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This tutorial is based on how to use Smooth-on's Oomoo- and Smooth-cast series materials for cosplay purposes. There is little special too about using fiberglass instead of smooth-cast. Hope you enjoy!

Ok. Lets get started!

"I need five identically same looking parts like in that center of the picture for my cosplay but making them one by one would take LOTS of time. What to do?"

If you have the right materials then the answer is simple: "Make one sharp prototype of that piece then mold it and cast it."

Here are the materials you need:

- Modelling paste for making the prototype (or what ever material you like. It won't affect to the final product)
- Smooth-On's Oomoo 25 or 30 for making the mold (mold max 20-40 works too but it' need more skill to use. So i recommend Oomoo)
- Smooth-On's Smoothcast series for casting (i recommend smooth-cast 320 because it is easy to paint with spray paint)

(Smooth-On got lot of resellers in few countries. Here in Finland is who sells their product with good service)

1) Making a prototype

I used modelling paste and made the part by my own with modelling sticks. This takes lot of time so being patience is key to the success. And using your imagination is good thing. For example i used airsoft bb's for the edges of my piece.

This is what my prototype looked like:

2) Making mold of your prototype piece

When your prototype piece is done then starts the molding part. First you have to find the right sized cup or basin where you pour your Oomoo. Cup or basin or what ever you use as a pool is good to be 1-2 centimeters wider from every angle than the piece. When you have it then put water in it and measure how much you want to use Oomoo (usually 2-3 centimeters from the bottom is enough but it depends on how big your piece is). When you have right amount of water then put it in two cups half and half. Now you know how much you need Oomoo. Put a mark on the both cups where top of the waterline is and then pour the water off. Glue the prototype piece bottom of the cup/casin (hot glue is good for this but not neccessary).

  Now take the Oomoo's part A and part B cans and pour it to their own cups where the mark of waterlines where. When you have the right amount of both stuff then put them to the same cup and mix it well. Now slowly pour the mixed Oomoo on the cup/casin where the prototype piece is laying on the bottom. Let it pour on the one spot because we don't want air bubbles in our mold. When all the stuff is poured wait 1-6 hours (this depends what type of Oomoo your're using). When the mold is completely dry/ready take it off and wola! You have mold for the mass production.

3) Casting the mold

This is the easiest part! Measure the molds surface area with water and pour the water in the two cups half and half. Put a mark again on the top of the waterline and now you know how much you need Smooth-cast in it. Take smooth-cast's two cans (part A and -B) and put them both in their own cups where the mark of the waterline were. Now mix both cups in to one cup well. Then pour slowly mixed smooth-cast inside the mold you made earlier. Try to avoid air bubbles. Wait until it's completely solid and take it off. Now you have done it! Repeat part 3) as many times as you like.

In this picture i used Mold max instead of Oomoo as a mold material but it won't affect to final results.

4) Painting the final product

I usually paint with aerosol spray paints. I recommend it to everyone! It's easy and fast to do.

First put a primer or base coat one the pieces. You can paint 1-3 layers what ever you want. When this is done wait 15 mins or when the surface is dry. Then put a right colored "normal" paint on the pieces. Now wait 24 hours or when the pieces are completely dry.

Then you can paint or paintbrush with acrylic paint or what ever you want to make the pieces look nice. And if you don't want to glue your pieces on your cosplay then drill few holes on the pieces and sew it on your costume like i did.


(!) Special info for people who like to use fiberglass in their cosplay! If you don't know how to use fiberglass then do this with someone who knows how to do it safely.

If your piece is big like a part of armor. You can utilize this tutorial and make sharp product with fiberglass. First do parts 1-2 and then follow this special part 3 and then jump to the part 4.

3) Making final product of fiberglass

What you need next is:

- Gelcoat
- Fiberglass
- Resin
- Hardener

Mix gelcoat with few percent of hardener. Then put a thick layer of ready gelcoat on the bottom of the mold. Brush is good tool for this. (You don't need any kind of "lube wax" because product is easy to sever from the mold) Now wait an hour or until gelcoat won't catch on your hand anymore and then put a nice layer of fiberglass on it. Now mix resin and few percent of hardener together and start fiberglassing. Wait until it's dry and hard (1-2 days) then take it off from the mold. Now you should have sharp copy of your prototype and it should be very durable.

There was my first tutorial! I hope this helps someone in the future or at least gives instructions for further projects. There are few things were i want to make tutorials that not so many even know about. But maybe somewhere in the future. :D

- Jarwes
  • Drinking: Coffee
Jarwes Featured By Owner Mar 27, 2013
Smoothcast maksaa n.35€/0,86kg ja Oomoo 39€/1,27kg + postikulut = yli 80€. Siihen vielä muovailumassa, maalit ym. Pieniin osiin tämä on hyvä tekniikka, joskin aika hintavaa touhua.

Itse suosin tuota lasikuidutusta Smoothcastin sijaan, koska se on halvempaa. :D
Lirlys Featured By Owner Mar 27, 2013  Hobbyist Artisan Crafter
Ihan yleisestä mielenkiinnosta, mitä tuollaisten tekeminen oikein loppupeleissä maksaa?
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March 1, 2013


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