Hi guys, hope everybody is doing good, just wanted to run this past you to see if anyone else has had any similar problems.
Basically I've started subbing for the local top supplier Channel Islands Ceramics, great number this, get to do lovely jobs and they pay well, plus there is a bit of status attached to working for the best in the island! Not that 'civvies' would understand!! Anyway they insist on supplying the adhesive for the jobs they give you. You buy it from them basically. They only supply Mapei gear which i was wanting to try out anyway as everyone on here seems to rate it. Previously I'd been using Ardex. Anyways the job is 300x300 vitrifies porcelain fixing onto wedi. When I first started I found that it just wasn't grabbing quick enough so had to quickly fix battens up. This kept being a problem so last night when I finished I left all the spacers in. Just got back in here today and was taking a spacer out and the tile came with it!! Let's face it, that's not ideal!! Got my scraper out and the gear just rubbed away, was still soft. Now this is at least 24 hours later. What do you guys think? Is this a big problem like a batch fault or is it just the way Mapei p9 is? Should I worry or should I just get on with it and be more careful with the spacers? As for bedding in the tile I give it some force so it's definitely got good contact and you could see the muck had been squashed down nicely. No gear at all was stuck on the back of the tile, came off clean

It claims to be a C2TE, so you should be fine. Check the date and batch number with Mapei.

any dust on the back of the tile and it might pay to back butter in future . what size notch trowel was used

I use loads and loads of it, no probs.. like above did you not back blade the tiles for full contact and if the temp was low in the room then it can still be soft the next day as it is a 16hr set at 20dgs..

8mm square. Didn't back butter though, didn't see the point as the tiles are clean and the backs are pretty flat

As above always back butter a thin layer of adhesive with these porcelain tiles. I think it makes a big difference but if you say the adhesive was still soft then maybe something else is amiss ?

I've just used P9 for the first time on a job, albeit ceramic on plasterboard, and I found the stuff sticks like the proverbial to a blanket..... Removing tiles to check coverage and adjust was a major task in itself, and even though they were 300x300 on a wall, any tile that was cut even slightly didn't really need spacers the initial grab was so good. Was Impressed!!!

JLM, has any of the scrapped adhesive set now? If it has then the adhesive would be fine, if not, then I'd say you have a moody batch.

8mm trowel on 300x300 and no back skim?

Fixer error IMO , we all learn from mistakes


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Originally Posted by Dave

8mm trowel on 300x300 and no back skim?

Fixer error IMO , we all learn from mistakes


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How would not back skimming stop the addy setting?

Originally Posted by Tabby Cranks

How would not back skimming stop the addy setting?

Read the thread , no adhesive stuck to the tiles, setting is down to p9 being a slow set and that is 16 hrs to grout and take longer to fully harden, for full contact you have to back skim
All pros know that


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Originally Posted by Tabby Cranks

How would not back skimming stop the addy setting?

It doesn't, but it does affect how the addy grips the tile and using standard set with porcelain tiles in cool conditions and on top of backer board can result in much longer setting times.....

So you back skim all your tiles? I'd personally only do it on large format floors (if not using a PTB), or if the ridges were particularly deep on the back of the tile.
I can think of a number of adhesives that I could use on a 300X300 tile to a wall, and not need to back skim.
I've used Mapei Keraflex, Ardex X77, BAL Singlepart Flex. All of them would hang a 300 X 300 with out slipping.

I think it's a bit strong to just say fixer error without considering the other facts. He could have been sold on out of date batch.

Originally Posted by Tabby Cranks

So you back skim all your tiles? I'd personally only do it on large format floors (if not using a PTB), or if the ridges were particularly deep on the back of the tile.
I can think of a number of adhesives that I could use on a 300X300 tile to a wall, and not need to back skim.
I've used Mapei Keraflex, Ardex X77, BAL Singlepart Flex. All of them would hang a 300 X 300 with out slipping.

I think it's a bit strong to just say fixer error without considering the other facts. He could have been sold on out of date batch.

If you had been sold out of date addy, then if you didn't check the date while taking the batch numbers for future reference, then it would still be fixer error......

