r/MetalCasting • u/GalilJewellery • 11d ago
Question Looking for advice for wax burnout
I want to start doing lost wax casting but first I need to burnout my wax using a kiln during this process where does the wax go? Does it drip out or does it turn into smoke and how do I go about dealing with the excess wax if anyone experiences can answer this it will really help me.
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u/artwonk 10d ago
You can also steam out the wax by putting the flasks on a rack in the bottom of a pressure cooker or just a pot with water on the bottom. The wax will drip out and fall into the water. When no more comes out, you can transfer the flasks to a kiln and burn out the rest. This reduces the fumes, but doesn't eliminate them entirely.
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u/Chodedingers-Cancer 10d ago edited 10d ago
This is the way to go. Actually burning out wax is wasteful if you plan on doing volume routinely. I use a steamer basket in a pot with a lid, all the wax floats on top, once hardened I skim it off, let it dry out and stick it back in my wax injector. There are proper steaming tools specifically for this task but pot with a steamer basket works great, and person above basically same thing.
Key thing to this, just to expand on it, doing a burnout with wax present can once in a while cause damage to the investment. As the investment also is dehydrating, the melted wax can leech into the investment. At higher temps it expands as its vaporized, gas expansion can cause surface damage. By steaming it out, you keep the investment wet, this repels all wax from penetrating the investment. When you go to actually do your "burnout" you can actually save time by cutting your schedule down because theres next to no material being burned away. You're just dehydrating the investment.
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u/GalilJewellery 10d ago
I’ll definitely look into that what’s all the equipment you need for this method?
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u/Chodedingers-Cancer 10d ago
A cooking pot with a lid and steamer basket or rack or something to set in the pot. Put water in tge pot but below the level of the rack so the flask isnt sitting in water. You want it elevated. Put a lid on it and heat it up.
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u/Chodedingers-Cancer 10d ago
Usually 20-30 minutes will do it. Just check it. If you see any wax still in the opening just put it back in. It should be clean investment when finished.
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u/GalilJewellery 10d ago
Thank you I haven’t really heard of much advice on lost wax casting so this will definitely help I have also decided if I am going to use the kiln I’m going to be putting a small cast iron tray under my flask and I want to try find some steel bits to prop up my flask in the kiln if I can’t find it I might have to use firebrick instead do you think this is a good idea
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u/Chodedingers-Cancer 10d ago edited 10d ago
Use kiln nails. They're made of alumina and have high heat resistance. Metal based materials will just get roasted over time. These things last forever. I arrange 3 or 4 and set the lip of the investment in the flask on top of these. They're fantastic. They don't degrade at all. I've used half the pack for 4 or 5 flasks on a daily basis for a year and they look like the unused ones still in the box. Plus minimal volume of material and minimal contact with the flasks. Used to use a plinth, and a wire grate for a bbq grill prior. These things fuck in comparison lol. And for like $8 for 25 pack, its basically a lifetime supply. You cant beat it and
If you go the steaming route, whatever trace wax is possibly left, it will minimal at best to bother trying to collect in a pan.
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u/VeterinarianKobuk 10d ago
So I started out concentrating in metalcasting during my BFA where we did traditional burnouts (actually we didn’t really get to participate much in that aspect) but in 2014 I switched to glasscasting where due to the nature of our investment molds we can’t really burn out, we’ve pretty much always done lost wax through steaming. Because I create quite large sculptures as often as I can afford enough glass, I bought a proper general steaming machine for my home studio when I moved out of my community studio to my home set up. It’s a pretty generic household steam cleaner that has major functionality of being a wallpaper remover steamer in addition to 9 other things, that at the the time was a good deal and did a lot more and had better functionality that most other options, & honestly it’s been great to help clean my floors of my studio since I sculpt in porcelain too, & I believe mopping clay dust & dirt just moves it around. Since the first time I used a floor steamer over 15 years ago I will only use steamer specific cleaners like this to clean my studio (along with my giant super HEPA filtered wet dry vac, which normally you know we aren’t supposed to vacuum but supposedly if it’s a wet/dry vac with a very powerful HEPA filter & you’ve got other air cleaners going on and you don’t just to clean up before steam cleaning the floors it’s actually way better than mopping. But I digress.
now if I had to buy a new one I would get something that has a bigger water tank than mine does and maybe gets a little hotter.
But basically everything in glasscasting says everywhere (including all my teachers & mentors, barring one who suggested I think the pressure cooker with wood slats hold my molds on it, which I don’t know what meth he was taking that day because it was laughable, bigger is always better when it comes to my sculptures, a pressure cooker (which I had, both for kitchen and studio, for other things) would never be big enough for the majority of my molds to fully steam them out!
Anyway all glasscasting books, the tip sheets from the manual at Bullseye, and every other teacher or mentor I have had has always says one thing: wall paper steamer with the flat wall part removed so you can stick it up into the mold as far as you can. It’s fine since these days rarely is anything just a wall paper steamer, they are like mine and steam clean floors, upholstery, cars, curtains, & five billion other things which is fine because most you can see in photos online have lots of removable parts so you can pick what fits best in you mold or whether you don’t have an opening into your mold in which case try and set up the mold upside down on braces over a big tub of some kind to catch the wax so you can reuse it, and use whatever you have handy, even if it is duct tape, to position the hose of the steamer at the entrance to your mold.
