Hullo again. I have to drill a hole in my exterior wall for my combi flue, (its sandstone) I believe I need one of these big cake cutter type drill bits, what are they called ? Do I need a special drill or is my little 850w house drill up to the job ? Is this the kind of thing I can hire ? Cheers
You`ll need a 110mm core cutter. Ebay is your best bet for a cheep one. I wouldn`t trust a small drill with it though, will probably burn it out. You might want to invest in a more powerful SDS drill. Alternatively just hire the lot from your local tool hire
John
In article , Dave D writes
Forget using your regular DIY drill - I can guarantee you will burn it out.
I hired the cake cutter (aka core drill) from the local hire shop thinking that my 650W black and decker would not let me down if I took things slowly. The smoke belching out of it combined with the heat that was coming towards my hand suggested otherwise - and I was hardly touching the wall.
Went out and bought a cheapo SDS drill - which pushed thru the wall no problem.
You can hire all this stuff - it may cost you 40-50 quid for a day (for the core bit, shank and drill combined). For that you can buy a not unreasonable SDS drill these days, and a core drill on ebay will be about 15 quid or so.
Hint: On ebay check the sellers web site. I bought one of these cake cutters recently for my toolbox, paid by PayPal, then went to the guys web site. The exact same cake cutter (I like that name ;)) was 5 quid cheaper. He charges more on ebay to take account of the charges they apply to each transaction.
PoP
For a one of job like this, you'll be better going to a hire shop and getting the right gear for a day. Shop about and get some quotes before making your final decision. The drill bit you need is called a core cutter and the drill machine itself needs to be able to handle one of these big babies, so you can imagine the power it has to have. Hiring one is the easiest way.
Have a look at the boiler manufacturers requirements for the flue size you'll need and then make the choice of the size of core cutter you'll need to do the job. You'll probably be charged for the amount of millimetres you wear down the cutter, but it is sandstone your cutting through so it shouldn't wear down that much. It's a small amount to pay for getting the whole job done in one go.
Good Luck with it. :-))
Hi All,
I need to do this as well, same story a sandstone wall, but what I was wondering was will the core cutter actually "hold on" to the core? The reason I'm asking is because I'm 3 floors up and will be drilling from the inside out - should I take precautions with pedestrians, or at the very least my car!
Also I've never fitted a combi before but I was reading through the installation instructions (for a baxi 105e) and it looks easy enough to install and commission. However I've heard that unless you get a CORGI registered bloke to sign it off the warranty will be void - is this true? Fair enough I'll get someone qualified in to pipe the gas round to where I need it, but do I have to pay him to actually fit the boiler?
Cheers, Stephen
It is safer to have someone looking out for slinters falling from this height to the pavement. You can wait until nearly through the stone before sending someone out into the cold though. :-))
You are also safer to have the gas work and commissioning done by a CORGI engineer. That way any come backs if the boiler does go belly up within warranty, then no one can say it was your faulty DIY installation. The rest of the system of course is down to you.
The CORGI engineer should only charge you for the work he's done, but check that he also signs everything off on the full requirements of the boiler installation sheet.
Hi All Hired all the kit yesterday, cutting away just nicely, turns out though its not plaster/bricks/space/sanstone its 30 inches of sandstone !!! Its not tough to cut but the corer only does about 8 inches at a time, so far Ive managed to snap each plug off by jamming a crow bar down the side. I'm now way inside the wall and cant get any leverage, how on earth do I snap the plug off ? Cheers
Not sure if you have a Makro near you, or if you have / can borrow a=20 card, but they have a cheap SDS drill with chisel action (comes with=20 about 4 chisel bits IIRC) - it`s about =A330 + VAT - that might do the job
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"Dave D" wrote | Hired all the kit yesterday, cutting away just nicely, turns out | though its not plaster/bricks/space/sanstone its 30 inches of | sandstone !!! | Its not tough to cut but the corer only does about 8 inches at a time, | so far Ive managed to snap each plug off by jamming a crow bar down | the side. I'm now way inside the wall and cant get any leverage, how | on earth do I snap the plug off ?
(a) Dynamite (b) Time to start working from the other side and hope you meet in the middle (c) Drill some holes in the plug, insert a bloody large Rawlbolt and screw and screw and screw until it splits the stone, hopefully the plug will come out in several large chunks
Owain
Not sure if you have a Makro near you, or if you have / can borrow a card, but they have a cheap SDS drill with chisel action (comes with about 4 chisel bits IIRC) - it`s about £30 + VAT - that might do the job.
Or put the crow bar on the plug and give it a Big Wallop with hammer. The shock should snap the plug out easily enough.
It's a bugger that the wall is this thick. I never expected you to come back with a problem on cutting a hole in a sandstone wall. Your building must be one of the best built if the walls are that thick.
But sandstone is soft enough to break easily, so take a big hammer and give it thump.
Cheers Guys I just went with the large hammer option and after 1/2 an hour of bashing it gave in. So now I have a lovely flue hole (I'm 3 stories up).. So I want to seal round my flue, I dont want to have to get scaffold put up to let me cement round the hole. I was just going to get a pipe and fire expanding foam stuff down the outside of the flue till I see coming out the exterior. Is this a goer ? What other options are there, apart from do it properly ;-)
Cheers
You can get a Flue Collar which sits around the pipe on the outside. Depending on the size of hole and the amount of space you have around the pipe, then the collar can be slipped on and glued or riveted just back from the end of the pipe and then pushed through the hole. It doesn't need to much space as the collar is very spongy. When you push it out passed the outside of the wall, it then springs back out to its original shape and seals the hole.
Have a web search for Flue+Collar and it should give you a few hits.
You are 3 stories up, and you've cut thru 30 inches of sandstone? Something sounds a bit odd to me!
Not that I'm knowledgeable about these things of course, but I wouldn't expect 30 inches of anything at 3 stories up.
PoP
but I
Neither did I or I would have got somone else to do it !!!! By the way that is one of the best double entendres I have seen. ;-) DD
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