North Kent Roll Off Roof Build

[Graeme]

Wet concrete calls out for having initials and construction dates scribed into it!

 

 

I'll have to sort out an @powerlord style plaque for the door later!

 

[Swoop1]

Where is the obligatory cat/ dog/ child footprint?

[Graeme]

Been up north this weekend so haven't done much observatory build. but I have today taken up the base timber, filled the gaps in the mortar so that the damp course sits flat on it and cleaned up and repainted the outside edge of the base timber. I cut the four pieces of the top timber section but then it started raining! 

I bought some paint on mastic to stick the damp proof course strip to the mortar but I need to cover up the mortar to let it dry out before I do that. I could use the damp proof strip to keep the rain off. And I bought some M10 Rawl bolts to add additional bolt it down strength but I might be over engineering it now! Hoping to get these bits done this week after work now there's a bit more light in the evenings.

Then I need to cut the uprights to length. I'll probably put the mount and telescope on the pier to double check the wall height before I get the saw out. I did a scaled drawing showing wall height with the telescope at an altitude of 20° and I measured the height of the whole thing when parked horizontally +100mm. So I'm vaguely confident my design height will be ok, but there's nothing wrong with  double checking!

Graeme

 

 

[Graeme]

I finished the top section this morning so the next job is to put the mount on the pier to check the wall height. But after I had put the mount on  it started to rain so I had to cover it up again.

[Graeme]

So I retired to the greenhouse and put some seeds in trays instead!

[Graeme]

The rain soon stopped so I put a 12V and a USB into the mount and slewed my first pier mounted slew! With an 1800mm wall height I can see down to 15° which is lower than I need to go, so that's good. With the mount parked at 180° az 0° alt I get 50mm clearance to the roof section. It was designed to be 100mm but I haven't cut the M16 stud back yet. I'll get the disc cutter out tomorrow. My park coordinates point the telescope to where I'm hoping to put the flat frame light box .

[Lumos]

Looking at your OTA, Graeme, I think that I have found the source of your lack of sharpness at the edge of your SCT

[Graeme]

4 hours ago, Lumos said:

Looking at your OTA, Graeme, I think that I have found the source of your lack of sharpness at the edge of your SCT

It's my 18th century 2" wooden refractor! 

[Lumos]

28 minutes ago, Graeme said:

It's my 18th century 2" wooden refractor! 

Look closely, that is a super collectible Takahashi 18th century 2" wooden refractor. £3000 on eBay al day long. You're Welcome.

 

[Graeme]

Starting to look like some sort of building now! Uprights are in, top section is on. 

Next step is to fix in some 2"x2"s for timber cladding on the outside and OSB sheets on the inside. Not sure whether to recess the external cladding to expose the corner posts as a bit of a feature or to do the cladding over the corner posts to hide them. I'm leaning towards the former. It might be wise to do the floor first though.

Edited March 19, 2023 by Graeme

[Swoop1]

Recessing will give you a tad more room and sometimes a tad makes all the difference.

[Graeme]

5 minutes ago, Swoop1 said:

Recessing will give you a tad more room and sometimes a tad makes all the difference.

Good point. And there's only a narrow 12" gap on the fence side!

 

 

[gaz81]

Looking good.   Looking forward to see the roof. 

[Graeme]

2 hours ago, gaz81 said:

Looking good.   Looking forward to see the roof. 

Cheers Gaz

Me too!

 

 

 

[Graeme]

First fix walls are done. I've been cutting up noggins all day. I started a bit early so didn't want to annoy the neighbours with the electric saw. Today was just 2" x 2"s and I have a new hand saw so I've been using that all day. I had forgotten what a joy it is to use a sharp saw! This observatory now officially has my blood in it! Next step is to get some of the OSB internal cladding in to stiffen the whole thing up before I put the roof on. I suppose it might be good to finish the walls completely before I start on the roof.

 

 

[Graeme]

OSB on the inside is all done. I put a tarpaulin on the top because rain was forecast.

 

 

Good job too!

 

 

The plan was to put some insulation in between the 2x2s and make a start on the external cladding today but there was a tsunami when I pushed the lake off the tarp! So I made a start on the roof section instead. The roof will sit on a frame the same size as the top and bottom sections, so I got that done and then had to stop and do some trigonometry to work out the angles to cut the trusses. Probably should have been doing that of an evening instead of messing about with a rain sensor and an Arduino! We're not quite at the stage for that yet. Who knew observatory roof design maths would be so much fun! I'm going for a 25° slope with the slope towards observatory rather than the gable end to maximise viewing angle when the roof is rolled off.