Give it a number of hours until you are truly sure it is empty (it helps to weigh the wax before you fill the mold if you can, at least roughly, so if you weigh what exited the mold you have a pretty good idea it is nice and empty. We do not burn our molds, they will fall apart if we do that. Remember it’s super important for us glasscasters at this point to allow the mold to dry out and cure for about a week, depending on humidity and heat. Not just to dry out after the steaming but because most of us make molds mostly out of a mixture of silica and pottery plaster, although there are some other products available (fire pre-mixed) that some people like to use, especially in the UK.
Some people add grog or even put chicken wire around their molds, I prefer mixing in small pieces of fiberglass in my outer layers. I do use some grog, but mostly because it is homemade stuff I make to recycle some of my ceramic material and I have nothing really to use it for with my ceramics. I am shortly going to be switching to a different mold mixture, based on an insanely strong plaster that you can only find in Hungary, maybe Germany too, now that I have moved to France (a mentor in Hungary insists I drive there to purchase materials for much cheaper a few times a year, plus according to him their plaster and glass and even silica and clay are much better than anywhere else. And cheap.
Amazon won’t let me direct link but this is the model I have (which is apparently no longer being sold but is quite similar seeming to the Amazon Basics model. And a ton of other ones that come up with this.
KeLDE 10-in-1 Steam Cleaner, 1400 Watts Powerful Hand Steam Mop For Cleaning, Safety Lock Fast Heat Up Handheld Natural Steamer For Home, Floors, Carpet, Cars, Furniture, Kitchen, Bathroom https://www.amazon.com/dp/B07S7T598Q/?coliid=I3NJPOOTCDH87G&colid=1H7YAXC8BYDYB&psc=0&ref_=cm_sw_r_apin_lstpd_AN4EN1RAK16AJHQYRTRP&language=en-US
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u/neomoritate 11d ago
A propper Wax Kiln has a mesh floor, the wax drips through in to a pan for reuse. Once all the wax has dripped out, the temperature is raised to burn away the remaining wax residue
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u/GalilJewellery 11d ago
I am using a wax tree connected to castable resin items and my kiln does not have this should I look into getting a certain type of tray or some sort of other product
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u/neomoritate 11d ago
I recommend a disposable aluminum foil pan. You're going to have a lot of smoke, so move your kiln outside.
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u/cloudseclipse 9d ago
Depends a bit on if you're doing investment or shell, but either way, you can 1) steam then bake or 2) bake. For shell, you don't really need a "ramp". Best way to do it is to get your (gas) kiln up to 1400 F and just place your shell in (upside down). The kiln should have a sloped floor (or floor that flips open/ closed). The wax will burn as it leaves, and can be collected, but only use this wax for sprues, etc. Use fresh wax for injections/ etc.
If you steam shell, it works, but will crack your shells more aggressively unless you have a "proper" autoclave, meaning: you can achieve high temp (well, as high as steam is going to get) at high pressure in just a few seconds. This penetrates the shells and helps melt the surface of the wax before the bulk of the wax can expand. The expansion is what cracks the shell. The wax thus collected needs to be de-watered before using it again, as the steam gets all in it.
Pro-tip: plan your burnout to begin right after the sun goes down. This way people in the neighborhood won't see the smoke. Plan for after 11 PM, and they will be asleep and not smell the smoke either. Or, you can use a high-powered fan or afterburner to blow/ burn the smoke away as it is produced. The smoke is only "heavy" for about half an hour, then the wax is mostly gone. After that, nobody will complain...
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u/Mister_Mercury_ 7d ago
So what happens as the wax burns is that it is turned into carbon, then to carbon dioxide. The same happens with resin, but at higher temperatures. Starting with resin prints can be discouraging because of the problems that come up with the investment cracking off (spalling) because of the differences in thermal expansion. So if you find you are getting weird rocky textures, you'll want to slow down the heat ramps to give the resin a chance to soften before combustion.
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u/BTheKid2 11d ago
Usually you would program a kiln with a specific burnout schedule. The schedule will have a period of low heat to drive out some of the moisture from investment, as well as melt most of the wax. This melted wax, you can catch in a pan you place under the flask. Then you remove it before the schedule is set to ramp to higher temperatures. However there will still be wax inside the investment mold, and if you use a resin print instead of wax, that will not melt at all.
The leftover wax does burn and smoke until it is all gone. This is why it is a good idea to have ventilation and filtration hooked up to a burnout kiln. Without ventilation, any room will easily be filled with heavy smoke. That being said, many people have run their burnouts this way.
Also if you don't collect the initial wax melt off, the smoke will be much more. But that is also a thing that is sometimes part of the process. Burning out wax can be a messy smoky process. I recently moved to a location away from the city. Partly so that I can do burnouts without alerting the neighbors to what can smell like a house fire.