Does this stuff need to be vacuumed before use to remove air bubbles? How long is the rubber stable for without degrading after hardening? Does it tear easily? How thickly does it need to be applied to a 1.5 foot tall object (the eagle)? I'm planning to use a fiberglass and epoxy shell around it to give it stiffness. Does anyone have recommendations for what kind of fiberglass and epoxy to use? Any particular brands that are good? Still not finished yet but here he is half way done... 20171118_001347-1 by Zapins, on Flickr 20171118_001326-1 by Zapins, on Flickr
I'm assuming that's an Auburn Warr Eagle. Can't help you, sorry. I am interested, though, in the success of this casting.
Regarding the fibreglass: I just use boatbuilder's epoxy and cloth from a company called Nuplex (used to be Fibreglass International). The boat builder's epoxy is a 5:1 two component water clear epoxy that goes a bit yellow with age after curing and there are three types of part B: slow medium and fast cure. I get the slow 24 hour cure as there's a fair bit of heat developed here in the tropics and thick sections can burn the resin from this heat. By mixing some sort of non abrasive filler (never abrasive sand) like aluminium shavings or sawdust or even small chunks of wood offcuts you will save a lot of resin and minimise the heat melting something or softening sticky tape and dumping the resin all over the table. Cheap digital scales are essential for batching out the resin, epoxy is a chemical reaction so the ratios have to be fairly precise for best strength/hardness. Tight sealing with silicon/silastic/RTV can also be used as well as lots of sticky tape is critical as epoxy gets very runny when warm from the cure to begin with and can find and tiny gap to leak through as soon as you turn your back. Carnauba furniture wax or mold release wax is used to coat everything you don't want the epoxy to stick to permanently, it will have instructions for that particular brand on how to apply and how long to leave, usually a half hour before polishing. For non structural stuff, using fabric instead of glass will sidestep any glass fibre contamination issues like cutting tool wear and itchy glass fibre contamination. You end up with a fabric plastic laminate something similar to Micarta and can use old jeans or bedsheets or rags for a source of fabric. I use the glass cloth, with the thickest weave used to build up thickness and the thinner cloth to wrap around complex curves/shapes as it's much more flexible. Older style tin snips work well for the really thick fabric and scissors for the thinner fabric with frequent sharpenings. You'll be able to tell your cutting tools are getting blunt as it will not shear the glass cloth so easily but spits it out of the cutting edges, a quick grind of the cutting edge with a bench grinder to give a sharp corner with a coarse finish helps grip the cloth for both the snips and the scissors helps. Pinking shears are expensive and also used to cut glass cloth as the serrated cut grips the slippery glass cloth better. Be prepared for glass fibre contamination if you are sawing cured fibreglass and prepare accordingly, like cutting outdoors in the driveway and hosing down the dust after. Cutting glass wet keeps any dust from power tools like jigsaws down and keeps friction heat low as the saw blade goes blunt. I have three red T shirts and a few old worn shorts I do my fibreglass work in exclusively and wash separately: in the sunlight you can see the fibres glint faintly and they are there for good. This is mainly to keep the workshop free from abrasive, itchy fibres. Glass fibres are considered harmless but itchy compared to asbestos, the reason asbestos is so bad is that the fibres can be divided into finer and finer fibres almost down to infinity where a fibre can pierce a human cell, damage the DNA and trigger a cancer from the inflammation, glass is too coarse by comparison with the squared off end of the fibre being a similar size to the cell itself.
