Help me out of these holes, please!

[Jeremy Harris]

1 hour ago, recoveringacademic said:

@JSHarris,  How long can I leave the bars in before concrete grips too hard to withdraw the bar?

 

 

 No more than around 24 hours, and you can probably screw them out a bit sooner than that, as soon as the concrete has gone off enough to be stiff enough to not risk a burst.

[ToughButterCup]

Thanks J. Pouring at 2.30 is, so Sparrow's Hiccup next morning, then.

And, in relation to our pour, the hole size is small - so the stone would block the hole pretty quickly. Anyway, looks like a very early rise the following morning.

 

Excellent. I really am so grateful  for all the help.

 

Ian

[ToughButterCup]

5 hours ago, ProDave said:

Probably too late for my solution, but sleeve the studding e.g with pvc conduit,[...]

 

Quite a bit of the job is left to finish.

It's 12mm threaded bar, @ProDave. I'd need approximately 14mm (o/d) conduit inserted in 16mm hole : my SDS+ is 16mm. Is it possible to get 14mm o/d conduit? I've looked, and can't find any.... yet

 

How about Heat Shrink .... 13mm. That should do it.

[iSelfBuild]

8 hours ago, Russell griffiths said:

They do actually make a thing for this exact purpose,for shuttering carpenters, it is very much like a piece of 3/4 overflow pipe 

it is placed inside the shuttering and the threaded rod goes through it, leave threaded rod in until fully cured and then remove, you will be left with a very neat 3/4 Diameter hole you can then fill. 

He is correct and I sell it to sites all over the UK. It's called tie bolt sleeve and cones. No reason why it cant be used on your form work but it's typically used with DYWIDAG formwork bar. You could also try using a tie bolt breaking agent on the bar. We supply something called bar break which coats the bar and allows it to be pulled out of green concrete. I don't know much about the chemical as I specialise in lifting systems and machinery for precast but here is the manufactures data sheet http://www.adomast.co.uk/images/uploads/files/docs/Adobreak Data Sheet 2014.pdf

 

 

 

[iSelfBuild]

50 minutes ago, recoveringacademic said:

 

Quite a bit of the job is left to finish.

It's 12mm threaded bar, @ProDave. I'd need approximately 14mm (o/d) conduit inserted in 16mm hole : my SDS+ is 16mm. Is it possible to get 14mm o/d conduit? I've looked, and can't find any.... yet

 

How about Heat Shrink .... 13mm. That should do it.

As per the above 20mm is the smallest we supply for 15mm tie bar.

[Onoff]

14 OD / 12 ID, so a 1mm wall thickness...in plastic? Need to be strong to be of any practical use other than a drinking straw for an off the shelf product. There's always carbon fibre, HOW MUCH???

 

http://www.easycomposites.co.uk/#!/cured-carbon-fibre-products/carbon-fibre-tube/woven-finish-carbon-fibre-tube/glossy-3k-woven-finish-14mm-12mm.html

 

Heatshrink, nah, it'd bite into the thread. I wonder if you would be better with Denso tape? Reckon you might still be able pull the stud thru that once the concrete has gone off as it's squishy. Messy stuff btw, you need your wits about you to handle it. 

 

So...Onoff to the rescue...

 

A wrap of h.duty DPM, cheap too:

 

 

[Jeremy Harris]

I still reckon it's a lot easier to just grease the studding and unscrew it afterwards.  I've done this when fitting cast-in anchor bosses, with threaded inserts.  I just greased up the threaded studding, screwed it into the cast-in anchor plate welded on nuts, poured the concrete, then unscrewed the studding a few hours later.  No problem at all, the most tedious part was unscrewing the studding, as even with a power drill it took a while to unscrew a foot or so of 12mm studding set down into a concrete anchor block.

Edited August 29, 2017 by JSHarris

[Construction Channel]

I may be a little late to this party but im going to stick my oar in anyway .

 

1) why are you pouring so late in the day? if your concrete companies are anything like ours the trucks wont be turning up until 3:30 - 4 if your lucky, ideally you want to be first on the list for the day.

 

2) how dry are your blocks, I have never worked with durisol but by the looks of them they will suck the life out of the concrete in no time, on that basis the only time you are likely to get a blow out is in the first hour or so, or while the concrete is pumping.

