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Post by dhdesigns on Feb 20, 2019 12:45:37 GMT -5
Hello, New to the forums and definitely in need of some help with some projects. My first project I was hoping to get some advice from is molding a small figure. The figure is more so a cylinder shape and is going to be about 3 inches tall and 2 to 2.25 inches in diameter. I attached a photo to help. The problem that I already for see is the mouth. I think it would be best to print the object in two halves and cast them separately. Here is a couple pics of what I mean by that. Do you think this would be the best way of casting this object? I know the teeth are going to be tough and the larger ring on both sides. I felt that by casting separately and with the ends of the teeth being pointed down that I could get a good cast but I would have to create a funnel on the top half and the bottom of the bottom half. Let me know if you have any other recommendations. I would like to mold the object in a clear silicone so I can make sure that the casting covers all areas. I have not figured out which product I would like to try first but I will be casting the object with some sort of epoxy resin. Definitely let me know what you guys think. I look forward to hearing back from everyone. Thanks for the opportunity to try and get some help with this project. I have been scratching my head on this one for a couple weeks now and felt this would be a great place to start looking for some help. Thank you again everyone. Best Regards
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Post by Brian on Feb 20, 2019 23:13:16 GMT -5
Is there anyway that you could provide more up close pictures of the mouth and teeth....the rest of the piece looks to be fairly simple, but as you already figured out , that mouth full of teeth could pose an issue.
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Post by notoes on Feb 21, 2019 8:16:54 GMT -5
Plat 25 is currently a clear-ish formula in the fact that it cures to a frosted glass look that you can still see the item inside it. I'd recommend either the Plat series (a food grade I use a LOT) or the Trans 40 (I haven't tried this one but it looks fairly clear from the videos I've seen) as the silicone mold material.
Yup those teeth are going to drive you batty - I speak from experience, I've had to mold spiky action figure hair and it was a pain on a smaller level. At least those teeth are going to be bigger and easier to handle. As it looks like the finished top and bottom are flat so I'd cast the mold with the teeth pointing down (one half will be upside down to do this) and the pour area as a big open spot since both the top and bottom are flat (you would be pouring from these spots). This will help with being sure to get resin in all the spots and being able to get out any bubbles easier.
If you pour the cast in 2 pieces with Clear, you might have a hard time hiding the seam between them - I don't use Clear a lot and usually not in 2 pieces so I'm not sure if it be a problem or not. If this does happen, you could try doing a 4 piece mold. The top half and the bottom half would be easier to demold if you use a 2 piece mold on each and if you combine the two molds you get a 4 piece mold. Hope this helps a bit and definitely keep asking questions, we don't mind adding anything that might help.
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Post by dhdesigns on Feb 26, 2019 12:13:38 GMT -5
Hey everyone, First and foremost, thank you both for getting back to me. I really appreciate the help! Definitely looks like this one is going to be a challenge so any help is greatly appreciated. I am attaching a couple pictures of the object from top and bottom. Both sides unfortunately are not flat enough to cast from the tops and these pictures will show what I mean and give a better look at the teeth as well. As seen in the above pictures, the ring around the top and bottom go back down on the inside and then it flattens out. I was thinking if I casted from that area, I would have to make a funnel for the pour and then maybe a couple exhaust chambers that start from the top of the ring and leads up the funnel. I have never had to make the exhaust chambers before ( if that is the correct name lol) so I was thinking of using a couple tooth picks that would support the funnel and more air flow for the resin to cast around the ring. Let me know what you think. In terms of the seams, I am not too concerned with that because the piece will be painted over once glued. In terms of the 4 piece mold, do you think it would help casting the piece as a whole object (both top and bottom portions) or should I just stick with casting in two separate pieces (object split). For the silicone, that sounds terrific, I will definitely check both of those out. I have couple other projects where I will be casting with the silicone itself and coloring it once mixed up. Would either of these be good choice to use for casting as well. I haven't posted the idea yet but essentially I am trying to cast a thin tube with a bendable wire on the inside. It would be great to be able to use whatever silicone that I order for the mold making process as well as for certain objects that need to be casted and colored. Let me know what you think. Thank you again everyone. Look forward to hearing back from you. Talk to you all soon. Kindest Regards
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Post by notoes on Feb 27, 2019 11:35:46 GMT -5
Personally I'd go with the split into two molds (two piece molds themselves), it would probably be the best way to get those teeth right.Just use the split between the two parts as the pour area as it will be flat anyway. Since the bottom and top are indented between the curved edges, you'll need to add something to raise the original item so that the silicone can flow under it. I have lots of "filler" silicone from molds that didn't come out nicely so I would just use three or four little chunks to raise it up. And since they're already silicone I wouldn't worry about trying to get them out - I'd just leave them in place.
As to the silicones, be aware that the Plat series is a "platinum" cure and as such is a little "picky" about what it cures next to but those look to be 3D models so it looks like you're going to use a 3D print and I know it has no problem with those (used it on a few myself). Be careful of some clays and anything that might inhibit the Plat - the data sheet should have a list of what will hurt the silicone's cure. Resin, glass, and most plastics won't bother it in the least but for anything else, you can always test a small unnoticeable area to be sure. If it stays "gooey" after 18 hours then you can't use it on that material.
Now if you plan on painting it after casting, be sure to "prepare" the mold before casting or you'll have a hard time getting the paint to stick. You'll need to either paint the inside of the mold before casting or spray it IMMEDIATELY after demolding (as in within seconds) with a primer. Heat is what helps the resin bond with paint and the resin bonds better when the resins itself is warm from curing. Now I don't know if warming up a cold casting (cold as in after the resin has cooled to the touch) will help the bond but I have been told that painting the mold or spraying with primer as soon as you demold is the best ways to do the paint job.
Also as for the seam area between the two castings, if you plan on gluing them together there, you could use a small amount of resin instead of glue. Mix up a small amount, pour it over one of the halves where the two parts will meet, and just put the other half on top. You may want to do a little wiggle and press down a little to get the resin spread out but it works fairly well when connecting two pieces of resin. You do need to be careful that you don't get drips where you don't want them (do a careful check when you do it) but it's my preferred method of connecting two pieces of resin.
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