Your chicken is looking good man! NO vacuum is needed with rebound 25. Hope you bought 2 kits for that thing! You are going to need it. 1st coat, nice and thin. Let dry then coat again with the thixotropic clear drops. Then goop it on. You will want the R25 about 3/8" thick. Are you planning on slicing the silicone from top to bottom after you have him encapsulated?
lol chicken I'd prefer not to slice it if possible. I've been watching some videos on youtube. Seems some people just keep the silicone in one piece like a sock and just roll it off in one go. Others seem to have a slit cast in the side and others seem to make individual pieces of silicone that socket together in grooves. I'm not sure which would be easiest for me. I think the instructions said to do 4 coats of silicone rubber and build it up to whatever thickness I need. So I guess that is 3/8" like you said. So something like this marine epoxy for boats will work? I couldn't find the "boatbuilder's epoxy" brand https://www.ebay.com/itm/Boat-epoxy...072249&hash=item362273e98d:g:Bl0AAOSwFNZW1K9i For the fiberglass, I see you use glass cloth, does it matter the brand? Can I buy any of the fiberglass cloth they have on ebay? I saw you said even cloth like jeans will work. That makes me think it doesn't really matter too much what I throw into the epoxy. Also, they still make asbestos fiber glass? :O I'll be sure to not buy that. I don't want mesothelioma.
i would do it as a sock if you can. Cover it and you will see how hard it is to remove. That will be how you will find out if you need to cut it. Wal-Mart sells a fiberglass kit in the auto repair section.... grab some extra hardener and some fiber glass cloth... i hate the chopped, but you'll want to use some of it too and I think the kit came with it. (about 20bucks) No asbestos to worry about, you can't buy it. You could run plaster of paris in a few sections for mother mold... Just another option. Use plasticine clay directly on the silicone to divide sections and PoP away...
That's not a damn chicken son, it's a pigeon! Zap, you aren't going to like the price of the epoxy resin. Why do you want to use epoxy anyways? POP will do the trick and ALOT cheaper.
Oh, and I don't see how on God's green earth your going to be able to avoid the slicing. That Pigeon has TOO many fine details.
POP is brittle and heavy to shake around during the wax molding process. Fiber glass and epoxy would make a good light weight shell. The epoxy seems fairly resonate at 50 shipped for a gallon? How much will I need? I'm thinking 1 gallon should be fine for the bird plus maybe 3 of the rebound 25 kits. I think I'll have to slice the bottom to get the feet out if I make it a sock. Might be easier to do it in 3 parts that socket together. Where's our friend who made the owl sculpture a while back. Is he still in the hobby? Alive? Too bad photobucket screwed us all, he had a lot of good pics that we didn't save (yes I have some saved and others emailed me some too, but still some missing).
Did you look at smooth-on's plasti paste stuff? https://www.smooth-on.com/products/plasti-paste-ii/ For that bird, I would invest in using the real stuff or fiberglass. I would cut it's legs off just like I did the jewelry box. (it's gonna really suck to do that, but I think you might not have much of a choice) The rest of it should work with R25. Don't use the R40 it will be too stiff in my opinion. The good news is you can reattach the legs in wax before shell so you wont be welding them back on in bronze. The owl was made by mantrid. I've searched high and low and cannot find him. I really wish we could find him as I could really use his guidance. The million dollar question is where are you going to "hole" him out at? Chest? Back?? He HAS to have a 3X3inch hole SOMEWHERE on him so you can cast him hollow??? And that piece will have to be cast and then welded back into the bird. If you still suck at tig welding... You'll be an expert at welding and chasing when finished... lol Get out the video camera, this I wanna see brother! You can do it!
There's no asbestos used anywhere in fibreglassing as far as I know, even historically, I just wanted to contrast the relative risk: fibreglass is itchy and you probably wouldn't want to breath it but that's about as far as it goes. As far as resin and glass cloth goes, the best stuff is whatever's cheapest, I think there's like only 5-6 epoxy plants on the planet and a few different chemistries involved, so cheapest is the go. As a rule of thumb, the closer to 1:1 mixing ratio, the more inert filler there is mixed in. The 5:1 stuff I use is I pay around USD $112 for 13 lbs of resin or $150 AUD for 6 kilograms.
