The Covert Pier begins

[koputai]

After going through a range of ideas for my pier, work started today.

The pier had a few requirements:

1. Big enough to hold my current maximum gear (Eq6 Pro, GSO 12",
ED80, plus cameras)

2. Big enough to hold something bigger in the future (20" RCOS and
big mount - dreaming again)

3. Mount through the existing deck, but be able to be moved out of
the way when friends come round for a barbie.

Here's the area it has to go.

73012

The deck sits on top of sandstone and clearance from the deck down
to the rock is 10 inches, so I figured a base unit, firmly mounted to the
rock, with a separate pier that bolts to it would work well. That way I
can unbolt the pier from the base, and put a hatch cover back on the
deck, and no one would be any the wiser.

Here is the deck with the hatch removed, and a view beneath showing
the rock:

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This rock is not just a little slab, this monolith is about 150 metres long,
30 metres wide, and 10+ metres deep. The whole house, and about 8
of our neighbours houses are built on this rock, and several swimming
pools have been excavated into it. I aint gonna move!

Now, how to mount the base.......

Cheers,
Jason.

[TrevorW]

What a neat backyard !!!

[koputai]

Well, for the base that sits below the deck, I was thinking about making
up a steel plate, 450 x 450 x 16, with pedestal legs a couple of inches
high, bolted in to the rock. I thought this was fine, but I got talking to a
friend who loves to over-engineer things (he's a big boy and his hobby is
earth moving equipment) and he talked me in to drilling a hole and sinking
a post in the rock. The post would then have a pipe flange welded to the
top, and the pier itself would have a matching flange, the two then would
bolt together.

We agreed that a bigger diameter is better, so decided on a 250mm
(10 inch) post and pier would be ideal.

We searched around for a suitable piece of 10 inch pipe to make this
from, but it's not that easy to get 1.5 - 2 metres of it. Then we realised
that I already had the perfect piece back in my Grandmothers shed!

That sorted, off we went to Kennards and hired a core drill, stand,
extensions, and a 250mm core bit.

This not unsubstantial bit of kit has to be bolted down for use, so we
drilled and set a loxin into the rock, and tied the drill stand down with
a length of threaded bar.

Here it all is, bolted down and ready to bore:

73015 73016

Water and power were turned on, and away we went. Boring the hole
went quite easily, and before too long we had bottomed (topped?) out
the bit, and had to get the first plug out of the hole. We did this by
setting an eyelet into the top, then driving a cold chisel down the cut.
The plug broke away at the bottom, and we lifted the first section out:

73017 73018

Next we added the second extension and continued down the hole:

73019 73020
73021 73022

[koputai]

We then eyeleted, broke out, and lifted the second plug of sandstone,
leaving a lovely hole:

73024 73025

The final tally, a hole 255 mm diameter, by 760 mm deep!

And here's a couple of shots to give an idea of how much rock we cut
out of the hole. Anyone have any idea what I can do with my backyard
core sample?

73026 73027

It will be a week or two before we get to the next part, epoxying the
10 inch base post in to the rock!

Cheers,
Jason.

[Terry B]

Now you just need to work out how to use the core as the pier. A nice solid bit of stone and would look very pretty.;)

[peter_4059]

That's going to be one solid pier Jason. I've been thinking about something similar on my deck although I don't have rock to deal with.

Peter

[RobF]

Sounds like a precision operation! Thanks for taking the trouble to document for the jealous onlookers here too Jason. Looks like a great project.

[marki]

Dam I love sand....top job mate that won't be going anywhere in a hurry.

Mark

[pmrid]

These cores have real texture AND a story. Why not have them cut and machined into 4 equal legs and sit a good piece of smoked glass on them as a coffee table?

Peter.

[koputai]

Thanks guys. If you like that, you're going to love the base post and pier we're fabricating!

Cheers,
Jason.

[koputai]

That's already been considered Peter, but just one central leg. Remember, it's 10 inches across and has quite a bit of weight to it. I don't think the missus would appreciate it sitting on the shag-pile though!

Cheers,
Jason.

[allan gould]

Now that's A pier.
Great job and well documented, a really interesting read.

[MuntiNZ]

Nice job mate.
What if trucks drive on that big rock will you get vibrations thru your pier?

[koputai]

We don't get many trucks around here, just the garbage truck during the day on a Tuesday, so no issue there. The only time I've ever felt vibration in the rock was when the next door neighbour was jack hammering to put a new garden in.

Cheers,
Jason.

[AlexN]

Me likey!!

Looks the goods so far... I dare say it will do everything you need it too.

[TrevorW]

Why epoxy instead of a cement ???

[MuntiNZ]

At my job we use epoxy a lot.
The stuff we put into rock and concrete with the epoxy is never ever coming out.
Some times fittings that has been stuck in to stone and concrete and stuff with concrete works loose fast.
Epoxy is there to stay forever.

[koputai]

Yep, what he said!

Concrete is for the home handyman, use epoxy if you want it really strong.

Cheers,
Jason.

[Moon]

If it's half as good as that hole, it's going to be a ripper. :thumbsup:

[ChrisM]

Jason, this is serious stuff! I like it.

Looking forward to the next installment...
Chris

[koputai]

Part 2 now completed, see here:

http://www.iceinspace.com.au/forum/showthread.php?t=79998

Cheers,
Jason.