Hello,

I had a go at plastering a plasterboard wall for the first time today
and it went quite well. I'm going to try to skim a wall tomorrow. I
understand this is harder, so wish me luck!

I've got a few questions based on my experiences so far:

I read that you should add the plaster to the water, not the other way
round, yet with mortar I mix the sand and cement and add the water to
that. Is it critical to add plaster to water? If done the other way
round would it cause the plaster to clump like wall paper paste does?

The problem for a novice like me, is knowing how much water to put in
the bucket. I read you should trowel the plaster in but that took me
ages so I gave up and just poured from the bag. What is the right way
of doing this?

I underestimated how much mix I would need. I mixed a batch then
cleaned everything and was cross to find I had to go back and make
some more and dirty everything again!

I see you can buy plasterers buckets which have tall walls. Is this so
you can make a very big batch to avoid this happening, or is it just
to stop if spraying everywhere if you use a paddle on the end of a
drill to mix it?

Is there a rule of thumb that you need so much plaster and so much
water to cover x square metres? I doubt there is as I suppose coverage
depends on what you are plastering on to?

I bought a cheap aluminium hawk. Are aluminium ones better or worse
than plastic? I suppose neither rust. I can see how an expensive
trowel might be better than a cheap one but with hawks is there any
advantage to buying an expensive one?

When should you clean the hawk? Before you start polishing? The second
plasterboard wall I did was larger and by the time I got to one end,
the first end was beginning to dry so I did not stop. I've cleaned the
hawk as best I can but there is some "staining". Does this mean I have
not removed all the plaster or is it some chemical reaction between
the plaster and aluminium? Need I worry?

What is the trick for long walls? How do you make sure you finish
covering the wall before the first bit dries?

Any tips for skimming an old wall? I realise I will have to PVA first.

TIA

On 27 July, 22:07, Fred wrote:
Hello,

I had a go at plastering a plasterboard wall for the first time today
and it went quite well. I'm going to try to skim a wall tomorrow. I
understand this is harder, so wish me luck!

I've got a few questions based on my experiences so far:

I read that you should add the plaster to the water, not the other way
round, yet with mortar I mix the sand and cement and add the water to
that. Is it critical to add plaster to water? If done the other way
round would it cause the plaster to clump like wall paper paste does?

The problem for a novice like me, is knowing how much water to put in
the bucket. I read you should trowel the plaster in but that took me
ages so I gave up and just poured from the bag. What is the right way
of doing this?

I underestimated how much mix I would need. I mixed a batch then
cleaned everything and was cross to find I had to go back and make
some more and dirty everything again!

I see you can buy plasterers buckets which have tall walls. Is this so
you can make a very big batch to avoid this happening, or is it just
to stop if spraying everywhere if you use a paddle on the end of a
drill to mix it?

Is there a rule of thumb that you need so much plaster and so much
water to cover x square metres? I doubt there is as I suppose coverage
depends on what you are plastering on to?

I bought a cheap aluminium hawk. Are aluminium ones better or worse
than plastic? I suppose neither rust. I can see how an expensive
trowel might be better than a cheap one but with hawks is there any
advantage to buying an expensive one?

When should you clean the hawk? Before you start polishing? The second
plasterboard wall I did was larger and by the time I got to one end,
the first end was beginning to dry so I did not stop. I've cleaned the
hawk as best I can but there is some "staining". Does this mean I have
not removed all the plaster or is it some chemical reaction between
the plaster and aluminium? Need I worry?

What is the trick for long walls? How do you make sure you finish
covering the wall before the first bit dries?

Any tips for skimming an old wall? I realise I will have to PVA first.

TIA

Good luck. I have resolutely given up skimming. I will never get the
finish a time-served plasterer does.
I always thought those folks who can mime being in a box (you know
what I mean) could make good plasterers. Gotta know where flat is.
Folks always say just slap on the first coat, then level it when its
reached plasticine stage. But that is nonsense. You can only push it
around so much. The first application has to be pretty flat - it's
localised peaks and ridges that don't matter. A fairly fast sweeping
movement helps to get it flat - going to slow gives undulations.
Simon.

