One skill I don't have is cleaning up after a long d-i-y session. I'm
ashamed to say that after my block making project, my cement mixer is
now 30kg heavier, and a lot smaller inside, with concrete.
I'm going to buy some HCl from a local supplier, but don't really know
what to ask for.
What is reasonable safe to use with caution, and a good read of the
COSSH documents, but powerful enough to corrode the unwanted
concrete. I thought maybe 1litre of 34% HCl, 66% water. Is that
anything like reasonable. And is that even the correct terminolagy.
Should I be asking for a 0.3molar solution?

I have a few ideas about safety, but aany advice on that too would be
most welcome.

Thanks

Tony

ps I'll put a video up on youtube on how I got on with making the
exposed aggregate finished concrete blocks as soon as I get aroudn to
splicing it all together. Not a job for a sunny day like this!

tonyjeffs coughed up some electrons that declared:

One skill I don't have is cleaning up after a long d-i-y session. I'm
ashamed to say that after my block making project, my cement mixer is
now 30kg heavier, and a lot smaller inside, with concrete.
I'm going to buy some HCl from a local supplier, but don't really know
what to ask for.

Just ask for "brick acid". Conc HCl is about 30-odd% (as HCl is a gas, so
it's the limit of what you can dissolve in water)

What is reasonable safe to use with caution, and a good read of the
COSSH documents, but powerful enough to corrode the unwanted
concrete. I thought maybe 1litre of 34% HCl, 66% water. Is that
anything like reasonable. And is that even the correct terminolagy.
Should I be asking for a 0.3molar solution?

Sorry, don't know for sure. But I would guess your solution is a fairly good
staring point. You don't really want to use 30% HCl as it gives off HCl gas
like a bugger which isn't good for your eyes or lungs.

Too weak and it will take longer. Gut instinct and a vague recollection of
chemistry lessons suggests 10% HCl (close enough to what you suggest)
should be relatively un-smelly but still reasonably effective.

Try a small amount of trial mix on a stationary bit of the drum and see what
it does to the cement.

I have a few ideas about safety, but aany advice on that too would be
most welcome.

Goggles, preferably non-ventilated and fully enclosed (eyes are hard to
replace), gloves and good thick overalls. Have a hose handy just in case
you need to wash down in a hurry. HCl isn't poisonous as such and in very
dilute form it's pretty innoculous (it's produced and used in weak form in
your stomach).

Cheers

Tim

tonyjeffs wrote:
One skill I don't have is cleaning up after a long d-i-y session. I'm
ashamed to say that after my block making project, my cement mixer is
now 30kg heavier, and a lot smaller inside, with concrete.
I'm going to buy some HCl from a local supplier, but don't really know
what to ask for.

First step is to fill the thing with water and a few bricks and get
spinning, then bash the outside with a mallet to crack off most of it.

Then just chuck in neat brick acid. Whatever they allow you to buy. Its
not that concentrated.

Continue chucking it in till it stops fizzing.

Then hose the whole thing down extensively. It corrodes steel pretty
well does HCl.



What is reasonable safe to use with caution, and a good read of the
COSSH documents, but powerful enough to corrode the unwanted
concrete. I thought maybe 1litre of 34% HCl, 66% water. Is that
anything like reasonable. And is that even the correct terminolagy.
Should I be asking for a 0.3molar solution?


I think you are getting altogether too concerned. What is sold as brick
acid is relatively safe. You can wash your hands in it. Not for long,
and any cuts will sting like bejasus, but thats the sort of level its
at. Eyes and clothes are your primary sources pf concern, so make sure
its tatty old clothes, and a glasses if you intend being cavalier with
the stuff.f it does get in your eyes, total and instant flushing to
reduce concentration is the way to go, with maybe a mild antacid like
bicarbonate - maybe someone medical knows better - and off to A and E
fast. It wont be nice, but it wont blind you instantly. The eye surface
hurts like hell, but repairs quickly.

But on skin - it will let you know if its doing damage: it stings. But
once washed off Ive never seen any permanent damage from it.





