View Full Version here: : My plans for a roll off
30-03-2012, 10:47 PM
I have a disused concrete water take I am planning on turning in an obs. I originally was going to save up and get a sirus dome or similar and put it on top of the tank. But due to the costs I've decided to go the roll-off design.
I have attached some pics of the proposed roof. Any body see any flaws in the general design, feel free to point them out.
30-03-2012, 10:52 PM
Some more pics.
I have also left the option for a second roll off opening.
01-04-2012, 01:15 AM
Looks great thats a ton of room for an ob :) the only thing you would wanna do is make sure of water run around your sliding roof. Last thing you wanna do is head to your ob and find it has became a water tank again :( Another great idea would be to partion an area of for a warm room during those cold winter nights and ap seasons :)
02-04-2012, 10:54 AM
Hi Jay, Yes there will be a heap of room. The roof will have a slope away from the opening and a lip around it too so hopefully leaks wont be a problem. I will run a partition across the middle and line the walls too to help insulate it a bit.
02-04-2012, 02:40 PM
Looks like an excellent idea. Wee bit of judicious pruning to improve the horizon limits and being part buried in the ground should keep the temperature quite stable. Even without adding a pier base block it's probably pretty solid beneath as well having had several tons of water pressing it down for a number of years. Also pretty secure although it's looks like intruders wouldn't be a big problem anyway.
02-04-2012, 04:04 PM
Hi Brent, The chainsaw has been sharpened. Security isnt too much of an issue out here but it will have a solid locking system just to make sure. Just goto work out the fitting of the door jam. The roll off, I will be able to secure from inside without to much hassel. I have been thinking of ways to keep it cooler by planting some low growing bushes around it too and a vent or 2 around the top.
Thats an interesting thought on the pier base. The main reason I was going the block was so that the pier/telescope is isolated from the tank and any vibrations due to walking around inside the tank, even entering/leaving the tank. I though of cutting a square section aroundthe mount to isolate it from the rest of the tank but think that wouldn't be stable enough without the block.
I will have to do some testing to see if there is any vibrations. I will be putting in a raised floor and isolating that from the pier/mount, so if I can get away without the pier block that would be good(less cost)(even better, less work).
03-04-2012, 11:47 AM
I'm doing the 'raised floor' isolation for 'SkySlab'. I'm sitting on an estimated 10 tonne slab attached to volcanic rock which if it moves I'm going to be running !! :eyepop:
I've secured my sewer pipe pier with M12 threaded rod through the concrete base. We'll see how it goes. I'd suggest you try first, you can always modify it later, looks like plenty of room in 'The Tank' to bring in power tools.
Keep us posted and have fun !! :thumbsup:
03-04-2012, 09:36 PM
John, an intriguing idea. Having two concrete water tanks on our property, Brent's comments are appropriate. You should have a relatively cool stable environment in the tank. However I think there a couple of issues to tick off:
I would be giving some thought to ventilation, or more correctly the lack of, in a solid tank that may lead to mold problems. This is especially so in the cooler months where the inside temperature will be lower and dew and other moisture settling inside during observing sessions etc is likely to cause mold and other problems if there is not sufficient ventilation to get rid of it.
Are you considering insulation under the roof - it is surprising how much heat is transmitted through and radiated off the inside of an iron roof on sunny summer days. Again, lack of adequate ventilation may compound this.
Maybe I should be draining one of our tanks and doing the same!
Keep us posted on progress.
03-04-2012, 11:45 PM
Thats a decent slab you've got there. I havn't thought about the pier yet, I think I'll bolt the tripod down till I source a pier down the track. "The Tank" Thats a good name.:)
Ventillation at the moment isn't a problem, it's the other way at the moment, deciding how best to close off between the top of the tank and the beams.
I will have bats and that silver paper under the roof and eventually I'll line the walls and do the same.
I may have to put a small fan or 2 in down the track if the dam is to big a problem.
