Hello. You can put 3-6 wax "wires" on inside wall of the flask, going from bottom to 3/4 of the flask, so the vacuum can "go" on the side of the flask, like if it was perforated. Not sure if you understand what i mean. Try to have less dead volume on the bottom of your flask too. The less the better.
I saw VOG doing this in his videos and wondered what the tiny wires of wax were for. This actually makes a ton of sense, thanks for explaining! I have all the parts for my setup, just need to find the time and I can try my hand. Good tip!
A vacuum gage would help you out. You need to run the vacuum for enough time to build vacuum before pouring your metal. Also, you'll get better results by sizing the flask to fit your wax. You don't want that airspace under the investment that you have in the video. You could work on the main sprue shape so that the bottom of the main sprue breaks into the feed sprues for the bottom 2 pieces. Another thing you can do is to run small vents from the top of the coins to decrease back pressure. You could also add a vacuum reservoir, essentially a thick walled tank that you can pressure to the correct vacuum level and then release to the casting table rather than depending on the vacuum pump to pull enough vacuum as they aren't really designed to get up to vacuum very fast.
Will this work with a perforated flask inside the vaccum chamber? Maybe making a lead with a hole of the size of the flask . Or maybe there is to much air in the vaccum chamber to do it effectively whole pouring
Is your vacuum table hooked directly to your vacuum pump? You could use your vacuum chamber as a quick way to boost your vacuum table if you plumbed it in with your table. Pull a full vacuum on the chamber and seal it with a ball valve. When your ready to pull vacuum on your metal you open the line from the vacuum pot to the vacuum table and also start the pump.
With the 3 way valve in essence its hooked to both. That's basically what I did, charged the vacuum chamber then when pouring opened the valve so that vacuum was pulled from both the pump and the chamber.
Uh just a little safety advice the plaster flask will sometimes come apart during the pour of the brass for various reasons with no container to catch that molten metal when it hits that plate there's gonna be some splashing 1000 degree run off on the bench.
Ikr, it's just gonna get sucked down the hose, wrecking the pump in a potentially violent way. It's bloody stupid to use this design. No chamber or trap etc
You might consider a flanged adapter that sits on top of the vacuum table, into which you seat a perforated casting flask. Let the vacuum build up and pour away. I suspect it work better than the straws method, but you won’t know until you try! Great video!
you can ad (drinking) -straws to closed flasks. running along the inside flask wall, from sucked bottom/side to well below the top/pouring side. This ad to the "ventilation" Also you could ad more sprues connecting the items from beneath to enhance the flow of metal.
I've found empty disposable bernzomatic propane and mapp cylinders can be turned into handy little DIY flasks. They're just shy of 3" in diameter. Just make sure to completely vent the tank first before taking a cutoff wheel and cutting it to the appropriate size. (This operation is probably kinda dangerous so for safety reasons nobody should do this but it worked for me)
This is yes, this method only allows the metal to walk in the mold. What I'm looking for is the casting unit and the mold, all together in the vacuum chamber, for the casting to take place in this room. The formation of pores in the metal cannot be prevented by this method. I see that everyone is after the shape of the right.
Cool. I just built one last week and am editing the video of the build now but mine is for a perforated flask. My question is, how do you know if you actually got a vacuum seal on your flask? Do you have a gage hooked up to it to see how much vacuum you are drawing?
Nice! You can see in the video me pushing the flask down with the crucible, I do have a gauge on the vacuum pump so that indicates if there is a vacuum as well. Yeah I think perforated flask is next...wanted to start out simple :)
Hey man you are doing exactly what I want to be doing with casting. In your links in the description you forgot your flask and rubber bottom for flask. Can u tell me where to get those mostly the rubber bottom.
you need to have a away to stop molten metal from entering your vacuum pump and destroying it, if your investment gets a crack, mine did, but I had stuffed the vacuum line with steel wool, saving my pump. also put on more legs, with a heavy pour the table could tip, very dangerous.
This actually happened to me but the molten metal cooled too rapidly to make it anywhere close to my vacuum pump. I ended up having to replace about a foot of hose. Either way its a good tip when building something like this to put a chamber below the vacuum table as a buffer just in case. 👍
Hello Sir I have been learning from you and your skills thanks for the work you do for us. I was wondering if it would be possible to make a pressure chamber attachment that can push molten further into the small crevasses of a mould to achieve better quality result ?
It could be possible, I know I've read of using a wet rag and placing it on top of a mold as soon as its poured thereby making steam the pressure of which would help push the metal into the details. I have tried it before with mixed results. I think in general you will get better results from vacuum casting though.
Thanks for this good video, if I have a constant mold(instead of a plaster mold), can I do this method? Is the pressure difference between the 2 parts the main reason for this high accuracy?
The investment (a mixture of plaster and other things) allows some air to move through it although only a small amount. SO it depends on what your constant mold is made out of.
@@r.sadeghpour put a cork of investment in the vent end of the mold and apply vaccuum while pouring. The investment plug will stop the metal from entering the vaccuum but still allow vaccuum due to it being porous.
Maybe check out 5:45...the fact that you didn't bother watching the whole video before commenting tells me maybe metal casting isn't for you....try another hobby.
