1st - You need to call Reynolds tech dept and find out what kind of temps that silicone can withstand. The epoxy resins have the strongest chain structure of all the resins manufactured so it will work, as long as the silicone can handle the heat. Your other dilemma will be whether or not it can insulate the wax chicken enough to keep it from melting or deforming. This is another quest you need to ask RAM tech dept. Personally, I would use POP and a shelling material for the exterior of the silicone investment.
The activated epoxy resin may also chemically attack the silicone as well rendering it useless. Another question which needs to be answered by RAM.
RAM's sells specific silicones which can withstand epoxy resin and I'm not sure the Rebound 25 is one of them.
POP's a bit too heavy for my liking. Most silicone rubber is good up to about 400F, not sure about the specific one I bought but I'd assume its at least a few hundred degrees since it is intended for pouring plastic/resin models. I'm more concerned about the wax bird inside than the silicone rubber. Perhaps I can just apply the epoxy in small thin amounts to dissipate heat? Or does even that put out too much heat?
I suppose I could give it a test when I get the stuff. Will the degradation happen immediately or will it take place over weeks/months if it happens?
Another thing, wear a respirator and rubber gloves when you do mix that epoxy resin for whatever project. Your in the medical field, read up on Isocyanates.
I would have just bought the fiberglass repair kit from walmart. It comes with cloth, the resin and hardener. It gets warm but not hot and shouldn't screw with the silicone and melt your bird. lol Even if it did, you'd already have the silicone sections of him... Once at that stage, you can us shoot a cool video of the original chicken in a pot melting to his death! You'll need all that wax to make more birds for shelling. Hey John, I know that table top stuff you speak of and have used it before. SUPER EXPENSIVE SHIT! It will never hang on a vertical surface such as his bird so he will have to use that cloth or chopped matt.
Heat concentration.... The thinner the application the less heat you will have to deal with. It basically all depends on "How" you plan on encasing the silicone mold with the resin, i.e., brush on vs. form & pour. Delamination issues? RAM would have to answer that one for ya. STOP being stubborn and just give them a call tomorrow. LOL Better to be safe than sorry.
Jason, your correct in your thinking. The table top resins are designed to be poured out onto a ..... Table Top and allowed to flow out. Thant's why I was thinking Zap was thinking he was going to build an outer form and pour the resin around the silicone mold.
So the consensus is chopped fiberglass and epoxy in thin layers should work at the bare minimum. I want to get everything ordered now so it arrives next week before the xmas parcel/post apocalypse. I will try call but I have long hours this month (until after they close) and a large exam on friday that is sucking up my time.
Fused Silicone can be added to any resins as a thickener base to basically create a butter, so to speak.
Nah I'm not going to pour an outer solid epoxy mold, just use it as a binder with the fiberglass. It's not too late for me to buy a more appropriate product if you have a name brand that works better.
In theory, thin layers of resin and chopped glass "should" work as long as it doesn't chemically attack the Rebound 25. "IF", you find out on your test piece the resin is too running, add a small amount of the Fused Silicone to thicken it up a tad bit so it will have some body. Fused Silicone is cheap. Hell, for that matter you can add some Baby Powder for thickener.
Tell ya what Zap, I'll call RAM tomorrow and find out the answers you need. I just hate to see you lose your chicken and possibly the silicone mold before you have the chance to actually cast it.
Straight from Smooth-On's Technical Data Sheet. Curing - Allow the mold to cure at least 6 hours at room temperature (77°F/25°C) before demolding. Do not cure rubber where temperature is less than 65°F /18°C. You can cure the mold faster by applying mild heat (150°F/60°C) for 2 hours. APPLYING, CURING & PERFORMANCE... Applying The Rubber - This product must be applied in layers. Mold makers generally find that four thin layers (minimum 3/8” thickness) is suitable for a strong, working mold. Using a stiff brush, the first coat of rubber should be applied in a very thin layer to capture intricate detail. Use dabbing strokes, especially around undercuts, to reduce entrapped air. Subsequent coats will add strength to the mold. Let the first coat dry for 60 minutes at room temperature until it becomes “tacky” before adding the next coat. “Tacky” is defined as sticky to the touch, but does not come off onto your gloved finger. Once “tacky”, you are ready to apply the next layer. Tack-time can be reduced with mild heat (hair dryer or heat gun). Repeat until the necessary mold thickness is achieved. Coverage: 1 gal. unit=7 sq.ft. (0.65 sq.m) - 5 gal. unit=35 sq.ft. (3.25 sq. m) Note: Although not necessary, adding a small amount of Silc-Pig® color pigment to every other mix of rubber will help you distinguish one layer from the next. Ensures that you apply a thorough coating each time and help build uniform layers. Option: Add Thi-Vex® thickener for greater thixotropy—adding a small amount of Thi-Vex® will thicken the rubber for filling deep undercuts and detail. Amount to add? 1% of the total volume of your mix will increase thixotropy substantially. Option: Add Smooth-On Silicone Thinner to your initial mix to lower the viscosity of your “print coat”. Apply A Support Shell - Once the mold is fully cured, a rigid support shell (mother mold) is necessary to support the rubber mold during casting. Plasti- Paste® II is a trowelable plastic is ideal as a mother mold material. Curing - Allow the mold to cure at least 6 hours at room temperature (77°F/25°C) before demolding. Do not cure rubber where temperature is less than 65°F /18°C. You can cure the mold faster by applying mild heat (150°F/60°C) for 2 hours. Using The Mold - When first cast, silicone rubber molds exhibit natural release characteristics. Depending on what is being cast into the mold, mold lubricity may be depleted over time and parts will begin to stick. No release agent is necessary when casting wax or gypsum. Applying a release agent such as Ease Release® 200 (available from Smooth-On) prior to casting polyurethane, polyester and epoxy resins is recommended to prevent mold degradation.
Thanks. I did see the 150F to speed up the cure time on their site last night as well but that's not the max temp it can handle I don't think. I'll probaby get around to emailing them later this week about the epoxy stuff.
Once cured, you probably could pour lead fishing weights in the stuff. It will tolerate some pretty serious heat. It tolerates 200 degree wax and only discolors a little. I doubt your fiberglass resin is going to bother it. I've seen many mother molds made of fiberglass used on rebound. Just save that expensive shit you bought for a bar top and go to walmart.
This belongs here as well. 9.1 Information on basic physical and chemical properties: Appearance : viscous liquid Odor/Threshold: Mild to sweet odor pH: N.A. (non-aqueous) Melting Point/Freezing Point: N.A. Low/High Boiling Point: N.A. Flash Point: >300 °F NOTE: Per RAM tech dept., the Rebound Silicone products can handle up to 455 degrees heat before becoming unstable. Evaporation Rate: Not available Flammability: f.p. at or above 200 °F UEL/LEL: Not available Vapor Pressure: None (Polymeric Resin) Vapor Density (Air=1): >1 Specific Gravity (H2O=1, at 4 °C): 1.05-1.15 Water Solubility: Insoluble Partition coefficient: Not available Auto-ignition temperature: Not available Decomposition temperature: Not available Viscosity: 5,000 – 50,000 centipoise % Volatile: Nil After specking with RAM's tech dept., I was informed that there shouldn't be any issues with using a epoxy based resin as an out support shell. Although epoxy resins can be used for an outer shell it was advised not to repeatedly attempt to use the silicone mold for repeated (epoxy) castings of the desired shape of the inner mold cavity as it will eventually cause delamination issue of the silicone. Is was advised to use one of their products called UltraCal 30, which is a Super Strength Gypsum Cement and cost right at $0.50/lb (shipping not included).
