Casting parts in Resin
I've worked with a lot of resin kits and parts before, but not until recently have I tried making my own parts. A few weeks back I found a nice inexpensive starter kit for resin casting and decided to give it a try.
This is the kit I found at Hobby Lobby. It provides just enough silicone to make three or four small to medium sized molds, and plenty of resin for casting. You'll run out of silicone before you run out of resin.
For my first attempt at casting, I decided to try to replicate a CIP (combat identification panel) from one of my 1/35 scale military kits. I know I'll need more of these for some of my other kits so it's a logical place to start.
I took one of my CIP panels from the Tamiya accessories set and used it as my master to pour a mold. I also made a mold for my Abrams CITV turret and a turret ring that was missing from the second Abrams kit.
The molds seemed to cast well, so I tried pulling a few parts from them. It's a little tough to estimate how much resin to use the first time, especially for a very small part. The first few had some excess resin that needed trimmed.
The CITV turret pulled well with the exception of the shield at the top, but it was easy to fix that with some styrene. Any small bubbles or flaws were filled with superglue and sanded smooth.
Satisfied with the initial results, I decided to invest in a larger amount of silicone and try making some parts of my own. I bought a one pound batch of Expert's Choice Low Viscosity molding material. It's a little easier to use as it mixes at 1:1 and I do like the dark gray color it cures to.
One thing I knew I would need to make copies of is Jersey barriers for my dioramas. I went online and found the standard dimensions, scaled them to 1/35 and printed out a template.
I cut out a cross section template to use as a guide for cutting a couple of pieces of thick flat styrene for the ends of the barrier. I cut three, but only ended up needing two. I then cut rectangular strips for the sides and starting gluing everything together with thick super glue.
Once the part was assembled, I did a little work sanding and filling seams and putting the forklift slots in the base. I didn't make it completely smooth, as these are made from concrete and I wanted some of the flaws to show up in the casting.
Once I was happy with the part, I glued it to a base and built a cardstock form around the part. I sealed the bottom edge to the base with super glue and polymer clay.I then poured the two part silicone mix into two paper cups and mixed them in another container.
It took three pours to completely fill the mold. Once it was poured, I left it to cure overnight.
The next morning, I removed the form and pulled the mold from the base. The master popped out of the mold with no problems, and I had a very clean new mold.
I mixed up a large batch of resin for pouring a single barrier. Resin is tricky stuff...it 'flashes' very quickly after it is mixed. You have no more than 5 minutes, tops before it starts to harden. It starts as a translucent amber liquid.....
And quickly starts to go opaque. The final color of the master will be an off white, unless you dye the resin.
I gave the part about 30 minutes to completely cure and cool down (the chemical reaction creates quite a bit of heat), then pulled the part from the mold.
Success! I'm very satisfied with the results. With a little random sanding and chipping I can make as many variations of barriers as I want, from new to chipped and cracked or even destroyed.
I have a few other parts I may try later to add to this section, and I might even try a two part mold if I have the need for one.
Chrome - adding, removal and repair
One thing about models, particularly cars and motorcycles, is the sometimes large quantity of chrome parts. Chrome can be tricky, as it doesn't respond to glue or paint well and damage can be tough to fix. However, there are a few products and techniques that are inexpensive and effective solutions for modeling chrome as well as other metallic surfaces.
While there are some paints out there that are called "Chrome", not many of them have the really reflective qualities of the real thing. One exception is Alclad paint. They make an excellent chrome paint as well as other metal finishes.I haven't used it in a long time but it's fantastic stuff. The next time I do I'll be sure to write something about it.
When it comes to adding small amounts chrome such as body trim, my favorite solution is Bare Metal Foil. It's real metal sheet, very thin with an adhesive back. It can be trimmed, polished, clearcoated, and the best part is if you make a mistake you can just peel it off. It picks up even the smallest details, even tiny emblems and lettering. It's available in a variety of finishes, including gold, copper, chrome, black chrome, aluminum and more. This Ford Starliner Police Cruiser's trim is all Bare Metal except for the bumpers.
Bare Metal can also be used to repair damaged chrome. Ultra bright BMF chrome is great for patching chrome parts where they have been cut from the sprue, or on areas that may have been damaged. It's thin enough that edges are hard to spot. I used quite a bit of it to touch up the chrome on my Harley Davidson kit.
1. Bleach
Chlorine bleach is great for stripping chrome parts. It works quickly and bleach is cheap. Non-chlorine bleach will sometimes work, but it does take longer. Simply drop the parts you want stripped into a glass jar of bleach, with just enough liquid to submerge them. You may need to use a piece of screen to hold parts down if they want to float.
Before (chlorine bleach)
Oven Cleaner
Easy-off oven cleaner is another effective chrome remover. Just spray it on, let soak for a few hours and rinse off. Repeat if necessary.
Bleche White
I've never tried this one, but I've heard that Westley's Bleche White is also good for removing chrome. Another spray on, rinse-off method.
Of these, I've found I prefer regular old chlorine bleach. It doesn't cost much, and you can get it in larger quantities if you need to soak larger parts or a lot at once. Non chlorine bleach also has no fumes, as it is hydrogen peroxide based so it's good for work areas where ventilation isn't as good.
