JamesF's observatory build

[JamesF]

I might even have some of those lying about.  I'll have to check.

James

[JamesF]

Hmmm.  Links don't seem to be working properly this morning.  I'll have another go.  The @MattGoo thread is here:

Ahhh.  That's better.

James

[carastro]

James, can I suggest that before you put the flooring down that you consider putting a membrane down on the soil below the obsy to reduce damp, and also put some sort of wire mesh around the perimeter to stop wildlife camping underneath. 

I did not get that advice and foxes dragged my membrane out, and I am pretty sure I have wildlife underneath mine.  There was a lot of wildlife digging around my perimeter for a while.  

It's too late to do it now as I have an adjacent shed and it is right against the neighbour's fence.  I gather that there is a lot of digging on my neighbours side to get under the fence and presumably under my Obsy base.  I have managed to stop up my side where I can with paving around the edge, but there is also a small bit between the shed and next doors fence I can't reach.

Wish some-one had given me this advice when I did mine.

Carole 

[JamesF]

Good plan, Carole.  I think anything large might not find it any easy place to call home anyhow, as the rock is so close to the surface of the soil, but I'd not be at all happy if foxes did try to move in quite so close to my chicken runs (not even 20m away).  Rabbits and suchlike would still probably get in there and dig about though, so stopping them would be sensible.

James

[JamesF]

Bah!  Just been into the local builder's merchant as I happened to be passing and they don't do hollow concrete blocks.  They could get them for me, but only if I wanted a pallet load.  That's a lot of piers.

Looks like B&Q might do them -- they're on the website, but that doesn't mean they'll be in stock.  It may be that they only do them by the pallet, too.

James

[JamesF]

Saved!  Found another builder's merchant in Watchet who is happy to deliver me a dozen on Wednesday.  Obviously that's a few more than I need, but covers me in case I get over-excited with the disc cutter.  Any I don't need will find an alternative purpose holding up beehive stands.

James

[RayD]

7 hours ago, carastro said:

Wish some-one had given me this advice when I did mine.

Someone gave me this great advice whilst building mine ?

[JamesF]

Just been mooching about in the workshop whilst waiting for the chickens to decide to turn in for the night and found about 2m of M10 threaded rod and a large number of M10 nyloc nuts.  I guess I'll be using that for holding the blocks together then ?

James

[Gina]

Sounds like a plan.

[martin_h]

I have foxes camping under my obs, one end is 2 feet above ground level, no problems so far but the do get the blood pumping at 3 am when the decide to have a fight!

Edited June 12, 2018 by martin_h

[SnakeyJ]

3 hours ago, martin_h said:

I have foxes camping under my obs, one end is 2 feet above ground level, no problems so far but the do get the blood pumping at 3 am when the decide to have a fight!

I'd be all up for the foxes, or badgers, hedgehogs (pretty much anything other than rats or a big wasp/hornet nest that closed the observatory.    However, having kept chickens briefly on multiple occasions, I totally understand James taking sensible precautions to dissuade the foxes 

[JamesF]

Today's arrivals:

Interestingly they're not all the same.  Some have a double-width centre web with a slot almost all the way through.  Should make it easy to cut them in half to give a two-and-a-half block high pier.  They're certainly not light, either.

Also had more ingredients for concrete arrive.  Hopefully sufficient for completing the foundations for all three piers.  My calculations are based on the fact that I have a bit over 1300kg of cement, sand and aggregate available and given on the volume of the foundations and a density of two tonnes per cubic metre, I should need a smidge over one tonne.

James

[Astrokev]

Looking good. Interested in seeing how you will join these together.

[Gina]

Good luck with drilling the concrete.  I hate drilling concrete the stones tend to make the masonry drill wander off course.

[JamesF]

The plan is to use gorilla glue between the mating faces combined with lengths of M10 studding.  If it doesn't work then it's a £40 experiment that failed.  If it does work then it saves me a huge amount more.

Probably best illustrated by this image from MattGoo's album:

James

[JamesF]

3 minutes ago, Gina said:

Good luck with drilling the concrete.  I hate drilling concrete the stones tend to make the masonry drill wander off course.

Shame my pillar drill doesn't have a hammer action.  I think I should be ok though.  I deliberately bought a couple more than I needed to cover any mishaps.

James

[Gina]

Is your pillar drill that big??? ?  Mine isn't.  I do have a decent mains hammer hand drill though and have drilled concrete quite often. 

[Astrokev]

22 minutes ago, JamesF said:

The plan is to use gorilla glue between the mating faces combined with lengths of M10 studding.  If it doesn't work then it's a £40 experiment that failed.  If it does work then it saves me a huge amount more.

 

Sounds like a plan. I guess the only risk is that the blocks may crack when drilling, but sounds workable.

[Gina]

I might go for this if I decide to build another pier for telescopes.  Much cheaper than a Skywatcher Pillar mount at over £200!

[JamesF]

13 minutes ago, Gina said:

Is your pillar drill that big??? ?  Mine isn't.  I do have a decent mains hammer hand drill though and have drilled concrete quite often. 

I've just been out to measure ?

There's easily 500mm between the chuck and base of the drill, so I might just manage to squeeze a block in if I tried.  I do have a separate hammer drill and an SDS drill though.  I shall experiment and see how things work out.

James

[Astrokev]

1 minute ago, Gina said:

I might go for this if I decide to build another pier for telescopes.  Much cheaper than a Skywatcher Pillar mount at over £200!

...and an air-con tube filled with a ton of concrete. My back is still aching!

[JamesF]

3 minutes ago, Astrokev said:

Sounds like a plan. I guess the only risk is that the blocks may crack when drilling, but sounds workable.

Yes, I'm a bit nervous about the slits in the end faces of the blocks.  Not sure why they're there when used for their intended purpose.  A little experimentation is required.  If someone else has managed it though, I'm sure I can work it out.

James

[Gina]

I was puzzled by those slits.  The blocks in my walls don't have them.

[JamesF]

8 minutes ago, Gina said:

I was puzzled by those slits.  The blocks in my walls don't have them.

If the intention was to pour concrete into the wall once built, they might be to allow rebar to be place horizontally in the wall.

James

[JamesF]

22 minutes ago, Astrokev said:

...and an air-con tube filled with a ton of concrete. My back is still aching!

A 280mm diameter tube 1.3m tall, Kev?  I reckon that's only about 160kg

James