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Cast Rubber Pistons?

Post about things you have launched or thought about launching. Also post about various materials used for building cannons. No posts about explosive projectiles!
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Cast Rubber Pistons?

Unread postAuthor: Kobl » Fri Aug 08, 2008 9:17 pm

I just order some 1" rubber rod from McMaster thinking it would be perfectly straight and smooth. Sadly, my hopes were in vain.

I was wondering if you cut it up into reasonable sized pieces and throw them into a lubed up copper tube and then proceeded to heat up the tube with a blowtorch would the result be the perfect piston? No need for a bumper or sealing face.

input appreciated.
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Unread postAuthor: Mitchza89 » Fri Aug 08, 2008 9:46 pm

I reckon the rubber would burn mate. Get yourself some Silicone for bathroom water proofing, lube up a mould, squeeze it in and your good to go ;)
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Unread postAuthor: hi » Fri Aug 08, 2008 10:19 pm

i think simply putting it in the housing will make it strait. you wont need much of it. unless its a circle, i wouldnt worry about it.
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Unread postAuthor: potatoflinger » Sat Aug 09, 2008 7:58 am

What does it look like? If it isn't straight you could just use a short section of it as your piston.
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Unread postAuthor: Fnord » Sat Aug 09, 2008 9:03 am

Yeah, post a picture of it. I was going to order some 1.5" but I want to see how bad it is before I do.

And I don't think you'll be able to melt it effectively. You'll have better luck with a belt sander.
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Unread postAuthor: Kobl » Sun Aug 10, 2008 6:36 pm

Alright, I'll try to post some pictures tonight or tomorrow.
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Unread postAuthor: nivekatoz » Sun Aug 10, 2008 7:42 pm

I dont know anything about pistons or sealing faces etc.. :scratch: but if you need to make a rubber plug of some kind, you could take silicone caulk or polyurithane caulk and squeeze it into the tube that you are going to use .When it sets push it out and there you go. :thumbright: Make sure you greese the inside of the tube first. I hope this helps. :salute: If anything, you could get an idea from what Im tring to say. Sorry MITCHZA89 I over looked your coment sorry to repeat it. :oops:
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Unread postAuthor: mark.f » Sun Aug 10, 2008 10:54 pm

If you could get it a bit undersized, you could add to washers to the ends and tighten, to expand the rod.
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Unread postAuthor: psycix » Tue Aug 12, 2008 3:26 pm

Well, you can melt anything.
Problem is, that when the melting point of the material is higher then the temperature of starting to burn (in this atmosphere), it will burn while it melts.
Solution:
Remove the oxygen!

You can either do it in a vacuum, or in a CO2, N2 or Helium environment. Or just anything else; you could even do it in a propane environment! As long as the oxygen is gone.
You can also remove the oxygen by burning a candle until it fades inside your "oxygenless environment container".
Take your "container" put the rubber and the copper pipe in, lit candle and close container, wait a few secs. Start heating up whole container for some time, and keep it at that temperature. Then, give it the time to cool down. And your done.

Only issue is finding an airtight and heat-proof container that is the right size. A glass jar may work.
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Unread postAuthor: Darkside 6ix » Tue Aug 12, 2008 4:03 pm

psycix wrote:Well, you can melt anything.



HAHA I love your attitude. :twisted: but your actually right.

BTW pics would help if you have the rod yet.
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