hot tip

[peterescue]

If you are handy with the old circular saw you can set the blade depth to less than half the diameter and do aq series of parallel cuts across the length of the pipe. Do it on both sides and make it neat so its somewhat aesthetic. You get more vent area this way.
AND
Do it before you cut it to the length you want so you have more to hang onto while you cut it.

 

[soulweaver]

We have been using the conduit over water heaters in NSW for the last 30 years, however we do not make it a snug fit. We normally allow a bit of space between the heater and the conduit, not to prevent melting, but to allow water flow throw the holes to get better heat transfer. Works very well and is cheap to make.

This is exactly what I was trying to get across Thanks bigguy
I was in no way having a go at you or your idea Matt, it's just that I know from experience, (keeping fish from the age of around 10), that a snug fitting tube WILL in time at least cause problems. Remember, just a small crack in one of the narrower diameter heaters will have your turtles swimming a lot faster as their water will be live

they had fish back then??

 

[africancichlidau]

Yes buddy, you young whippersnippers didn't invent EVERYthing you know

 

[soulweaver]

whippersnippers???? couldn't pay me to cut grass!!

what was the last thing a whippersnipper invented?