Page 1 of 1

Nasty mould after water ans sugar shots.

Posted: Fri May 15, 2009 1:21 am
by microman171
Hey Guys,

Been a while since I was on here! Before I left I built the Bazookair cannon, the Bad Ass Kiwi Co-Axial.

I have fired all sorts of things from the barrel, including sugar. Being a pneumatic, it is easier to fire a larder range of things.

Sugar, water, and time = mould. I don't know what mould does to PVC. Does it make it more brittle?

And how about UV exposure? I know that makes it more brittle, but does it affect the pressure rating?

I'm not too keen on building another cannon for cost reasons, so would love to fix up this one. I will have learnt my lesson from the sugar xD.


Thanks,

Microman171

Posted: Fri May 15, 2009 1:33 am
by jackssmirkingrevenge
Being organic, I doubt mould would have any effect on PVC. As to UV exposure, thay would tend to weaken the pipe.
microman171 wrote:Being a pneumatic, it is easier to fire a larder range of things.
Hah! invisible pun :D

Posted: Fri May 15, 2009 6:30 am
by microman171
Hah! Larder range... Oops.

So will this thing still be safe to use? It is class E and F (200+PSI).

Posted: Tue May 19, 2009 4:14 pm
by jackssmirkingrevenge
It's hard to tell, depends on the level of exposure. I wouldn't trust it to high pressure.

Posted: Wed May 20, 2009 12:22 am
by microman171
Hmm, would I notice any discolouration? The pipe is still nice and white.

Posted: Wed May 20, 2009 1:48 am
by jackssmirkingrevenge
It usually tends to go a bit yellow. Was it exposed to direct sunlight though?

Posted: Wed May 20, 2009 3:42 pm
by microman171
Not that I know of, more just sat in a garage in the light for a long time.

Posted: Wed May 20, 2009 4:00 pm
by Biopyro
Was it outside in the sun or was the exposure through a window?

Posted: Wed May 20, 2009 4:51 pm
by Brian the brain
I wouldn't worry about the mould.

Would people use PVC for wastewater if that were a problem?

sunlight is a problem.
Try to hydrotest it.
Fill 'er up with water all the way and then apply airpressure to it.
Water holds a lot less energy under pressure as it can't really be compressed, so when it fails it's no real problem safetywise.

Hydrotest it to it's rating and use it below...

Posted: Wed May 20, 2009 7:18 pm
by microman171
Thanks for the info guys =) The light was ambient, not direct. So I'm guessing the pipe will be perfectly fine. I will give it a good hydro test before using it though.

Good to hear about the mould thing. I wasn't sure if it would affect the pressure rating or not. Waste pipe doesn't need to hold pressure?

Posted: Thu May 21, 2009 8:14 am
by Brian the brain
No it doesn't.

but it needs to ..well..function..for years without leaking..without it being " eaten" by mould..
If mould would damage it, we would never use it.
:wink:

Posted: Fri May 22, 2009 12:56 am
by microman171
Cool, glad to hear my gun should still be good =)