Epoxy resin is thick stuff to work with. Do Not thin it out. The free flowing table top epoxy is a totally different epoxy from the epoxies which are used for glass matting. If anything bring it to room temp or slightly higher. The higher the temp the quicker it’ll activate. Epoxy resin has the strongest molecule chain links of all resins. As long as your finished fiberglass mold encapsulation is 3/16” finished out (cured), you’ll be fine.
Zap if you find your fiberglass mother mold flexing, you can always layer on more resin and glass. Hell, you can lay some Popsicle sticks on it and glass over them. That will keep it from flexing. A little flew is okay as long as it's not enough to deform the silicone which will deform you future wax chicken. Did you solve the pour hole yet? Or are you going to open face pour that wax into the silicone then assemble the halves of the chicken?
If the resin isn’t a laminating resin then additional layers of resinated glass will not adhere to the previously applied resinated glass matting once it has been activated and cured out. The resin “Must” be a laminating resin for chemical bonding purposes if additional layers are required after the initial layers have been laid out.
This is the car stuff wally world sells... Should work. I've used it before and built up layers days later.
I'm using the resin from walmart for cars. I decided not to use the table top resin. Pics soon. This project is getting laborious and I want it to end now. Too much time molding. Painstaking work.
So your using the Bondo glass? Well I wish I had known that previously. Wouldn’t have bothered explaining about bonding properties of resins. Labor of love Zap. Are those dollars signs starting to get to ya? Lol Hobbies = $$$$$ Poor Zap, while we’re seeing sheep jump over the fence in our dreams Zaps seeing dollars sign getting sucked into a flaming furnace. Everything will be ok Zap. Just take your time and have patience.
I'm going to cut the pour holes in where the eagle's feet are located. I'm making the claws separately. The fiberglass shell doesn't flex very much at all, in fact, I can't flex it at all with my fingers. Pics as promised. I finished the one side of fiber glass, flipped it over removed the clay put a silicone retaining clay wall in and then sprayed with releaser. 3 more coats then I fiber glass over it and I'm done. Gonna go start on the claws now. Will just block mold them all. 20180101_202934 by Zapins, on Flickr 20180101_202841 by Zapins, on Flickr 20180101_202806 by Zapins, on Flickr Multipart silicone rubber mold for lost wax by Zapins, on Flickr 20180101_213320 by Zapins, on Flickr Multipart silicone rubber mold for lost wax by Zapins, on Flickr 20180101_213316 by Zapins, on Flickr
Question You did spray some silicone mold release on the back side of the bird and the fascia silicone mold edges before applying silicone to the back side didn't you? Don't know why but am thinking you should have snug the protruding feathers on the back side up against the body.
It's not a big thing john. That's one of the good things with rebound 25. Super flexible and handles undercuts. He will just need a sharp knife when it comes time to free that wax section of the protruding feathers from the completed silicone. It could have been avoided easily if he would have placed a thin wall of clay right under the feather. Too late now, but not a big deal. ZAP, You'll be pulling the wax original in no time flat! ROCK ON!
Yes I managed to spray some release on the wax before I molded it. I forgot it on the first half of the wooden perch so hopefully I can peel off the silicone without it ripping from the wood but everything else has release on it. I figure even if those tail feathers tear off I can just pick them out and reattach them. Hopefully they will cast in the silicone. I have my doubts that they will but we will see. I'm thinking ahead to the shelling process. Trying to figure out how I want to sprue this guy. Going to be tricky I think. Not sure I even have the capacity to cast it with my 16B crucible (51 lbs), I will know when I finish the wax copy and weigh it if I can do it in one pour. I think the ratio was around 10.5:1 for bronze:wax right? I will have to direct cast it, rather than bottom feed like I do with the smaller objects, but even so I don't think I can pour from the perch without the metal freezing before it fills the entire thing. Maybe I will have to have 1 large 1" diameter sprue running straight down the belly branching off to feed the front of the body. Also probably going to need at least 8 coats of ceramic shell maybe 9 to get it thick enough so it doesn't break when handled, and I'll need to find a way to tie it up vertically so it can't flop over during the pour. Honestly mold making is so labor intensive I really didn't enjoy it. I spent 12 hours today, and about 12 hours yesterday and another 8 the day before molding it. And I still have to put the fiber glass on tomorrow afternoon before I can start pouring shells. I see why the mold makers charge big bucks for this stuff. Anyway, the 4th and final silicone coat is on. Tomorrow I'll fiberglass it and be done with the molding. I also block molded the claws which I'll post pics of tomorrow. 2018-01-02_03-18-15 by Zapins, on Flickr 2018-01-02_03-37-57 by Zapins, on Flickr
Good work! I know the kind of hours you have put into this. Get some sleep and you'll knock it out tomorrow.. NICE PINK LIGHTER! At least no one will steal it from you.
Yeah my pink lighter Built in safety feature that. I think something like these sprues will work. Internal spruing would make the outside look good, but be impossible to remove most of them, so maybe I'll do external sprues.
