First time pier build - is my thinking ok?

[Mr Spock]

I don't do much observing these days due to the EQ6 being too heavy for my back. The solution is some sort of permanent site for the EQ6, but I don't have the space. I've taken the decicion to dismantle the greenhouse to free up space, it was old and twisted anyway. That has now gone and I'm left with what to do next.

Here is what I was thinking:

• Foundations: four 440x215x100 concrete blocks laid vertically in a big hole, seated and levelled, concreted in and back filled. These will support the corners of,
• a 610x610x50 paving slab to be fastened (glued?) to them.
• Two 440x215x215 hollow concrete blocks bolted and glued to each other and then to the paving slab.
• EQ6 bolted to the hollow block.

I know others have used these hollow concrete blocks successfully to make piers. I'm hoping what I've planned above sounds ok.

Please let me know if there are any things I've missed or overlooked, or if there are other suggestions for best practice.

Thanks.

[Psychobilly]

Sounds OK... 

About 20 years ago we use  Evostick Gripfill to build a pierced block wall  it went up in no time and it's still there....  There are more recent adhesives  that should do the job as well...

Peter...

[Peter Drew]

I wouldn't bother with the foundations. I have 2 large block piers, one for a 8.5" F12.5 equatorial refractor and another for alt-azimuth mounted long focus scopes. Both are free standing on a base of 4 paving slabs in a square each bolted to an upper single paving slab to which the pier blocks are bolted. Saves a lot of extra work and can eventually be dismantled if necessary.   

[Scott]

I wouldn't bother with the foundations. I have 2 large block piers, one for a 8.5" F12.5 equatorial refractor and another for alt-azimuth mounted long focus scopes. Both are free standing on a base of 4 paving slabs in a square each bolted to an upper single paving slab to which the pier blocks are bolted. Saves a lot of extra work and can eventually be dismantled if necessary.   

I do often wonder if we go way over the top with some of our designs. I dug quite a hole and concreted the steel pier into it as seemed to be the norm. It works a treat but I cant help wondering if its overkill

[Mr Spock]

The four slab idea is interesting. I imagine the huge weight creates a lot of stability. Hmmm...

[malc-c]

Just go with tradition.. did a hole, bung a length of 6" pipe in it, fill the hole with concrete.  When set, mark the pipe for height and cut to length.  Fill pipe with concrete, use a length of 2x1 to remove air and ensure the concrete settles.  Whilst wet, place the pier head with lengths of suitable threaded bar bolted to the bottom section into the tube and orientate the pier head so the mount will be level and pointing North.  Leave to cook for 24 hrs minimim.  Once dry, remove the pier head and paint the tube to blend in to your garen (matt balck, dark green dark brown works well).  If you really want to be cleaver, you can turn pier into a bird table for daytime use and keep the other half happy

[Peter Drew]

You could build 20 block piers in the time that would take! 

[nightvision]

You could build 20 block piers in the time that would take! 

Good point Peter.  I will be doing a block pier soon (don't want to be messing with concrete pouring etc).

Is there a particular thread that covers the block pier build in detail?

[Mr Spock]

There's one here I've just been looking at http://stargazerslounge.com/topic/247617-another-hollow-concrete-block-pier/?hl=%2Bblock+%2Bpier+%2Bbuild#entry2699823

I think it's very similar to what I'll be doing.

[Tinker1947]

Making the base solid has to be the plan, but to big means you will walk on the slabs, this will make them unstable, a single 24" square paving slab 2" thick so you don't need to stand on it would work, with a foundation of rubble with 3" off concrete  and the paving slab laid on top nice and level, the concrete  pier block glued to the slab and each other to gain the right height will make a nice firm pier without spending to much energy or money.......

[Mr Spock]

Here's a snag, none of the builders merchants I've been to have the 440x215x215 hollow blocks. Apparently there's a country wide shortage

[Tinker1947]

Try this site i googled , the delivery charge will be the iffy bit, but less than a fiver has got to be worth it....????

https://www.mkmbs.co.uk/prodb004313-440mm-x-215mm-x-215mm-hollow-concrete-block-7n/

[Mr Spock]

I've been there this afternoon (they are a couple of miles away) - they don't have them.

