pipe for pier

[Daniel-K]

any one no were i can get a pipe for my pier?? thanks guys

[JamesF]

What sort of design were you planning? Steel? Concrete?

James

[Daniel-K]

i was going for a concrete filled steal pier, but if any one can suggest anything better would be great full,im by no means a diy man so im needing all the help i can get i put my base down early this year (flags) but have decided now i want a pier so im going to get all the materials and try and do it over 4 days in july i will have some help form my friend whos a joiner i hoping we can do it

[Bizibilder]

If you have a base then you could put some bolts in it and mount a steel pier on that. (Modern epoxy glues will hold your bolts in drilled holes). For the steel you will need to find a "steel fabricator" - these are the folk who make things like fire escapes and ornamental fencing etc. If you go and visit one you will often find they have what you want in their "offcuts". They will often cut to size for you for the price of a pint. My own friendly fabricator provided the steel and welded my pier for well under £100.

It may take a couple of visits to find exactly what you want - let them know what it is for and they will probably be helpful.

[JamesF]

Depending on how thick the steel is you may not need to fill it with concrete, but if you are going to fill it then a section of 4" or 6" drain pipe would do the job depending on how big you want to go.

I found a supplier of air conditioning ducting on ebay that supplies 1.5m, 2m and 3m lengths of ducting at quite reasonable prices. They're in a range of diameters so you could pick the size you want. They probably would need filling with concrete as the walls aren't very thick. The supplier I used has gone, but there are others still active on ebay.

James

[sologuitarist61]

Depending on how thick the steel is you may not need to fill it with concrete, but if you are going to fill it then a section of 4" or 6" drain pipe would do the job depending on how big you want to go.

I found a supplier of air conditioning ducting on ebay that supplies 1.5m, 2m and 3m lengths of ducting at quite reasonable prices. They're in a range of diameters so you could pick the size you want. They probably would need filling with concrete as the walls aren't very thick. The supplier I used has gone, but there are others still active on ebay.

James

Thanks James, will look out for these suppliers.

[Bizibilder]

The problem with concrete is that it is permanent and totally non-adjustable! (Meant to say that in the post above).

[Daniel-K]

i have to take 4 flags up and dig a hole to pour a concrete base in 3x3 my obs is going to be 8x12 i want a really solid pier.

[leelee970]

I used 250mm x 1.5m galvanised steel spiral ducting tube as used in heating/ventilation @£18 from ebay

http://www.ebay.co.uk/itm/250mm-x-1-5m-galvanised-steel-spiral-ducting-1off-hydroponics-ventilation-/170843333816?pt=UK_Home_Garden_Hearing_Cooling_Air&hash=item27c70e64b8

I also bought an end cap to finish it off after i filled tube with concrete and sunk four M10 x 1m studding threaded bar zinc plated.

[Daniel-K]

I used 250mm x 1.5m galvanised steel spiral ducting tube as used in heating/ventilation @£18 from ebay

http://www.ebay.co.u...=item27c70e64b8

I also bought an end cap to finish it off after i filled tube with concrete and sunk four M10 x 1m studding threaded bar zinc plated.

that looks good do you have a picture of your finished pier?

[leelee970]

Hi Daniel, if you look at my profile i've added a photo showing the steel tube, cap and rods, including base plate- not sure how to add an attachment on this thread.

[Daniel-K]

thanks for that it looks great

[ollypenrice]

What is the concrete filler intended to do? Concrete is strong in compression and very weak in tension. It is also very rigid which means it is good at communicating vibrations. I'd have thought that, in brief, it was the opposite of what you want! Personally I don't think that steel piers need filling but my home made ones are filled with a mixture of sand and old engine oil, which is a good damping medium and rust inhibitor. This attractive cocktail is what an engineer was recommending in a discussion ages ago, I can't remember where.

To be honest, the piers sold by Astro Physics, Mesu, etc are large diameter light guage metal with no filling at all and they are intended for large telescopes. Very large. The Mesu is rated to 100Kg.

Olly

[JamesF]

Steel is exceptionally good at transmitting vibrations too. Probably better than concrete I do actually agree with your point though, Olly.

On reflection I think perhaps it's better not to consider the pier on its own, but in the context of the observatory construction generally. Looking at Olly's current construction, I can understand that a tubular steel pier, bolted down or otherwise, is perfectly good for the job. But that's partly because it will be sitting on top of a concrete raft weighing a couple of tonnes which is not going to start vibrating and transmit those vibrations to the mount in anything we might consider "normal" circumstances. I also imagine that Olly and his guests can generally trust themselves not to go leaning on the pier or kicking its feet, too. Olly can probably walk around his obsys in his sleep without tripping over stuff by now, Perhaps he already does

If you're constructing an obsy with a suspended floor and no concrete slab and/or there are children or pets running around who might not be quite so careful then first you need a foundation that won't shift about when you attach a large lever and a lot of weight to it (ie the pier and telescope + other gubbins) which is perhaps most easily achieved with a reasonable size lump of concrete sunk into the ground. To create a pier that won't move if you accidentally knock it then I don't think it matters whether you bolt a steel tube to the concrete block, or extend it to make a full concrete pier. When constructed with appropriate dimensions either is going to resist deflection pretty well. Steel is surely the more flexible approach, whereas concrete may well be cheaper and easier for the occasional bodger to construct themselves.

