Those Photoetch Hobby Saws


I’ve been using the Hasegawa Tritool hobby saws for years. They’re very thin, sharp teethed, and slice through plastic very fast and cleanly. However, they are quite delicate in that they’re very thin and I’ve bent my fair share of these blades. They are simple to use, just hold the small blade in your fingers and slice away at the plastic.

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Nothing against these blades as I’m still using them, but yesterday, I finally cracked open one of the three sets of Tamiya hobby saws I had picked up two years ago. I picked up the sets for about 7 bucks a set on a trip to Hong Kong; but I’ve seen them locally and on various online sources. The project I’m working on now needed a little cutting for some of the parts. Opening the package, I cut one of the saws out and immediately started using them like I did the Hasegawa tritool set; holding them in my fingers and cutting away. I found no difference than using the Hasegawa saws. After getting my parts cut, I looked at the instruction sheet that came with the Tamiya saws. Apparently, there are two folds in the blade that once folded, the blade can then be slipped into your standard hobby knife holder. Duh. So I snapped some pictures, took a quick little video, and put it all together here:

For scratch building and cutting plastic, these saws beat the piss out of the x-acto hobby saws 413S586EGEL when it comes to precision cutting and focus on small parts. But like all the other tools, it’s how you employ them in your builds and what works best for you.

Sticky-Tack Camouflage Masking


On my recent Rick Dom II I used the rolled sticky-tack masking method. The idea is that the rolled edge of the sticky tack gives you a slightly soft edge on your camouflage that simulates a to-scale overspray patterns from a paint gun. It’s very common among airplane modelers. Since I don’t see this camouflage technique used much in the world of Gunpla, I decided to make a tutorial.

Aircraft modelers often use sticky tack to create camouflage patterns on their airplanes. One method is to blow up the instruction manual to match the size of the model and cut out the camouflage pattern. They put sticky-tack on the back of it and stick it to the model. The sticky-tack raises the edge of the paper mask and allows some of the spray to slip under it and create a soft edge to the mask that simulates to-scale overspray from a real-world camouflage painting process.

You can create the same effect even if you don’t have an instruction manual with a camouflage pattern. Just roll up strips of sticky-tack (roll it on a table or piece of tile from home depot) and place the rolled strips on your model in a camouflage pattern. Since the rolled sticky-tack has a rounded edge, it also makes a slightly soft edge to the camouflage as long as you don’t press it down too hard. An advantage of this no-paper technique is that you can wrap the sticky-tack all around the model. It would be hard to wrap paper around the various contours and arms and legs of a robot.

Now you need to mask off the areas you don’t want to spray. For this, I sued Parafilm. You can purchase Parafilm from MicroMark. It’s a wax-coated plastic. It works kind of like Saran Wrap in the sense that you can stretch it around stuff and it kind of sticks by itself, but Parafilm is thicker and a lot less likely to get all stuck on itself. Cut out a piece of parafilm about ¾ the size of the area you want to cover and then stretch out the Parafilm until it’s thin and pliable.

Place the Parafilm over the area you don’t want to paint. You can stretch it a bit more in the process (but not so much it pulls the stick-tack off) and wrap it around corners. Where you have to go around something and the Parafilm comes around to itself again, you can seal up the seam with more sticky-tack. You can also sticky tack places where sharp edges on the models could (or did) poke through the Parafilm, or where the Parafilm had to be folded to get around a curve.

In the above picture, I photocopied my decals and stuck the copies to my model using sticky-tack. I usually had to cut the decal where it went across the line of the camouflage. The reason I’m doing this is that the brown color I’m spraying over the green is supposed to represent field-applied camouflage to a Dom that already had markings on it. Real-world field-applied camouflage often skirts around existing markings to save the person applying the camouflage from having to repaint national insignias and squadron markings, etc…

Then you have to remove the excess Parafilm. I used my small scissors for this. You can leave a little bit of overhang, because you can just smash it onto the sticky-tack.

Next you airbrush the camouflage color. You want to try to spray the paint perpendicular to the surface of the model. You don’t want to paint into the crevice where the sticky-tack meets the surface of the model. The goal here is that the spray pattern hits the sticky-tack at the fat part and then diffuses slightly into the crevice giving you a soft edge.

