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Melting PVC and vortex block

Posted: Tue Jan 27, 2009 9:27 pm
by achs_xc
Has anyone tried melting and molding PVC to make their vortex block? It has a rather low melting point and some noxious fumes(I believe). I have seen some people heat and flare the ends of PVC for rockets. Just a thought...

Posted: Tue Jan 27, 2009 9:41 pm
by rp181
Yes, when PVC burns, it creates hydrochloric acid. When PVC is molten, it is very thick, so you would have to put small chunks, heat, and press it.

Posted: Tue Jan 27, 2009 9:46 pm
by inonickname
Hot oil is used to flare rocket ends. Personally I wouldn't melt PVC, especially with the ultra-noxious fumes it produces. If you try it use a fan that can move a lot of air, and a mask with filters. Chlorine and plastic polymers are nasty shit

Posted: Tue Jan 27, 2009 9:49 pm
by Davidvaini
hmm considering there are many quick ways to make vortex blocks out of PVC, I don't see any advantage in doing it this way. In fact the only thing I see is disadvantages, as it would be harder to make, more time consuming, less accurate, rougher vortex circle.


Now forming pvc with heat is fun and all.. so its really up to you.. I really only see disadvantages in doing it this way.

Posted: Tue Jan 27, 2009 10:18 pm
by rp181
You could just buy a block of plastic (mcmaster-carr) and drill it.

Posted: Wed Jan 28, 2009 12:39 am
by Davidvaini
or just use 3/4" pipe and just drill a whole into the side of it for an air inlet and another hole for a barrel. just use the shape of the pipe for the vortex shape.

Posted: Wed Jan 28, 2009 9:54 am
by psycix
There is a difference between melting and simply making soft.
When people flex a piece of pipe into some shape after heating it (like the rocket thingies you were talking about) the PVC is warm, soft and flexible.
Melting it, means making it a liquid and I have never seen liquid PVC...
Besides burning instead of melting and besides releasing toxic fumes, the properties of the pvc will be affected aswell.
Why not go with a piece of wood?

Posted: Wed Jan 28, 2009 4:59 pm
by rp181
I might be mistaken, but it is molten, PVC is just very viscous.

Posted: Wed Jan 28, 2009 6:34 pm
by psycix
From wikipedia, properties of PVC:
Glass temperature 87 °C
Melting point 80 °C

Its not a liquid.
I think you are confused with glass. Glass is actually a liquid. (Thats why really old windows are wobbly)

Posted: Wed Jan 28, 2009 7:32 pm
by Hotwired
Noooooo..... that's other reasons.

There's no definite answer but even very ancient glass artefacts have not given evidence of flowing. However you can't tell that in ten thousand years it might not have moved a smidgeon so it's still moot for the obsessive.

I can't be bothered waiting that long so I'm quite happy to file glass under "solid at rtp".

Posted: Fri Jan 30, 2009 12:45 pm
by jimmy101
Neither glass not PVC is a liquid. Not even "super cooled liquids". By all standard definitions of "solid" and "liquid" glass, PVC etc. are solids. Glass and PVC are non-crystaline amorphous solids (which is what often confuses people, they equate "amorphous" with "liquid").

"Liquids" are a subclass of "fluids". Fluids are defined as the states of matter that quickly assumes the shape of their container. Liquids and gases are the two subclasses of fluids. Since glass and PVC, at normal temperatures, does not assume the shape of their container they are not liquids.