On 27 July, 22:07, Fred wrote:
Hello,

I had a go at plastering a plasterboard wall for the first time today
and it went quite well. I'm going to try to skim a wall tomorrow. I
understand this is harder, so wish me luck!

I've got a few questions based on my experiences so far:

I read that you should add the plaster to the water, not the other way
round, yet with mortar I mix the sand and cement and add the water to
that. Is it critical to add plaster to water? If done the other way
round would it cause the plaster to clump like wall paper paste does?

The problem for a novice like me, is knowing how much water to put in
the bucket. I read you should trowel the plaster in but that took me
ages so I gave up and just poured from the bag. What is the right way
of doing this?

I underestimated how much mix I would need. I mixed a batch then
cleaned everything and was cross to find I had to go back and make
some more and dirty everything again!

I see you can buy plasterers buckets which have tall walls. Is this so
you can make a very big batch to avoid this happening, or is it just
to stop if spraying everywhere if you use a paddle on the end of a
drill to mix it?

Is there a rule of thumb that you need so much plaster and so much
water to cover x square metres? I doubt there is as I suppose coverage
depends on what you are plastering on to?

I bought a cheap aluminium hawk. Are aluminium ones better or worse
than plastic? I suppose neither rust. I can see how an expensive
trowel might be better than a cheap one but with hawks is there any
advantage to buying an expensive one?

When should you clean the hawk? Before you start polishing? The second
plasterboard wall I did was larger and by the time I got to one end,
the first end was beginning to dry so I did not stop. I've cleaned the
hawk as best I can but there is some "staining". Does this mean I have
not removed all the plaster or is it some chemical reaction between
the plaster and aluminium? Need I worry?

What is the trick for long walls? How do you make sure you finish
covering the wall before the first bit dries?

Any tips for skimming an old wall? I realise I will have to PVA first.

TIA

I share your pleasure!.
Years ago I bought an old house needing a lot of plastering and soon
learnt that plasterers tended towards being either stupidly expensive
or rubbish at plastering or ****heads or not arsed to turn up.
As a keen DIYer, I just watched one guy doing a wall and started doing
it myself. Never looked back. Even got round to skimming a few
ceilings!.
All that's needed is enthusiasm and willingness to 'get in there'.
I've no longer a need to plaster but remember the tin bath as being
really handy and yes add the plaster to the water or it's a **** to
mix up.
Best help I remember was making one of those mixing tools that stick
in a drill. Have easy access to a hosepipe to keep the kit washed
down. And *always* use fresh plaster. All else is just propaganda

On 27 Jul,
wrote:

And *always* use fresh plaster. All else is just propaganda

There is the odd occasion that old plaster is useful. You don't have to wait
long for it to go off. Handy for a small job.

The most useful is old bonding compound used for dot&dab. goes off as you
hold the dot in alignment.

--
B Thumbs
Change lycos to yahoo to reply

On 27 July, 23:56, wrote:
On 27 Jul, *
* * wrote:

*And *always* use fresh plaster. All else is just propaganda

There is the odd occasion that old plaster is useful. You don't have to wait
long for it to go off. Handy for a small job.

The most useful is old bonding compound used for dot&dab. goes off as you
hold the dot in alignment.

--
* B Thumbs
* Change lycos to yahoo to reply

I'd quite gotten into the plaster stuff and started 'running'
mouldings. First moulding mix I ever did, used two (supposedly fresh)
bags of Plaster of Paris. It went off about 30 seconds into the
mixing. Stirrer locked into the solid mass and the bathfull of mix
started steaming. I could feel the heat from feet away. An overactive
imagination deduced it was somehow going 'critical' ,so rapidly exited
stage left. (I lived and learnt

In article ,
writes:
On 27 July, 23:56, wrote:
On 27 Jul, *
* * wrote:

*And *always* use fresh plaster. All else is just propaganda

There is the odd occasion that old plaster is useful. You don't have to wait
long for it to go off. Handy for a small job.

The most useful is old bonding compound used for dot&dab. goes off as you
hold the dot in alignment.

