Bob J's No.21 Steam Engine (drawings and STP files by Pat J)

[a41capt]

I don't know the technical properties of PETG and PLA...?
But this would probably run of 2psi of steam, too? - Providing piston and cylinder are the same material (for expansion).
K

PLA isn’t very heat resistant, and prone to deformation at temps around 120 F. PETG is more heat resistant and I use it for applications where the item might see higher temps. Living in Arizona, summer temps (especially in a vehicle) get to extremes and tend to melt PLA where PETG weathers the storm.

I have considered live steam for a PETG model, perhaps even a PETG/carbon fiber IC model with some metal components since I’ve been successfully printing spur gears for a couple years now.

John W

 

[bobcjohn]

That's impressive at 2psi. Very nice-looking engine and prints. Definitely a smooth runner. My engines made of aluminum brass and steel need 5-10psi.

I'm really new to this 3Dprinting. The white filament I used is called poly cast. It's supposed to burn out clean for investment casting. However, I have had very little luck with that process. The finish on this project wasn't all that good, not near as nice that in your video. The filament I used for the base (gray) was much better, but on the smaller parts it had trouble sticking to the printer bed.

Bob

 

[a41capt]

That's impressive at 2psi. Very nice-looking engine and prints. Definitely a smooth runner. My engines made of aluminum brass and steel need 5-10psi.

I'm really new to this 3Dprinting. The white filament I used is called poly cast. It's supposed to burn out clean for investment casting. However, I have had very little luck with that process. The finish on this project wasn't all that good, not near as nice that in your video. The filament I used for the base (gray) was much better, but on the smaller parts it had trouble sticking to the printer bed.

Bob

Bob,
Depending on your printer and print bed, a good washing with dawn dish detergent and a follow up coat of Elmer’s glue stick on the print bed usually takes care of getting the filament to stick.

A bit of time spent with calibration (temperature tower, pressure advance, flow rate, and retract setting) makes a huge difference in consistency and finish. Loads of info specific to your printer on “The Tube”.

John W