Plumbing

Well the plumber has come and done the first-fix plumbing, including gas pipework, but that's not what I want to talk about.

I'm talking about the polypipe conduits I want to use for network cabling. I installed one 13 mm pipe as a test to see how easy it would be to push CAT6 cable up it once it is installed. Answer: very bloody hard. I can get CAT6 up about 2 m, and CAT5 about 3 m (due to being slightly thinner). Once you get this much cable in the cumulative friction means the cable just bends in your hands as you try to jam more in.

Okay, so I decided to do some more tests at home. I have had lots of suggestions so I now needed to know if any of them would work. Lots of people have said I need to put a string in there to pull the cable through -- but how do you get a string in, especially if your pipe is already mounted in the wall and ceiling. John suggested fishing line and I wondered if I could use a pump at one end to suck the line through, if you attached it to a suitable ball of fluff. Here I am with my test rig. I used a tiny ball of scrunched up paper towel (no strings attached first) and it worked a treat. Pump, pump, Fump!

Next I tried attaching the fishing line. This worked at first, but the nylon tends to get tangled easily and eventually the drag within the pipe seemed to overcome the suction. But by putting the polypipe directly over the pump inlet (avoiding the use of a restricting nozzle) I managed to get enough suction to pull the nylon line through. Hooray!

Then the simple job of pulling a stronger piece of string through... turned out to be not so simple. Just the friction of the nylon line inside 15 m of pipe was too much to overcome -- it just stretched. But once I straightened out the pipe a bit, so that the line wasn't in contact with the entire length of the pipe, I did managed to pull the string through. Nevertheless, at this point I was thinking that this is a hell of a lot of effort and I will probably just fix the CAT6 cable in directly.


Anyway, a greater concern is how am I going to insert the cables with thermometers into the identical pipe conduits I have already put in the slab -- I can't even get to the other end of these. Instead I need a better way to push the cable in up to 8 m (I had planned to use CAT5 cable for this since it happens to be cheap, and I thought it would be easy to push down the pipe). I wondered about using fencing wire, since I have some, and I thought it might be rigid yet flexible enough to push down a bendy pipe, pulling 8 m of cable behind it. But John happened to have handy something called a 'drain snake'. This is a very long, flexible strip of flat steel about 3 mm wide, but less than 1 mm thick, so it easily bends in one direction, but is strong enough to push through blockages in kitchen drains. It has a funny-looking 'snout' on the end you push into the drain so it can clear a blockage, and also to help it navigate corners.

Anyway, I tried this in the installed conduit and it works -- you can push this thing all the way into the 13 mm conduit. However it is only 8 m long; not long enough to reach to the other end of the conduit I have already installed in the walls + ceiling, and this is by no means the longest run I have to do. 8 m is long enough to reach the end of the thermometer conduits under the slab though. So I returned home for some more testing.

The plan is to use the drain snake to pull the CAT5 cable into the conduit, by attaching the end of the CAT5 cable to the end of the drain snake and pushing them into the pipe together. But I need to be able to remove the drain snake afterwards without pulling the cable out with it, so I can't use the end of the drain snake with the snout on it. Instead I needed some way to attach the other end to the CAT5 cable which would be strong enough to pull 8 m of cable through the pipe, but be easy to disengage by pulling on the drain snake. I made a new snout for the drain snake out of a plastic pen lid, but I attached the lid firmly with duct tape to the CAT5 cable. The drain snake itself was not attached to the lid, it is simply inserted into the lid, next to the cable. This way it can push very hard, but be easily pulled out.

Incredibly this worked. I had to file down the sides of the lid a bit to make it fit better, and I also used another of John's suggestions: talcum powder in the pipe to reduce the friction. With all these steps implemented I managed to successfully insert 8 m of CAT5 cable and remove the drain snake from a 13 mm polypipe that meandered around a few gentle corners.