If you look in the picture, the “back side” of the sticky tack is not painted. This is how you get the soft edged effect. Once the paint is dry enough to handle safely, pull the sticky-tack off the model. Ta-da!

Weathering Techniques

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This tutorial will be completed in multiple parts. The idea is that any of these techniques can be stand alone, or can be combined in any number of combinations depending on what effects you want. There isn’t a specific order of operation but a matter of personal preference. For the purposes of this tutorial, I’m starting with the filter/fade technique.

Filter/Fade Technique

This technique is similar to the wash technique for panel lines. There are rules that MUST be followed for this technique to be successful. The kit’s painted surface must be protected with a clear coat that is a different type of paint from the filter. On the Gouf Custom’s leg in this example, the paint surface has been clear coated with a lacquer based gloss, Mr Super Clear Gloss. The clear coat layer has been cured for a full day. Next, I’m going to use enamel based paints which do not react with the lacquer based super clear. Effectively, for some of you folks that use graphics programs, I added a new layer when I clear coated the surface. The underlying paint, decals, panel lines, etc, are preserved under the clear gloss.

The filter/fade technique basically adds some tonal variance to the part. A filter uses multiple colors to create different tonal effects to the surface. A fade uses one color to create a tonal effect. There are many ways to use the filter to create even more interesting and varying effects such as applying the filter to a satin finish, or applying the filter to a flat finish. This example only shows the application of the filter to a glossy surface. The enamel paints I’m using are model master’s white, dark earth, and rust. The first part of this technique is to dot up the surface with a fine tipped brush, and let the dots dry for a minute or two. See the video below:

The Gouf Custom’s leg is now dotted up with different colors of paint. Note that the choice of colors is entirely personal. Color choice should be based on the ideal environmental effects you want affecting your model. With the part dotted up, here is a picture with both Gouf legs for comparison.

The next part of the technique is to remove the dots. The dots allowed to dry for a small amount of time, then a stiff rough brush is dipped into some lighter fluid and then used to wipe and blend the dots. See the video below:

Now with the dots blended, you can clearly see that one leg has a great deal of tonal variance and looks quite weathered. Below are a two pictures showing the comparison between the two legs on each side.

Dry Brushing/Paint Chipping Technique

After the filter/fade has cured, you can optionally spray a lacquer clear coat to preserve the filter before moving on. Again, this is the layering technique of saving your previous work with a protective layer of clear before moving on to the next step. With that done, I’m using an enamel based paint for the paint chipping. Color choice here is also open to personal preference. For this demonstration, I used a metallic silver.

This technique is a continuation on the dry brushing technique. The brush is loaded with paint then the paint is wiped away leaving very little paint on the brush. The brush is dry as opposed to wet with paint. The brush is then carefully applied to the hard edges of the part. I used reference pictures of old equipment, old aircraft, and tanks for ideas on how to place paint chips on gunpla. If too much paint is applied, it can be easily cleaned off with some lighter fluid and a paper towel. If you clear coated the part, doing this does not remove the previous weathering effects. This is a very slow and tedious process, but the results are worth it. Watch the below video:

It is also very easy to go overboard with this technique, but again, the amount of weathering is personal preference. Depending on the situation, you may need more or less weathering. Here are some pictures of the legs for comparison.

For some close up pictures, the chest piece looks almost like I went a little overboard with the paint chipping. It is a good idea to look at your other pieces and keep a certain balance so that the weathering isn’t overly heavy on one piece in comparison to another.

Pigments and Chalk Pastels Technique

After the clear flat has cured, we can move on to the third weathering technique. This technique uses pastels and pigments to create effects like rust, dirt, dust, oil stains, etc. This technique relies on a flat coated surface as the tiny bumps on a flat coated surface work to hold the pastel or pigment particles. These particles will not stick to a glossy surface; so it is very important that the surface of the parts are flat coated. Here I will be using chalk pastels and weathering kits from Tamiya.