--
* B Thumbs
* Change lycos to yahoo to reply
I'd quite gotten into the plaster stuff and started 'running'
mouldings. First moulding mix I ever did, used two (supposedly fresh)
bags of Plaster of Paris. It went off about 30 seconds into the
mixing. Stirrer locked into the solid mass and the bathfull of mix
started steaming. I could feel the heat from feet away. An overactive
imagination deduced it was somehow going 'critical' ,so rapidly exited
stage left. (I lived and learnt

http://news.bbc.co.uk/1/hi/england/l...re/8303246.stm

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

On Wed, 28 Jul 2010 08:51:58 +0000 (UTC), Andrew Gabriel wrote:

http://news.bbc.co.uk/1/hi/england/l...re/8303246.stm

Bloody Hell. Though the student didn't follow the instructions she
had been given, make a mould with clay and pour in the plaster of
paris...

Also seems a bit odd that no one could get the PoP off, doesn't the
school woodworking shop have a hammer and chisel? Getting the lump
free from the bucket might be hard once out would be a lot easier to
deal with. Wouldn't be nice for the people wielding the hammer/chisel
or the student but then niether are the burns... Serious situations
call for drastic measures.

--
Cheers
Dave.

In article ,
John Rumm writes:
On 27/07/2010 22:07, Fred wrote:

I had a go at plastering a plasterboard wall for the first time today
and it went quite well. I'm going to try to skim a wall tomorrow. I
understand this is harder, so wish me luck!

Good luck!

I've got a few questions based on my experiences so far:

I read that you should add the plaster to the water, not the other way
round, yet with mortar I mix the sand and cement and add the water to
that. Is it critical to add plaster to water? If done the other way
round would it cause the plaster to clump like wall paper paste does?

Yup easier to mix without lumps if you add plaster to water. Stick a
paddle in the end of a drill (with speed control or low speed!), big

You want low gear. If you haven't got a gearbox, you'll need to
select low speed, but this is a very good way to burn out a drill,
as it's quite a load with not enough cooling. If the drill does
start to get hot or smell, take the paddle off and spin the drill
at top speed with no load to cool it down.

floppy bucket. Chuck say 4L in the bottom and the top of a bag. Get
mixing, and trowel in some more plaster to get the mix consistency you
want.

I use a firm plastic bucket. You must find one with a flat bottom
inside, no ridges or indentations, as that will stop you mixing it
completely.

The problem for a novice like me, is knowing how much water to put in
the bucket. I read you should trowel the plaster in but that took me
ages so I gave up and just poured from the bag. What is the right way
of doing this?

A bit of both in my experience - you can gustimate the right amount to
tip in, and then fine tune by troweling in extra as you mix.

Start off by 1/4 filling the bucket with water, and keep troweling
in plaster as you mix it smooth. Try not to entrain air into the mix
or to mix it much more than is necessary; you aren't making a cake.
Finish coat should be slightly more runny that scratch coat. When
you load up the trowel face, if you swivel it round vertical, finish
coat should slide off, whereas scratch coat should stay put just,
but slide off if you give the trowel a small vertical movement to
get the plaster to break grip.

Once you get more familiar with mixing, you can adjust the quantities
appropriately.

I underestimated how much mix I would need. I mixed a batch then
cleaned everything and was cross to find I had to go back and make
some more and dirty everything again!

That's completely normal. You have to clean everything between each
new mix anyway, as contamination by the previous mix will cause the
new mix to set faster.

When I've mixed up, I pour it out onto a board (damped first time),
and then go and clean up the bucket and paddle. The new plaster will
wait a few minutes, but trying to clean up the implements after you've
put the plaster up is harder. Don't let the plaster washings go down
a drain. I chuck them over the lawn.

It always take more than you expect!

I see you can buy plasterers buckets which have tall walls. Is this so
you can make a very big batch to avoid this happening, or is it just
to stop if spraying everywhere if you use a paddle on the end of a
drill to mix it?

The big floppy buckets with two handles I quite like. You can mix a
whole bag in one go in one if you need to.

As a novice, you'll only get through half of it before it's set though.
I tend to use the black 3 gallon/14 litre buckets. One of those full
is what I can comfortably get on the wall in time (less so for finish
coat). If you're pouring out onto a board (which is probably easier
for a beginner than loading the plaster from the bucket), then you
need a large enough board to hold the amount you mix up.

