Lo-fi Micro-pier build

[codemonkey]

I was originally going to lash out and get a shiny new pre-fab steel pier, but I've caught the DIY bug and considering I'll probably save about $900, I figure it's worth a crack ;-)

Having seen some builds on SGL with people using besser bricks and adhesives I decided it was too simple and inexpensive not to try.

The pier will stand a mere 58x19x19cm and will be glad in gold aluminium composite panel left over from my "micro-obs" box that houses my gear currently. The "micro-obs" only stands about 120cm tall, and I'm trying to keep the pier as short as I can so that I can park the mount in the standard home position..

It will sit on the pier footing I had done many months ago now; from memory it's 110x110x60cm deep.

So today I made a trip down to Bunnings to get started. I purchased:

1x 39x19x19 besser brick
1x 19x19x19 besser brick
1x 19mm V-groove router bit for the composite panel
1x arbor
1x 64mm hole saw, again for the composite panel
1x M12 bolt with wing-nut
1x file
1x tube of construction adhesive
1x caulking gun

Total cost about $125.

Work began tonight by gluing the small besser brick onto the large one.

I pulled out the trusty ol' router to do a practice run on the composite panel. If you're not familiar with aluminium composite panel, it's basically some plastic sandwiched between two thin sheets of aluminium.

Using a v-groove router bit you can route through one layer of aluminium, the plastic, but leave the other layer of aluminium intact, at which point you can bend the sheet, rather than cutting it, giving a nicer finish. Or so I've heard, I've never tried it myself.

So, I pulled out the trusty ol' router, and it wouldn't start... checked power etc, no good. So day one came to a rather abrupt end.

To be continued...

[Atmos]

Sounds exciting! I have been thinking about making something so that I can leave my tripod outside protected. Don't know how long it'll last though! Hehe

Love to see it when you're done!

[codemonkey]

Definitely the way to go! I don't know how people image while having to set up / tear down every night; I couldn't do it.

[Meru]

Excellent work Lee,

A micro-pier/obs sounds very sensible. I was very fortunate to have a friend who does this work and got mine made very cheap. Seems like you got everything sorted but here is a link to my (totally overkill for a future 16" APO when I become a Billionaire) pier if it helps with any ideas:

http://www.iceinspace.com.au/forum/showthread.php?t=114718&highlight=Meru

Do post pics as you build!

[bugeater]

What's the stability likely to be on something like this for imaging? I'm busy planning how to build an observatory, but getting a pier together is the current unknown.

[Somnium]

when are you building ? i would love to see some pics

[codemonkey]

Cheers mate. Nice pier, and that a good price too... if I was able to get a steel one for that I wouldn't be bothering with this.



Hopefully very good, because I only do imaging so if it doesn't work for that, it'll be a complete waste of time/money/effort.

Once it's done I'll give some more solid answers but all I can say now is other people are doing it and it seems to work for them.



Just bought a new router yesterday; I plan to do some work in the coming days. Maybe tonight, maybe not... depends how the weather goes.

At the moment the only pics I have is a couple of bricks being glued together which isn't terribly exciting but I'll add pics as I go :-)

[codemonkey]

Ok I've finally got some more work done on this.

I routed the channels to enable me to bend the composite panel a hair to short on one side which caused it to split when I tightened it all up. I might have to find some capping to go over the corners to tidy it up a bit.

Besides the cosmetic issues, it seems to be ok so far. Only thing left after the cladding is fully fixed it to figure out what I'm going to use for the azimuth alignment bolts to push against. Might make a quick trip out to Bunnings and grab some aluminium.

Not entirely sure if the adhesive will work to hold the cladding on; says it works on anodized aluminium and concrete, so should be ok, but I guess we'll see.

[Atmos]

For a cheap fix it is looking pretty good and in the dark... No one will notice :P

[codemonkey]

This is true... if nothing else it'll fit perfectly in my "could have looked nice if I was good with tools but instead looks dodgy" micro observatory that's built out of the same composite panel :D

Hoping to get it up in the obs and glued down today and then I'll be imaging in a few days if we get the forecasted clear skies. Fingers crossed.

[codemonkey]

Well I glued the pier to the footer last night. Fairly rough alignment based off some marks I'd drawn on the footing previously; what can I say, I like to live dangerously!

Hopefully tonight will find the pier well enough aligned.

[glend]

Maybe I missed it Lee, but what 'glue' or additional method did you use to attach the pier to the footing?? If you have jjust glued the blocks to the footing I would suggest caution. While most any adhesive will hold on your side panels, the base attachment is the real concern. Many of the 'epoxies' sold at places like Bunnings are actually hydroscopic over time and will absorb water and break down the bond surface. Sikaflex type boat building Polyurethane is probably a better choice but stress and shear forces acting on the relatively small pier foot area would concern me. I'd be thinking of using some additional mechanical support in the form of strong galvanised L brackets at the base locked in place with Dynabolt type anchors. The last thing you want is for your whole pier and scope to fall over one night a year from now.

[codemonkey]

Thanks Glen, appreciate your concern!

I've used a polyurethane based waterproof construction adhesive. I saw recommendations elsewhere that these adhesives are "stronger than the bricks themselves" so thought this should do the trick.

Admittedly physics isn't my strong suite, but would the forces really be that large? We're talking a balanced load (well, almost), which should mean, to my physics-impaired brain, that almost all of the force would be downward, no?

[glend]

Well Lee I rarely run my rig balanced as it resulted in over correction oscillation, most experts (not me certainly) suggest running unbalanced rigs to keep gears meshed, reduce possible wind effect, etc. I am not saying very unbalanced but enough to allow the mount to work against a little weight.
Other weight shift factors are: bumping into the pier or scope, unbalanced load during setup, scope changes and gear or counter weight movement, etc. So while theory says its a balanced vertical load in real life I believe its a bit different.
The weight is also at the end of an arm (the height of the pier and mount head) so it has a lever affect on the joint between the footing and the bottom block.
I am not trying to trash your approach but to suggest keeping an eye on it and maybe put in a backup safety feature.

[codemonkey]

Thanks Glen :-)

[codemonkey]

Had a quick look for more details on the particular adhesive that I used. It "exceeds the requirements of BS-EN204 D4". That particular standard specifies a minimum bond strength of 4N/mm^2 and that is in 7 days of "standard atmosphere" followed by 4 days underwater, and another 7 days in standard atmosphere.

To put that into real numbers, that's about 14,700kg worth of force, minimum. I'm pretty confident it can handle the slight imbalance of my gear :)

[acropolite]

Lee, i'm with Glen, despite the adhesive being mre than capable, the concrete block itself may be prone to breaking. Concrete blocks can break at or near the surface with very little force, when drilling besser blocks often huge chunks of concrete break away at the exit point, you could well find you have an intact adhesive bond with a sliver of concrete left while the pier lays collapsed on the floor. I wouldn't be attempting to simply glue the block base without additional support.

[codemonkey]

That's an interesting point, I hadn't thought of it like that. Thanks Phil!