The pastels I use are found at your local art stores and are soft chalk based. Using a hobby knife or sand paper, I can grind/scrape the pastels into fine pigments into a paint tin, then apply the pastels with a brush. Once applied to the surface, a q-tip, cotton swab, or paper towel can be used to blend the pastels or create directional streaks. Using some lighter fluid with the ground up pastels is another application technique, and I can create little oil stains with the black pigments and the lighter fluid. The Tamiya weathering kits work the same as the pastels, they’re just already ground up. The benefit of the pastels is that you can grind different colors and custom mix a color. The tamiya weathering kits are basically glorified makeup sets without the perfume. Modelers have been known to use makeup kits to create these weathering effects on their kits. Below is a video that shows the application of the pastels and pigments to the surface of the kit.

Below is a comparison picture of the legs.

After this third weathering session, I sealed everything up with an optional clear flat. Since I travel and handle my kits often, I spray on a final clear flat to seal all the pastels. This is completely optional. The clear flat has a tendency to fade out the pastels so a little heavier pastel weathering may be necessary if you are planning on sealing this. There are modelers that do not seal the pastels as they feel that the additional clear flat will diminish the pastels effect.

Here are some sample picture of the Gouf after application of the three weathering effects. Soot marks were added to the bullet areas, some rust is added to the corners where the paint was chipped, dust was added to the feet to show the terrain the suit has been traveling through, oil stains were added, and dirt is added in the corner areas of the kit. Pigments are a very powerful tool for creating a huge array of effects.

This concludes the three basic weathering techniques. There are hundreds of variations on these techniques and several cool effects that can be achieved. Using these three basic weathering techniques, it is highly recommended to experiment further to explore additional effects aside from what was shown here and in the videos.

Cosmetic Modifications To Gunpla


There are millions of ways to modify your out of the box gunpla kit. The ever growing aftermarket for add on metal thrusters, LED gimmicks, resin weapon packs, and various other detail up parts help make it very easy to separate your kit from the box stock version. For the article, I will discuss and show a few techniques on adding small modifications to your kits.

A very simple mod is the replacement of existing parts on the kit. For this example, I’m replacing the waist cables for the HGUC Sazabi. I found that the cables were rather boring and lacking in detail. So the cables were thrown away completely and a new one was built from scratch. The new cable is assembled from plastic wrapped wiring, adlers nest armor collars, a spring created from wrapping 28 gauge magnet wire around a 1/8 inch brass rod, and some round molds from wave.

The first thing I did was to glue the round molds to the front and back waist areas where the original cables terminated. Once the parts set, I drilled small holes on each end. The plastic wrapped wired is used as the main cable internal structure. This gives the cable an internal skeleton to help support the rest of the cable components. With the internal wire measured, cut and shaped, the magnet wire spring is threaded. This is followed by threading the metal collars. The internal wires terminate inside the drilled out holes keeping everything in place. Once the kit is painted, these wires are glued into place with epoxy glue. This is a very simple mod that adds a bit of detail to the otherwise bland original part.


The next modification requires a bit more planning and some more work. Putty, priming, and sanding will need to be repeated a few times for these types of modification. Feeling that the Sazabi’s fuel tanks were a little on the short and stubby side; this modification aims to lengthen the tanks. This technique can be used to lengthen any gunpla piece.

Starting off with the planning. I found a piece of styrene tube that was as close to the diameter of the original Sazabi tanks. They were a little thinner than the tanks. I drilled out both internal areas of the original tank pieces. Next I measured out the tubes and cut two sections in the same length. Additionally, I cut to thinner tubes slightly longer than the previous set to act as an internal contact and glue point for the two ends of the tank pieces as well as the center tube piece. Gluing all three of these pieces, the tank end pieces are glued using epoxy glue for maximum strength. The middle tube is glued as well. This assembly is then left to set up over night.

With the glues set, I wrapped stripes of styrene around the center part of the extension tube, and the thickness of the styrene strips was just enough to level out the difference in thickness between the extension tubes and the tank ends. These stripes were glued together using styrene glue, clamped down and left to cure over night.

Once the glue is set, the entire assembly is roughly sanded, then primed to show all the areas that need putty attention. With the primer cured, putty (in my case, light curing putty) is used to fill in the defect areas, then the entire tank piece is sanded smooth for another layer of primer to check the fix. Several cycles of priming, putty, and sanding will continue until the part looks like a single piece cylinder.


