can you skim straight onto bonding coat????

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platinum

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can you skim straight onto bonding coat..... how long do you have to leave it before you can??? and must you pva it or pva and scratch it?????? why is everything so complicated !!!! :p

cant wait till i'm answer the questions instead of asking! ;D
 
Yep just like any other backing plaster and certainly no need to PVA unless its been on a good while and then you can just wet it.
PS 30 years of plastering and I still ask at times.
 
i always try and get any bonding or hardwall skimmed up the same day if its gotta be left a few days then i give a quick coat before is skim it
 
nice one guys thanks.... ;D

but how long do you leave the bonding coat before you can add finish onto it..... and i really dont need to pva it or scratch it or anything??? ??? ???

basically can you give me an idiots guide to doing it ;)
 
you can skim bonding when its hard enough to touch without leaving a mark i was taught that bonding doesnt need scratched up with a devils float just rule it an leave it but other backgrounds such as hard wall and s&c do
 
float bonding.
have lunch, when you see the bonding / hardwall start to change colour, get on it with the skim.
if you get little pimples in it (you prolly will, everyone does) dont panic, just wait till its gone hard (brown) and hard trowel off
leave it till the day after before you skim it and itll drink water like fish..and pva...
and what napper just said too..
 
I found it very useful to rig up a board to 'play' with in the beginning.

If you want to see how / why / when you do something (like PVAing very dry hardwall) slap some hardwall on the board, leave it 3-4 days and try and skim it. It should take you about a foot to answer the question :)
 
platinum have you tried ringing a few plasterers in your area see if they would be intrested in having some cheep labour offer yourself for free for a couple of weeks if you can afford to you will learn a hell of a lot more that way
 
I think bonding needs a devil float or pva before skimming.

Ive been to a few jobs where previous plasterer has bonded ceiling flat and skimmed the next day and a few weeks later the old bubble appears and off the skimming comes. Needs a key

Rich B
 
ah what the hell i was searching the forum via mobile phone yesterday trying to find the answer tho this as i was quite literally a stodd around waiting for bionding to go off (over artex) i jumped int hevan and mad an excuse to shoot off and grab something id forgot at home, but infact it was my trsuty fan heater! by the time i got back to the house it was firm and not too moist yet at the nice damp feel finger tip touch as to not stick to your fingers or make and kind of indentation yet still be viable for a lovely spread of BG's finest Gypsum powdery goodness, next thing i know ive created a masterpiece, i searched round for Paul Daniels for a little while and i must have spent 3 hours searching for Debbie McGee but alas, they were nowhere to be seen! i must have worked my own magic ;) :D
 
All backing plaster should be devil floated, flattens the abcking plaster and gives a key for the skimming.
 
i find that finish plaster will stick to bonding no problems atall regardless.... but of its been floated up nice and smooth with a scratches all over it from the devil float it just makes it bleb like hell., personally i get it on, smooth it off and leave it, had fewer props with bubblin/blebs this way, saves alot of time also and surely the slighy gaps/grooves in the bonding would help with adhesion?
 
Thanks to everyone for there comments but i'm still non the wiser as you all have different opinions ???

Can anyone tell me if this would work...... not gonna pva brick... just wet it with a brush to ensure no dust.... then mix up some thistle bonding coat and bang in on.... flat'en it then have a brew... wait till it starts to brown and is not markable with the finger test... then mix some multi finsh and without pva or anything just bang it on.... let that hazel expect bubbles then second coat it nice.... if it bubbles just let it brown off then hard trowel........ well pro's hows that sound..... please please please say fine!!! ;D
 
Hardwall is far better on brick backgrounds, alright bonding is more "versatile" for use on various backgrounds, but on old brick I give it thumbs down.
 
sounds fine to me maestro, tho personally id add some PVA to the water that your gonna spread over the brickwork, not alot mind... depends what your using, personal preferances and depends what PVA your usin, tho i guess some is better than none but certainly dont over do it and completely seal the brickwork with a tiny wattery coat like pee of PVA, just control the suction as its intended 8)
 
ok guys got it.... gonna just bang it straight on as soon as the bonding can be touched but not leave finger marks..... one more thing though.... should i use scrim tape where the bonding coat meets the existing wall or doestnt it matter???.....
 
yes - plaster shrinks as it dries (well it would do wouldnt it, the waters coming out of it, just look at dried mushrooms) and that includes backing plasters..
 
Just to bump this.

Been speaking to plasterers both of whom seems very experienced - one lives on my road and has been doing it 15 odd years - the other teaches it in a colleague.

Neighbour suggests when using bonding coat you need to wait a few days before skimming - I think he suggested 7 days - to be sure that it does not crack.

Teacher guy says do it same day no problem.

In my particular case waiting 7 days is no big dea - BUT - there is a big difference of opinion there so interested to know what you think.

As it goes, my neighbour prefers dot/dab as it is quicker and the customer usually doesn't want to wait whereas the teacher thinks bonding is better than dot/dab.
 
Bonding can be skimmed the same day but I find it tends to bleb a bit so I try to leave it till the next day but then it needs a bit of a drink to control the suction. I would never leave it for 7 days before skimming, suction will be sky high and you'll need loads of water or pva
 
interesting.

i spose it can't be that much of a problem if he (neighbour) has been doing it for so long...he certainly seems a perectionist.

perhaps he is a bit old school...is that how they used to do it in the past maybe before more modern materials?
 
leaving it for a week is not old school,, i have never known anyone leave it for a week through choice
 
mo7 said:
interesting.

i spose it can't be that much of a problem if he (neighbour) has been doing it for so long...he certainly seems a perectionist.

perhaps he is a bit old school...is that how they used to do it in the past maybe before more modern materials?
Click to expand...
I'm old school, not through choice mind, but never leave it for a week unless your forced to
 
Bonding is for plasterboards and concrete surfaces because they are low suction backgrounds - although the concrete may need a drink of water before applying the bonding coat. Splash it and see. If applying a bonding coat it should be skimmed the same day so ideally should be on the wall by mid-morning to give it time to take up.ALWAYS devil float it :RpS_thumbup:
A competent plasterer will be able to skim a bonded wall the day after, perhaps splashing a small amount of water on it after scraping it down. I know a lot of plasterers use PVA between backing and skimming coats but it's still a WTF thing in my book. BG sell many things but not PVA, ask yourself why?
*Tip* Adding a few good scoops of finish to a bucket of bonding helps it take up quicker. DO NOT ADD CEMENT UNLESS YOU WANT IT GOING OFF IN THE TUB! :RpS_thumbup:
 
OK, seems I have been a bit stupid.

I was talking about BONDING but my neighbour was actually talking about SAND AND CEMENT. I now know they atcually mean 2 different thigns although people seem to generally talk about 'plasterboard' and 'wet plaster' though there appear to be a number of variants of wet player - bonding, hardwall, sand cement - is this right?

So I can see other discussions on here about sand and cement and leaving it 5 days.

Is sand and cement considered better than bonding?
 
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