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About Julia

  • Rank
    Mostly Harmless
  • Birthday 06/06/1987

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  • Gender
  • Location
    Yläne, Finland
  • Interests
    Casting, drawing, painting, jewelry, metalwork
  1. My Journey into Lost-Wax Metal Casting

    Hi, like I said before, I do not have an electrical kiln for melting, so I asked around and here's what I got: heat the metal at least 100F over the desired temperature, that way you'll ensure that the metal has melted completely. So in this case it'll be around 1880 deg, 1900 degrees also works and 2000 is a max before the metal is too hot to cause problems. Your burnout temperature is ok, 950 sounds about right for a casting temperature, 1000 is for finer designs: filigrees and such. I've heard that it's recommended to heat the flask 75-100F hotter when using a vacuum, but I'm yet to test it myself. There are two things that can cause partly filled casts: temperature and sprues. Like Kang said earlier, a failed burnout will leave evidence, the surface is like bad case of acne or a side of a moon with all those little craters and such. If it's too hot: it'll do craters, tiny holes, cavities, plus this stuff that looks like sand and if too cold, the metal doesn't usually even reach the sprues and looks kind of sluggish and sad. You don't have any of that, so my bet is in the sprues. With small objects like these, make them as short, even and straight as possible. Try to avoid curves, bumps and too much of tapering, because if the sprue gets too thin too fast, that kind of shape will act as a nozzle and it will sort of spray the metal around instead of moving it forward. The thickness should be around the same as the model's. If the sprue is too thick, I've noticed that not only does it slow the metal down, but it will act as a storage unit for heat and that'll cause porosity on the ring shank. One last thing is that I see that you're using a secondary sprue. Try to get it to fill at the same time as the main one; now what happened is that the main sprue started to fill ok, but the flow was suddenly cut by a secondary sprue which started to fill at a slightly different time than the main branch and without a good momentum, it solidified. Just a thought :) To be continued tomorrow, G'night!
  2. My Journey into Lost-Wax Metal Casting

    Hi and ack! That's a real bummer and real odd is the way how the models are all only partly filled. I don't see any porosity or shrinkage due to temperature, the parts that has been filled looks solid, but there are a few things with the sprues that I need to take a closer look at. Looks like a flow issue. I'm a bit in a hurry at the moment, but I'll take a closer look of the model and sprues later today. What's your final kiln temperature and do you let the mold temperature set before pouring? ~Julia
  3. My Journey into Lost-Wax Metal Casting

    Awesome! I can't afford to buy a Kerr either, can only dream and drool I've been looking for a used electric melting furnace, but people tend to ask for a same price as what you'd get by ordering brand new from China... Those graphite crucibles don't need to be seasoned, right? I've only heard about tempering to make them last longer. Do you have something to swirl the melted metal around to make sure it has liquefied completely? Like a charcoal stick or something? ~Julia
  4. My Journey into Lost-Wax Metal Casting

    Hi, Sorry to hear about the cast gone bad. Have little knowledge about the electromelts, except that I'd like to have one :) Like you said yourself, It looks like the metal was too cold: we usually overheat it a little, because once you're ready to pour and especially with precious metals, at the beginning you tend to be more careful and try to pour slowly, which makes it to cool even more. (By the way, it will become easier as you'll get rid of the idea of pouring silver...it's just the mental image of pouring something expensive that gets on the way. I had that at the beginning and having silver dust at my clothes ended to this atom search and could spent quite some time gathering every little bit I found...now I just pretty much dust my clothes like it's wood dust. Same goes with the casts, now it's just like bronze, but the color is different :D I also like to use long cylinders and long trees for all of the casts, even if there's not too many items to be cast. I'll lose some investment in the process, but the casts turn out better because the poured material gathers speed along the way and the fill rate is much better, because at the end of the tree the velocity forces the material into the small cavities better than anything else. Was the crucible coated before you started to melt the silver? Was it a new one? I've had a cast go nasty, because the crucible had too much sediment from previous casts: the metal didn't melt at all, it remained in this weird gummy state. Anyway, the pink stuff is copper, I normally don't do anything about it. It might look like it's a big portion of the copper content, but it's not. It usually comes off by scrubbing with a brass brush. It would only make a difference if you'd keep on melting the same item over and over again. The copper would eventually burn away.
  5. Boxer Rebellion: Box-Turtle Folk, WIP

