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What you will need:
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Due to the complexity of this prop, full instructions with detailed illustrations are available in the DC Prop Book, which is available in the DC Prop Shop.
This project is going to describe how to mold and cast your own gargoyles, but the same information can be used to create a mold for any prop. My only suggestion is that when you are designing a prop, keep in mind that the mold itself will only stretch so far before it rips, so try and keep the deep caverns and undercuts to a minimum.
The use of an armature will significantly reduce the cost and weight of your prop, as well as give you a basic form for the creation of your prop. You can also use an armature itself as a prop.
There are many commercial bought armatures that you can purchase, but I recommend building one for your specific application. You have a basic idea of what you want the finished product will look like, so a custom armature is almost always the only way to go.
The first step to building an armature is to mold a basic form out of chicken wire that is approx. 1 to 2 inches smaller then your finished product . Once you have the armature constructed, you are ready to fill it with "Great Stuff" expandable foam. I recommend first placing the armature on a sheet of polyethylene to avoid the foam, clay, urethane and fiberglass from sealing itself to the work area. When you purchase polyethylene, be sure to buy the smooth surfaced type. Once your armature is on the polyethylene, you are ready to start filling it with foam. Start from the bottom and work your way up. Use 1 can at a time and allow the first coat of foam to setup before trying to apply the next coat. Also if you do not give the foam a significant time to dry, the applications you add above the first will force the foam to compress and you will have to use additional foam and run the risk of the bottom coats not drying.
Once the armature is completely filled with foam and it's fully dried, you are ready to begin shaping the form. To do so I suggest first cutting off the large segments of extra foam with a razor blade, then go in with a small disc grinder or a roto-zip with a course sandpaper disc. Before you begin to sand the foam be sure to protect yourself. Use a particle respirator, safety glasses that seal onto your face and proper clothing to protect your skin from the foam particles. Now begin grinding your armature down until you achieve the basic form you need to work with.
Once the form is complete you are now ready to begin applying clay. I recommend using Monster Makers oil based clay. It is by far the best clay I have ever worked with. To soften the clay I suggest you purchase a heating pad with a removable cover. Now remove the cover and expose the plastic sheet. Lay your strips of clay directly to this sheet and allow the clay to warm up. This warming process will make your job a lot easier.
Once you have a good foundation to your armature you are ready to start sculpting. Keep in mind that the mold you are going to be making is a 2-part mold, so keep the form as simple as possible, while still achieving maximum detail.
Once your model is completely finished, it is time to cut off the parts that will not work with a 2 part mold. In the case of these gargoyles, I had to cut off the wings, teeth and ears. Once the parts are removed and you have a simple form you are ready to apply a minimum of 3 coats of Krylon clear coat. This will seal the porous clay as well as allow the clay to hold together when you remove it from the female mold. Once the clear coat is dry, you are now ready to begin making the mold.
To make the mold you will first need to build a retaining wall that will serve as the wall between the 2 halves of your mold. To do so, take pieces of your water based clay and cut them into strips that are approximately 1" thick by the length and width of the clay (should be approx. 8" square). Now cut those 8" strips in half and begin using the strips to build a wall up and over the sides of your model. Now once your main wall is built, you will need to go over the edge that is in contact with the model with a small stiff bristled paintbrush to smooth out the gaps. First dip the brush in water, then slowly go over every inch of the walls contact point to make sure that you have a good seal (on the side you are planning on molding first). Once that is done, you will need to spray the model and the retaining wall with a couple of coats of Synair's mold release spray and once that is dry, you are ready to begin applying the S333 urethane rubber.
I strongly recommend that you use a squirrel mixer to mix the 2 parts. It doesn't seem necessary, but believe me it will be the best $10.00 you have ever spent. The squirrel mixer will hook up to your drill and take all the work out of mixing the S333.