Is there a rule of thumb that you need so much plaster and so much
water to cover x square metres? I doubt there is as I suppose coverage
depends on what you are plastering on to?

You can get a rough idea by working out the volume you plan to apply.
Also the British gypsum site has some expected coverage details in their
spec sheets. See the PDF on this page for example:

http://www.british-gypsum.com/produc...ding_coat.aspx

I bought a cheap aluminium hawk. Are aluminium ones better or worse
than plastic? I suppose neither rust. I can see how an expensive

I prefer the ali - but there is not much in it.

trowel might be better than a cheap one but with hawks is there any
advantage to buying an expensive one?

Not really...

Cheap plastic ones can suffer fatigue after a lot of use and the
handle breaks off.

When should you clean the hawk? Before you start polishing? The second
plasterboard wall I did was larger and by the time I got to one end,
the first end was beginning to dry so I did not stop. I've cleaned the
hawk as best I can but there is some "staining". Does this mean I have
not removed all the plaster or is it some chemical reaction between
the plaster and aluminium? Need I worry?

Dip in big bucket of water and wipe off with your hand - usually does it
for me!

Talking of which, buy a tube of barrier cream (Savlon and Boots do them).
Chemists often have it, or you can order it from CPC. Plaster can do
quite nasty things to your skin otherwise. Also, avoid repeatedly washing
with soap during the job - just wash plaster off with water if you need
to, until you've finished.

If you end up with cracked hands through not using barrier cream, then an
after treatment is to rub in vasalene. However, as someone here said before,
it's much easier to get a skin problem than it is to get rid of one, so do
use barrier cream.

What is the trick for long walls? How do you make sure you finish
covering the wall before the first bit dries?

You don't need to. You just need to apply the next area before the
previous one sets.

I did a long post some time back describing how to make the scratch
coat flat using a technique known as "dots and screeds".
http://groups.google.co.uk/group/uk....f98e8d4f?hl=en

To extend this to a long wall, you use several screeds, and you can
level them by using a string streched across the screed fronts.

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

Fred wrote:
Hello,

I had a go at plastering a plasterboard wall for the first time today
and it went quite well. I'm going to try to skim a wall tomorrow. I
understand this is harder, so wish me luck!

I've got a few questions based on my experiences so far:

I read that you should add the plaster to the water, not the other way
round, yet with mortar I mix the sand and cement and add the water to
that. Is it critical to add plaster to water? If done the other way
round would it cause the plaster to clump like wall paper paste does?

The problem for a novice like me, is knowing how much water to put in
the bucket. I read you should trowel the plaster in but that took me
ages so I gave up and just poured from the bag. What is the right way
of doing this?

I underestimated how much mix I would need. I mixed a batch then
cleaned everything and was cross to find I had to go back and make
some more and dirty everything again!

I see you can buy plasterers buckets which have tall walls. Is this so
you can make a very big batch to avoid this happening, or is it just
to stop if spraying everywhere if you use a paddle on the end of a
drill to mix it?

Is there a rule of thumb that you need so much plaster and so much
water to cover x square metres? I doubt there is as I suppose coverage
depends on what you are plastering on to?

I bought a cheap aluminium hawk. Are aluminium ones better or worse
than plastic? I suppose neither rust. I can see how an expensive
trowel might be better than a cheap one but with hawks is there any
advantage to buying an expensive one?

When should you clean the hawk? Before you start polishing? The second
plasterboard wall I did was larger and by the time I got to one end,
the first end was beginning to dry so I did not stop. I've cleaned the
hawk as best I can but there is some "staining". Does this mean I have
not removed all the plaster or is it some chemical reaction between
the plaster and aluminium? Need I worry?

What is the trick for long walls? How do you make sure you finish
covering the wall before the first bit dries?

Any tips for skimming an old wall? I realise I will have to PVA first.

TIA

When skiming old plaster, make sure there are no nails, tacks, blue-tack,
clumps of wallpaper or any other 'bits' on the wall, if there are, remove
them prior to applying PVA.

Apply PVA generously, don't skimp and give it two coats if possible, the
second after the first has dried....it doesn't matter whether you skim over
the pva dry or wet, but any patches not treated with pva will dry almost
immediately and make a ******** of the trowelling-up process.