[Mr Spock]

I'm currently investigating the feasability of using solid blocks and bolting the EQ6 tripod plate to them with an adaptor (angle iron bolted to where the legs attach).

[nightfisher]

Michael, how about a wooden pier, sounds a bad idea but wood is good for damping vibration, easy to work with and good for visual use

[Mr Spock]

The brain is ticking over now and I'm having ideas.

I've just dismantled the greenhouse, the remains of which are off to the dumpit site. I've just noticed the door frame is made up of 20mm U shaped aluminium. Two of these back to back fit exactly between the EQ6 base tripod lugs as the gap is 40mm. This would then have three large chunks of aluminium pointing down where I could fit it to a base...

For the base I could use 440x215x100 blocks arranged like this (top view) seated on a 610x610x50 paving stone. Or maybe four of them as mention above. Even an earthquake isn't going to move that bulk!

Four like this, and the next four on top but reversed; this would give and almighty solid pier. The centre square is 115x115 down which the aliminium would fit easily. The centre could then be filled with concrete thereby securing the aluminium.

There is enough space to get a hand in to fasten the EQ6 to the base plate. Despite the top of the pier being 315x315 the C9.25 clears the top by a mile.

The 880 height of the pier plus about 100mm of aluminium at the top puts the eyepiece, when vertical, at the right hieght for sitting on the 520mm high stool I have.

It looks over engineered but those blocks and consumables add up to less than £25... I already have everything else.

[iamjulian]

First proper test of my 2 hollow concrete block pier night before last. Setup was quick and easy. Polar scope aligned as best I could, 1 star align on Vega then 60 seconds on M57. Nice round stars. Grinning like a Cheshire Cat. Pier cost about £5, half of which was paint

[richyrich_one]

First proper test of my 2 hollow concrete block pier night before last. Setup was quick and easy. Polar scope aligned as best I could, 1 star align on Vega then 60 seconds on M57. Nice round stars. Grinning like a Cheshire Cat. Pier cost about £5, half of which was paint

Feels good doesn't it? Beating the system

[iamjulian]

I'd never say don't bother going the big concrete pour route.

I just wanted a toe in the water with something temporary for now.

And it seems you don't have to spend a fortune to make a useable pier.

Anyway, it would be dull if we all did exactly the same

[nightfisher]

Hows this coming on? what "glue" is used to assemble the blocks?

[Mr Spock]

I'm using Gripfill.

Each block will have a rawlbolt through the 100mm thickness to add additional strength to the bond.

Each block will have 75mm concrete screws projecting 25mm inside the 100x100mm space and the base will have a rawlbolt sticking upwards - this is so when I pour concrete in the whole thing will become solid.

Base will be 4 610x610x50mm paving stones.

A 300x300x35mm paving stone will be bolted to the top with four rawlbolts and no glue - this is so I can fine adjust leveling. There will be a hole in the centre for the EQ6 bolt.

This will be a permanent fixture. I can remove the mount by undoing the four top rawlbolts if I need to (another reason the top won't be glued down).

At the moment I'm still clearing up. The former greenhouse site looks like a bomb site!

[Mr Spock]

I've already drilled one of the 610mm paving slabs ready for the centre bolt without incident. Once I've got the bottom one in place and levelled with the bolt fixed in, then threading the other three onto the bolt will be interesting - they are heavy!

The rest of it is like an oversized Lego construction.

An earthquake isn't going to shift this lot!

[Mr Spock]

Bombsite - pier is going in the centre where the brown plantpot is.

Lots of clearing up to do...

Will create patio around the pier; raised flower beds towards the fence, existing paths removed and flower beds put in, better site for Stevenson screen.

[nightfisher]

Michael, when i first saw your post about this i had a bit of doubt, n ow i have seen how they work i am most impressed, toying with doing one at home, but i carry mount and tripod out in one go and use a CG5 tripod so dont really see that i need it, but this will be a top move for your self

[spaceboy]

You and me both Jules. I already have a drain pipe pier but it was done when astronomy was more a side line hobby so I didn't throw much enthusiasm in to digging the hole so I have less than half the ideal 3' in the ground which every time a heavy waggon goes past 20 yards away I suffer vibration. With the obsy now built around it I would have a nightmare replacing it but this way I only need to cut the pier back to the ground drop a slab on top of the old footings of the pier and build on top of that