 

 

I bought some fixed castors this week and I'm looking for 2 x 6m lengths of angle iron for the next step. @malc-c's observatory build thread was resurrected with perfect timing to point out the need for air bricks in the base brickwork, for which I'm thankful. So I need to put a couple of those on the shopping list too.

 

 

 

Edited April 8, 2023 by Graeme

[malc-c]

The build is coming along nicely... Glad my build has helped in a small way...  It's a really easy job to chisel out the mortar and replace a normal brick with an air brick.  In the course of recovering the cables that ran from the mount to the warm room I lifted the hatch and was please to see the underside was clean and dry, so they work !

[carastro]

3 hours ago, Graeme said:

OSB on the inside is all done. I put a trapline on the top because rain was forecast.

 

 

Good job too!

 

 

 

It's coming on well Graeme, I love the puddle of water in the tarpaulin.  Lol

Carole  

[Graeme]

10 hours ago, malc-c said:

The build is coming along nicely... Glad my build has helped in a small way...  It's a really easy job to chisel out the mortar and replace a normal brick with an air brick.  In the course of recovering the cables that ran from the mount to the warm room I lifted the hatch and was please to see the underside was clean and dry, so they work !

Thanks Malcolm

It would probably be a good idea to put them in before the floor goes down. And an access hatch is a good idea too that I didn't think of!

 

[Graeme]

8 hours ago, carastro said:

It's coming on well Graeme, I love the puddle of water in the tarpaulin.  Lol

Carole  

Thanks Carole

It was lashing it down on Thursday night! I'm off work this week so I'm hoping to get on with it to at least the stage of watertight. It would be a significant stage to reach because I could start using it! I haven't captured an image since last August (except for a go at Jupiter that wasn't too good) And I'm suffering serious withdrawal!

 

 

[malc-c]

3 hours ago, Graeme said:

Thanks Malcolm

It would probably be a good idea to put them in before the floor goes down. And an access hatch is a good idea too that I didn't think of!

 

Here's an image of the access hatch.  Still has a gap around the pillar so that no vibrations get transmitted, but tight enough to stop rodents getting through.

 

Oh and don't do the same mistake as I did and use overflow pipe for the cables.  Use 1.5" sink waste with gentle bends rather then sharp 90 degree.  I had a few issues pulling cables through but by that time it was too late to change the pipes.

[Mr H in Yorkshire]

46 minutes ago, malc-c said:

stop rodents getting through.

Mice can get through a 10mm gap. Might I suggest stuffing stainless steel wire wool down all the gaps, I had a problem with plastic water pipes getting gnawed and stuffed every hole I could find, no problem since. The material I used was for pot cleaning, be careful if you do use it, wear gloves because a single thread will slice through your fingers if pulled on.

Edited April 8, 2023 by Mr H in Yorkshire

[Graeme]

4 hours ago, malc-c said:

Oh and don't do the same mistake as I did and use overflow pipe for the cables.  Use 1.5" sink waste with gentle bends rather then sharp 90 degree.  

 

Another good idea. I have this one covered though. I used 1.5" waste pipe with 2 x 135° bends in series at every right angle. It makes a nice sweeping bend.

[Graeme]

20 hours ago, Mr H in Yorkshire said:

Mice can get through a 10mm gap. Might I suggest stuffing stainless steel wire wool down all the gaps, I had a problem with plastic water pipes getting gnawed and stuffed every hole I could find, no problem since. The material I used was for pot cleaning, be careful if you do use it, wear gloves because a single thread will slice through your fingers if pulled on.

 

One of the observatory build threads on here had a circle of rubber stretched over the pier and then fixed to the floor. I can't remember whose thread it was but it was a quality build.

 

Edit: It was @ArmyAirForce's Pinetree Observatory:

I will be copying this idea if that's ok Stephen!

 

 

Edited April 9, 2023 by Graeme

[ArmyAirForce]

19 hours ago, Graeme said:

I will be copying this idea.....

Feel free. We're all here to help and support each other, so if that idea will work for you, great. 👍