To do a long wall, start at one end (point 1) with stepladders and apply a
band across the top of the wall about 2 -3 feet down from the ceiling, all
the way from one end to the other.
Get down, remove steps out of area and apply another band the same width in
the middle of the wall, then, apply the last band whilst you are kneeling
down, don't be tempted to drop back onto what's already covered.
Once the full wall is covered in plaster, start again where you started
originally (point 1) and apply a thin 2nd coat, taking out most of the
imperfetions, don't be too picky, this is still only an initial phase.
Follow the same route over the wall as you did with the 1st coat, until it's
had a 2nd coat and is looking fairly flattish.
Wash implements, hawk, trowels, mixers and buckets.
Start again at point 1 and go over the entire wall with a light splash of
water over about a square metre at a time and take out any imperfections,
repeat this process until you are happy with the finish.

If at any time you are putting more marks in than you are taking out, stop
and wait for 5 minutes to allow the plaster to go off slightly then have
another go, starting from point 1 again.

--
Phil L
RSRL Tipster Of The Year 2008

Phil L wrote:


To do a long wall, start at one end (point 1) with stepladders and
apply a band across the top of the wall about 2 -3 feet down from the
ceiling, all the way from one end to the other.

This should have read, 'a 2-3 foot band, from the ceiling down', that is to
say, the top 2-3 ft of the wall

--
Phil L
RSRL Tipster Of The Year 2008

On Tue, 27 Jul 2010 14:25:39 -0700 (PDT), sm_jamieson
wrote:


Good luck. I have resolutely given up skimming. I will never get the
finish a time-served plasterer does.

I'm not sure that I will ever get that finish either but if you are
going to paper over it, it doesn't matter if it is not 100% perfect,
or at least that was my line of thinking. I've had two different
plasterers do work for me before and neither of them have a perfect
finish; there were odd swirls here and there, so I'm not sure even a
pro gets it 100% right, or perhaps my plasterers weren't good ones!

I always thought those folks who can mime being in a box (you know
what I mean) could make good plasterers. Gotta know where flat is.
Folks always say just slap on the first coat, then level it when its
reached plasticine stage

One thing I have not understood is how you know that the thickness is
uniform. I have managed to smooth the surface but how do I know I
don't have 4mm on one side, sloping to 2mm on the other? OTOH the
walls weren't straight or smooth in the first place; if they had been,
I wouldn't have needed to plaster them, so things can't get any worse
than they already were, can they?

On Wed, 28 Jul 2010 11:32:10 +0100 (BST), "Dave Liquorice"
wrote:

Bloody Hell. Though the student didn't follow the instructions she
had been given, make a mould with clay and pour in the plaster of
paris...

Also seems a bit odd that no one could get the PoP off, doesn't the
school woodworking shop have a hammer and chisel? Getting the lump
free from the bucket might be hard once out would be a lot easier to
deal with. Wouldn't be nice for the people wielding the hammer/chisel
or the student but then niether are the burns... Serious situations
call for drastic measures.

I had heard this about this accident when, IIRC, they were talking
about it on the Jeremy Vine show on Radio 2 a few months ago.

I was surprised to hear it set so fast and so hot.

On the radio they mentioned there had been a similar accident at a
school in Scotland but details were not circulated to other schools;
if they had been, perhaps this accident could have been prevented?

A quick google found this:
http://www.tamesideschoolssupport.ne.../1610_PS72.pdf

That talks about a Scottish accident "years ago". I don't know if it
is the same one. It says that the pupil lost two fingers and that the
rescue attempt did "harm", so I'm unsure whether they are implying the
chisel did more damage than the plaster.

OTOH how would they know what damage would have been done if they had
not got the chisel out? I would like to think that they were right to
try to help.

On Wed, 28 Jul 2010 10:35:55 +0000 (UTC),
(Andrew Gabriel) wrote:

You want low gear. If you haven't got a gearbox, you'll need to
select low speed, but this is a very good way to burn out a drill,
as it's quite a load with not enough cooling. If the drill does
start to get hot or smell, take the paddle off and spin the drill
at top speed with no load to cool it down.