We have 3 other tanks that hold 5000gal each, so we didn't need it. Saves any need to get permits etc.(well I hope as I didn't check)
Thanks for suggestion, advice. I want to make sure i have all things sorted before I begin.
04-04-2012, 11:54 AM
My EQ6 is quite stable just sitting there without bolting down so good idea to start from there. You might need to extend the legs to get it up a bit with a 2 meter roofline. On my old tripod I used to hang a heavy iron weight ( ~5 kg) down between the legs to keep it stable. Worked quite well actually.
How about some vent louvres in the door? There are bound to be airgaps up around the roofline and roll off area so heat will naturally pull air in and no need for fans. Even a couple of low level industrial type vents on the roof or a couple of boat vents that face the wind will shift air.
13-04-2012, 07:28 PM
I notice in one of your pic that their is still a pipe attach to the tank ,I hope you have it disconnected from any water supply.
14-04-2012, 12:24 PM
Unfortunatly the house and sheds that used to feed that tank are no more:mad2:. So the pipe just goes into the ground.
But on the bright side I get to convert it.:D
19-08-2012, 07:42 PM
Well over the last 4 months I have been SLOWLY getting my obs happening.
After pulling the old roof off and draining the water and giving it a bit of a clean. I started building the main roof frame in the garage which made it a lot easier to do the cutting as it meant I wasn't balancing on ladders or chairs while wielding a cirular saw.
I went with hardwood for the main frame, which was bloody heavy, (7.2m x 150mm x 50mm)
Once I was happy with the garage build I then dismantled it and have started reassembling it on top of the tank.
The frame is almost finished, just need to cut the last 2 bits so they sit down 50mm inside the tank.
Anyway here's some pics of the build so far.
19-08-2012, 07:45 PM
And some more
20-08-2012, 09:00 AM
Hey, Cool to see John. Looks awesome.
I didn't realise you would be replacing the whole roof structure. Over here water tanks are concrete capped, sort of cone shaped. Bit harder to cut and remove.
Keep us posted on progress.
20-08-2012, 03:48 PM
I didn't think the existing roof would have supported very much weight, it only had 2 x 1" pipes holding it up and the tin had to many holes in it. Easier to start again than try and water proof it.
A few more sundays and I should have it ready to put a roof on. Provided the weather plays nice.
21-08-2012, 09:09 AM
Are you keeping the roof square overhanging the tank ? With the beams notched you have a built in ventilation louvre all round. Bit of wire mesh at strategic places and you should get a nice crossflow of air.
Door, cut out a hole with diamond saw, drilll and dynabolt the frame in.
At a later stage when you figure out what you're doing with a pier I'd put a false floor in around it to isolate and vibration and get you up to a usable height.
Any idea how thick\solid the tank floor is ? You could always section out a piece with a concrete cutter to isolate it. Seal the gap with Silastic against water etc.
So many options !! So much fun !!
21-08-2012, 10:38 AM
I was thinking of cutting the roof to match the tank but keep 200-300mm over hang just to minimize how much sticks out. I will need to seal most of those gaps somehow as the south half will be my warm control room.
I should be able to raise the floor a good 6-8" and still have head room.
I've no idea how thick the floor is, 2-3" maybe. Its a long way from flat so I will need to use some of that self levelling stuff they use on top of concrete floors to level them. I'll build a 1m form work around the pier location and just level that area. Evetually I may dig a hole and put in a concrete block to put the pier on if it needs it.
I'm a bit concerned about having an isolated section that it may tilt/move around a bit as the scope is moved around over time.
I'm putting the cutting of the doorway off till later. Thats the part that I could stuff up. At least if I stuff any of the rest up I can just go buy anthor length of timber and try again, not so easy with the tank.:D
But yes lots of fun and to many ideas. I think this might be work in progress for a long time.
21-08-2012, 01:03 PM
'Astronomy' is always a work in progress as I have found. :D.
Whats is the soil like around there, looks pretty dry and hard from the pix. Any Rock base ?
The fact that it has had water (heavy stuff) previously for long periods says it will probably be pretty compacted and stable beneath (mentioned earlier).
