Concrete Pier or Steel?

[Adaaam75]

Okay, I'm pretty confident I can get an un-powdered steel pier made locally for my AVX mount for approx £150. Add onto that some concrete mix and wood for framing and I'm looking at £200.

But then I see really good examples of home made concrete piers in plastic tubing for reportedly next to nothing. As I understand it the cement piers are constructed from long thick plastic tubing (not metal as condensation becomes an issue), concrete base and wood for frame, M12 ish rods and bolts for mounting a pair of brake disks (I'll listen to any suggestions for the most appropriate make/model car disks for my AVX!!!!) and plenty of concrete to fill.

Does this really come in under £200????

Experienced pier guys out there please shed some light on this and advise accordingly.

Clear skies

[Dr_Ju_ju]

I used 2x 2 metre air conditioning ducts, one @ 350mm diameter (metal) & the other @ 200 mm diameter (plastic), sunk into ground & filled with concrete\postcrete. Although it can't be seen in photo, I have an AZEQ6 pier top bolted to 4 M12 600mm stainless steel studding, sunk into the concrete. And yes the most expensive part was the pier top (off eBay from Holland) & total cost ~ £150..

[Adaaam75]

17 minutes ago, Dr_Ju_ju said:

I used 2x 2 metre air conditioning ducts, one @ 350mm diameter (metal) & the other @ 200 mm diameter (plastic), sunk into ground & filled with concrete\postcrete. Although it can't be seen in photo, I have an AZEQ6 pier top bolted to 4 M12 600mm stainless steel studding, sunk into the concrete. And yes the most expensive part was the pier top (off eBay from Holland) & total cost ~ £150..

I had originally planned to use air conditioning duct too and was going to fill it with concrete but when I looked at how much cement that would take, added to the concrete base of the pier, it seems like I'd be paying £100 just on concrete! I am uneducated in the stuff though, all I really know is how much a bag is roughly (£5) and how small an area a bag of postcrete fills. I didn't intend on using postcrete but equally, I don't have a cement mixer! I like your space saving idea of double skinning the pier with an inner tube. Presumably the 150mm width is solid with minimal vibration and the minimal heat retention that some have rightly raised before with a concrete pier would be significantly reduced with the hollow centre?

How much (20kg bags if possible) cement did you use Doc?

[Dr_Ju_ju]

The design is based on an article I found (can't find at the mo) that discusses the required sizes for concrete piers to minimize vibrations, and the reccomendation was for at least a 250mm diameter main tube...

Most of the tubing\ground hole is filled with self mixed concrete & I just used the postcrete to 'finish' off the tops (If the weather allows, I'll post more pictures when I get home).

The ducting came to £15, stainless steel studding £20, pier top £40, & approx £70-80 on in-fill (I already had some stuff kicking around & the nature of my garden means I have lots of hard core\rock )

 

 

[spillage]

Hi @Adaaam75 

I am not to far away from starting my build. So far I have the brake discs ready to go (classic car brake discs) with some m12 stud to use as an anchor and managed to get some black ribbed 6" plastic pipe for free.

I am going to buy a dumpy bag of balast/sand from bradfords and a few bags of cement to make a base and fill the pipe. Luckily I have a cement mixer from when I built my shed/mancave so this will make things easier.

Regarding a metal vs metal pier I have seen that metal ones can cause lots of vibration due to oscillation if poorly designed. I guess this is why a astro made metal pier is so much due the R&D put into them.

Going to keep an eye on this thread to see where you go with it.

Spill

 

[Adaaam75]

For some reason the pics of your pier didn't display on my phone when I saw your entry. However it seems i'd misunderstood the design and I thought you had two tubes with concrete inbetween them and the internal part of the inner tube was hollow. But your pictures have cleared that one up! That design is spot on to prevent the scope from making contact with a wider pier whilst maintaining the structure. Can you confirm the inner tube that protudes from the main pier is resistant to vibrations etc as the pier would only be as good as its weakest point.

I am trying to avoid buying a purpose made mounting block for my AVX and with the mulitude of varying sizes of brake disks there must be an appropriate size for me. Thanks for the pics though, more food for thought!

[Dr_Ju_ju]

I get no vibrations & the M25 is only 75 meters away.....

[laser_jock99]

1 hour ago, Dr_Ju_ju said:

I get no vibrations & the M25 is only 75 meters away.....

....nice Acers though!

[Adaaam75]

10 hours ago, Dr_Ju_ju said:

I get no vibrations & the M25 is only 75 meters away.....

Ha ha ha! Perfect answer with a test of vibration not many could match!