What type of drill are we talking about here? recently I posted about
core drilling and I made the mistake of thinking a large hole required
a slow speed until John pointed out that an sds on full speed is
relatively slow compared to a "traditional" drill.

I wouldn't use an expensive sds drill to mix plaster but I have a £50
Screwfix model I could use. Would you still need a low speed for an
sds drill?

I remember Wickes sold a special "high torque" drill for mixing but I
think they discontinued it last year. Perhaps people don't buy/need a
special drill for mixing any more? Are they any good?

I see Tool station sell different sizes of paddles quite cheaply. Some
are hex to fit into a normal drill chuck, others have a thread. Do the
cheap hex ones do the job? Do you just buy the biggest one you can or
is there a danger that the biggest ones will overload your drill?

Start off by 1/4 filling the bucket with water, and keep troweling
in plaster as you mix it smooth. Try not to entrain air into the mix
or to mix it much more than is necessary; you aren't making a cake.

Finish coat should be slightly more runny that scratch coat. When
you load up the trowel face, if you swivel it round vertical, finish
coat should slide off,

Yesterday everything went well. Today less so. I don't know whether
this was because I was plastering a wall rather than a plasterboard.
Perhaps the PVA was too wet, too dry, too dilute (I used 5:1 as stated
on the label)? Perhaps it had nothing to do with the PVA.

I think I may have mixed it too dry and I think this is why I found it
harder to spread and why it seemed to dry before I was ready.
Yesterday it was quite running and a few dollops fell off and onto the
floor. Today I think it would have stayed put if the trowel was upside
down, so I think today's problems were too little water.

I think I am probably overmixing too. Being new I suppose I was
nervous about it being lumpy so I may have mixed too long. I think
there were some air bubbles when I first spread it on the wall. If
they are there, I guess I'll find out in a few years if I use a steam
stripper to remove the wallpaper!

That's completely normal. You have to clean everything between each
new mix anyway, as contamination by the previous mix will cause the
new mix to set faster.

It's just a bit soul destroying to have to clean the same things over
and over again and ity doesn't help if you are cleaning them in the
garden but plastering the bedroom furthest away, like I was!

When I've mixed up, I pour it out onto a board (damped first time),

I was caught out by this. I had assumed that you got the plaster
straight from the bucket. Fortunately I had some plasterboard off cuts
and used those. The problem is they are for one-off use only and then
had to be thrown away. What do others use: a scrap of plywood?

As a novice, you'll only get through half of it before it's set though.
I tend to use the black 3 gallon/14 litre buckets. One of those full
is what I can comfortably get on the wall in time (less so for finish
coat).

I have done half a wall with one batch but then got nervous that by
the time I had mixed the second batch the bit I had done would have
set. I think the wall looks ok, so it was probably beginner's nerves
worrying about nothing but I don't suppose I'll know for sure until I
look at it once dry.

Thanks for all your help to everyone who replied.

On Wed, 28 Jul 2010 01:32:21 +0100, John Rumm
wrote:

Good luck!

Thanks. Your post and Andrew's overlapped, so I have tried to reply to
you both in one post. Thanks again.

On 28 July, 21:15, Fred wrote:
On Wed, 28 Jul 2010 11:32:10 +0100 (BST), "Dave Liquorice"

wrote:
Bloody Hell. Though the student didn't follow the instructions she
had been given, make a mould with clay and pour in the plaster of
paris...

Also seems a bit odd that no one could get the PoP off, doesn't the
school woodworking shop have a hammer and chisel? Getting the lump
free from the bucket might be hard once out would be a lot easier to
deal with. Wouldn't be nice for the people wielding the hammer/chisel
or the student but then niether are the burns... Serious situations
call for drastic measures.

I had heard this about this accident when, IIRC, they were talking
about it on the Jeremy Vine show on Radio 2 a few months ago.

I was surprised to hear it set so fast and so hot.

On the radio they mentioned there had been a similar accident at a
school in Scotland but details were not circulated to other schools;
if they had been, perhaps this accident could have been prevented?

