2 coats from 1 bucket

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Plaster is not firerated and I doubt ever will or put on paper like one- too many variables to guarantee any level of fireproofing. As for the op question , it's more a case of can you deal with it or not. The fire ratingwill be your last concern. Remixing plaster at late stage is disastrous and you will end up with ripples , dragging, tigers and anything but good finish. If is at early stage , maybe, but still the risk is there. The plaster sets diferent ,in patches, and there is no way you can have the finish you are after. Have I done it? Oh yes. Have I mastered? Oh yes. Have I pulled my hair after seeing disaster result ? f**k yeah! but avoiding at any cost, especially big areas , is a rule . If you are concern about knocking back plaster , think of sponging. Does exactly the same.
 
vfr12 said:
Plaster is not firerated and I doubt ever will or put on paper like one- too many variables to guarantee any level of fireproofing. As for the op question , it's more a case of can you deal with it or not. The fire ratingwill be your last concern. Remixing plaster at late stage is disastrous and you will end up with ripples , dragging, tigers and anything but good finish. If is at early stage , maybe, but still the risk is there. The plaster sets diferent ,in patches, and there is no way you can have the finish you are after. Have I done it? Oh yes. Have I mastered? Oh yes. Have I pulled my hair after seeing disaster result ? f**k yeah! but avoiding at any cost, especially big areas , is a rule . If you are concern about knocking back plaster , think of sponging. Does exactly the same.
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Also adding to that, Plaster that is not mixed well enough will cause the same problems.

The only jobs that can be done with un smooth plaster is beading or dot & dab.
 
Dynamite-Kid said:
Adding and using dirty water weakens the mix, this causes rapid absorption of moisture on the surface of the plasterer which in turn causes the plaster ( if it adheres ) to be dryer than it should be which then creates a quicker burn time in the event of fire.
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And that gentlemen is Science
 
Dynamite-Kid said:
In fairness to the original question I would say that nearly every spreader has knocked gear back up at some stage in their life. But it really shouldn't be done, tried taking the easy option as an apprentice once and got a wack in the mouth from the Labourer ( no kidding ).

f**k**g beast he was, the days before the whisk. He had a lollipop stick and a welded bike cog for mixing and could easy keep to Spreaders going at full pace. Plastering Labouring is an un-respected job and I would argue there isn't any harder job. A decent Plastering Labourer is a rare breed.
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I applaud you...I learnt via 'being on the shovel', it was a plastic bath, a shovel cut down at the end to knock up the hardwall and a stick & podger for the finish...it was f##cking brutal keeping to spreads going. They then started giving me cupboards to do...ahhh, heaven!
 
Lastlaff said:
I applaud you...I learnt via 'being on the shovel', it was a plastic bath, a shovel cut down at the end to knock up the hardwall and a stick & podger for the finish...it was f##cking brutal keeping to spreads going. They then started giving me cupboards to do...ahhh, heaven!
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Excellent stuff, same here. I wasn't allowed near a trowel and hawk for a year, my boss was proper old school and always said labouring is an art form, if you don't get your mixing right you should get another trade.

He is passed away now but his skill level was f**k**g mental.... Clean, sharp and quick work... Mind you he had an arm span like an albatross..
 
Dynamite-Kid said:
Also adding to that, Plaster that is not mixed well enough will cause the same problems.

The only jobs that can be done with un smooth plaster is beading or dot & dab.
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Just a little tip don't dot and dab with plaster no matter how it's mixed
 
If I might be so bold.

Dynamite-Kid said:
Adding and using dirty water weakens the mix,
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Yes it does.

Dynamite-Kid said:
this causes rapid absorption of moisture on the surface of the plasterer which in turn causes the plaster ( if it adheres ) to be dryer than it should be which then creates a quicker burn time in the event of fire.
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No it doesn't.

Gypsum plaster (board, skim, backing plasters) calcinate when exposed to high temperatures. The chemically bonded water is purged which forms a layer the thickness of which increases as the temperature and duration increase. It's an accurate enough reaction to be used in fire investigation.

That calcination process will occur faster if there's less chemically bonded moisture, which will neither increase nor decrease the fire resistance. It simply means that the initial calcinated layer (which is what gives gypsum it's fire retardant properties) will form quicker.
 
imago said:
If I might be so bold.



Yes it does.



No it doesn't.

Gypsum plaster (board, skim, backing plasters) calcinate when exposed to high temperatures. The chemically bonded water is purged which forms a layer the thickness of which increases as the temperature and duration increase. It's an accurate enough reaction to be used in fire investigation.

That calcination process will occur faster if there's less chemically bonded moisture, which will neither increase nor decrease the fire resistance. It simply means that the initial calcinated layer (which is what gives gypsum it's fire retardant properties) will form quicker.
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Came here to learn, a bit to educated for my head but certainly explained cheers.
 
Dynamite-Kid said:
Came here to learn, a bit to educated for my head but certainly explained cheers.
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There's always something new to pick up, which one of the (few) good things about the building industry. Anyone open to learning new stuff is always going to do well. (y)
 
On this thread we have experienced spreaders giving different views regarding fire retardant qualities of plaster.