This is the basics to lengthening any part. Now with the tanks lengthened, I felt that they needed some additional details, so I cut a large styrene cylinder in half and used the halves as detail pieces for the tanks. This type of modification is commonly done by many modelers when they want to add in raised surface details to their kits. Styrene plates, cylinders, tubes, strips, etc are simply cut to a measured size and shape, then glued onto the surface. It is very simple, yet adds a great amount of surface detail to some rather bland areas in some kits.

The tubes are cut. The lower corners are also cut to add a little cosmetic flavor. Holes are drilled at the angle points to add more details and the styrene tube halves are glued into place. Once painted, the modified tanks are beefier and more stylized than the original small tanks. Again, cut rods, strips, plates, etc glued over bland surfaces add a great amount of detail and is a very simple way of pumping up the surface details.


The next modification is similar to the tank extension in that additional plastic is glued to the surface of the original kit parts. For this technique, I am extending the length of the Sazabi’s shoulders as well as reshaping the chest piece slightly. For the shoulders, a strip of styrene is glued onto the ends of the Sazabi shoulders. Once the glue sets, the excess plastic areas are cut and sanded down. Putty is applied to the gap areas and then sanded smooth. The shoulders are primed to check for mistakes and the cycle of prime, putty, sand repeats itself until the shoulder pieces look complete.

For the chest, thin strip of styrene was glued along the main ridge of the chest. The styrene will be the main frame work for the putty and the ultimate reshaping of the part. With the glue set, putty is applied to the frame following the contour of the original part. Once the putty cures, the area is sanded. This sanding process shapes the putty around the frame work to create a beefier and more pronounced shape to the chest piece. Again, the process of primer, putty, sanding is repeated until the chest piece is free of defects. Reshaping and lengthening mods are quite simple if you break down the steps and understand the repeated process of priming, putty, and sanding. Modelers use these techniques to fix proportion issues and various other aesthetic cues.


Adding lights to models has been done for years. Most MG kits are very suitable for lighting mods. Lighting mods require a great amount of planning. Cutting and modifying parts will result in losing the part if the proper precautions or planning measures were not fully thought out. Each model is different so the approach to adding lights will differ greatly. For this example, I added lights to the HGUC Sazabi shoulder thrusters.

These thrusters are very small. My original idea was similar to the other lighting mods I did for the other, much larger thrusters on the kit. Drill through the back and through the thruster bell base; then insert the LED. This was not going to work, even with the smallest LEDs I could find. Cutting into the thruster didn’t work either. I ended up completely ruining one of the arm thrusters. So back to the planning.

The remaining thruster piece was used to make a silicone mold. The thruster bells were cut from the destroyed arm piece and the thruster bells were molded in silicone and resin cast. These resin cast thruster bells were then drilled and 1.8mm LEDs were glued into the thruster bells. The ends of the resin thruster bells were capped with sticky tack to protect the LED bulb, then placed into the mold of the entire thruster assembly. With the LED and thruster bell inside the mold, resin is poured to create a custom thruster assembly that have LEDs embedded within the part.

Some work to hide the wiring using wave ring molds and springs made from magnet wires compete the modification. The entire process took several days, but the time spent planning and executing each step was totally worth the effort. This is a fairly extreme level of LED modification. What I had hoped to illustrate is that you can go beyond drilling and cutting into the original parts and completely fabricate the necessary parts for the job.


The next technique is a gun modification that boarders on scratch building. For this, a base part is used as a start point for which something completely different is built. I didn’t care for the sniper rifle that came with the GM Sniper. So starting with a resin ore gun from Akocreation, I added styrene tubes, stripes, brass and aluminum tubes , and parts for various kits, a custom made sniper rifle is created.

Starting off with the front and back of the original resin ore gun. The front barrel is drilled and a styrene tube is fitted as the main barrel. The back was drilled and an aluminum rod is added as the base for a rifle stock. Another hole was drilled in the center of the larger hole on the ore gun’s front barrel. An thinner aluminum rod is inserted as the main rifle barrel. The outer styrene barrel was cut into two sections, one for an outer barrel piece and the other for a silencer piece.

