Astrokev's ROR - The Build

[RayD]

For the sake of £8 I'd get a couple of bags of MOT 1 (sub base) from Wickes and firm it down in there with anything really heavy you can get your hands on.  It's a hardcore/sand mix, so beds in really tight.

You'd probably be ok, but this will lessen the likelihood of heave and movement when the clay dries.  It just spreads the load more evenly over a larger area.

Wickes MOT 1

All looking good.

Edited August 27, 2017 by RayD

[Chefgage]

I second that of putting down a gravel bed before pouring the concrete.  I too have very clayey ( im sure thats a word ) soil.  When i put  down the foundations for my decking/pergola i put a good layer of gravel in each hole and tamped it down hard with a bit of a 100x100 post.

[Astrokev]

On ‎27‎/‎08‎/‎2017 at 08:58, smudgeball said:

Looking good.

My hole bottom was a bit clayey as well.

I put a layer of gravel in and tamped it down before I poured the concrete. (more of a "felt it's a good idea to do", than having any technical authority behind it )

Neil

Thanks Neil.

[Astrokev]

On ‎27‎/‎08‎/‎2017 at 18:29, Alan White said:

Kev

Following the build with interest, the weather has not been your friend in this endeavour.

Just had a look at your website link, have you not updated it for a while or was it me, interesting images and story, very similar to my own but a few years adrift, you have managed more travels than myself to date.

What set up are you expecting to locate within the observatory when completed?

Keep on building and posting.

Hi Alan

Thanks. As you've noticed, I've neglected my blog recently. The hobby has taken a back-seat for the last few years for various reasons. Now I'm back into it, I must start posting again!

My current set-up is a 10" Newt on an NEQ6, though I'm seriously tempted to upgrade this - not sure what to as yet, but a frac is probably on the list for wider field imaging, in addition to a longer focal length scope for planetary and lunar work.

cheers

kev

Edited August 28, 2017 by Astrokev

[Astrokev]

On ‎27‎/‎08‎/‎2017 at 18:55, RayD said:

For the sake of £8 I'd get a couple of bags of MOT 1 (sub base) from Wickes and firm it down in there with anything really heavy you can get your hands on.  It's a hardcore/sand mix, so beds in really tight.

You'd probably be ok, but this will lessen the likelihood of heave and movement when the clay dries.  It just spreads the load more evenly over a larger area.

Wickes MOT 1

All looking good.

Thanks Ray and Chefgage. I think I'll be following your suggestion there!

[Astrokev]

This weekends update -

Family matters didn't allow much time, but managed a bit of progress on the pier. I made the sheets to put on top of the pier block once it's filled with concrete, to stop the weight of the concrete in the tube pushing the concrete out of the hole (no image of this yet).

More interestingly, I cut a few holes in the pier tube and installed plastic drain pipe to carry whatever cables I end up needing, to prevent them trailing all over the floor - well that's the theory. The bottom outlet in the images will be below floor level so will be hidden. A pipe from this outlet will go to the warm room. I cut the top outlet in the side of the pier instead of out of the top, because the top plate I will be using may make it difficult to access the pipe outlet if I put it in the top.

I also made 2 small frames to put around the tube (at top and bottom). These will be held in position to keep the tube vertical by long supports fixed to the frames and hammered into the ground.

Here are a few images.

[Adam J]

52 minutes ago, Astrokev said:

This weekends update -

Family matters didn't allow much time, but managed a bit of progress on the pier. I made the sheets to put on top of the pier block once it's filled with concrete, to stop the weight of the concrete in the tube pushing the concrete out of the hole (no image of this yet).

More interestingly, I cut a few holes in the pier tube and installed plastic drain pipe to carry whatever cables I end up needing, to prevent them trailing all over the floor - well that's the theory. The bottom outlet in the images will be below floor level so will be hidden. A pipe from this outlet will go to the warm room. I cut the top outlet in the side of the pier instead of out of the top, because the top plate I will be using may make it difficult to access the pipe outlet if I put it in the top.