Now that you are ready to begin applying the urethane mix up an ounce or two of each part in a polyethylene cup. If you cant find these types of cups locally, I recommend ordering them from Tap Plastics website. The cups will hold up to abuse as well as give you exact measurements and ease of cleanup (nothing sticks to them). Once you have equal portions of each part of the S333 stir them until you are sure that both parts are well mixed. Also scrape the bottom and sides constantly to avoid having any urethane that will not dry. Also when you are running low, I strongly recommend making another batch instead of scraping the bottom and sides of the cup.
Once the urethane is well mixed, apply a thin coat (approx. 1/8" to the side you are working on as well as the retaining wall). Allow this to dry overnight. hat the first coat is dry, begin cutting strips of fiberglass cloth to lay between the first and second coat of urethane. Doing so will greatly improve the strength of the mold and hopefully prevent you from tearing the mold while removing it from the model or finished product.
Once you have enough strips to completely cover the mold, you are ready to mix up another batch of urethane. Once again only make a small batch. Once the mixture is completely mixed, apply a thin coat to the first coat, than apply the strips of fiberglass cloth. Press them lightly into the urethane so then become fully saturated.
Once they are fully saturated, cover them with the rest of your batch of urethane. As soon as this coat is applied, begin mixing another batch of urethane. This time you can make as much as you think you can apply evenly in about 10 minutes (depending on the outside temperature). Once mixed, apply it to the mold. You may also wish to add more fiberglass cloth if you wish, especially in areas that you believe will have a tendency to rip. In the gargoyles case the area around the fingers, knees and inner elbows. The thickness of the S333 should be about 1/2"-1" thick by the time your finished building it up.
The second you are done applying the urethane, you will want to put on a pair of latex gloves and spread baby oil onto the outside of the mold and smooth out the surface. This will allow you to make a hard fiberglass shell, without having to worry about the fiberglass sticking to any ridges. Wipe away any excess after your done smoothing it out, and allow the mold to dry for a minimum of 24 hours.
You should now have half of your mold complete. You will now need to do the same as above to the second side. First remove the clay retaining wall, than spray the front of the model with a couple of coats of mold release. I also highly recommend coating the dried urethane retaining wall with a thick coat of mold release wax, than spray it with a couple coats of release spray. You need to be extremely careful when you are applying urethane to urethane. They really like each other, so if they come into contact, I assure you that you will not be able to get them apart.
Once you have applied the wax and the mold release spray, repeat all of the steps above. Your mold should now be just about complete. Our last step will be to create a sturdy shell, so the mold will keep its shape prior to it being filled. To do so you will first need to cut a bunch of strips of fiberglass cloth. Once those are done, cover the outside of the mold with a coat of mold release wax. Before you work with fiberglass resin, take the proper precautions and wear the proper respirator, glasses, and gloves as well as take special care when handling the fiberglass cloth. The cloth is made up of fibers that are very irritating to the skin. Also use fiberglass in a very well ventilated area, I'd probably be a lot smarter today if I took my own advice. Once your all suited up and your materials are all within reach mix up a couple of ounces of fiberglass and begin applying the fiberglass resin to the mold with a cheap and disposable brush. Apply the strips of cloth evenly around the mold and saturate each piece with resin. The cloth will turn almost clear when properly saturated and will have a much higher tensile strength.
Once the resin is hard, repeat the steps until you have a shell that's about a 1/8" thick. Also pay a lot of attention to the retaining walls, since this is where you will be bolting the walls together, but be sure to keep your fiberglass away from the 2 dividing walls or once again you'll have a huge mess on your hands. Once the shell is to your satisfaction let the fiberglass completely dry overnight.