Starting with the outer barrel; a pattern traced out with strips of masking tape is laid along the four sides of the barrel. A drill is used to cut holes along the masking tape pattern. With the masking tape removed, we have a ported outer barrel. Next, a rail system is created using styrene strips. Three copies of the created rail are made. The outer barrel is fitted over the inner barrel. A metal collar is threaded and used to separate the outer barrel from the silencer. Small dents are made into the silencer to mimic the socom style silencer.

The aluminum rod on the stock end is cut and the back piece of a MG Kampfer shotgun stock is glued into place. At this point the rifle has a barrel and a stock but there was still something not quite right about the weapon. The fore grip of the original sniper rifle was cut and glued to the bottom of the barrel and front of the ore gun. This worked to create a more rifle like look. A styrene strip is added to the top of the outer barrel connecting to the fore grip. Putty is used to fill in gaps and create logical transitional areas between parts.

The rail system is glued. A thin ring cut from a tube of styrene is fitted over the silencer to add some more details. The space between the inner barrel of the silencer is filled in with consecutively smaller rods and glued into place to get a centered inner barrel. Putty is used to fill in any remaining gaps.

With the rifle built from various parts, it still looks very frankenstinish. Primer is sprayed and the weapon is cleaned up along the transitional areas, putty areas, and general surface fixes. After a final coat of primer, the weapon looks more solid. Paint and decals finish the weapon. This technique bashed different kit parts together and used basic styrene building blocks to create a finished product. Everything comes together with glue, putty, and some paint.


Hopefully this tutorial has broken down some of the various styles of adding modifications to a kit to create a more customized look. There are thousands of other techniques that modelers use to customize their models, some simple and some very extensive. It all comes down to how much time you are willing to spend and the kind of modification you want to add to your kit.

Working with Water Slide Decals

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This is a tutorial for applying water slide decals. I prefer these decals over the dry transfer decals for ease of application. There are a couple of important steps that need to be applied to the parts before applying the decals. The most important step is to apply a gloss clear coat and allowing this to cure prior to applying decals. A gloss clear coat creates a very slick and smooth surface on the parts and this is the perfect environment for the decals to stick. If the surface has not been properly prepared, the decals will not stick very well onto the surface.

As a side note, the decals I use are from In come cases, the decals can be a bit on the delicate side. Meaning the ink for the decals rub off VERY easily. To counter this, simply spray a thin layer of Mr Super Clear over the decals and let that set and cure over night. This gives a protective layer over the decal ink. The down side to doing this is that it makes the decals thicker so after the decals have been applied, you will need to deal with the decal edges.

The decal is placed into water and let the decal soak for about10-30 seconds – this all depends on the age of the decal, the decal paper, etc. There is an adhesive in the decal that the water loosens up, but keeping the decal in the water for too long completely dissolves this adhesive. This in turn makes the decal harder to stick to the surface and may lend towards decal silvering (edges of the decal lifting up off the part).

Next, remove the decal from the water and set it down on your work area or paper towel. The water will soak into the decal backing and after another 30 seconds to a minute, the decal will easily slide around on the decal backing. Simply slide them onto the parts. You can use a toothpick to position the decals while it is still wet. Another technique to positioning the decals is to use a moist q-tip. With the q-tip, the decal can be carefully lifted and repositioned. Once the decal is in the proper position, take a paper towel to soak up the excess water. Then carefully press the paper towel against the decals to rid most of the water. Let this sit and dry for a while before moving on.

Now that the decals have been applied, you may notice that some of the decal edges are noticeable or not conforming well to the curves of the part. To fix this, I use a decal setting solution, Micro Sol setter to set and soften the decals. There are several brands of decal setting solution, and some are stronger than others, so care must be taken in choosing the correct decal softener. Mr Mark Setter and Mark Softer are gsi products that are meant for use over lacquer based products. Microsol is acrylic based products safe to use over acrylic surfaces. The decal setter/softer melts the decals so that it conforms to the shape of the surface. All I do is apply the solution with a brush and let it evaporate on its own.

Here is a video of the process:

In some cases, when the solution is applied to the surface of the decal, you will notice that the decal wrinkles up. Just let this sit and it will evaporate on its own. DO NOT TOUCH the decal. Once it evaporates, the wrinkles will be gone. Then let the setter sit for a full day before proceeding with the next step. Here are pictures of decals wrinkled, then without wrinkles after the decal setting solution has fully evaporated.

