Concrete base in garden

[tramsden]

I've decided to put a concrete base in my garden to attach an altair astro pier to. Can someone help with the possible dimension for the base I should use. I want it to be stable enough for imaging but I'd like to keep it small if possible to be SWMBO off my back.

thanks Tony

[Psychobilly]

I dug a bell shaped hole and left the concrete a couple inches below the lawn surface the turf grows back to within an inch or so of the pier and the gap is filled with loose gravel...

How big..? it depends what you find when you start digging... I

'm on made up ground so would have to dig a hole about 15 feet deep to get to "clay"... so I use lengths of rebar driven at angles into the soil and leave long ends in the hole that end up cast into the concrete...

Peter...

[ScubaMike]

I am building a pier, and will be making a "bird table" type top for it.

During Summer, I'll take the mount down (not much to do in the light months anyway). During winter, my mount gets attached.

SWMBO has been convinced it will not therefore be an "eyesore" (her words - not mine).

Both parties happy.

[Bizibilder]

You can usually get away with about 2'x2'x2' (60x60x60cm) or bigger. Remember if this is your first "base" that any surrounding concrete or slabs must NOT be in contact with the pier base - leave a gap of at least an inch (2.5cm) - this is to prevent the vibrations of yourself walking about from causing the pier to vibrate.

[laser_jock99]

How big..? it depends what you find when you start digging...

Peter...

I hit the bedrock 2 feet down- can't get much more stable than that!

Size- many people say 3 feet (1m) cube is about right- but that's a LOT of concrete. As previous posters have said- it's important to keep the pier block isolated from where you are moving around it. A non-touching wooden floor above pier block level is good.

[tramsden]

Thanks all.

I won't be digging through bed rock that's for sure. I'm going to aim for a 2'x2'x2' hole with some rebars. The volume difference between 2'x2'x2' & 3'x3'x3' is a lot of concrete.

I wasn't planing on putting any decking around the area, just leaving the grass to walk on. Just shouldn't case any vibration transmitting to the pier , should it ?

Tony

[Psychobilly]

Sounds like a plan

[izakimak]

I'm in the process of checking the planning permission for my observatory.

You can't go in front of your house without permission. I have the main structure (which I will go in front of) but a bit of the garage and porch that extends beyond (which I won't).

Looked into various piers and decided that £500 was taking the wee wee for what is a post that has a plate on each end and some ribs down the side. I'm having a custom one built for less than £100. That includes galvanising and then painting. If you just use a steel painted post it will rust wherever the paint gets damaged (like where bolts go through).

[laser_jock99]

If you just use a steel painted post it will rust wherever the paint gets damaged (like where bolts go through).

If the steel is thick enough a bit of surface rust won't matter. I assume you will be keeping the pier covered most of the time so it will be dry anyway? I used a layer of zinc paint on mine- no sign of rust yet. Galvanising will of course reach where you can't easliy paint- inside the tube.

[Smeg]

I would say dimensions about big enough to hold 1 or 2 bodies.

[Bizibilder]

To do the inside of mine I just poured some paint in and swilled it around then poured the remainder back out - seems to have worked.

[Glider]

I've got 3 off 2" thick by 2'x2' slabs lying around.

I'm planning to dig a hole 3'x3' by 1' deep. Then I'll hammer in rebar at various angles and leave 2" sticking up. I'll then layer 2" concrete, slab, 2" concrete, slab, 2" concrete and final slab.

Then raw bolt the pier down.

Does that sound like a reasonable plan?

[Bizibilder]

Glider I have a nasty feeling that if you do that then the layers will quickly "de-laminate" especially at the first sign of frost - go for solid concrete - 'tis cheap enough and easier in the long run.

[izakimak]

Agree, surface rust isn't a problem. Until it spreads to bolts, etc.

My painted counterweights are showing signs of rust and they have never been stored outside, only used when observing.

I design gear that goes inside cars. It's made of 316 stainless (look up the price of 316 if you want a fright) due to the fact the "dry" interior is anything but. Never had a seized nut/screw/bolt or had to replace a single part due to any sign of corrosion in 4 years. This gear has replaced the "leading product" as the prefered equipment due to it's ability to survive the enviroment and ham fisted user without a problem.

Galvanising is approx £0.80 per kilo (ie. if your pier weighs 20kg it will cost £16 to galvanise).

Also, for a minor cost difference (don't know why steel and stainless steel rebar has little price difference), use stainless rebar for anything that appears above ground. Use stainless nuts and bolts for fixing the pier and for any adjustment devices. Stainless is also a very hard metal, so fitting will not be easily damaged by tools.

This way you will not have an issue when future removals/upgrades/adjustments are required. You will probably need to adjust the alignment after a few months unless you dig down to bedrock like laser_jock99. In fact, if you dig down much further than laser_jock99 you'll probably have various oil companies contact you ;-)

Look forward to seeing how you get on. I'm learning lots from these builds.

[yeti monster]

I would say dimensions about big enough to hold 1 or 2 bodies.

Are these laid out and toes up bodies, or neatly hacksawed and stacked bodies?

[yeti monster]

About 1/2 way down page 2 I'm building my pier and patio...

http://stargazerslounge.com/members-equipment-gallery/131538-proper-obsy-2.html

[izakimak]

Yeti monster

Pier and patio! How many bodies required for that?

[yeti monster]

^^^I did it single handedly...

Oh, you mean underneath? That, my friend, would be telling....