making lime mortar in a cement mixer

[piapiapiano]

We've raked out the walls in one-and-a-half rooms now, and next week are going to start the re-pointing. I've read a couple of posts here about how cement mixers are not ideal for making lime mortar -- unless you tilt them at the correct angle.

What's the correct angle? 0 degrees, so that it's horizontal? 90 degrees, so that it's vertical? Or a specific angle inbetween?

Thanks in advance!

 

[robgil]

ive never heard of this before unless you are adding hair.

 

[chuckey]

Yes I found this out, as the lime starts to congeal(?), I noticed that each individual lump when it rolled over from the top to the bottom of the mixer, did not break up or otherwise disrupt the centre of the two lumps. Changing the angle helped (bits of wood under the wheels. In the end I added four large smooth pebbles which was the real improvement.
Frank

 

[MdB]

I mix three loads in a mixer and then decant into buckets (with lids). It will then keep until I need it. When I do need it, I remix half a bucket using an SDS drill and a paddle mixer. I do this even if I need it straight from the cement mixer as it improves the mix no end. I also remix if the bucket has been left to stand for a day just to get it back into top stickiness form.

It is worth noting that when mixing, it is very easy to add to much water and end up with lime soup. This isn't a problem, either add more ingredients or leave to stand for a couple of days and then pour off the excess water. Also note that you need to mix for far longer than you would with cement. Big thanks to whoever it was that told me these tips on this forum years ago...

 

[skier-hughes]

Our lime plaserers/repointers used a cement mixer, I've used a cement mixer.
Leaving it much longer runnign does help.
Mixing leaving for half an hour to an hour and then giving it another good mix was what they did.
I didn't see any special angle, it looked at around 45' to me, same as when mixing cement.

 

[Andrew Bodenham]

I've experienced no problems mixing lime mortar in a normal mixer, either using lime putty or just using hydrate straight from the bag. A long mixing time does help. For smaller batches I use a paddle on an SDS drill and a bucket.

 

[piapiapiano]

Thanks, everyone. That was really helpful!