journeyman Mick
11th October 2004, 09:59 PM
Well I finally got around to one of my "gunnas", been on the list for just over two years (ever since we moved into our house). There are commercially available "first flush" gizmos that divert the first few litres of water so that you don't get all the dust that's built up on your roof since the last rains. My method has no moving parts and only costs a few dollars. Basically it consists of a T junction (actually an inspection opening-I.O.) cut into a horizontal run of pipe. This has a length of pipe (about 1.5M) running down to an easily accessed height and a screw cap on the end.
Any dust generally drops out of the flow and into the vertical pipe. It will also catch some leaves etc. A small hole (1/8") drilled into the cap will ensure that the pipe empties after the rain is finished, thus preventing it from becoming a mozzie breeding site. We had a bit of rain the day after I fitted these to my roof, first rain for about a month and there was about a cup of black sludgy dirt in each one afterwards.
One of the downpipes ran down about 300mm and then to the nearby tank via several bends. This required fitting the T piece instead of the first 90 deg bend and then reusing the rest of the fittings. I could have just cut the pipe and used a joiner but I wanted a neater job (and I'd forgetten to buy a joiner :o ) . So, how did I get around this?
It's possible to reuse PVC pipes or fittings in a pinch (but not both!) With larger diameters it's handy to have help, but you can do it by yourself. If reusing a fitting cut the pipe off about 50mm from the fitting. Saw along the length of the pipe. You're trying to split the pipe without cutting into the fitting. You probably won't split it completely but the more you manage the easier it will make it later.
Working quickly:Apply PVC solvent cement liberally to the inside of the pipe (or get your helper to do it) and then cap the bottle and take it away. Light up the glue and as soon as it's finished burning blow out any flames that may still be burning on the PVC itself, grasp the pipe with pliers just next to the saw cut and roll it up, peeling it away from the fitting (a bit like opening a can of corned beef). It may take several applications of glue if the pipe has been glued for any amount of time.
Make sure you cap and remove the solvent cement to a safe distance (otherwise BOOM! :eek: ). Hold the pipe and fitting so that the flames are drawn out of rather than into the pipe, otherwise you will soften and distort the fitting. Two or more sawcuts will make it easier. Have a fresh piece of pipe handy to push into the fitting to mould it true if it's been distorted. Avoid breathing the fumes from the burning glue and PVC, it's nasty!
This is really only worthwhile if you're caught out, you won't be using it as a method of recycling used fittings. Lastly, this is definitely not suitable for use on pressure fittings. It may be of help in some of the more complex dust extraction systems some of you are building (ie: bugger, I just glued that bend on 180 deg out of alignment!).
Mick
PS, wouldn't hurt to have an extinguisher handy ;)
Any dust generally drops out of the flow and into the vertical pipe. It will also catch some leaves etc. A small hole (1/8") drilled into the cap will ensure that the pipe empties after the rain is finished, thus preventing it from becoming a mozzie breeding site. We had a bit of rain the day after I fitted these to my roof, first rain for about a month and there was about a cup of black sludgy dirt in each one afterwards.
One of the downpipes ran down about 300mm and then to the nearby tank via several bends. This required fitting the T piece instead of the first 90 deg bend and then reusing the rest of the fittings. I could have just cut the pipe and used a joiner but I wanted a neater job (and I'd forgetten to buy a joiner :o ) . So, how did I get around this?
It's possible to reuse PVC pipes or fittings in a pinch (but not both!) With larger diameters it's handy to have help, but you can do it by yourself. If reusing a fitting cut the pipe off about 50mm from the fitting. Saw along the length of the pipe. You're trying to split the pipe without cutting into the fitting. You probably won't split it completely but the more you manage the easier it will make it later.
Working quickly:Apply PVC solvent cement liberally to the inside of the pipe (or get your helper to do it) and then cap the bottle and take it away. Light up the glue and as soon as it's finished burning blow out any flames that may still be burning on the PVC itself, grasp the pipe with pliers just next to the saw cut and roll it up, peeling it away from the fitting (a bit like opening a can of corned beef). It may take several applications of glue if the pipe has been glued for any amount of time.
Make sure you cap and remove the solvent cement to a safe distance (otherwise BOOM! :eek: ). Hold the pipe and fitting so that the flames are drawn out of rather than into the pipe, otherwise you will soften and distort the fitting. Two or more sawcuts will make it easier. Have a fresh piece of pipe handy to push into the fitting to mould it true if it's been distorted. Avoid breathing the fumes from the burning glue and PVC, it's nasty!
This is really only worthwhile if you're caught out, you won't be using it as a method of recycling used fittings. Lastly, this is definitely not suitable for use on pressure fittings. It may be of help in some of the more complex dust extraction systems some of you are building (ie: bugger, I just glued that bend on 180 deg out of alignment!).
Mick
PS, wouldn't hurt to have an extinguisher handy ;)