You could sprue him internally. But it will require a bigger hole on his chest which of course means more welding. If you are careful with the placement of some 3/8" wax rod inside him, you can use a dremel flex tool with a 1inch cutoff wheel and slice the bronze sprues off. You won't get it all out, but bronze is cheap. You're welding no matter what because you have to get the inside coated with ceramic shell. SO maybe a larger hole in his chest would be easier later on... This one is all you man. Getting the shell out of the inside of the bird is another story too. Here's a small tip to file away about welding up that chest while I am thinking about it. After he is in bronze and you go to weld that chest plate back on... Drill a hole somewhere else. Like bottom of a foot. This will vent out the expanding air inside and make your welding easier. A long time ago, I was working some copper fittings on an AC system and played hell getting that last bit to soldier up. I learned the hard way, you always remove the valve cores from the service ports. Did I feel stupid! When you pour him in wax and IF the thickness is pretty consistent, it wouldn't matter if you pour bronze through his beak! I thought the bronze to wax ratio was 1:9. I tend to oversprue the hell out of my stuff due to my inexperience so it is going to be interesting to see what road you take to get this thing in metal. FWIW, 9 or 10 layers is really a lot of shell. 6 or 7 is what I'd shoot for. He is already going to be heavy, don't make it harder on yourself. Just be more careful handling him. Perhaps some wax venting strategically placed around the bottom can also act as a base for him to stand on during the pour. Upside down during dewax will be fun too. (big ass pouring cup maybe?)
Finished the mold today. Fiberglass shell was ok. I cracked it open and removed the bird and the stick. The bird did not fare too well. Critical damage to the original but the mold looks good. Only minor air bubbles here and there, not many. I was too tired to make a wax copy. I'll do that tomorrow. I wonder if that mold release would help the wax flow into all the little nooks and crannies? I might just end up painting the first layer of wax on before I slush cast the wax. I don't think I will have time to dry the ceramic shell and cast by friday night. I might have to postpone casting the bird for several months (up to a year) until I can get back to CT. Ugh... I need to drive back to tennessee on saturday so I can rest sunday and start my next rotation monday morning somewhat fresh. Also, what the hell, nobody mentioned how sharp fiberglass shells are. I sliced my hands up really well. Lots of blood spots on the exterior of the fiberglass. A nice little veneer. Block molds of the claws (will open and cut them tomorrow) 20180102_181859 by Zapins, on Flickr Finished fiber glass shell. 20180102_201734-1 by Zapins, on Flickr Took the top fiber glass shell off. Looks ok so far. 20180102_230101 by Zapins, on Flickr Bit of a problem getting the stomach out of the mold. The silicone was suctioned into the fiberglass pretty tightly. Oh the feels. It hurts to see my work damaged like this, but its probably ok because the mold is done and I can pour copies now. All for the greater good. The greater goood. 20180102_232702-1 by Zapins, on Flickr 20180102_232907 by Zapins, on Flickr 20180102_232917 by Zapins, on Flickr 20180102_232848-1 by Zapins, on Flickr Inside of the mold: 20180102_233123 by Zapins, on Flickr Oh and the stick was rotten, badly rotten, so when I pulled it out it crumbled to bits. I'll have to scrub off the bits that stuck to the mold tomorrow under some running water. 20180102_232820 by Zapins, on Flickr
UH... You did REMOVE the fiberglass mother mold OFF the silicone BEFORE trying to pull the silicone OFF the bird right???????? Please tell me that fiberglass is not bonded to that silicone.
A light spray of mold release won't hurt when you go to pour the wax. It shouldn't be necessary that's for sure. One thing I have found with this silicone is the first wax pour NEVER works for me the first time. It's almost as the silicone has to be seasoned either from the wax or more likely the heat from the wax. From the looks of the two halfs and no pour hole, I'm still guessing you will pour the wax copies in two halves then assemble the bird. I would brush the first layer so it gets into all the little areas with pretty hot wax.. Say around 200... After a couple of minutes, I'd slush it with slightly cooler wax.... and just repeat. You may have trashed the original, but your replicas will be much stronger because ALL the wax will be bonded to itself completely. Unlike when you built it with a piece here and a feather over there stuff. If you do decide to cut a pour hole for the wax setup, you can still brush your first layer and then assemble the halfs... Then dump in, slosh and pour out... Wait and repeat. Savvy? Btw, that silicone looks like it did a spectacular job on copying that bird. The detail is amazing. You'll still have a little wax chasing work, but it won't be bad at all.
Hey Zap, Don’t forget to trim & sand the fiberglass edges before handling. You can use compressed air to dislodge the casting(s) from you mold. Just be gentle and inject air at multiple points until it comes loose. 1 last thing, Don’t forget to trim & sand the fiberglass edges before handling.
I plan on cutting the entire chest open. So a hole 6" by 4". The fiberglass isn't stuck to the silicone I just put it back in place. I also did end up taking my angle grinder to the shell and sanding the bastard down which coated my workshop in glass and resin dust. As for the pour hole I'm going to cut holes in the feet stumps so I can pour wax in from there. I won't be making two separate halves. I'm really curious to see how much wax the final piece will weigh.
that's good to hear Zap. From the photos, I thought the glass and silicone stuck. I think you will surprised to see how little the bird will weigh in wax. My guess... Bird only, no stick. 2lbs. any other guesses folks?
Yeah office pool it up. Correct guess gets a wax claw. Lol I'm going to say 4 lbs for the bird and stick without sprues. By the way do any of you have whatsapp? Might be fun to start a group conversation on there.
