I have to make 4 copies of an engine from a Buck Rogers Starfighter for my XJ and was wondering. Would it be okay to do a one-piece mold poured in from the top (fuselage side of engine), or a 2 piece mold? I've only just cast small 1 piece molds before (TIE engines) and am apprehensive about a 2-piece for a round shape.
Any thoughts?
casting question
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Lonnie Sweet
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casting question
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Stu Pidasso
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I Gooooooooogled the images and if it's the main engine thrusters you're talking about, here's what I would do if I were to cast them. I'd use a one piece mold, but I would "jeweler's" cut the mold to ease extraction. Here's a quickie tutorial.
Do your one piece mold with RTV, after curing, take a FRESH ULTRA SHARP exacto blade and cut into one side of the mold, alternating directions, the more edges the better. This pic is kind of what I mean. The rough edges mean it gets a better grip and less slip than a regular straight edge would, less chance of misalignment. When you get to the inside edge of your mold (the part that meets the master) try to cut down along the edges of any detail on the master (like panel lines, raised edges, etc.) that way, most of your cut will be hidden, less flash!
Rubber band your mold (but not too tight!) and pour your resin. After curing, peel away the one side you cut, and you should be able to pull your part out.
Do your one piece mold with RTV, after curing, take a FRESH ULTRA SHARP exacto blade and cut into one side of the mold, alternating directions, the more edges the better. This pic is kind of what I mean. The rough edges mean it gets a better grip and less slip than a regular straight edge would, less chance of misalignment. When you get to the inside edge of your mold (the part that meets the master) try to cut down along the edges of any detail on the master (like panel lines, raised edges, etc.) that way, most of your cut will be hidden, less flash!
Rubber band your mold (but not too tight!) and pour your resin. After curing, peel away the one side you cut, and you should be able to pull your part out.
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A two piece mold isn't really that hard. There are plenty of resources on the internet with easy ideas, such as substituting mold release with vaseline (a product that may already be in your home). Why not expand your skills and try a two piece mold? It may start a new era in your model making.
TazMan2000
TazMan2000
Thanks JimiStu Pidasso wrote:I Gooooooooogled the images and if it's the main engine thrusters you're talking about, here's what I would do if I were to cast them. I'd use a one piece mold, but I would "jeweler's" cut the mold to ease extraction. Here's a quickie tutorial.
Do your one piece mold with RTV, after curing, take a FRESH ULTRA SHARP exacto blade and cut into one side of the mold, alternating directions, the more edges the better. This pic is kind of what I mean. The rough edges mean it gets a better grip and less slip than a regular straight edge would, less chance of misalignment. When you get to the inside edge of your mold (the part that meets the master) try to cut down along the edges of any detail on the master (like panel lines, raised edges, etc.) that way, most of your cut will be hidden, less flash!
Rubber band your mold (but not too tight!) and pour your resin. After curing, peel away the one side you cut, and you should be able to pull your part out.
I'm interested in this technique as well.
My concern is
accidentally cutting into the master itself when digging into the rubber. Any advice on how to avoid doing that?Thanks
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I agree. Once you know the trick about diluting vaseline, and getting a proper clay (not playdoh) you can easily make a two part mold. The parts of interest are not that big. So no heroic efforts to suspend the master to get the first half of the mold, or creating a special plug to cut down the thickness of the casting, are not needed for this discussion.Kylwell wrote:It's easier.tetsujin wrote:I've never actually made a mold this way - I always pour one half and then the other. Any advantages to pouring the whole thing in one pass?
To my knowledge, nothing beats a properly clayed up set of molds.
WWW.YOUTUBE.COM is your friend. Just look up casting resins, or making a mould. They'll show you the eaisest way to do it. I use a wooden box with the part inside. This is deep enough to put two parts in so that once you have the first mould made you can brush vasoline, or petroleum jelly over the rubber to keep the two from imbedding the parts. After the first half of the rubber has cured, you can use the mould release, then add more rubber to make to parts. This will make it a lot easier do. You'll want to remember to seal your box if you use wood. I brushed lacquer over it to make a seal. This keeps the rubber from sticking to it. It won't stick to polystyrene or resin. I only sticks to itself, or porous surfaces. I hope this was in time enough to help.
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Mark Yungblut
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Lonnie, I have to agree that the best route is a "keyed" two part mold. The problem with "jeweler's cut" molds is they can (with little effort) slip and get out of register. I used to use jeweler's cut molds all the time in my jewelry business, but towards the end we switched to keyed molds as it allowed me to choose where my seam would be not leave it to luck. An added benefit was not having to worry about cutting the master.
Most modern jewelers are switching to RTV two-part molds to make their waxes these days.
Most modern jewelers are switching to RTV two-part molds to make their waxes these days.
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