Back at it. Lost pla cast iron ceramic shell

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Shopgeezer

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So what temp did you use to burn out the PLA? I want to do this as well for aluminum casting. I have read that PLA leaves ash residue. Did you burn out the mold with the sprue up or down?

Don
 

aonemarine

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So what temp did you use to burn out the PLA? I want to do this as well for aluminum casting. I have read that PLA leaves ash residue. Did you burn out the mold with the sprue up or down?

Don

Pla leaves no ash behind. I burn out with the sprue down. The burn out is to calcify the investment and the top end of the burn out temperature is 900c and held for 1 hour following the manufacturers instructions.
 

Willyb

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Great job with the castings. Very interested in this method of Casting instead of using Sand Molds. Would be interested in hearing your procedure to get such good castings. I would call these Castings perfect.
Questions
What are you using for the Slurry coat and how many coats did you use? Did you add sand after each coat?
I would like to try lost PLA Casting with aluminum. Hope you don't mined the questions.

Cheers
Willy
 

aonemarine

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Great job with the castings. Very interested in this method of Casting instead of using Sand Molds. Would be interested in hearing your procedure to get such good castings. I would call these Castings perfect.
Questions
What are you using for the Slurry coat and how many coats did you use? Did you add sand after each coat?
I would like to try lost PLA Casting with aluminum. Hope you don't mined the questions.

Cheers
Willy
That was suspend a slurry fs by ransome and randloph. Yes sand after every coat and i put a total of 9 layers on it. You can get away with less if your using wax.
If your going to be casting aluminum then you might want to look into the investment block method and use vacuum assist. But if the part is too large for that then use the shell.
 

pjpickard

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Excellent! Do you have further info on the whole process?
 

pjpickard

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I guess the entire process...I can just look it up, but your results are so great that if you have any other info showing the process i would love to see it. I'm in process of setting up for a lost wax foundry at the moment, but tis for smallish stuff only. I'd like to do bigger eventually.
 

aonemarine

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I guess the entire process...I can just look it up, but your results are so great that if you have any other info showing the process i would love to see it. I'm in process of setting up for a lost wax foundry at the moment, but tis for smallish stuff only. I'd like to do bigger eventually.
Its really quite easy, but at the same time there is so many little things that make all the difference and every casting is inherently different. Might be easier if you showed me what you were going to cast and I could explain how to go about doing it and why I would do it that way.
One of the biggest things is to have a nice clean melt of a known alloy, not just random mixed scrap. This allows you to get to know how an alloy acts when it is cast and you can adjust your techniques based off previous results.
 

abby

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That is very impressive aonemarine , what plastic are you using for the patterns ? my own experience of burning out printed plastics , albeit in block moulds , has not been promising as the pattern expansion prior to burning damages critical mould surfaces.
Of course , as you know , this does not happen with wax as it melts quickly.
Dan.
 

pjpickard

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Thanks for your reply, I want to make mainly parts for live steam locomotives, not so much large parts like drivers and cylinders, but smaller stuff like details and pumps, etc..
 

pjpickard

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OK so I watched a lot of your videos, great stuff! But I have this nagging question having some lost wax experience...how do you get such great fill with just a static pour, no vacuum? Your parts fill with the top down and bottom up with air pockets above no problem??!!
 

pjpickard

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Yes I have considered it...along with everything else! I'm reading and watching a lot now. I still don't get how the cavity is able to fill without and air pockets with the ceramic shell method, but in many videos it does not seem to be a problem.
 

dazz

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I suspect the ceramic is porous enough to let gas escape.
 

pjpickard

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Interesting...I never thought of that! Lots to learn here but aonemarine's results certainly are great!
 

aonemarine

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Interesting...I never thought of that! Lots to learn here but aonemarine's results certainly are great!
Some of my casting are block investment and i use vacuum assist to get the molds to fill. The ceramic shell is just static pressure.
 
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