My Resin is Too Old, But It Doesn’t Matter, Because I Have Forgotten How To Cast (day 3)

I’ve run into some trouble with the mold rubber I was using to try to produce a new mold of the “spike fringe” part for the shoulder pauldron. While I wait for yet another new mold to cure, I’ve decided to find another part of the project to work on, to keep moving forward. I wound up finding some existing molds of another part and worked on casting some parts I needed from them. Unfortunately, due to the age of some of my supplies that has proved problematic as well.


My attempt to make a new mold of the shoulder spike fringe has so far had mixed results. I aborted the first attempt because I decided it was important to have a way to align the bottom surface of the part with some precision, so yeaterday I started again with the part attached to a flat styrene plate, so that when I cast the part I can use another styrene plate to form a flat back face for the part. The mold turned out OK, more or less – what concerned me was that even after more than 24 hours curing time, it was soft and very tacky to the touch. I decided to pop it in the toaster oven and see if some heat would help it cure properly. I’m not sure if it really had any benefits, but it did cause air bubbles in the mold rubber to swell up, causing some interesting (and temporary?) deformation of the mold. Concerned that the new mold might be compromised, I started again with another attempt. This container of mold rubber was previously unopened but it had been sitting around unused for a couple of years. It’s possible that it’s just gone bad and that I’ll need to buy new mold rubber. But for this project I need to make a fair number of “throw-away” molds for parts that need to be duplicated in some intermediate step of construction – so for now I’d like to use the old rubber that I have instead of buying new supplies right away.


Since that new mold is going to require at least another 24 hours to cure, and I can’t really make too much progress on the new shoulder sculpt until I have enough new cast copies of the spike fringe part, I decided to work on the forearm instead.

The next big step for the forearm part is to take the “knob” parts and integrate them into the light blue forearm part, creating something that looks more like a (standard) Zaku forearm, and then integrate the vambrace part to create the look of the Zaku FZ forearm. However, while I do currently have two of the “knobs” available, one of them is a scratch built original, while the other is a resin copy. When I do the integration I’d prefer both integrated parts to be resin copies: this way the scratch built original is kept in reserve in case I need to re-make the mold for some reason. Fortunately (given the trouble I’ve been having with my mold rubber) I still have one of the old molds I made years ago. Unfortunately I also have the resin that I had years ago…

Fortunately that wasn’t the only resin I had on hand. I checked and I also had two unopened packages of resin.. I’m not sure exactly how old they are (I tend to mark the date on them when I open them, not when I first receive them…. But it was likely no later than 2020.) so I gave one a try…

That’s no good. I have this resin another try (thinking my mixing procedure might have been the issue) but I got similar results in the mixing cup, so I didn’t waste my time trying to pour this junk into my mold. I think it’s possible that it’s just settled, and that re-mixing the contents might make this stuff usable, at least for rough jobs… But it might not be worth it. So I tried yet another package of resin…
This stuff appears to be a bit newer (mainly because the label has more references to social media links, etc.) – I don’t know the exact timing but I think I bought this stuff when I was working on the Zaku legs a few years back. I’d been working on matching up the rough forms for the left and right lower legs and got casting supplies so I could create hollow copies of the parts and use those to add details, etc. Fortunately this resin seems to behave a whole lot better than the first or second packages did. It mixed to a smooth consistency and poured nicely through the mold.

Wading through all the old, expired supplies isn’t fun. But ultimately with expired supplies it’s usually better to just trash them and move on. They’re not worth the trouble… Perhaps tomorrow I can move on to integrating the forearm parts.