As soon as the plaster cast was dry and hardened, I removed the the modeling clay I used for bordering the plaster flow and pull the enclosed JT-9T scale model airframe away, gently. Brushing the area with an old tooth brush, I removed unwanted dust or small broken plaster pieces.
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Johnson's baby oil or similar is well know to anybody who have children in house. If you don't have children yet, ask your girlfriend - all girlfriends have a tiny bottle in their cosmetics drawer. If you don't have a girlfriend, close this web page, shut down your PC/laptop and get your feet out of house to meet one! Scale modeling is nice, but feeling a nice female next to you is much better. Continuing with the project, thin layers of vaseline based mixtures can be also used instead of baby oil to apply with a soft brush as a segregative material between the plaster cast and generous quantities of polyester filler applied on the plaster cast.
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The specific polyester filler I used, comes with the proper catalyst which provides a solid rock build and approximately 3 to 5 minutes time window to form it into shape. I prefer to use epoxy putty or polyester filler with fiberglass grains for special purposes, because:
- It becomes solid rock within only few minutes or seconds,
- it does not shrink and does not crack after months or years,
- you can pour to any shape that you want but you need to work fast because as soon as you mix it with catalyst cream approx 5%, you have limited time before becoming solid rock,
- you can also put additional layers of epoxy or polyester filler to build up,
- you can sand it, you can drill it, you can use any type of scale modeling glue, any type of primer or enamel / acrylic paint on it with no problem,
- can be purchased at any good crafts store into 250ml, 500ml, 1lt (comes with a tube of catalyst hardener) or bigger canisters and if you can't find it, fear not and try your local decent hardware store and finally...
- it is cheaper than dirt - estimated prices are £3 to £10 depending the canister size, the quality, if contains fiberglass grains for maximum strenght etc.
Keep in mind that the chemical reaction after mixing the polyester filler with the catalyst hardener, produces some heat that possibly effect on thin plastic parts, so test it first before try it on your scale model. I don’t think that the produced heat is more than Fahrenheit 110, but better watchout. Remember that epoxy materials are dangerous when breath or shallow and could result skin, eyes or lungs problems or even cancer when used for long period with no precaution measures. Always keep in mind, that a powerful vacuum system to suck away the epoxy dust should be used all time to keep the workbench area clean while sanding or milling epoxy or resin materials. Using an issued breathing mask and a pair of surgery latex gloves to prevent dust contact with lungs and fingers while sanding or milling epoxy, is also an important matter that you should seriously take care of! My recommendation is to also wear an overall working suit (as I do) to keep your clothes dust free while sanding epoxy. Some people might find it too much, but I wouldn't like to bring epoxy dust & grains from my work bench into living room and my beloved.
When the plaster cast used as a "negative image" of the right side fuselage, was filled with a thick layer of polyester filler and had enough time to polymerize and get solid rock, it was sunk into water and stayed wet for few minutes, in order to get moistened, become soft and let the right side fuselage replica made of polyester be removed easily.
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…if you still read this, you are a father already or have a girlfriend
To produce a thin-skinned right side fuselage, the polyester part, must be vacuum formed. That means, that I should build from the beginning a new vacuum chamber box. Vacuum forming is a very simple technique that can produce thin-skinned parts of various forms. I mainly used vacuum forming for producing a variety of components for scale modeling. Basically, it’s all about a box with a connection for your household vacuum cleaner and a series of holes in its top plate and try keeping the box airtight at the seems. The basic idea is to build from scratch or buy one if you find something similar, a wooden box like the one I present. I found the following item (which supposed to be a display box or something, for placing plants, colored sand & stuff inside and make them look nice as a decoration on the wall) at my local
IKEA. Looking exactly like what I've been searching for and considering the low price (not more that 5€), I preferred to buy it instead of building a new wooden box like this from scratch. As you can see at the following pictures, I removed the glass, applied a generous layer of water based white glue for wood (which becomes transparent when it dries) across the inner joints, to keep them as air tight as practical and be sure that no air could escape from there.
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Visiting my local
Dexion store (shelving & racking solutions), I got a 135x85cm
hardboard sheet (more than 1 square meter area) for 8€. This is actually a louvred panel, designed to stand against the wall and accept hooks & spigots for easy storage of everything from belts and hose clips to spools and reels and all kinds of other parts. I cut a piece on the right dimensions and slide it into rail to test the fitting. The 35x25cm top plate has many 4mm wide holes to allow air to be pulled through them. The locations of the holes are not important, and can be also drilled by hand using a hand held drill. Just make sure that they are fairly close together. This top plate should be pretty sturdy to hold the subject being duplicated. I made mine from
hardboard high-density fibreboard plate, but I have seen them made out of aluminum too. The top plate finally was slided into inner rails - otherwise it would be screwed down with flat head wood screws. Be sure to countersink the holes to make the heads flush with the top surface. I also epoxied it down, just to also make it a little more air tight. As long as 1 square meter area
hardboard plate, is more than enough for me and can be used to build more than 5 or 6 vacuum forming device plates, I gave the rest to other fellow modelers who are also interested to build one.
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