Wooden pier

[Anthonyexmouth]

please move this if its in the wrong place.

is anyone here using a wooden pier for imaging? the guy i bought my spiral duct off on ebay turned out to be a less that truthful about the condition so looking for something else to fill the hole now. pricing steel but seen a few pics of 4x 6x6s bolted together and used as a pier. anyone here got wood?

[Peter Drew]

A concrete "Todmorden" type pier would be better and cheaper.   ?

[Anthonyexmouth]

Just now, Peter Drew said:

A concrete "Todmorden" type pier would be better and cheaper.   ?

i can get oak for next to nothing that would suit construction , but the todmorden design would make my eyes bleed looking at something that ugly out of my window. wouldnt be so bad if i had a bigger garden and could tuck it away behind some trees

 

[JamesF]

Then clad it with some oak?

James

[michael8554]

I have a wood pier.

It's made of four 4"x4" posts glued and studded together, with the end grains randomised to reduce the effects of humidity.

The end in the ground is coated with bitumen.

Not concreted, that just encourages rot.

Pea shingle instead in a 2ft wide hole.

It is in a dome which probably minimises the effects of weather.

Carries an 8"  LX200GPS and guidescope and 3D balance weights on a very heavy steel AE Mega Wedge.

I PA to 5 arc-mins with the drift to the south, so I can Dec guide in one direction mostly, to minimise the effects of Dec backlash.

People will tell you wood is a no-no.

I drift align every couple of months when I start to notice PA isn't as good as it used to be.

Way easier than cubic-yard holes filled with concrete, fabricating a steel pier, or sourcing 8" tubing for a concrete pier.

Michael

 

 

 

[Peter Drew]

2 hours ago, Anthonyexmouth said:

i can get oak for next to nothing that would suit construction , but the todmorden design would make my eyes bleed looking at something that ugly out of my window. wouldnt be so bad if i had a bigger garden and could tuck it away behind some trees

 

You can make it look however you choose.    ?

[cletrac1922]

Anthony

Some of my club members just use piece of 8'' PVC pipe, buried down 600mm into the ground, and then filled with concrete, and insert piece of 800mm threaded rod, into top, while concrete is drying, ensuring is straight using a level to mount your scope

John

[Carbon Brush]

If you still like the spiral ventilation duct route, look up ductwork manufacturers within a reasonable distance of you. Check on their site, or phone, to see if they have a spiral duct machine.
some companies buy in their spiral duct.

Work out what length and diameter you want (or can accept) and knock on the door, waving £5 notes and don't ask for a VAT receipt.

Quite possibly they will have suitable offcuts or damaged parts to go in a skip. Dents and dings don't matter that much as you can hammer them out and you are going to be filling the tube with concrete.

If all else fails you pay a bit more for a piece made to order.
By that I mean the machine operator will run off a piece for you and not go short of beer that night.

My pier was purchased in this manner.

Hope this helps. David.

[Anthonyexmouth]

22 minutes ago, Carbon Brush said:

If you still like the spiral ventilation duct route, look up ductwork manufacturers within a reasonable distance of you. Check on their site, or phone, to see if they have a spiral duct machine.
some companies buy in their spiral duct.

Work out what length and diameter you want (or can accept) and knock on the door, waving £5 notes and don't ask for a VAT receipt.

Quite possibly they will have suitable offcuts or damaged parts to go in a skip. Dents and dings don't matter that much as you can hammer them out and you are going to be filling the tube with concrete.

If all else fails you pay a bit more for a piece made to order.
By that I mean the machine operator will run off a piece for you and not go short of beer that night.

My pier was purchased in this manner.

Hope this helps. David.

think lindab is the only place local to me. might pop down and ask on site. 250mm is my goal. looked at pvc but far too expensive. 

just waiting on a quote for a steel pier. hoping to get this done fairly soon before it gets cold. 

[michael8554]

So wood didn't appeal ?

Michael

[Anthonyexmouth]

4 hours ago, michael8554 said:

So wood didn't appeal ?

Michael

it does, would look much nicer, just pricing up options at the moment and hoping some more wood pier advocates will jump in with their experiences. if i go for wood i'll use 4x 6x6 bolted together. 

[michael8554]

Since I installed my wood pier in 2015 I have seen a product called Postsaver used to protect farmer's wooden fence posts.

I only saw them when they were installed, I'd guess they are placed over the end of the post then heat-shrunk, I could see the section above ground.