I have a few ideas about safety, but aany advice on that too would be
most welcome.


Just be sensible and make sure it doesn't splash, or if it does you
arent where it does.

IT acts very quickly on cement presumably turning some carbonate into
some chloride. I guess the end result is H2O and CO2..anyway, when it
stops fizzing, youve either run out of carbonate, or HCl :-)

The actual residue is pretty harmless.

On Sat, 20 Sep 2008 02:43:11 -0700 (PDT), tonyjeffs wrote:

One skill I don't have is cleaning up after a long d-i-y session.

Maybe this is a lesson you will learn from?

I'm ashamed to say that after my block making project, my cement mixer
is now 30kg heavier, and a lot smaller inside, with concrete.

I'm going to buy some HCl from a local supplier, but don't really know
what to ask for.

It'll take a lot of HCl to dissolve 30kg of concrete... And you'll still
have some fairly acidic waste to get rid of. Have you tried taking a cold
chisel and lump hammer to the concrete inside the drum? If you can get a
few cracks in it or better still a lump or three out the rest will fall,
perhaps with a little persuasion, off the drum.

--
Cheers
Dave.

Dave Liquorice wrote:
On Sat, 20 Sep 2008 02:43:11 -0700 (PDT), tonyjeffs wrote:

One skill I don't have is cleaning up after a long d-i-y session.

Maybe this is a lesson you will learn from?

I'm ashamed to say that after my block making project, my cement mixer
is now 30kg heavier, and a lot smaller inside, with concrete.

I'm going to buy some HCl from a local supplier, but don't really know
what to ask for.

It'll take a lot of HCl to dissolve 30kg of concrete... And you'll still
have some fairly acidic waste to get rid of. Have you tried taking a cold
chisel and lump hammer to the concrete inside the drum? If you can get a
few cracks in it or better still a lump or three out the rest will fall,
perhaps with a little persuasion, off the drum.

Established practice is to fill the drum with water betwen mixes, and
leave it turning, or at the time of the last mix of the day, and then
add bricks. These chip most of the dross off the drum and blades. The
rest usually comes free with a few good whacks of a mallet.

What doesn't probably isn't worth worrying about.

Dave Liquorice wrote:
On Sat, 20 Sep 2008 02:43:11 -0700 (PDT), tonyjeffs wrote:

One skill I don't have is cleaning up after a long d-i-y session.

Maybe this is a lesson you will learn from?

I'm ashamed to say that after my block making project, my cement mixer
is now 30kg heavier, and a lot smaller inside, with concrete.

I'm going to buy some HCl from a local supplier, but don't really know
what to ask for.

It'll take a lot of HCl to dissolve 30kg of concrete... And you'll still
have some fairly acidic waste to get rid of. Have you tried taking a cold
chisel and lump hammer to the concrete inside the drum? If you can get a
few cracks in it or better still a lump or three out the rest will fall,
perhaps with a little persuasion, off the drum.

Agreed. I spent a happy(?) morning years ago spent crouched inside a
concrete mini-mixer with hammer and chisel... I remember the noise being
absolutely deafening!

David

Lobster coughed up some electrons that declared:

Dave Liquorice wrote:
On Sat, 20 Sep 2008 02:43:11 -0700 (PDT), tonyjeffs wrote:

One skill I don't have is cleaning up after a long d-i-y session.

Maybe this is a lesson you will learn from?

I'm ashamed to say that after my block making project, my cement mixer
is now 30kg heavier, and a lot smaller inside, with concrete.

I'm going to buy some HCl from a local supplier, but don't really know
what to ask for.

It'll take a lot of HCl to dissolve 30kg of concrete... And you'll still
have some fairly acidic waste to get rid of. Have you tried taking a cold
chisel and lump hammer to the concrete inside the drum? If you can get a
few cracks in it or better still a lump or three out the rest will fall,
perhaps with a little persuasion, off the drum.