    Hey, You can cut the bronze bar into chunks with an angle grinder, but it's not a fun task: lots and lots of fine bronze dust, sparkled like a champ for a few days. We use an old horizontal metal bandsaw, the saw itself is something specific for stainless steel, but the bronze is so soft that a normal saw blade will do just fine.
  6. Sculpting and casting

    Hey! Just finished The Last Order. Phew. I look like something 'fresh' dug straight out of a grave; ragged clothes, dirty hands, messy hair and a pale winter face to match the rest. My husband has been reading zombie novels and is convinced that I'll Turn in any given moment Jeeze, what a month! Anyways, thank you robin and Kang! The spirals were tricky and without the small gates, there's no doubt that the spirals would have been incomplete. I did notice some shrinkage, so next time, I'll make the gates a little bit bigger to ensure a good flow. Finished the milk churns. Ended up using silver sheet and wire instead of casting. We had some nasty weather which blinked our power on and off. Power failure and kiln...umh, no thank you. I'm off to rummage through the fridge, make a fortress out of blankets and pillows...and then I'll buy a book. My whole meaning of existence for the next day or two is to get fat and happy. Sounds like a plan. It's the Best plan ever. ~Julia
  7. Sculpting and casting

    Whoo! Thanks for the luck The cast was a success! The picture below is what it looked like after I removed the investment with citric acid. This tree were cast in silver, so those white specs that you see is actually fine silver and the gray stuff is oxidation- this is normal, I use 925 sterling silver which has 92.5% of fine silver and the rest is copper. The copper in the silver reacts with oxygen and what you'll get is that dark surface, which needs to be removed before polishing. That's what I'm doing now. Lots and lots of sanding, sawing and filing. Here's a few of those hands after the first rough sanding. Had no dents or holes, which is really nice: Back to work, cya! ~Julia
  8. Sculpting and casting

    Jack, Thanks. I'm hopeful, that someday someone would like to have a whole set...*fingers crossed* emmagine, thank you so much for the info- I'll definitely test both Fimo and Primo. Every now and then I get these commissions that reach my workshop just way-too-late. For a caster this is a nightmare, because I only have enough time to make a single cast, that has to be perfect. It feels like taking a swim in the middle of the night...and knowing that there are sharks. You'll most likely be just fine, but the idea that something can go very wrong lingers inside your mind like some kind of superglue. I'm commissioned to make 20 hand shaped logos, that has a spiral in the center and spirals are nasty things to cast! Here's the master: The tree that I whipped together today and is going to be cast on wednesday: Wish me luck ~Julia
  9. Sculpting and casting

    Today was more of a traditional work day. My workshop looks like a war zone. I made a silver brooch for a customer using 1mm silver wire and a whole lot of soldering and polishing. The pin wire is stainless steel, so it will keep it shape better than silver. Don't know how many times I lost the miniature hinge...dropped it a few times, lost it in the chaos among the tools and before soldering, found it wrapped to my clothes
  10. Sculpting and casting