Our mold is now complete, but before you go ripping it apart I suggest drilling holes through the retaining walls, so that when you bolt the two sides together, you wont have to worry about lining them up. Once the holes are drilled, remove the fiberglass shells and carefully peel the urethane cast away from the model. It should come out pretty easily and if not you may want to fire compressed air into the tough spots to break the mold away from the model. Hopefully you are able to get the 2 halves apart fairly easily and you are happy with how your female mold looks and works. Now you will cast your first product. The first thing you will want to do is remove any of the small pieces of clay that may be still inside the mold. Also look for pieces of the clear urethane you sprayed on the model since that may have also stuck to the mold.
Once your mold is clean we are ready to coat the inside with mold release. I have tried many types of mold release and the ones that I have had the best luck with were a mixture of mold release paste wax and a thin coat of silicon mold release spray. To add the mold release, apply the paste wax to the insides of the cast, then allow it to dry for about 20 minutes.
Once the paste has set up, spray an even coat of the silicon spray across the entire mold and across the retaining walls. Avoid saturating the mold and if puddles form, pour them out before adding your casting material.
*When purchasing silicon release spray pay attention to how fine the spray is. Some silicon spray that you purchase from hardware stores spray extremely thick so if you choose to use these spray them into a "Preval" sprayer, then spray the Preval mister into the mold halves. Preval sprayers are a compressed air canister that can be screwed into the supplied glass jar. They work great for just about any application and are fairly priced and are carried by most hardware stores.
Now that the 2 halves of the female mold are ready to go, you can begin mixing the Pour-A-Kast in small amounts. Pour it into one of the mold halves and swish it around to achieve an even coverage. Repeat this step on the other half of the mold, then once both halves are just about done you can bolt the two halves together and apply a final coat of pour-a-kast to the seam.
If you are planning on mounting lights in the eyes, and having smoke bellow from the gargoyles mouth, you may want to run a piece of 3/4" vinyl tubing from the mouth and out the base, as well as a piece of 1" PVC pipe from between the eyes and out the base. This will save you a lot of time, as well as the hassle of having to dig out the foam. You should now have a rigid shell for your model, but were not done yet. Next you will need to fill the mold with the expandable foam. This will dramatically increase the strength and durability. To do this you will want to have the mold inverted so the foam will pour into the deepest parts of the mold and rise upwards. Mix the foam in small batches and do small pours until the model is completely filled. You may want to have your sheet of polyethylene ready to stop the foam from overflowing. Your model is now completely done. Wait the required amount of drying time then unbolt the 2 halves, remove the fiberglass shell and carefully peal away the urethane exposing your finished piece.
You will most likely have to do some minor sanding to remove the line from the retaining wall, but it usually isn't a big deal. Well unless you mismatched the molds, but you would have already realized you had a problem on your hands, when the foam and pour-a-kast started spilling onto the floor.
Now you are ready to do the mold for each wing, the teeth and each ear. The teeth and ears are small so I don't recommend using a 2 part mold unless there are a lot of undercuts and also you can skip the fiberglass shell on these for the same reason. To make a mold for the wings, repeat the steps you did for the main mold. After you cast the teeth, ears and wings you are ready to glue them to the body.
Before any gluing or painting takes place you must first wash the silicon off of the finished piece. Just as the urethane wouldn't stick to the silicon, neither will the paint or glue. To date, the best solution for cleaning these is a solution of mild laundry detergent and orange hand cleaner, mixed in a bucket of water. Scrub every inch of these then hose them off and leave them out to dry. Once they are clean you are ready to glue on the parts. I suggest using 90 second 2 part epoxy so you have a strong bond, but you don't have to sit there holding the parts for hours while they dry. Now that the glue is dry, take silicon caulk and seal any gaps or spaces that the glue missed. You may not have any gaps if your molds fit together perfectly, but if you do its no big deal, you just have to fill them.
Once the silicon is dry your ready to paint. First apply a couple of coats of primer, then when that is dry begin painting with the granite paint. Remember to seal the granite paint with outdoor varathane to protect it from the elements.
Now that your gargoyles are done, your ready to go display them. I don't recommend leaving them out overnight though. You may have some really jealous neighbors.
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