Once the decal setting solution has cured for a day, it’s time to get rid of the decal edges that may still be present. For this, the first step is to spray a clear gloss to sandwich the decal. At this point, a decision on if the part will be glossy or flat comes into play. If the part will have a flat finish, the decal work is done and a flat can be sprayed onto the surface and the decal lines will fade away easily. However, if you want a glossy finish, there are a few additional steps that may be necessary for dealing with the decal edges. First, I spray several layers of clear gloss that completely covers and encapsulates the decal on the surface. The gloss is left to cure over night, or for two nights depending on how thick a layer of gloss is sprayed. This usually removes the decal edges.

However, if the decal edges are still visible after the above steps, then I recommend trying the following. Use a high grit sanding pad, and lightly sand along the edges of the decal. The idea is to slowly remove the gloss that is built up around the edges, and only sand the gloss. In the following picture you can see the decal edges fairly clearly.

Imagine a cross section of the decal as it sits on the surface of the part. Below the decal is a layer of gloss, and below that is the paint layer. Now above the decal layer is another layer of gloss. The gloss builds up around the edges as well as the area of the parts that don’t have the decal. So there is a slight leveling difference if looked at on a cross section. To resolve this, a very high grit sanding pad is used to run across the edges of the decal. Since the paint and decal layers are protected, slight sanding will only remove the excess clear gloss layer. The surface will look cloudy after the sanding session.

Here’s a video on that process:

The following pictures shows the fuel tanks sanded. The edges are sanded and the overall luster of the gloss is clearly gone in the picture.

This is fixed with the final layers of clear gloss sprayed over the sanded decals. And with the final clear coats, the decal edge lines should be completely gone. And here are some images after the final clear has been sprayed.

In the above picture, I have several parts that are glossy and two that are flat coated. Decal edges are much easier to hide with a flat coat than with a glossy surface. The sanding process was not used on the flat coated pieces, only the glossy surfaces.

Texturizing with styrene glue

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The idea is to create a cast iron effect or a rough surface to the plastic. The process uses a solvent glue (I am using Mr Cement Deluxe) other thin solvent glues for model building can also be used; and an old toothbrush. Beginning with a cleaned part (seam lines, mold lines, and spruce nubs have been sanded down). Apply glue to the surface of the parts, the use the brush to rough up the surface of the part. As the glue works against the plastic, melting it; the toothbrush works to get the surface very rough. The plastic parts will be very rough and have some plastic burrs from the brushing process.

The second part to the technique needs to let the glue completely dry and cure before progressing. I usually leave the parts to dry over night to fully cure. Once cured, a medium grit sanding pad is used to remove the rough burrs and bigger rough spots leaving the surface that is textured. The parts can be left alone, or painted at this point.

Silicone Molding and Resin Casting

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This is a little tutorial for resin casting. There are two parts for resin casting: making the mold and making the casts. The first step is to make the molds. I like to use legos to make the mold containers because they’re plastic and I can basically build a box of any shape and size. The master piece is measured and a box is built around the master. The master is then placed inside the box.

The material I’m using is RTV silicone rubber and comes in two parts, the silicone base and the activator. The base and activator is to be mixed by weight, at a ratio of 10 parts base to 1 part activator. Your standard digital kitchen scale is very handy here when measuring. Using some disposable cups, the RTV is mixed.

Once thoroughly mixed, the silicone is poured into the box. I have small bits of cut up old silicone molds that I use as filler, this saves on the amount of raw silicone I have to use. So as I pour, I fill with the bits of cured rubber. The rubber bonds very well with itself so it works as the perfect filler. Once the silicone is poured, you will notice little bubbles slowly surfacing. This is the escaping air that is trapped when the silicone is poured. Now if all these bubbles don’t escape, your mold will have small bubbles. To counter this effect, I have a pressure pot that is powered by my airbrush compressor. The mold is placed into the pressure pot chamber and sealed. The compressor is turned on and a constant pressure of 40 psi is filled. This is enough to force all the air out of the mold creating the most bubble free molds.