This does seem to be a debatable issue, I always believed and was told that weakened mixes does have an effect, but reading others perhaps not.

I know one f**k**g thing for sure, you shouldn't knock up mixes again.

End of....
 
imago said:
There's always something new to pick up, which one of the (few) good things about the building industry. Anyone open to learning new stuff is always going to do well. (y)
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Appreciated mate, had a bit of a rough time on here so far. Own fault. I was trying to be funny. (Didn't go down well) .
 
Dynamite-Kid said:
Appreciated mate, had a bit of a rough time on here so far. Own fault. I was trying to be funny. (Didn't go down well) .
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You're only the latest in a long line of people that tried to be funny and it wasn't well received. Most of your predecessors are now regular members and all's well as it all settles down fine. Obviously a few are w4nkers, and a few carry on their p1ssing contests for years. :LOL:

Just keep in mind that it's all just bollox on a forum that won't make any difference to anything and you'll be good.
 
Dynamite-Kid said:
had a bit of a rough time on here so far
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Yeah mate, I think that's cos ur giving out advice on retempering gear and fire-retardant qualities of gypsum...after asking "do I PVA bonding before I skim"
Half of us r probably on our man period tho lol, poor Kate had to verify her ID before her photos of bad plastering were taken seriously in the other thread

It`s a fun place here tho :)
 
GypsumSnorter said:
Yeah mate, I think that's cos ur giving out advice on retempering gear and fire-retardant qualities of gypsum...after asking "do I PVA bonding before I skim"
Half of us r probably on our man period tho lol, poor Kate had to verify her ID before her photos of bad plastering were taken seriously in the other thread

It`s a fun place here tho :)
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Yeah...your right, just trying to get known I guess. I will hopefully get the hang of it. I've learnt already and even after 22years it's great to get feedback. Nobody knows everything and in any building trade no job is ever the same. Cheers
 
Dynamite-Kid said:
Appreciated mate, had a bit of a rough time on here so far. Own fault. I was trying to be funny. (Didn't go down well) .
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Stuff the rest of them, you are sound, only once or maybe twice on thread that anyone has even mentioned the finish,alot of posts have been off spreads who have had many year's plastering and imo one coating or even 2 with same mix is an art that comes with experience (some may say it isn't),besides the ins and outs of weather it is right or wrong imo the op should be encouraged to do 2 coat system of skimming to achieve best finish possible.
 
I do agree with you, 2 coat work brings a better finish. I was taught that system and I try to stick to it when skimming any background.

I have done one coat work but I have always found that I spend a lot of time filling out and trying to get a finish. It makes trowelling up hard work. Just as well but a laying down coat on.

Not once doing one coat have I been happy with the finish.
 
I've second coated with the same mix that I layed on with plenty of times
There's nout wrong with it the trowel time are different that's all.
If am doing 3-4 buckets then a fresh bucket for 2nd coat
And if there's any left I just bang a small ceiling or wall with one coat.
It's each to there own as long as it's left neat and tidy
 
Jerseyboy said:
I've second coated with the same mix that I layed on with plenty of times
There's nout wrong with it the trowel time are different that's all.
If am doing 3-4 buckets then a fresh bucket for 2nd coat
And if there's any left I just bang a small ceiling or wall with one coat.
It's each to there own as long as it's left neat and tidy
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Since I have been on here ( which isn't long ) I have noticed that different people have different working practices. Wether it is right or wrong is down to veiwpoint, but anyone who says they have followed the rules completely in building is either a liar or a f**k**g good blagger.

100% agree. Each to their own.
 
If the gaff goes up in flames the last thing the fire brigade will be doing is contacting the plastering contractor to consider burn times ffs

@Lodan its been done many many times mate crack on and as you said just get at it rapido.

@Kitchy your also right its a fancy 1 coat using the same gear for both coats but we do it daily on house bashing. Its also a s**t finish. I think the sponge monkeys probably get a better finish on it because i'd imagine it rubs the trowel marks out of it but trowelling always makes them grin through a bit in my experience. Looks passable when painted for house bashing but wouldn't do it on domestics....usually
 
Dynamite-Kid said:
Sponge Monkeys..? that is f**k**g brilliant.
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As I've said before
If you know how to one coat properly using a sponge or being a sponge monkey it's perfect.
Let's not blame the method.
It's multi finish that sets.
Do it right it works.
I can one coat,two coat and 3 coat if I need to.
NOUT WRONG WITH A SPONGE!!!
 
There is everything wrong about using sponge! Well, at least until you try and master the dance. Then you look back and realise you have been the gorilla in the room all the time:(. Question is, can you admitted to yourself?
 
Stone the crows , on domestic over skim @Lodan don't for the love of plastering use a sponge and one coat.

Worst case scenario for saving time if it really is a problem, mix fresh laying in gear in bucket used for first coat or do smaller area gauges
 
theplasterman said:
Stone the crows , on domestic over skim @Lodan don't for the love of plastering use a sponge and one coat.

Worst case scenario for saving time if it really is a problem, mix fresh laying in gear in bucket used for first coat or do smaller area gauges
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dont even own a sponge
 
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