Michael

[Anthonyexmouth]

2 minutes ago, michael8554 said:

Since I installed my wood pier in 2015 I have seen a product called Postsaver used to protect farmer's wooden fence posts.

I only saw them when they were installed, I'd guess they are placed over the end of the post then heat-shrunk, I could see the section above ground.

Michael

if i do go the wood route i'd just soak the oak in danish oil. 

[AstroNowt]

If you go the wood route I would consider a single 10x10 oak post. It will look better than 4 posts screwed together. Danish oil will protect the above ground part although oak weathers nicely without anything. The below ground portion will be the problem and danish oil is not the solution. At a minimum a large dose of wood preservative. Maybe a bitumen paint or similar. 

Any wood will move over time and you may end up having to adjust your top plate every so often. No big deal.

My preference would be for concrete formed in a ‘cardboard’ tube. However I know of one successful oak post installation although that is undercover. 

[nightfisher]

Dont be afraid to use wood, look at some of the very best tripods, highly regarded and made from, you guessed it......wood, a local saw mill could run up an oak post to your size, coat the below ground section in about 3 coats of resin like used in GRP boat building, and make sure you have some adjustment in top plate

[AstroNowt]

I am not sure that a wooden tripod is a good guide to how an oak pier will perform. The tripod being made from top quality kiln dried timber and kept indoors. 

A green oak post will move significantly over the first few years. If you can get an old post from say architectural salvage it will be much more stable.

If you have some clamps how about laminating your own post from marine ply? Would be very stable, although a bit of a pain to make. 

[nightfisher]

1 hour ago, dhb368 said:

I am not sure that a wooden tripod is a good guide to how an oak pier will perform. The tripod being made from top quality kiln dried timber and kept indoors. 

A green oak post will move significantly over the first few years. If you can get an old post from say architectural salvage it will be much more stable.

If you have some clamps how about laminating your own post from marine ply? Would be very stable, although a bit of a pain to make. 

 

Hmm, you make a very interesting point about Marine plywood, Hanson plywood stock a product called SP101 ply, we put a small piece in a bucket of water, its been soaking for more than 4 months and no sign of delaminating its rather expensive but one sheet would do it at a push

[Anthonyexmouth]

if i did go the wood route, anything in the concrete i would probably drench in resin. use danish oil on all the bare oak on my boat and like the look, although deks olje is awesome stuff too. 

 

as for a 10x10 post, its harder finding stock that big and in good condition without getting too expensive. 4x 6x6's are easier to get and the lengths i need can get a few for next to nothing. also glued and bolted together should be more stable. 

[michael8554]

Not to be pedantic, but to get the length of bolts you need it's easier to get stainless studding, 

Use big washers through pairs of posts, then join those two pairs  together with more staggered studding.

No way of knowing if one big post would move more or less than four smaller posts with the end grains randomised.

Michael 

[Anthonyexmouth]

got a stack of bronze bar i can use for fixing, if i do this in wood it might end up looking too nice. 

[mountainmadman]

I bought a railway sleepers (new, not reclaimed) cut it in half and bolted them back to back. I put some pictures and a description on my blog. Scroll down through this post for the details.. 

http://www.astromadness.co.uk/p/diy-astronomer.html?m=1

Hope it helps

Tony

[Anthonyexmouth]

Ok, i've decided on concrete clad in wood. I bought a 300mm spiral duct but now i'm worrying that its too wide. can anyone calm my nerves or give a good reason its too big before i set it in and do the concrete pour. 

[JamesF]

300mm is quite hefty, but not, I would have said, completely unreasonable.  I've pointed out in a few other threads over the years that you can get reducers for the larger diameter ducting so you might be able to take it down to, say, 200mm or even 150mm at the top, which would help to avoid problems with the top of the pier obstructing a mounted OTA, which would probably be my main concern with that sort of diameter.

James

[Anthonyexmouth]

when i put my 300mm template disc below my mount when its on the tripod at a distance i predict the top of the pier to be it looks to be ok but at the moment only have the heq5 and my ed80 to test it on. what kind of equipment in the future would be most prone to having a problem with such a wide pier? would these issues be reduced or increased if upgrading to a larger mount? 

[Alan White]

This is an interesting thread as it's something on my mind at present too.
When you get building, please be so kind as to take some images and post them up.
Good luck with the construction.