life of the mold. Alginate is some type of seaweed extract, it terms of what it's like and how it works, imagine Jello only stiffer and faster setting and just like jello, you leave it sitting around it's going to dry out and crack.

I reproduced this walnut using the lost wax method, the wax model was made using an alginate mold