Micro observatory

[Bubbles82]

Victory is mine!!! I have gone from being given the thumbs up for a pier in the garden to a small obsy. I am currently working on some ideas for a roll off micro obsy which will be basically big enough to house the pier, and mount. I'm planning on building this just behind the garage and using the garage as a warm room. For the moment the rest of the project is in the background and the only thing I'm interested in is the pier foundation/ mounting block. I'm going with a pre made metal pier which is bolted down and understand that this is the most important piece of the project because if this bit is not right the rest is pointless. So here comes my first question to anyone who has a pier metal or concrete,what type of cement mixture did you use to create you founding block. I'm wondering if I can use post Crete or a similar type of mixture to ensure I get a solid base to work with.

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[gary1968]

Get bags of premixede balast from B&Q or somewhere like that, it has the sand and chips mixed already. Also get a suitable amount of cement in bags, I cant remember the ratio off hand but there is mixing instructions on the balast bags

HTH,

Gaz

[Gina]

I got mine from Wickes for my pier etc. - big bag ballast and several bags of cement.

[Zakalwe]

I used a mini-mix company. They rock up with a lorry that mixes the required mix (C12) and pumps it into a wheelbarrow. You can then wheel it from your curb to your foundations. Just under a cubic metre cost me £115 and it was in and floated off in about 30 minutes. Far easier than faffing about with getting a mixer and mixing it yourself. A lot less hard work too and a lot cleaner as well.

[red dwalf]

don`t use post mix, not the best material for this kind of job, builders merchants 1 cubic yard of ballast, about a ton and costs around £40 and 6 or 7 bags of cement about £5 each,

mix in the ration of 5 ballast to 1 cement or maybe slightly stringer mix of 9 ballast to 2 cement, don`t make it too strong, cement gets stronger by itself over time, a 3 foot square should be more than enough if not over kill, most important thing is depth, if your too shallow you can get whats called frost heave which is not good for a pier, alot depends on what type of soil you have, clay is worst.

[Bubbles82]

Thanks for the replies everyone will go with the ballast and cement route shouldn't work out to expensive and should be able to mix this either in a barrow or mixer if I can borrow a friends:) really excited about this as I've said before on here my imaging time is really limited by shift work and having an obsy and permanent pier will save critical time

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[r3i]

When I did my pier, which was about 1.5ft square and 3ft deep, I think I used around 16 bags of ballast and 2 or 3 bags of cement - mixing was roughly a 5:1 ratio give or take.  For mixing I just used a thick plastic sheet - I piled a quantity of ballast & cement onto the sheet, added the water bit by bit and rocked the sheet from side to side, being careful to keep the stuff on the sheet and not spilling onto the lawn.  Once mixed, you pick up the sheet by 4 corners and carry it over and pour ti into the hole.

[dmahon]

4:1 ballast/cement (mastercrete is good). 1m3 is probably over the top, but seems to be the oft quoted figure. That will need about 15 bags of cement (25Kg) and 2 jumbo bags of ballast.

Wickes is cheaper than Jewsons on mastercrete, even with a trade discount - but readymix  is much easier and is the same price (about £125-£150).

If you do it yourself, definitely borrow (or hire, they're cheap) a mixer.

[Gonzo]

here's a micro one http://stargazerslounge.com/topic/150387-the-nano-observatory-v20-the-borgkube/

[Gonzo]

here's another idea if you're interested http://www.budgetastro.com/The_Budget_Astronomy_Micro_Observatory_Project-1.pdf

[Bubbles82]

Very similar to what I was thinking

[Gonzo]

if you're still looking for designs, check out this one http://stargazerslounge.com/topic/147991-pier-and-roll-off-cover-mostly-pics/