A quick google found this:http://www.tamesideschoolssupport.ne.../1610_PS72.pdf

NB link at bottom of page1 of that pdf links to a 2005 BBC news report
- so it was publicised but not picked up (enough) what else was
occurring in 2004 (assuming the case took the usual min 6months to
trial?

cheers
Jim K

On Wed, 28 Jul 2010 21:15:55 +0100, Fred wrote:

On the radio they mentioned there had been a similar accident at a
school in Scotland but details were not circulated to other schools;
if they had been, perhaps this accident could have been prevented?

The student hadn't followed the instructions, perhaps if the
information had be circulated the instructions may have been
reinforced and the dangers pointed out. Hindsight is wonderfull...

A quick google found this:
http://www.tamesideschoolssupport.ne.../1610_PS72.pdf

Interesting document particulary figure 2 and the text associated
with it. 4l of PoP gets to skin damage temperature in less than 30
mins and gets an awful lot hotter in the next 30 mins.

That talks about a Scottish accident "years ago". I don't know if it
is the same one. It says that the pupil lost two fingers and that the
rescue attempt did "harm", so I'm unsure whether they are implying the
chisel did more damage than the plaster.

It isn't clear, maybe the removal of the setting PoP also removed the
skin? But which is worse removing some already damaged skin and the
heat source or letting the whole hand slowly cook...

I would like to think that they were right to try to help.

That is my view. Sometimes seemingly drastic action is required to
produce a better overall outcome.

--
Cheers
Dave.

Fred wrote:

I was caught out by this. I had assumed that you got the plaster
straight from the bucket. Fortunately I had some plasterboard off cuts
and used those. The problem is they are for one-off use only and then
had to be thrown away. What do others use: a scrap of plywood?

I used part of an old kitchen carcass last time. Anything that's
non-absorbent basically.

I admire you having a go at a whole wall as a beginner. I'm happy
levelling up to to beads, but freehand is a skill I fear I won't have
time to acquire in this lifetime. Also, I find plaster THE most
frustrating stuff to work with. With most d-i-y jobs you can get a
professional result if you take your time but, with plastering, there's
only one way to work, and that's fast.

On Thu, 29 Jul 2010 09:30:32 +0100, stuart noble
wrote:

I admire you having a go at a whole wall as a beginner.

If I had done half of the wall, it may have looked a bit funny

Now that the plaster is dry I have been able to have a closer look at
it.

I had skimmed over a brand new plasterboard wall and a wall which had
been skimmed, painted, and papered previously. I had removed the
wallpaper and in places the paint had come off with the paper, so it
was a mixture of painted plaster and bare plaster; I PVA'ed all of it.

The plasterboard wall seems to be better. I had heard that PB was
easier to do. I wonder why? Perhaps it's because it is perfectly flat
to begin with? OTOH I don't know how flat the other wall was because I
never thought to look beforehand.

I hadn't mixed plaster before so I had one batch that was too runny: I
got more on the floor than the wall! I overcompensated on the next
batch and it was too thick. Consequently I think it set quicker and
was harder to work with. I think this stiff mix is responsible for
some of the undulations. It's a shame I have only noticed them now,
rather than at the time.

One web site I read talked of the plaster not falling off the trowel
but I now think that is too stiff. I think it is right when it slides
slowly. Do you agree?

Are professionally done walls completely flat? If you look at my wall,
you cannot see any obvious bumps; it's not like parts stick out
inches, so that's something but if you run your hand over it, you can
feel slight rises and falls in places. Hopefully no-one will go
hugging the walls to find out.

There are one or two rough patches which I am more concerned about.
What's the best way to smooth them out? I did try light sanding with a
120 grit paper. I worried that a coarser grit might damage the plaster
but the problem is that the paper clogs almost straight away. Should I
use a different grit or is there something more appropriate than
sandpaper?

Thanks again.

PS I forgot to say that I had a patch where the skim coat of old
plaster had come off the wall. I did wonder whether I should fill this
before skimming but decided to carry on regardless. Even though I
PVA'ed the patch, it still caused the plaster to dry and crack. Should
I have used more PVA or should I have polyfilla'ed the hole first?

On Wed, 28 Jul 2010 15:43:00 +0100, John Rumm
wrote:

BTW - Makro have some cheap mixer drills at about £30 currently...