I also made 2 small frames to put around the tube (at top and bottom). These will be held in position to keep the tube vertical by long supports fixed to the frames and hammered into the ground.

Here are a few images.

Hope you have a mixer as thats too much by hand in one continual pour trust me, your dimensions are almost exactly the same as mine. On the other hand I poured the base and pier separately and it has not suffered for it at all, you just have to use epoxy and scour the interface. Also make sure that the pipe you put inside your tube form for the wires is at least and inch from the edge or you will risk cracking and voids within the concrete. In any case I would recommend using an emulsifier to get it flowing around better.

Edited August 28, 2017 by Adam J

[Alan White]

Very neat job with the plastic pipe Kev, one for the ideas pile for myself.

[Astrokev]

After rescuing a frog from the bottom of the hole, today I added some Wickes sub-base (thanks RayD) to try and firm up the clayey base to the pier hole. I think this has helped, but it's still pretty soft down there.

I also found a length of aluminium frame from an old bed during a clear-out of the shed. Perfect to add a bit more strength and support to the pier tube, so bashed that into the bottom of the hole as well. I'm fairly confident now that the pier will be pretty solid . Next job is to order a delivery of ballast, but I'm not sure how much I'll need - see my other post on this!

Other work focussed on the pier plate (no pics yet). I realised that I'll need to push the threaded bar that will attach the plate to the pier into the wet concrete after I've finished filling the pier tube, so started playing with the plate and fixings to help me make a form to hold this in place while the concrete goes off.

A few images before and after adding sub-base...

 

Edited September 2, 2017 by Astrokev

[Bizibilder]

If you are embedding threaded bar into the pier the easiest way to ensure it is solid is to put a 90° bend in it (you may have to heat it to red to be able to do this - easy enough if you have a blow torch) at the "embedded end" as well as running a few nuts onto it - these act as locks within the concrete.  When you have run the nuts on the threaded rod give them a good "bash" with a centre punch - or cold chisel etc - in order to damage the thread so that they cannot move on the thread.

[RayD]

Looking really good Kev.  Once you've got the base and pier done the rest is really enjoyable.  This, fortunately, is the hard bit.

[Astrokev]

On ‎03‎/‎09‎/‎2017 at 09:29, Bizibilder said:

If you are embedding threaded bar into the pier the easiest way to ensure it is solid is to put a 90° bend in it (you may have to heat it to red to be able to do this - easy enough if you have a blow torch) at the "embedded end" as well as running a few nuts onto it - these act as locks within the concrete.  When you have run the nuts on the threaded rod give them a good "bash" with a centre punch - or cold chisel etc - in order to damage the thread so that they cannot move on the thread.

Thanks Roger. Don't have a blow torch that I can remember, but will be trying to bend the ends to prevent risk of twisting if I apply excessive torque. I'm using M12 stainless rods, so not sure how easy this will be - it'll give my vice and lump hammer a good work-out

[Astrokev]

18 hours ago, RayD said:

Looking really good Kev.  Once you've got the base and pier done the rest is really enjoyable.  This, fortunately, is the hard bit.

Thanks Ray. Yes, really looking forward to getting the pier finished. I'm on much more familiar territory working with wood!

Kev

[Astrokev]

Concrete mixer being delivered tomorrow . The plan is to install the air duct tube and make the supports to hold it in place tomorrow, then mix all the concrete for the block and pier on Sunday.

Praying for dry weather

[Astrokev]

Big weekend - despite having to dodge several torrential downpours, I managed to finish my pier. Hooray!

36 bags of ballast. Thank heavens for the electric mixer, which made light work of it.

I supported the air-con tubing with stud-work attached to pegs driven into the ground. After filling the hole, I screwed MDF sheets to the frame around the hole to prevent the concrete being forced out by the weight of the concrete in the tube. It was really satisfying reaching the top of the pier tube and "topping-out"!