Agreed. I spent a happy(?) morning years ago spent crouched inside a
concrete mini-mixer with hammer and chisel... I remember the noise being
absolutely deafening!

David

SDS + chisel bit + the bestest ear defenders in the world?

Tim S wrote:
Lobster coughed up some electrons that declared:

Dave Liquorice wrote:
On Sat, 20 Sep 2008 02:43:11 -0700 (PDT), tonyjeffs wrote:

One skill I don't have is cleaning up after a long d-i-y session.
Maybe this is a lesson you will learn from?

I'm ashamed to say that after my block making project, my cement mixer
is now 30kg heavier, and a lot smaller inside, with concrete.

I'm going to buy some HCl from a local supplier, but don't really know
what to ask for.
It'll take a lot of HCl to dissolve 30kg of concrete... And you'll still
have some fairly acidic waste to get rid of. Have you tried taking a cold
chisel and lump hammer to the concrete inside the drum? If you can get a
few cracks in it or better still a lump or three out the rest will fall,
perhaps with a little persuasion, off the drum.
Agreed. I spent a happy(?) morning years ago spent crouched inside a
concrete mini-mixer with hammer and chisel... I remember the noise being
absolutely deafening!


SDS + chisel bit + the bestest ear defenders in the world?

For sure, but I don't think SDS drills were even around back then - if
they were, my employer certainly didn't have one (or ear defenders
either, for that matter!)

David

Lobster coughed up some electrons that declared:

Tim S wrote:
Lobster coughed up some electrons that declared:

Dave Liquorice wrote:
On Sat, 20 Sep 2008 02:43:11 -0700 (PDT), tonyjeffs wrote:

One skill I don't have is cleaning up after a long d-i-y session.
Maybe this is a lesson you will learn from?

I'm ashamed to say that after my block making project, my cement mixer
is now 30kg heavier, and a lot smaller inside, with concrete.

I'm going to buy some HCl from a local supplier, but don't really know
what to ask for.
It'll take a lot of HCl to dissolve 30kg of concrete... And you'll
still have some fairly acidic waste to get rid of. Have you tried
taking a cold chisel and lump hammer to the concrete inside the drum?
If you can get a few cracks in it or better still a lump or three out
the rest will fall, perhaps with a little persuasion, off the drum.
Agreed. I spent a happy(?) morning years ago spent crouched inside a
concrete mini-mixer with hammer and chisel... I remember the noise being
absolutely deafening!


SDS + chisel bit + the bestest ear defenders in the world?

For sure, but I don't think SDS drills were even around back then - if
they were, my employer certainly didn't have one (or ear defenders
either, for that matter!)


Does the OP have an SDS?

In article et,
"Dave Liquorice" writes:
On Sat, 20 Sep 2008 02:43:11 -0700 (PDT), tonyjeffs wrote:

One skill I don't have is cleaning up after a long d-i-y session.

Maybe this is a lesson you will learn from?

I'm ashamed to say that after my block making project, my cement mixer
is now 30kg heavier, and a lot smaller inside, with concrete.

I'm going to buy some HCl from a local supplier, but don't really know
what to ask for.

It'll take a lot of HCl to dissolve 30kg of concrete... And you'll still

I imagine it will diossolve the drum first.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Andrew Gabriel wrote:
In article et,
"Dave Liquorice" writes:
On Sat, 20 Sep 2008 02:43:11 -0700 (PDT), tonyjeffs wrote:

One skill I don't have is cleaning up after a long d-i-y session.
Maybe this is a lesson you will learn from?

I'm ashamed to say that after my block making project, my cement mixer
is now 30kg heavier, and a lot smaller inside, with concrete.

I'm going to buy some HCl from a local supplier, but don't really know
what to ask for.
It'll take a lot of HCl to dissolve 30kg of concrete... And you'll still

I imagine it will diossolve the drum first.

No, it won't.

Ive used it to clean cement of trowels and the like It goes for cement,
and only slowly attacks the steel.

