Fixing pier to concrete slab

[Brutha]

Hi All,

Just preparing to get my concrete slab poured for my Altair astro pier. 

After a bit of reflection, have decided not the use the j-bolts that I ordered with the pier, since the shape of the slab is a little unusual, and I don't want to be juggling too many things when pouring the concrete. So, I'll pour the slab, get the surface nice and level, then we'll drill it later.

I quite like the idea of using the chemfix chembolts as suggested in a previous thread - since then I can just put M12 bolts down through the base of the pier, and not have much sticking up.

However due to my location, they want a truly ludicrous amount for delivery (i.e. 4 times the cost of the bolts!!!), so that's not an option, and they don't seem to be sold anywhere apart from the link in the above thread.

Has anyone used simple drop in anchors for this purpose? Something like these?

Cheers

Brutha

[Kimboman]

Hi I would recommend using threaded studs and chemical anchor in a tube that fits into a standard mastic gun(applicator) these are available from Tool station 

drill the relevant sized hole for the chosen stud size, ensure to remove all dust and debris from the hole just follow instructions.

I have used these actors up to 30mm die to hold down machine tools with no problems

[pete_l]

4 hours ago, Brutha said:

the chemfix chembolts

There are loads of similar products. Widely available in hardware shops or online.

[david_taurus83]

You could also go for a long through bolt but you'd need to drill deep for it.

 

[M40]

The drop in anchors work fine.......unless the concrete is too sandy then they may just pull straight out regardless of how hard you hit the thing. If the chem fixing is not an option then I would go for the rawlbolt type fixing that david_taurus83 mentioned. 

[Brutha]

18 hours ago, Kimboman said:

Hi I would recommend using threaded studs and chemical anchor in a tube that fits into a standard mastic gun(applicator) these are available from Tool station 

drill the relevant sized hole for the chosen stud size, ensure to remove all dust and debris from the hole just follow instructions.

I have used these actors up to 30mm die to hold down machine tools with no problems

Yes, I think on reflection this is probably the route to go!

[StevieDvd]

2 hours ago, Brutha said:

Yes, I think on reflection this is probably the route to go!

Not sure of your location, you may want to give us a clue as we have many international members. But in UK the chemical bolts sets are sold in B&Q and Wickes, and Screwfix & Toolstation will do the parts if not an actual prepared set.

 

[Brutha]

1 hour ago, StevieDvd said:

Not sure of your location, you may want to give us a clue as we have many international members. But in UK the chemical bolts sets are sold in B&Q and Wickes, and Screwfix & Toolstation will do the parts if not an actual prepared set.

 

Thanks - yes, Western Isles of Scotland, we're a bit short of B&Q megastores round here

But it should be possible to order what I need fairly easily - the trick is identifying just what I need!

[Brutha]

18 hours ago, pete_l said:

There are loads of similar products. Widely available in hardware shops or online.

Yes, I thought there would be - but I just seem to finding mechanically fixed drop in anchors with interior threading, and threaded rods that can be chemically fixed.

There don't seem any chemically fixed drop in anchors though - just the ones in the original thread that I can find. But it's entirely possible that I am looking at them on the page and simply not understanding what I am looking at!

[ollypenrice]

I just use a tube of builder's epoxy to fix a length of threaded bar into a hole drilled in the concrete. It has worked on a dozen piers or so over the years and never failed. Just be sure when you squeeze the gun that both components of the epoxy are coming through properly. You can check that by giving a short squeeze before putting the long mixing nozzle on.

Olly

[david_taurus83]

2 hours ago, ollypenrice said:

I just use a tube of builder's epoxy to fix a length of threaded bar into a hole drilled in the concrete. It has worked on a dozen piers or so over the years and never failed. Just be sure when you squeeze the gun that both components of the epoxy are coming through properly. You can check that by giving a short squeeze before putting the long mixing nozzle on.

Olly

+1  to what Olly says about the resin. Always push it through the nozzle until it mixes a gunmetal grayish colour. You might have to waste a little first until it starts to mix properly. And make sure the hole is clean from dust after drilling. Can use a blower like a bicycle pump to blow it free or even better, a vacuum cleaner!

[Brutha]

Thanks all! 

Last question then: in the pier installation instructions, it mentions to drill a hole with a 12mm masonry drill.

Since the threaded bar will be M12, that presumably means there will be very little space around the bar. The picture shows some space between the bar and the hole, filled with resin.

Should I leave any gap, i.e. go up to a 14mm drill bit or so?

Cheers

Brutha

[david_taurus83]

1 hour ago, Brutha said:

Thanks all! 

Last question then: in the pier installation instructions, it mentions to drill a hole with a 12mm masonry drill.

Since the threaded bar will be M12, that presumably means there will be very little space around the bar. The picture shows some space between the bar and the hole, filled with resin.

Should I leave any gap, i.e. go up to a 14mm drill bit or so?

Cheers

Brutha

Yes, 14mm would be the minimum sized drill bit for a 12mm bolt.

[Brutha]

Thanks! I said that was the last question, but now I realise I lied!

How deep do you think I need to set the bolts? I've seen one thread on here where they drilled 200mm deep holes, but I am wondering if that is necessary.

[fifeskies]

With the type of anchor you are using I would think 200mm would be best (and certainly no less then 150mm)

It will depend in part what you are putting on the pier , a 12 inch newt with a 4 inch refractor guider and a couple of cameras on an EQ8 grade mount will need a better fixing then a single 80mm refractor being used visually on a small mount.

As always plan for the worst case scenario , we always end up upgrading our kit to bigger and better.

 

My Altair pier has 300mm cemented in J bolts.

[Brutha]

Thanks! Yes, for now the requirements are not serious, it will have my C8SE on top, being used visually. But part of the idea of the pier is that it would still be useful in case I upgrade to something bigger later.

So, 200mm it is!

[iwols]

and you will😁

[Swoop1]

4 hours ago, Brutha said:

Thanks! Yes, for now the requirements are not serious, it will have my C8SE on top, being used visually. But part of the idea of the pier is that it would still be useful in case I upgrade to something bigger later.

So, 200mm it is!

A permanent pier is a recipe for bank balance disaster. It is a major precursor to feelings of inadequacy and envy as far as aperture and the like are concerned.

DAHIKT