 

if it were me (and i appreciate even the best laid plans can go awry)  i would aim to get the lorry and pump there for 8:00, finish the pour by about 11-12, have some lunch and tidy up then undo the bolts with a socket on an impact driver at about 3-4, tap them through with a hammer and then pull them out the rest of the way with some kind of a crowbar.

 

the conduit idea sounds very nice but is also adding a LOT of unnecessary complications IMO

 

Just my 2 cents  

[Nickfromwales]

Ian, remember to wind the nut on only a few turns past the hut head on all the bolts on one side of the wall. That way when you come to remove them you can use a socket in the impact driver rather than a spanner. Then on the other side, just clamp the chuck onto the longer end to whizz them out under power. 

Grease will suffice as there's little area really where the concrete will gain any purchase, and whilst green they'll offer little resistance even to a cordless drill on gear 1. 

Knock this out sharpish and grab yourself a beer. ??

[Triassic]

52 minutes ago, Construction Channel said:

tap them through with a hammer and then pull them out the rest of the way with some kind of a crowbar.

You could made a simple diy slid hammer using some spare threaded bar and a couple of nuts.

[Nickfromwales]

25 minutes ago, Triassic said:

You could made a simple diy slid hammer using some spare threaded bar and a couple of nuts.

Yup. With one of these.

[ToughButterCup]

Ha! This problem is almost fun now. Its kind of you all to pitch in....

[Declan52]

Just leave them in and you can hang up all your coats, tea towels, cups, hats, pictures, dartboards etc. The list is endless!!!

[Pete]

Climbing wall. 

[ToughButterCup]

Declan, behave yourself , this is serious.... And you Pete...

[Pete]

I meant to add sorry Ian.

Sorry Ian

[Onoff]

There are some idiots on here! Pity there's no cavity:

 

[ToughButterCup]

Just now, Pete said:

I meant to add sorry Ian.

Sorry Ian

 

No you're not, not in the least bit sorry. Just wait until you need some welding doing, then you'll be sorry

[Construction Channel]

29 minutes ago, Nickfromwales said:

Yup. With one of these.

i was thinking something you could just hook over the nut / washer, threading anything on is going to take a while over 60 bolts.

 

all you need is a bit of angle iron welded to the end of a threaded bar with a 14mm slot cut in the end, a short length of old iron pipe and 4 nuts on the threaded bar spaced apart with the pipe between (the nuts in pairs acting as locking nuts), if you catch it right they should pull out fairly easy but you will need to be able to get them all out fairly quick else you will wish you had ignored me entirely and carried on with the conduit scenario.  

[ToughButterCup]

2 minutes ago, Construction Channel said:

[...]

all you need is a bit of angle iron welded to the end of a threaded bar with a 14mm slot cut in the end, a short length of old iron pipe and 4 nuts on the threaded bar spaced apart with the pipe between 

[...]

 

The old iron pipe acts as the slide hammer, yes?

[Nickfromwales]

7 minutes ago, Construction Channel said:

i was thinking something you could just hook over the nut / washer, threading anything on is going to take a while over 60 bolts.

 

all you need is a bit of angle iron welded to the end of a threaded bar with a 14mm slot cut in the end, a short length of old iron pipe and 4 nuts on the threaded bar spaced apart with the pipe between (the nuts in pairs acting as locking nuts), if you catch it right they should pull out fairly easy but you will need to be able to get them all out fairly quick else you will wish you had ignored me entirely and carried on with the conduit scenario.  

That's the only problem with this forum, too many geniuses in one place 

 

[Construction Channel]

2 minutes ago, recoveringacademic said:

 

The old iron pipe acts as the slide hammer, yes?

You got it. I know you have got all the tools to make such a device because you have injured yourself with them ?

[Russell griffiths]

being a welding god you should be able to knock something up in a jiffy. 

[Nickfromwales]

1 hour ago, Russell griffiths said:

being a welding god you should be able to knock something up in a jiffy. 

Agreed. Only a welding God could weld a foot to a boot. 

?  ?

[Construction Channel]

it might be an idea if you have the time and a few spare blocks kicking about to have a practice before the end of the week, 

 

stack a few blocks up, drill 4 or 5 rods through them, Knock up some fairly wet concrete in a barrow and fill up the blocks. then try pulling them out at hourly intervals just to get the timing right for Monday,

 

also you want to make sure you pull out the rods the right way, e.g hit them with the hammer on the side with all the concrete and pull from the side with the insulation, no point pulling more rod through concrete than you need to.