Dave Liquorice wrote:
On Sat, 20 Sep 2008 02:43:11 -0700 (PDT), tonyjeffs wrote:

One skill I don't have is cleaning up after a long d-i-y session.

Maybe this is a lesson you will learn from?

I'm ashamed to say that after my block making project, my cement
mixer is now 30kg heavier, and a lot smaller inside, with concrete.

I'm going to buy some HCl from a local supplier, but don't really
know what to ask for.

It'll take a lot of HCl to dissolve 30kg of concrete... And you'll
still have some fairly acidic waste to get rid of. Have you tried
taking a cold chisel and lump hammer to the concrete inside the drum?
If you can get a few cracks in it or better still a lump or three out
the rest will fall, perhaps with a little persuasion, off the drum.

Clearly a need for 'percussive maintenance'.


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk

On Sat, 20 Sep 2008 12:52:42 +0100, The Natural Philosopher wrote:

Established practice is to fill the drum with water betwen mixes, and
leave it turning, or at the time of the last mix of the day, and then
add bricks. These chip most of the dross off the drum and blades. The
rest usually comes free with a few good whacks of a mallet.

Yes, best not to let it build up a 30kg layer of set concrete in the first
place but the OP by his own admission said he was hopeless at cleaning...

--
Cheers
Dave.

On 20 Sep, 15:22, Lobster wrote:

For sure, but I don't think SDS drills were even around back then

Mid-70s from the patent, but rare.

On Sep 20, 11:16*pm, Andy Dingley wrote:
On 20 Sep, 15:22, Lobster wrote:

For sure, but I don't think SDS drills were even around back then

Mid-70s from the patent, but rare.


Thanks all.
Not heard of an SDS hammer drill before, but will buy one next time
around. How does it work in a way that is so much more efficient?
Have today had great success with hammer, earplugs and chizel.
(Figured the technique. Cut a radial slot outwards from the centre,
and widen it. If you try to cut concentric circlese, the concrete jams
up like an arch.) Have identified local supplier of brick acid, but if
the chizelling goes well (a bit at a time ,so itll take a few days ) I
might not need it.

tony

tonyjeffs wrote:
On Sep 20, 11:16 pm, Andy Dingley wrote:
On 20 Sep, 15:22, Lobster wrote:

For sure, but I don't think SDS drills were even around back then

Not heard of an SDS hammer drill before, but will buy one next time
around. How does it work in a way that is so much more efficient?

http://www.diyfaq.org.uk/powertools/sds.htm

If you're familiar with a conventional hammer drill?, then the
difference between that and an SDS is massive - I'd say go and buy one
now, you won't regret it. Would certainly make your current job a doddle.

David

Lobster wrote:
tonyjeffs wrote:
On Sep 20, 11:16 pm, Andy Dingley wrote:
On 20 Sep, 15:22, Lobster wrote:

For sure, but I don't think SDS drills were even around back then

Not heard of an SDS hammer drill before, but will buy one next time
around. How does it work in a way that is so much more efficient?

http://www.diyfaq.org.uk/powertools/sds.htm

If you're familiar with a conventional hammer drill?, then the
difference between that and an SDS is massive - I'd say go and buy one
now, you won't regret it. Would certainly make your current job a
doddle.

As long as its a 3 function SDS drill of course.


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk

On Sep 21, 1:15*am, tonyjeffs wrote:
On Sep 20, 11:16*pm, Andy Dingley wrote:

On 20 Sep, 15:22, Lobster wrote:

For sure, but I don't think SDS drills were even around back then

Mid-70s from the patent, but rare.

Thanks all.
Not heard of an SDS hammer drill before, but will buy one next time
around. How does it work in a way that is so much more efficient?
Have today had great success with hammer, earplugs and chizel.
(Figured the technique. Cut a radial slot outwards from the centre,
and widen it. If you try to cut concentric circlese, the concrete jams
up like an arch.) Have identified local supplier of brick acid, but if
the chizelling goes well (a bit at a time ,so itll take a few days ) I
might not need it.

tony

It'll get harder each day, so dont hang about.


NT