A pressure pot is not absolutely necessary, as you can get fairly decent molds without one. But for the cleanest and most bubble free molds, the pressure pot facilitates this. The mold is left in the pot over night to cure. The normal cure times for this particular RTV is about 6-8 hours. And this will vary depending on relative humidity and temperature.

A few days later, the mold is ready to be removed. However, after checking on the mold and removing it from the lego casing, the rubber didn’t feel completely cured. To lower the risk of ruining the mold, the mold is left to sit for a few days so that it can fully set up and cure.

After about a week, the mold has completely set up. The mold may not have completely set up due to a problem when mixing the silicone. If not enough activator is added, the mold will cure too slowly or not cure at all, so it is very important to measure out the correct mixture ratios. The mold is solid and we can now un-mold the clay master. Using a hobby knife, the mold is cut carefully down. Once the clay master is exposed, carefully cut around the master while slowly releasing the master from the mold. I don’t cut all the way through the mold creating a clam shell mold. Once the master is removed, the mold is cleaned up with an old toothbrush to remove any clay that may have been left from the demolding process.

The mold is then sprayed with some mold release that will help preserve the life of the mold as well as help in resin removal from the mold. The mold release is heat activated. So a hair dryer is used to heat up the mold, activating the mold release. With the molds ready the resin casting can begin.

The resin is two part urethane resin. They are mixed at a 1 to 1 ratio by weight, so using the kitchen scale and a disposable cup, the two parts are mixed. The two resin components react exothermically, and learning from an experience when casting in the middle of winter – it is a good idea to preheat the resin components in a hot water bath before mixing. I had once ended up with a mixture that never fully cured because the base parts were too cold when mixed. The reaction is fairly quick, so you need to work quickly after mixing the two ingredients and pour it into the silicone molds.

Once poured into the molds, the molds are quickly placed into the pressure pot. Again, the pressure pot is an optional piece of equipment, but to reduce the amount of bubbles that may form, the pressure pot is employed. The resin will cure very quickly, within minutes. A full cure will occur after about 15-20 minutes. I usually allow the pot to sit for about an hour before de-molding.

After about an hour, the part is de-molded. Since I have extra resin, I poured some into another mold, and removing that mold, the resin didn’t fully fill the mold, this happens. I can just mix more resin and pour another mold and continue until I get the perfect replicated part. The casted resin head came out nice. In hindsight, I could have marked off where the original master fit and cut the mold so that the mold lines are easily removed. But these castings are pretty clean. I can cast an unlimited number of these parts now.

Products and where to buy

I have picked up the silicone RTV rubber from various locations. I have seen aluminite at local arts and crafts stores as well as brookhurst; however, since these products do expire, I usually like to hit up my local plastic retailer: Plastic Depot located in Torrance. They also sell various resins, but the resin product I have been using is Silwhite from; and this company is located in Pomona where folks local to Southern California can pick up the products. Baring that, I would search your local plastics dealer and inquire about silicone RTV and urethane resin products.

Pressure Pot

THe pressure pot I picked up at my local harbour freight needed some modifications before being used as a pressure pot for resin casting. The first picture is the complete setup; there are a few things that need to be attached to the out of the box pressure pot. Several fittings need to be added to plug up the various ends of the pot and an optional modification will help make the pot easier to use for casting larger items.

Starting with the optional modification. The pot has a metal tube that runs down the pot for extracting paint. I cut this tube out with a pipe cutting tool. Since the tube runs down the pot, removing it allows for casting of bigger items. The pot can be used with the tube in place, but in my uses, I have found that the tube just gets in the way.

Next I plugged up the exterior end of where the metal tube is attached. This is the end where a hose attachment that leads to a paint gun is attached for spraying paint. So this end needs to be closed up. The connection end is a 3/8″ pneumatic male connection. Since I wanted to use a drain valve that is a 1/4″ fitting, I needed to get an adapter fitting from 3/8″ to 1/4″. From there I have a coupler for which the drain valve is attached.

Next up, is the regulator/gauge setup. I plugged both ends with quick connect female ends. These are both 1/4″ fittings. I can then connect from the compressor to one of these ends, and with everything plugged up tightly, I can start pressure casting.