Originally Posted by Tabby Cranks

So you back skim all your tiles? I'd personally only do it on large format floors (if not using a PTB), or if the ridges were particularly deep on the back of the tile.
I can think of a number of adhesives that I could use on a 300X300 tile to a wall, and not need to back skim.
I've used Mapei Keraflex, Ardex X77, BAL Singlepart Flex. All of them would hang a 300 X 300 with out slipping.

I think it's a bit strong to just say fixer error without considering the other facts. He could have been sold on out of date batch.

Just goes to show , it isn't about slippage it is about coverage for full tensile strength, in the OP owns words he used 8mm trowel on a largish tile with no back skim, tile came away with no coverage on the back, what is there to defend tabby.

And you say you only back skim floors, ok I rest my case on that .

We all have our own fixing methods and personally I will always backskim
To get a better coverage and suction


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Originally Posted by Dave

Just goes to show , it isn't about slippage it is about coverage for full tensile strength, in the OP owns words he used 8mm trowel on a largish tile with no back skim, tile came away with no coverage on the back, what is there to defend tabby.

And you say you only back skim floors, ok I rest my case on that .

We all have our own fixing methods and personally I will always backskim
To get a better coverage and suction


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I said I only back skim floors, or where the tile has a deep ridge on the back. That would include walls as well. The guy hasn't said this tile has a deep ridge. If the tile has deep ridge, then I'd say an 8mm trowel is probably not man enough and he'd need to back skim, or use a deeper notch.

We have two issues with this guy, one the slippage, that could well be down to poor coverage from an inadeqaute notch. He also says it's not setting. If come Monday that still hasn't set, he has a problem with his addy. IMHO.

Shame we don't have any pictures of what he found.

I do love a debate about fixing methods.

Lol, it good to debate and do it nicely

My main concern was just with it being porcs

But I am a big p9 user and I know it can n certain tiles/backgrounds take longer to set, after learning this , I switch to rapidset.

I agree, best to wait another day


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True, he has a waterproof backgroud too, so that would make the setting process longer.

Right the rooms pretty cold so I think it's a case of slow setting. Had to take a different tile off anyway (fixed it the previous morning, just wasn't happy with it) and it was stuck like REMOVEDto fur, broke it taking it off. I think it was just a case of set time and the coverage was very good. Shoulda taken a pic but didn't think about it at the time. Not liking this fixer error abuse!! Only joking, you've all got good points but like i said the ridges aren't deep and the coverage seemed good when I started. I woulda said anything bigger than 8 mm woulda been excessive, it's not like they weigh a huge amount either. They aren't gonna fall off the wall (I hope!) The rest of the muck has gone off fine, thinking about it now I'd say vitrified porcelain (obviously not very absorbent), waterproof material, cold house all adds up to slow set. When I said the tile was totally clean it wasn't like it was shop clean, it had traces on it. Should have taken a photo cos I can't explain it very well!

Oh yeah I reckon it had only been on the wall about twelve hours. If it's a 16 hour set at twenty degrees then it would still have had some time to go. Wasn't like it was wet soft, it was m

We all live and learn

Whoops! It was more like it was scrapable. Came off easily but still had to get i'n there with the scraper. Just panicked a bit cos usually use Ardex x77 and find that stuff REMOVED hot and it's an important job to me

Might be worth a read http://www.mapei.it/Referenze/Multim...ex%20P9_UK.PDF

Temperatures, substrates, good contact etc all make up experience for us all.
We all still learn new things regular and thats what makes this place so sweet.

Originally Posted by JLM Tiling

Oh yeah I reckon it had only been on the wall about twelve hours. If it's a 16 hour set at twenty degrees then it would still have had some time to go. Wasn't like it was wet soft, it was m

There we go.. no need to panic.. ..

Oh! and checking in for replies at 20 to 1 in the morning is an addiction and we can help with that as well.

Ha ha!! Yes it is a bit of a problem!! Well the missus seems to think so anyway!! Cheers for all the help peeps, much appreciated. I'd be lost without this forum I tell you!! Not been in the game long so lacking experience. I'm good with the tools ( in my opinion! ) but yeah still got a very long way to go!!!