The pier top-plate is 16mm aluminium. I attached this to a temporary piece of MDF to act as a spacer and to cover the entire top of the tube to keep the concrete level, using stainless steel threaded rods. This went into the concrete easier than I expected, requiring only light  taps with a lump hammer to get it to touch the top of the tube. The white tape at the top of the tube has a reference line which I matched with a similar line on the MDF, to indicate approximate true north. I'll leave this a couple of weeks to go off. Next week I'm at Kelling so won't be tempted to remove the supports and MDF prematurely!

Glad the concrete work is finished. More enjoyable woodwork from now on .

Edited September 17, 2017 by Astrokev

[Astrokev]

A few more pics....

[Astrokev]

Had a great time at Kelling. On returning home I couldn't resist taking down the props and removing the block cover. Amazed to find that the pier didn't fall over! Actually, it's absolutely rock solid. Probably way over-engineered, but that's the way I tend to do things. Top of the pier needs a little tidying up once it's completely dried, so will worry about that later.

Next job is ordering the wood and building the floor.

 

Edited September 24, 2017 by Astrokev

[Astrokev]

A while since I've posted - mainly because work on the observatory has essentially stopped of late, due to family commitments, a short holiday, and a delay while I ordered and awaited delivery of my first batch of timber.

So, to restart things, I did manage to tidy up the site during a break in the horrid weather we've been having lately.

The floor joists arrived the other day, so praying for some dry weather this weekend to make a start on the main building!

 

[Alan White]

Looking like a nice job; 
await the wood butchery story to begin.

[Astrokev]

Managed to make a start on the floor today. I used double joists around the edge - partly for extra strength since these will be load-bearing, and also to provide a wider base to support the floor panels. The double joists were simply bolted together. Corners were braced with 90' brackets, and the joists were screwed to the brackets I inserted into the corner blocks to stop the whole obsy shifting - or worse still - blowing over should we have a hurricane!

The joists were insulated using squares of rubber pond-liner and strips of plastic DPC laid onto the concrete blocks (bit overkill there I think, as usual!).

Rest of the joist-work will hopefully be completed tomorrow, weather permitting. May even try and put the mount and scope on the pier to check the planned height of the walls. I'm wondering whether I need to make the South wall with a drop-flap to give easier access to lower altitudes. My SketchUp drawings tell me I don't need to, but I'm nervous and want to check this out before I commit to making the walls.

 

[Bizibilder]

Looking really god - straight and level as well.

Now is the time to make dead sure it really is all dead square and level - Just stand some heavy weights (or helpers!) on the base frame to make sure it is firmly on the base blocks and then go round with a spirit level - if you have a long straight edge (plank?) check the diagonals as well.  You can use bits of DPC/Pond liner to shim everything to perfection.  Well worth spending an hour or so getting it right at this point in the build!

[Astrokev]

It took longer than expected but I managed to finish the joists and noggins this afternoon .  Just need to douse them with preserver the next chance I get (I put preserver on the undersides before I installed the joists, so just the top and sides to do).

Didn't have enough time to check the wall heights, but I did manage to get the EQ6 onto the pier. Pleasing to find that I got the dimensions of the pier bolts correct! After dark I attached the Esprit 100 and enjoyed "First Light" through the new scope. This was Capella, then M31 and the Pleiades. The mount wasn't aligned so had to content myself with undriven views. Sky was rather washed out by the Moon, but the stars were pin-sharp. I think I'm going to like this scope!

The fourth joist from the left is double - this will support the dividing wall separating the warm room and scope room.

Roger - I haven't checked the levels yet. it was getting dark by the time I'd finished the noggins (and I was cream-crackered). I'll do this next weekend.

 

Edited October 29, 2017 by Astrokev

[Astrokev]

First chance for a while to work on the observatory. Today I started on the walls.

I decided to change the design and use fence posts for the corner posts. These were positioned vertically using temporary 45' bracing, and then built the wall frame between the posts. This is starting to look more and more like YesYes's fabulous build of a few years ago!

I had to pack up before completing the end wall as it was getting too dark to continue. Next job will be to insert noggins and corner bracing, so I can remove the temporary 45' bracing.

 

[RayD]

Looking really good, I feel your excitement 

[smudgeball]

We're all rooting for you to get it finished !