The main way this test differs from what I have to do in practice is that the cable will have two or three transistor-sized digital thermometers attached at precise locations along it's length. I hope if I wrap each of these 'knuckles' with Teflon tape it won't make too much difference. But John has another suggestion: use telephone cable instead of network cable. That should reduce the friction significantly, and these digital thermometers only need two wires for up to 64 thermometers so it should be fine.

Windows

Well it was a busy week. My building supervisor is starting to annoy me already. I'm not going to say who my builder is until we've actually finished, but I will say that the company name rhymes with Conehead and they are a major South Australian builder that is affiliated with chapters in each state (each with a different name).

We are having double-glazed windows. These are surprisingly rare in Australia and thus really expensive. Ours are uPVC from Certainteed, costing about A$16k. We also looked at CozyHome, but their pricing policy seems to be geared towards architects (who presumably want to specify the style and size but don't care how much it costs) rather than a consumer, who wants to be able to determine what is the best value. Anyway, the builder preferred that I arrange the windows which means they get to have nothing more to do with them. I took Thursday off to help the truck driver unload the windows (they came from Melbourne) because my supervisor assured me that nobody else would be at the site, because the frame would be completed on Wednesday.

As it happened the carpenters were there all day Thursday and Friday. I guess it wasn't as close to finished as the supervisor had thought. It turns out it was probably just as well the carpenters were still there as it looks like they made some last minute adjustments to the window openings to accommodate the actual windows. Note the packing on the bottom and right -- that wasn't there yesterday! This is ironic as the window people went to a lot of effort to make sure the builder understood what size openings were required. Luckily the carpenters worked fast enough to allow the windows to be installed on Friday as I arranged -- on the supervisor's instructions!

However, since the carpenters were running behind I wasn't able to check all the door and window openings before the windows were installed, so this happened (see right). There are two things wrong with this picture.

1. The fixed window is sitting on the wall plate not the floor so is not at the same height as the sliding doors.
2. There is a (unnecessary) post between the fixed window and the sliding doors. In fact two post because there's another fixed window on the other side.

The post is unnecessary since the huge lintel you can see spans all the way across the entire opening (including the fixed windows). So hopefully the carpenters can rearrange this on Monday (oh yes, they're still not quite finished), putting the fixed windows at ground level and right next to the sliding doors, with the posts on the edges of the opening.

...

It's funny how you take a day off to do one thing and end up doing something else. I planned to do network cabley sort of stuff for the rest of the day on Thursday, but since there was a gang of carpenters shooting nail guns on the roof I thought it best not to. The window bloke suggested I might want to paint the window frames, since these will be sitting in the weather from now until the roof goes on. So that explains why at 7:30 pm I was in the dark wearing a head-torch, painting a part of a window frame that nobody would ever see once the house was finished. At the time I thought, "This is something my mother would do.. and very few others."

The framing begins

Slightly late, but what's another week and a half between friends. The timber has arriven and the frame is starting to go up. Above, a big pile of timber and below, starting to be turned into house.
On day three the roof trusses started going up.

Today I bought 100 m of polypipe to use as network cable conduit. This was my friend Steve's idea. Rather than run 100 m of network cable throughout the house which will inevitably be obsolete within a few years, run a flexible conduit in a star configuration which you can then put Cat5, Cat6, optical fibre or Qubit channel -- whatever you want. This would have been an even better idea if Steve had thought of it before I bought all my network cable -- I could have just bought as much as I actually need, when I need it. But I guess that's small fry. Less than half of the networking cost so far has been the cable itself, although it was certainly the biggest single cost.

This is the breakdown so far:

• $120 for 80 m CAT6 cable from Jaycar
• $12.50 for 10 stud brackets from Ebayer Sysintonline
• $20 for crimp tool, punch down tool, network tester and wire stripper from Ebayer Soho_utopia
• $30 for 100 m of 13 mm polypipe conduit from Bunnings
• $8 for 100 cable ties with nail holes for anchoring conduit from Bunnings
• $40 for 10 CAT6 jacks from Ebayer Eascable
  
• $30 for 2 x 4 port faceplates with shutters, plus 8 CAT5 jacks I don't really need (not my best deal) from Ebayer Easycable