Wednesday, April 13, 2011

[Lantz's Corner] Casting Tutorial Part 2

My Part II Is Equally As Epic

Welcome back. If you haven't already read Part One of my casting tutorial, you're going to be quite lost on this post. So head back and fill yourself with knowledge of rubbery things and come on back. Don't worry, I'll wait for you...Okay, we good? Fantastic. In Part Two we're going to take a look at getting your rubber mold to duplicate all of your little plastic thingies, and hopefully save some time and money in the process. Even more-so with this part of the tutorial, I suggest reading the whole thing before attempting any work as your resin mixes take a lot less time to solidify than the rubber cast. More after the break.

First, let's take a look at what we'll need. As mentioned in my previous post, for this tutorial I purchased Alumite Regular for my resin. But what about all of the other pieces? Here's a short list:
  1. Alumite A and B resin liquids
  2. Mixin' sticks
  3. 2 measuring cups
  4. 1 mixing cup
  5. Your neato rubber mold

We'll first take the A and B bottles shown above. Be sure before you take any action with these that you shake B thoroughly. Over time the bottle has a tendency to separate the more and less dense substances and if not shaken back together your resin will have odd results. For my AdMech symbol, I'm not going to need a very large batch, so I'll fill two separate measuring cups with the separate liquids bottle equally like so:
It's good to make too much resin mix rather than too little. You don't want to have to go back and fill in more resin as this can make your model a tad fragile if there's too much time in between pourings.

The next few steps I really wanted to get pictures of, but this isn't really possible without another person helping you out. And because I had just downed a bowl of chili, no one was willing to help me with this. The reason why this is so difficult to pull off is that the curing time of the resin mix is about 60 seconds. No, I'm not kidding. If you're not quick enough, you'll be pouring your mix out of the cup...and well:
No Comic Relief Intended; This Actually Happened...

So explaining in as much detail as possible, take both of your measuring cups with equal parts A and B and pour them into a larger mixing cup. From this point on, it's a race to the finish line; you have around 60secs to get things right.

Quickly and thoroughly mix your liquids together to make sure there are no "swirls" in it; so that we have a solid color of liquid. After this is accomplished, take your mold and tilt it slightly as you poor in your resin mix. This will help eliminate possible air bubbles that can occur. When pouring your mixture, I would suggest wearing latex gloves or something to that affect as this stuff can be messy. Once you've got your mold filled, it's good to have a backup mold you can pour excess resin mix into so you're not wasting any. I set aside some molds, but typically end up filling the one on the far left I created to make more bases:

Once you've got your mix in your cast, you'll begin to see the mix completely-solidifying in a matter of minutes:

For a cast to be ready to be removed, you'll need to wait anywhere from 5-15mins depending on how big your model is. I tend to wait a half hour regardless just to be safe. Once our new AdMech symbol looks ready to go, we'll remove it in the same manner we did with the original:

You'll notice I still had some issues with air bubbles on this one. I'm still experimenting on ways to eliminate or reduce air bubbles for both molds and resin pouring. But until then, we'll shave down the indentions and we'll use GS to fill in these gaps:

We now have a perfect duplicate from our original, ready to make models for the history books!

As always if you have any questions at all, feel free to post a comment or email me at Sinaura40k(at)gmail(dot)com.

TLDR Version: This whole post is the TLDR Version.

Until next time.

~Lantz aka Sinaura


  1. I've found that lightly powdering the mold with talcum powder before pouring the resin will greatly reduce the bubbles in the final product.

  2. Avoiding the "above method" when making the mold, and using vaseline or talcum powder when casting it's pretty much the key to get rid of the bubbles. And hitting the table or tilting the mould when casting. ;D

  3. not just that. Agitating the mould works wonders. You can lightly tap on the surface near the mould or you can use a cheap electric toothbrush/lolypop to get the air bubbles out. I hear blowing helps to make pressure that releases the bubbles. I am not sure if it has to do with surface tension or what not, but taping and agitation works really well. The talcum I have never used.