    Thank you. I'll make a master straight out of the wax model- I want to be sure to have at least one plan B, if the cast comes out incomplete spending a few bucks on mold material is a way better option than having to start all over again. That's why I love RTV-silicone, being able to make a mold from the wax model or any other material, that would be destroyed in vulcanizing temperatures. But the wax will be cast in bronze, after the mold is complete. I want to see how the blue carving wax burns and does it need a longer burnout than the injection wax. I've heard that the hard green and purple waxes needs to be at the highest temperature at least an hour extra to have a clean cast. This was the first time I used the blue carving wax. It's quite nice to work with, especially now when I've started to understand more of what kind of tools I like to use as it's so much different than working with soft waxes. That ring is mostly done with burs, wax files and an exacto-blade that I modified to have only just the tip for carving very small, tight places...cut only just one finger, so I'm evolving Oh and the wax can be polished with turpentine, which is nice.
  11. Sculpting and casting

    Kang, ravens are beautiful creatures...from a distance terrifyingly big birds. We run out of gas for melting, so I still have time to make a few new tests for the next cast. I'm in a hurry, so I'll have to keep my ramblings short Carved my first celtic knot! It still needs to be polished and cleaned up, but I'm pretty happy how it looks right now. Got to run, cya!
  12. Sculpting and casting

    Hey! Andy, it sure does save a LOT of batteries- it does help if you clean the tip with a brass brush once in a while, the wax tends to build up and burn, making the burner less effective. The wood burner sounds interesting, just thinking that will it be too hot for wax? If there's smoke, it means that the wax is burning and that changes the wax structure somehow. What I've gathered from the casts gone bad, it may be a reason for porous bits along the sprue channels. I've had it happen to me once, but there are so many things that can go wrong, that it's difficult to say what caused it. Wang, wow..googled the wax pen, never realized it shares a name with a vaporizer. Oops, heh. What I used before was a Matt speedy wax pen, it's great when fixing and melting small bits of wax, but when it comes to building a tree, it takes ages to get everything attached. So, $29 is just about the right amount, plus taxes and shipping. DIY is the best Mori, it's nice to meet you too! Did you happen to finish the elf yet? Eagerly waiting to see it painted! Strawhat, thank you! I kind of locked myself into the workshop for couple of days; had a maddening phase of procrastination. It's driving me insane to get stuck on everything I try to accomplish; my head is as useless as trying to catch farts So at the moment, it's pretty much a big no-no to read the forums before I get to work. Oh well, this usually doesn't last more than a week (hopefully): can't wait to be able to function again! But thanks to the lockup, I did manage to make a new model of a raven. The model has a bird on both sides and I'm thinking that I'll make yet another spoon collection...or a really fancy fork... or a hair pin? Well, something usable anyway. I'm going to try the medallion idea next, just to see what it looks like after it's cast.
  13. Sculpting and casting

    Popping in to say hi. I've been making wax models to assemble at least 4 big trees for both silver and bronze casts. A vital tool for me has been a wax pen, that I use for melting wax for various purposes. I'm so used to it, that losing an equipment like that feels like being without power and that's what happened yesterday; it stopped working. I panicked, because buying a new one (even while being cheap) is not an option at the moment. So, after a frantic search around the house to find something similar, I came across an old glue gun. I modified it. There's now a thin silver wire at the end to conduct heat, held firmly in place by a bit of green stuff I now own one of the world's cheapest wax pens ever made. It cost me around 6€. Behold! The DIY wax pen. It's darn ugly, but it works:
  14. Sculpting and casting

    Thanks might make more squids later: perfect for left-over green stuff. Cleaned up a bronze cast that I made a while back- never done a scythe or any weapon/tool of this size. Was on my "things to try"-list. Just like the dragon this will be made to be part of a spoon, plus a few to be made as pendants. This is a master for a mold, so as much as I'd like to tidy and clean it more, it needs to have as much material as possible for future casts. I'll solder a sprue to it later today.
  15. Sculpting and casting

    Had a training day for sculpting. Have a bit more control now: tested a mix of super sculpey firm and green stuff 50/50...not a bad mix, adds some working time and is not as sticky as green stuff alone, plus the color is quite pleasant grayish green. Might work well with the jewerly modelling, it takes twice the time to cure tho'. My end result is kinda weird, chubby and cranky squid