Thanks. I hadn't realised Makro were still about. I thought they had
been closing branches?

For finish coat, that's true. For bonding, it depends on what you are
plastering, and how thick IME.

That's the thing that puzzles me. Once the (finish coat) of plaster is
on the wall, how do you know you have a uniform thickness and not 8mm
on one end and 2mm on the other?

My walls seem to be horrible sandy browning with skim on top. It seems
that people just keep skimming on top of the previous layer. I know we
are only talking a couple of mm each time but does there ever come a
point where you should strip off all the skim back to the browning?
After all you don't paper over paper or tile over tiles.

What if you chiseled off the whole lot? How easy is it to plaster a
bonding coat to masonry? Not that I'm about to try it! Are there
different types of bonding coat? I won't be using browning that's for
sure!

Thanks.

On Thu, 29 Jul 2010 12:46:04 +0100, John Rumm
wrote:

Well the ideal is a "mixer" drill. These are usually geared down to 500
rpm or similar, so they turn with high torque, slow speed, but keep the
motor running at speed and hence well cooled.
[snip]
unless that is your line of work, you won't be doing enough to make it worthwhile
buying a dedicated drill.

Although they are geared and slow spinning, I don't think they have a
clutch do they? It's a shame because wouldn't a slow spinner with a
clutch have served a dual purpose as a core drill?

The Wickes one was reduced to clear whenI saw it but that was a year
ago, at which time I had no thought of ever trying to plaster.

I think it was a less colourful (grey) version of this:
http://www.kress-elektrik.com/Power-...x_commerce_pi1[catUid]=32&tx_commerce_pi1[showUid]=40


For DIY levels of plaster mixing, the smaller paddle with a couple of
twisted flutes on the end is usually plenty.

Toolstation sell a number with sizes from 60mm across to 120mm across:

http://www.toolstation.com/shop/Hand...ools/d10/sd140

I wonder whether 60mm is too small? I tried the 120mm one but when I
mixed too stiff, the resistance of the mix pulled it out of the chuck!
The hex looks a bit rounded, whether it arrived like that or whether
falling out caused that I don't know. Perhaps I will get a smaller
one?

On 2 Aug, 22:35, Fred wrote:

There are one or two rough patches which I am more concerned about.
What's the best way to smooth them out? I did try light sanding with a
120 grit paper. I worried that a coarser grit might damage the plaster
but the problem is that the paper clogs almost straight away. Should I
use a different grit or is there something more appropriate than
sandpaper?

Use a coarse grade glasspaper - 60 grit should be fine. Use it in a
hand sander, so you can sand flat. Wear a mask ;-)

Cheers
Richard

On 03/08/2010 10:23, geraldthehamster wrote:
On 2 Aug, 22:35, wrote:

There are one or two rough patches which I am more concerned about.
What's the best way to smooth them out? I did try light sanding with a
120 grit paper. I worried that a coarser grit might damage the plaster
but the problem is that the paper clogs almost straight away. Should I
use a different grit or is there something more appropriate than
sandpaper?

Use a coarse grade glasspaper - 60 grit should be fine. Use it in a
hand sander, so you can sand flat. Wear a mask ;-)

Cheers
Richard



Screwfix decorator rolls are good for plaster

On Mon, 02 Aug 2010 23:40:33 +0100, John Rumm
wrote:

Well to an extent you don't. However uniform thickness is not the goal,
a flat top surface is.

But couldn't you have a flat surface that was triangular in cross
section if you put too much on one side? But perhaps I am being too
hypothetical. I know my attempt wasn't perfect but it's not that bad


Normally when the skim is "blown" and falls off as you strip the paper,
its a good indication it needs re-doing.

But isn't that just a sign that the skim is bad? Why should the
bonding coat need redoing, or is it just that you can't remove the
skim without knocking off the bonding? I had a small patch of blown
plaster that I didn't bother to fill before skimming. Surely for an
odd patch of blown plaster, that doesn't require the whole wall to be
redone? Is it only when lots of plaster becomes blown?

I did put PVA in the blown hole but even so the skim cracked. What did
I do wrong? Should I have sued more PVA?Should I have filled the hole
with polyfilla first?

Thanks.