Mortar will not set

EntropyUK · 7 Mar 2009

Why does mortar not go off. I am at my wits end with this. I have tried to mortar up the brickwork around a window 4 times now and every time the mortar will no set.

I have tried fresh cement, made sure all equipment inc water was clean and I even resorted to using a bag premixed mortar. Every time it dries out but just doesn't set. The mortar is firm but I can rake it out with a small chisel.

This time I used a bag of premix, I mixed the dry mortar to ensure the mix was correct and used clean tools. The only common factor is that I am mixing it in an old washing up bowl (its only 4 trowels worth) but it is clean and I cannot see how plastic would inhibit the set.

Any ideas most appreciated.

noseall · 7 Mar 2009

Surely you don't expect it to reach full strength within 24hrs?

Mortar will still be considered 'green' within the first 48 hrs. It will continue to harden for the next two weeks.

Always thoroughly wet the area to be pointed first, then allow the excess to dry a little.

If you thing it may go off too quickly, i.e. direct sunlight, porous bricks etc, then it does not hurt to spray a mist of water over the pointing once in a while.

EntropyUK · 7 Mar 2009

It been 24hrs since it was applied and I can easily push an awl over an 1 1/2" into it with very little pressure. I wasn't expecting it to be fully set but I was expecting a little more resisitance than that.

The small lumps of discarded mortar than fell down when I applied it can easily be crumbled between my fingers, it just doesn't feel right from the other bits of mortaring I have done.

Is there a mortaring 101 anywhere?

^woody^ · 7 Mar 2009

You will easily be able to push a fine point from your awl into fresh mortar, and scrape it with a chisel or your nail for several days.

But you wont be able to push you thumb into it.

After all Its lots of grains of sand, not superglue

Give it a bit of time

karlosmaximos · 8 Mar 2009

are your bricks bone dry when using them?if they are they could be absorbing the moisture from the cement too quickly,thus they dont "bond" together,try dipping the bricks in a bucket of water for a few seconds each before you use them

EntropyUK · 15 Mar 2009

I have left the mortar sinc emy last post and I can still rake it out with a blunt edge. I thoroughly soaked the area before applying the mortar so cannot see what I am doing wrong.

hotrod · 15 Mar 2009

entropie said:
I have left the mortar sinc emy last post and I can still rake it out with a blunt edge.

Hmmmmm.....that's not right. You didn't use silver sand did you?

kevindgas · 15 Mar 2009

hotrod said:
entropie said:

I have left the mortar sinc emy last post and I can still rake it out with a blunt edge.

Click to expand...

Hmmmmm.....that's not right. You didn't use silver sand did you?

certainly isn't Quicksand

just leave it alone! give it a week! and it should be nearly dry. theres lots of reasons for slow setting including moisture in the air, moisture in the bricks etc

^woody^ · 15 Mar 2009

I can rake the joints on my house with a blunt edge, and its been up nearly 40 years

Shytalkz · 16 Mar 2009

^woody^ said:
...and its been up nearly 40 years

Ah, from that period of such wonderful architectural design, the late 60s....

^woody^ · 16 Mar 2009

Yes, a bit before my time but you older guys seemed to have enjoyed designing in those days.

Shytalkz · 16 Mar 2009

Heheh, any rumours abounding that I'm 50 on Thursday are entirely unfounded

^woody^ · 16 Mar 2009

I'll notify the fire brigade

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Mortar will not set

hotrod

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