Flaring the End of A PVC Pipe

Recently I've been building a chicken coop for my sister and I've finally come to the end of the project.  One finishing touch that still needs to be done is for a downpipe to be fitted to the guttering.  To keep costs down I'm trying to use materials that we already had, and it turns out my sister had a piece of 40mm PVC pressure pipe from another project.  As it turns out it wasn't quite the right size, so I thought I'd document how to make the pipe bigger.

Original PVC Pipe

Finding a fitting to connect the pipe to the guttering isn't easy as it's 40 mm pressure pipe.  40 mm isn't a standard size for guttering downpipe, so I found a fitting that was almost the right size and decided to flare the end of the pipe to fit it.  I think the fitting was for a floor drain, but it'll do what I want.

Flaring the PVC Pipe

Flaring the end of the pipe is easy.  You need something round and tapered, and a heat gun.  The pipe is evenly heated at the end by rolling it backward and forward under the opening of the heat gun until it becomes pliable.  It doesn't need to be too soft, just soft enough to insert the fitting, but before that can be done you need to flare the pipe as the fitting initially won't fit into it.

The only tapered thing I had that was the right size was a coke bottle.  After filling the bottle with water so it wouldn't compress, it was pushed against the pipe to expand the soft end.

PVC Pipe and Fitting

Once the pipe is slightly expanded, the fitting can be inserted.  I left the fitting in the pipe until it cooled naturally.  I figured cooling the pipe too fast might not be a good idea.  Better to be safe than sorry.

PVC Pipe with Fitting in place

PVC Pipe with Fitting in place

It's a really tight fit but it still needs a fastener to hold it in place.  A pop rivet is ideal but a screw will also do the job.  After putting a couple of screws into the sides it was then attached to the gutter with 2 more screws.  Pop rivets would have been better but you do the best with what you've got.

To save an extra couple of bucks I put a bend in the bottom end of the pipe with the heat gun instead of buying elbows. Below is a shot of the finished chicken coop with the downpipe fitted.  There are a few things I wish I'd done differently, but as it is I'm pretty damned happy with it.

Down Pipe Fitted, Chicken Coop Finished

Removing Dynabolt Sleeve Anchors

While putting up the frame for my sister's chicken coop I made a slight mistake.  My attention wandered and I managed to fit a Dynabolt, or sleeve anchor as they're sometimes called, in the wrong place.  The bolt was being used to anchor a 35 mm thick pine frame to a concrete slab and once in place they're notoriously difficult to remove, so I thought I'd document how to go about doing it.  I'll refer to the bolts as Dynabolts from here on.  Although it's a brand name, it tends to be what all bolts like this are called in Australia.

First remove the nut from the bolt and tap it into the hole with a hammer until it bottoms out.  The key to removing a bolt like this is being able to get to the sleeve that surrounds the bolt.  To do this I had to remove the nuts from the surrounding anchors and lift the frame slightly.

Top Sleeve in the Frame

Dynabolt and Lower Sleeve

To understand how to remove Dynabolts it helps to understand how they work.  In the image below you can see the 4 parts of the bolt I was using.  The nut, bolt, upper and lower sleeves.  Before installation the bolt needs to be assembled by placing the lower and upper sleeves onto it and doing up the nut loosely with your fingers.  A hole is then drilled into the wood and concrete you want to join and the whole assembly is tapped into place by hammer.  The nut is then tightened with a spanner until the required torque is reached.  As the nut is tightened it draws the bolt with the flared end up into the lower sleeve and spreads it against the walls of the hole wedging it into place.

Dynabolt Parts

Trying to remove the bolt at this point is futile, the nut needs to be removed and the bolt tapped into the hole to release the pressure forcing the sleeve against the wall of the hole.  The sleeve will stay in place due to its own springiness, but it's now moveable.  I was lucky as I could still get at it.  If you can't somehow get to the sleeve you might as well cut the bolt off with a grinder.