There is also the issue of not having vibration from outside the obsy transmitted to the pier and scope, but if that's a real worry then perhaps you need a decent foundation, a steel pier and some fixing arrangement that will damp vibration between the pier and the foundation.

James

[Kai]

I used to have a 3x3 concrete block into which i used a yellow gas pipe filled with concrete , it didnt move and more importantly no vibrations.

Only thing i would reccomend is not to mix the concrete by hand

[laser_jock99]

I went for a 9" dia steel pier which seems fairly sturdy. If you hit it hard it will 'ring' for a few seconds- so don't do that while imaging!

Filling with concrete is semi permanent- which is something I didn't want. You'll leave yourself (or the next house owner) with a problem when it has to come out.

My pier has a large flange welded to the base so it could be bolted to these M18 x 500mm studs. Once the pier is removed the observatory is just a shed again!

The tube itself cost £100 from a local steel fabricator (every town has one)- seems like a lot but the whole assembly weighed in at 80kg and was a two man lift.

[Daniel-K]

i found this http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=260841086351#ht_1215wt_1031 but i think the 6" diameter is to small? and the walls might be to thin? what you think?

[JamesF]

Wall thickness doesn't make a great deal of difference. I think it only needs to be thick enough to resist denting. Diameter makes a big difference. If you're going to set it in concrete I think those are going to be too short, and if you decide to bolt it down then they might still be, but you're going to need some additional fabrication work to add the mounting flanges. Stainless isn't particularly cheap compared with painted steel, either. I'd have thought 6" diameter would be fine. 8" diameter will be more rigid, but you're not mooring the Titanic to it; it only needs to be rigid enough.

James

[Geoff27]

Hi Daniel-K

I built a pier and observatory a few years ago. A good place for pipe work is a scrap yard. I picked up 6" steel steam pipe 3 foot long for £5 (2007). Below are some links to photos of my set up and building it. Total cost including building the observatory about £400. Most satisfying thing I've every done. Obsy is 7ft by 5ft (wife insisted it wasn't too big!). Had to paint it green as well. If you want more info or pics let me know. Since then have built a pier for a Skywatcher 180 Pro. Total cost including welding about £100.

Geoff27

http://i1129.photobucket.com/albums/m509/Geoff2707/fHoleforpier20-10-03.jpg

http://i1129.photobucket.com/albums/m509/Geoff2707/jTestfitting01Nov2003.jpg

http://i1129.photobucket.com/albums/m509/Geoff2707/kInstallingpier1-1.jpg

http://i1129.photobucket.com/albums/m509/Geoff2707/pRooffinished.jpg

http://i1129.photobucket.com/albums/m509/Geoff2707/qTransitofVenus080604.jpg

[Daniel-K]

i bought this as lee did just encase i cant find anything else were its 8inch in diameter and 1.5m tall i was quite surprised how strong it was for £18 so im going to get my leveling plates made up and if i haven't found anything else by then then this is getting filled with concrete. going to dig the hole this weekend hopefully weather permitting. im not planning on moving from this house so making it as permanent as i can ive even got pans to stick another pier in the middle of a stone circle for my buddy who regualy use'd my garden for AP because its darker than his own but the obsy is first before that. Geoff that look brill!

[leelee970]

Good luck. If you do decide to fill it with concrete - DON'T mix it by hand, lol (really back breaking).

I dug a nice big hole, and filled the hole and tube with concrete and rebars. just over 1 tonne in weight.

The observartory is suspended and in truth I don't get any vibration even when the pier is knocked.

[ollypenrice]

This comes up often but don't compromise the strength of your pier by adding what can sometimes be flimsy levelling bolts. Mounts do not have to be level to be polar aligned.

Olly

[Daniel-K]

This comes up often but don't compromise the strength of your pier by adding what can sometimes be flimsy levelling bolts. Mounts do not have to be level to be polar aligned.

Olly

thanks Olly what would you recommend?

[ollypenrice]

You just need a top plate to which your mount can attach. You can buy them, or buy height extenders for tripods which you then bolt to your pier.

What you often see are mighty piers ending in three or four lengths of threaded bar sticking out of the top for levelling. I can't see the point in this since the lengths of threaded bar don't seem very stiff after all the effort put into the main pier, and the levelling they provide is entirely unnecessary.

Olly

[laser_jock99]

I agree with Olly about 'leveling top plates' - no point building a solid pier only to top it off with three flimsy 'leveling bolts' which aren't actually needed anyway.

One further point about filling a pier with concrete- a hollow tube is a great way to run your cables tidily away from the scope. Fill the pier the concrete and you won't have that option, unless you plan ahead and run some conduit inside.