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Help! Moldmaking- how to mold an eel?

Kai RottmannKai Rottmann ✭✭✭
edited December 2017 in Fabrication

i am wondering, how to go with a mold for an eel like creature. 

I was thinking about a 3 part mold- one part for the face, two parts for the rest of the sculpture?

I would love to not going crazy with that mold, because its on a budget. 

The finished creature has to be able to open the mouth- that means that i have to install an underskull for the mouth mechanism. But how would it be the best to go?

It should have also: 
- a latex skin
- filled with foam for holding the shapes and make it stable

I would be very happy if anyone could help me. 




  • Chris EllerbyChris Ellerby Los Angeles Admin
    Your thoughts about doing it as a 3 piece mold sound like how I would tackle it.  Since you are casting a flexible material you should be able to cast that face with a single mold.  And that way your seam lines would be behind the head and easy to clean up.

    If you are looking to save money (and since you want to cast latex) a stone mold (ultracal 30, etc) could work for you.  Though at that size a 3 piece mold would be pretty heavy.

    I would mold the back with 2 pieces.  One for each side, so your seam line would be along the top and bottom edges and easy clean up and hide.  I'd design those 2 mold halves so they have keys for the front mold segment, so it can lock into them.

    I would put the pour spout hole at the end of the tail, somewhere that is less likely to be seen, but could be patched easily.

    Sculpt is looking great!

  • Thank you very much Chris.

    I will try that 3 part ultracal mold as you mentioned- 1 part front- 2 parts back + spout hole in the back.

    I will report here about what happened xD

    Very happy, that you are here for us :-)


  • For the most part, I agree with what Chris said. Except, I would mould the interior of the mouth seperately. This will help allow you to detail the mouth more intricately, AND avoid some serious undercuts. Also, by doing so, you could use the mouth opening as your pour spout, without altering the body.

    Depending on how thick you want the latex skin, you might consider making the mould out of White Hydrocal instead of Ultracal-30. Ultracal-30 is very dense. Therefore, it will not create as thick a latex skin. White Hydrocal is much more porous, allowing the mould to suck up more moisture, quicker. This will in turn create a thicker latex skin. That being said, Ultracal-30 is a more durable "stone", which makes it ideal for casting foam latex, ('just not an ideal material for slip-casting regular latex). White Hydrocal on the other hand is the hardest, most durable "plaster" available. It is what is traditionally used for casting latex halloween masks.

    Now, to clarify the difference between "plaster", and "stone". White Hydrocal is a plaster, like Plaster of Paris, but MUCH stronger. Ultracal-30 is clasified as a stone, (it contains a small portion of plaster, (approx. 40% plaster), and a much larger proportion of Portland Cement, (approx. 60% Cement). The exact proportions are a trade secret, (but, this is the general jist. I know this can get a bit technical, but it is an important difference.

    In regards to the underskull, (if you'd rather avoid fiberglass & polyester resin), you might try "Worbla", which is a "thermo-setting plastic" sheet, 'favored by a lot of co-players. All you would need, equipment-wise, would be a heat gun, scissors, and maybe a box-knife. Best of all, it is very non-toxic, (unlike polyestesr resin).

    For the eyes, if you want to install them seperately, rather than have them be a cast part of the latex skin, I would recommend checking out "Van Dyke's Taxidermy". They have a wide assortment of painted, glass eyes, that look pretty good, and are very affordable. At the very least, if that does not interest you, I would still recommend getting their print catalog. It can be a great resource for inspirations, for possible paint schemes, to make your creature look more real.

    In regards to the number of mould pieces, I would think a simple two-piece mould would work well for the creature's main body, (split right up the middle, left-side & right-side). And, of course, a seperate, one piece, open mould for the mouth interior, (essentially, the mould would be kind of bowl-shaped). I would also suggest making a seperate mould for any, and all fins. (You could directly model the fins onto the finished puppet. But, if you intend to make more than one casting of your creature, moulded fins will allow better consistancy.)

    Keep up the good work. It looks like it has a lot of potential!

    -Jeffrey Warren Park

  • Thank you very much for that detailed answer, Jeffrey :-)

    I will try that what you mentioned. 

    I would love to get Hydrocal, but here in germany i have no chance to get it.
    Only ultracal 30, which i have to order from a shop in the netherlands :-(


  • 'My appologies. I made the assumption that you were located in the USA.

    Unfortunately, I don't know much about the plasters & stones available in Europe. I believe there is a close equivalent to White Hydrocal, in Britain, called Crystacal. It may be worth contacting some of the suppliers there. They would be able to give a better answer to what you can find, closer to where you live. Also, you might want to contact Kryolan. Being based in Germany, even if they don't carry what you need, they should definately be able to refer you to more local resources.

  • Thank you very much, Jeffrey. 

    I will look for that Crystacal. I have found datasheets for the strenght and its really close to hydrocal.

    Thanks again^^


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