Go with the tripod to start with and work out what to do from there. I sat mine on concrete slabs for a while without a problem if you need a bit of height. You also have enough room to step well away from the setup while imaging unlike my shed which is very small. Wish I had your space (and horizon) to work with.
If you think it is not stable you could always punch a few holes through with a post hole borer and pour column foundations (upside down piers) to support a solid slab. An 8" slab on that i not going to move.
21-08-2012, 08:48 PM
The soil, what there is of it, is mostly clay type of stuff. there's no dry stuff in those pics, the darker patches in the paddocks is mud, sloppy, mud, and the greener bits are just undisurbed mud:D. The horses really make a mess.
It will be a while before I get a pier so will probable use the concrete slabs under the tripod to start with.
I like the idea of putting in colomn foundations. Yep, plenty of space, :D.
thanks for all your input.
01-01-2013, 07:35 PM
A bit of advancement on "The Tank" obs.
I was able to get a lend of a demolition saw over the new year break, so have cut a hole in the wall of the tank to put a door in.
The cuts aren't to straight as it was hard holding the saw straight.
The torque when 1st turned on was huge and had a big kick. But the hardest part was combating the gyroscopic effect from the 14" blade.
Unfortunatly I had to cut from both sides as the wall ranged from 12.5cm(5") at the top, to 14.5cm(5 3/4") at the bottom and I only had 10cm(4") cutting depth.
Doing the bottom cut, I destoyed the blade on a piece of reo running right across where I was cutting. Of course i couldn't see it till I had pushed the slab out. So a quick trip to Just Tools to get a new blade. Those blades are a lot more expensive than I imagined.
01-01-2013, 07:43 PM
And a couple more pics looking in. And 1 of the side of the slabe.
Anyone need a door for a bunker?
The door will lead into the office/warm room, with a partition running from the left of the door, thru the center post to other wall, and my scope sitting in the far qtr, between the broom and spray can. With room for another scope in the qrt to the left of the door way.
thanks for looking
01-01-2013, 07:49 PM
Thats some neat bit of cutting John,
Did you cut the bottom before the top? How tall is the opening?
since its curved how will the door frame sit? maybe a curved door??
01-01-2013, 09:56 PM
Thanks but they're not to good up close.
No I cut the inside top last. I cut the outside 1st then the 2 inside verticles then bottom then top. Since its quite thick I should be able to build a door jam inside the hole.
The hole dimensions are 1900 x 1050. Allowing 50mm thick doorjab all the way round will bring it down to about 1800x1000mm. The door I have is 2030x900mm so will have to make the verticels thicker to match and trim it down a bit.
02-01-2013, 03:10 AM
Won't it be 1800 x 950 if its 50mm all around?
For the warm room, are you adding insulation in the roof and sides?
You could have a glass window in the partition to keep an eye on things and still keep warm
02-01-2013, 10:11 AM
Ops yes it should.
I hadn't considered a glass partiton. Might have to look into that idea. See what available 2nd hand.
Yes the warm room will be insulated eventually.
20-03-2013, 03:04 PM
Bit more of an undate.
I have most of the roof on now but have to make a few changes. I need to cut the 3 longest lenghts of roofing, (the middle length and the ones left and right of the openings) so they end at the opening. Then raise the short pieces to match the pitch of the peices at the north end of the openings. Then I'll attach some marine ply around the opening giving me a 100mm lip all the way around the opening. I will use flashing to make it water proof. The roll off sections will close up against this lip on the northern end where the roof of the roll off section will over hang 200-300 mm all around.
Here are a couple more pics showing the roof before amendments.
20-03-2013, 03:44 PM
Looks really good John. I can see you spending a lot of long nights in there. I'm pretty sure you have already told me, but how are you going to operate the roof, manual or electric?
Next step is to have it all operating remotely, while you are sitting in by the cosy log fire.
20-03-2013, 04:03 PM
At some stage a long way down the track I might go electric, but for the time being it will be manually operated.
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