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High Pressure Materials for Pistons

Posted: Mon Sep 11, 2006 9:44 pm
by Infernal2
I'm wondering if there is a possibility of using a high pressure rated material for the formation of pistons. I don't have much access to a lathe but I have a rather large selection as far as anything from steel, concrete, wood, and rubber for casting. I imagine the obvious materials as steel and rubber would be excellent but casting density materials are expensive.

A high density wood would be brittle but a hydraulic concrete would (in theory) provide an excellent pistoning material. Has anyonne tried a resin or concrete piston?

Posted: Mon Sep 11, 2006 10:00 pm
by ProfessorAmadeus
Use an endcap that fits in either the tee or if its a coaxile in the pipe. And a good bumper and a sealing face and your done.

Posted: Tue Sep 12, 2006 1:37 am
by rna_duelers
Concrete sounds very heavy,the lighter the piston faster it open and thus better performance a good trick is to get a shit load of hot glue gun sticks and melt them in an old frying pan and mould a piston from that it is said ot work very well. and u can also hollow the inside a little,not a lot but a little to make it even lighter.

Posted: Tue Sep 12, 2006 2:39 am
by MrCrowley
oh,no not the glue melting thing,i tried that lol and the non-stick stuff caught on fire so i turned the element(heating thingy)off and the glue dried really fast and the pot...well lets just say the pot got phucked.its all black and has a gluey coating on the inside. :oops: my piston is made from a pringles sleeved in 3" dwv pipe filled with some blue foam stuff, i made a post about it last night......http://www.spudfiles.com/forums/viewtopic.php?t=3609&

Posted: Thu Sep 14, 2006 9:25 pm
by Infernal2
Well, I'll post pictures as soon as I get done shaping. I used a three inch pipe and a mixture of Sonoguard 55W, Emaco P24 Hardener (PT 2), and a siliconzied rubber caulking. These materials took a little experimentation but appear to take the properties of a non-flaking semi-rigid caulking. I'm letting them cure for four days to insure total cure.

The Sonogaurd 55W should provide an oilly surface so lubrication may not be needed on the piston. According to weight estimates the inch and a quarter piston should weigh about 15 grams.

I'll let you know...

Posted: Sun Sep 17, 2006 12:06 pm
by Infernal2
Ok, well, the combo didn't work. However, I did find an excellent material for pistons. Dow Corning makes a coloured silicon caulk (451) that makes an awesome piston. As long as you let it cure for the appropriate time then you can make a solid piston without using neoprene or rubber. AT least, it works for me.

I set the caulk in a three inch tube of sch 40 and suspended a compression spring in the top of the pour. After this set for 48 hours (pressure should also be rising, as with any caulk) I removed the tube, peeled back the caulk ( I use form board with form oil as a bottom for my mould), and voila, spring and piston. I then drilled a hole for my washer and backed the whole thing with galvanized pipe cap.

Posted: Sun Sep 17, 2006 1:23 pm
by POS
Nice doing. Could you post a picture of that piston ?

Posted: Wed Sep 20, 2006 8:26 pm
by Infernal2
I'd love to but alas, it too did not work.... Good for one use only...LOL