I used to talk to Mantrid via E-mail a good bit, but suddenly he disappeared. I have attempted to contact him a number of times. His web page is gone; his e-mail is invalid; he is gone . . . I have rarely seen a man just evaporate like that. I have Mantrid's complete posts on his horse project and on his owl project, complete with all photographs. If you (or anyone) are interested let me know. They are the best tutorials on mold-making I know of. Why are you using epoxy? Polyester resin is much cheaper and works great for mother molds. Thicken your resin (either epoxy or polyester) with Cab-O-Sil (fumed silica available from any plastics supplier). (For those who haven't learned the hard way) One of the most important considerations in making a mother mold is: Can you get it off when it has hardened? You have to think this through. Undercuts in your silicone mold will lock your mother mold on. You must either fill in the undercuts with silicone, or make the mother mold in more than two pieces. Richard
I have and his name starts with the letter L. Have to agree with Rasper on all accounts here. Rasper, would you kindly start a thread and add the info and wherever pics you have on this topic?
Yeah I think reposting his threads would be a good idea since the images in the original thread are dead. What is polyester resin? I haven't heard about it before. Do I add fiberglass in the same way to it to stiffen it up? I think cutting the legs off is probably the way to go especially since I will be casting the stick he is sitting on as well. And a hole in the chest for the hollow core. That is one of the reasons I blended the feathers on the chest instead of having them with sharp edges like the wings. It will be much easier to weld and grind the smoothed feathers. By camera do you mean film the mold making process? What's the name of that editing program you use again? Windows movie maker is irritating to use.
Polyester resin is what everything made from what we call "fiberglass" is made from: boats, Chevrolet Corvettes, bathroom shower stalls, etc. It is normally used with fiberglass cloth, but can be used with fabrics or mixed as a putty. Bondo (automotive body filler) is just a fast setting polyester resin with some fillers added. Richard
I will have to speak with David F (the owner of this forum) before I can do that. They are both posts off of other forums, one from Alloy Avenue and the other from Sculpture.net. Richard
Looks like a lot of time and effort has gone into it Zap. Nice work! Whatever method you use (sock/split) the outer casing will have to be seamed and split? I would look to incorporate the silicone with the outer shell so that everything keys together properly. Doing separate halves makes sense to me, but I haven't done any yet!
Mantrid did pull a vanishing act the likes I haven't seen too often.... Makes me wonder if he is even alive? Zap, go get Shotcut. It's free and works a treat! You will delete windows movie maker after you get the hang of shotcut. Toboho Mott turned me onto this recently and I love it for clipping videos together quickly. Hell if I could get OCD using it after 20 mins on the phone, you'll have no issue with it. https://www.shotcut.org/ To piggy back on what Richard said about locking a mother mold on... During the silicone process, you can add additional silicone up, over and around those details in large amounts to prevent the MM from locking. Artopsy (John) in france recently passed on a great tip about "bulking" up silicone molds to save a buck. Grab some cured junk silicone and chop it up and add to your mix. Adding it to coats 3 and 4 wont effect surface detail and will give you the bulk you need. Floppy silicone baking pans from goodwill are great candidates for this. Vote 1 for cutting the hole in his chest. You should be able to hide the rework on his chest a little easier than on his back. Grinder and paint make me the welder I aint! This is what I'm using at the moment. The stuff is pure chinese GARBAGE, but they are working so well, I bought more! lol http://forums.thehomefoundry.org/index.php?threads/bronze-chasing.171/
Geezzzzz Jason, Thanks buddy. What ya trying to say here, That I'm "Special/Slow" ? Zap, Fiber glass resins are activated with a hardner. Fiberglass matting, (all you need is a lightweight matt for what your doing) is then saturated with resin. The saturated matting is then laid upon the area of application. Now, if it were being used for actual repairs to boats, cars, etc, a perforated roller would be rolled over it a few times to release and remove trapped air. If it were me that was utilizing it in the manner your want to use it I'd do it in a vacuum chamber because there's no way on God's green earth your going to remove the trapped air any other way, at least non that I'm aware of.
Oh and by the way, you must have been drunk that night because we were on the phone for about an hour just messing around with the program. Actually, I think we were drinking that night. Zap, word of caution, save Often & Frequently.