In most cases your hole won't be deep enough for the bolt to be pushed under the level of the sleeve, this means you can't just grab the sleeve and pull it out, and pulling the bolt will just wedge the sleeve against the walls again.  The trick is to pull them both out at the same time by using a pair of vice grips to lock the sleeve onto the bolt.  This can then be pried out with a wrecking bar or similar tool.  You may need to reposition the vice grips a couple of times, but you'll get there in the end.

Prying out the Dynabolt with Vicegrips

Prying out the Dynabolt with Vicegrips

Once removed you should be able to reuse the hole.  In my case the hole was in the wrong place and the easiest option was to fill it and put the bolt in a different place.  You could probably reuse the bolt if you wanted to, but I had plenty of spare ones and didn't want to run into any problems.

The main advantage of a Dynabolt is also its biggest problem.  They are really hard to remove.  So if you make a mistake be prepared to spend a bit of time to get it out.  Take a couple of minutes to asses the situation and figure out the best course of action.  Not every application is the same, and different situations may require a slightly different method to remove the bolt.

Damaged Anchor

Securing Reinforcing Mesh When Concreting

When I started this blog I intended it to be about electronics and technical things, I also said don't hold me to that.  So today's post is a little different.  Recently my sister moved into a new house and had her heart set on keeping chickens, therefore a coop was needed.  The ones available on the market are nice but expensive, not only that, from what I can tell they're all made in China out of wood that isn't going to last long when exposed to the elements.  The best solution was to build it ourselves.  Due to this, my time for the aforementioned "technical things" has been limited, but to keep the flow of information happening here I'll write about problems encountered during the build.

The design of the chicken coop is basic, it's pretty much a 1.8 m cube, with a corrugated iron roof.  The original plan was to build it so it could be moved, but as it's in an exposed location, wind became a problem.  From what I could determine from available information, a worst case uplift force of 2 kPa could be exerted on the roof.  For a roof that's 1.8 m square, that means a lifting force of 6480 N, or 660 kg.  With this information we decided to build it on a concrete pad.  It means it's not really movable any more, but at least it'll be secure in strong winds.

I've concreted before, but it's been a while, so I wanted to use this job as practice for future projects.  We may have been able to cut some corners in places, but because I'm not an experienced concreter I did everything by the book.  To start with I levelled and compacted the site by hand, 3.5 inch wooden boxing was then constructed.  As the ground contains a lot of clay it expands and contracts depending on how wet it is.  This means that the level of the ground can change considerably, in some parts it looks like a golf course. That combined with the largish size of the block, 2 by 2 meters, reinforcing mesh was pretty much mandatory.

Concrete Formwork / Boxing with Reinforcing Mesh

The above image shows the boxing with the reinforcing mesh in place.  One piece of mesh wasn't large enough to cover the area, I had to use two and overlap them.  If you look closely you can see the three rows in the middle that were tied together with wire.  The mesh is held 40mm above the ground by plastic supports called bar chairs.  Just a note, googling "bar chairs" is not the way to find out more about them, you will however find plenty information about bar stools.  The supports aren't entirely necessary for a block this size, you could just lay half your concrete, throw the mesh in and put more concrete on top.

Placing the mesh on the supports is easy except for a small problem I came across, one corner of my mesh was slightly bent upwards.  Not too much, but enough to make it come above the level of the finished concrete.  To correct this I needed to pull it towards the ground.  Initially I planned to just put some tent pegs in the ground and wire them to the mesh, but this breaks one important rule of using reinforcing mesh.  The mesh should be completely encapsulated to prevent rust penetrating the concrete slab.  Rust could have made its way to the mesh from the external tent peg via the tie down wire.  It takes time, but it does happen.

Bar Chair Pinned to the Ground

The solution turned out to be simple.  By pinning the bar chair to the ground with tent pegs, and cable tying the mesh to it, the mesh remains isolated and completely encapsulated in the concrete.  Although it's probably not necessary on a job like this, I like to do things properly on jobs that don't matter so when it comes to jobs that are important I know what I'm doing.

After this, the concreting went smoothly and turned out pretty well if I don't say so myself.

Concrete Pad