Render serring very quick

[cooptaza]

A friend of mine phoned me yesterday for advice, said he was mixing sand and cement for internal render. 4:1 I think.
He said after about 30 min the mortar was going off.

He said he could feel it tightening of after 10 minutes and after 30 minutes it was getting very hard ot apply it to the wall it was that tight.

Only thing i could think of was he was using frostproofer in the mix instead of mortar mix, but he said it was def mortar mix.

Anyone heard of this before

 

[johniosaif]

Probably using rapid additive, that's the only thing that causes this..

 

[CTPlastering]

Any lime in it ??

 

[leebo02]

if hes mixing it as he says then i have never heard of this happening in over 30 years of plastering

 

[essexandy]

A friend of mine phoned me yesterday for advice, said he was mixing sand and cement for internal render. 4:1 I think.
He said after about 30 min the mortar was going off.

He said he could feel it tightening of after 10 minutes and after 30 minutes it was getting very hard ot apply it to the wall it was that tight.

Only thing i could think of was he was using frostproofer in the mix instead of mortar mix, but he said it was def mortar mix.

Anyone heard of this before

At 4:1 I would expect it to tightening up a bit after thirty minutes this time of year. Not as in actually setting right off but definitely enough to be not so nice to put on and needing a quick remix. Even a 6:1 mix left standing for half an hour will usually need a quick remix.
My questions would be how much is he mixing at a time that he can't use it within fifteen minutes and what is he working over that warrants a 4:1 mix internally?

 

[craigw]

He probably using rapid set cement
only thing that can make compo go off that quick

 

[carlos]

He must be using quick set cement.

 

[kebab king]

Can he tell the time,perhaps get him a Mickey Mouse watch.

 

[CTPlastering]

Rapid set cement hes probably jus seen a bag with cement written on and got them

 

[lilharbs]

Spec'd 3:1 for damproofing before Andy.

 

[essexandy]

Spec'd 3:1 for damproofing before Andy.

Yeah that would make sense.

 

[carlos]

I use tonnes of gear mixed at 3:1 for DPC work. I don't find it stiffing up that quick maybe it's the sand???

 

[CTPlastering]

I no ive never had the problem my self never really been a consern of ours fair enough dont jus fuk about thou lol

 

[timeservedspread]

Did he prep the masonry? pva or sbr to reduce suction?
Did he incorporate hydrated lime into his mix?
I doubt it..........zzzzzzzzzzzzzzz

 

[cooptaza]

He said is was setting alot quicker than normal in the wheelbarrow. I give him some mortar mix I had. He said it done the job. he said the stuff he had was well out of date. Never heard of that happening before, he said he was sure it was not frostproofer but sorted now cheers all