Mixing lime mortar

[MDE]

I have an area of about 70sq m to repoint and render and my back is suffering using a hand-held paddle mixer - if you don't heave it up and down it just sits in the middle of the bucket and does nothing. So I think I need to hire or buy a better mixer. The Baron E90 is very good but rather expensive to buy and a bit bulky to store (I guess I could sell it afterwards, but I will have other jobs to do). I could hire one, but since I won't be doing the work all in one go, that could get very expensive. I found this - http://www.refina.co.uk/acatalog/Automix-65-Tub-Latex-Mixer-702900.html#SID=19 - on the net, which is smaller and cheaper; has anybody used one or have any other thoughts to offer?
Many thanks for ideas and experiences.

 

[mal92]

That's quite an expensive mixer! I bought an Electric Cement Mixer, 63L Litre, 240V Volt 220W Portable one from an auction site. Free next day delivery and it's worked a treat. Had it over two years and works perfectly. Easy to move about, clean and store.

 

[MDE]

Do you find that an ordinary cement mixer works the lime mortar well enough to make it sticky?

 

[MatthewC]

I bought a new "ordinary" drum electric cement mixer from my local hire shop in 2010 and it worked fine with lime mortar and plaster - lots of small-ish jobs with lime mortar and a huge amount of lime plastering. Got rid of it last year for £50. You just have to make sure at first that it doesn't cling to the paddles if you are mixing from scratch.

 

[Flyfisher]

I've bought a standard Belle mixer when I started our project about 8 years ago and it has been fine for all my lime mortar mixing - and it's still going strong. During that time I've also employed 'specialist' heritage builders on occasions and they've used standard mixers (sometimes mine!) or sometimes one of those heavy-duty two-handed drill-type paddle mixers. I've never seen one of those large 'lime mixers' being used.

 

[Andys]

My mixer is a board on the workbench and a gauging trowel.

It's ok for batches up to 10 kilos at a time which about suits my work-rate!

 

[MDE]

Thanks for all the comments. I decided to buy ready-mixed mortar for this job, then it works up fairly easily with my hand-held paddle mixer. Next time if I make my own, the small cement mixer looks like a good idea.

 

[Flyfisher]

My mixer is a board on the workbench and a gauging trowel.

. . . which is probably not too far removed from the way mortar was mixed when our period houses were built in the first place

 

[mr-squirrel]

A plasterers bath or wheelbarrow combined with a mixing hoe is great for smaller jobs, i find that lets you mix a good size batch with little effort. This is the traditional way (forces the materials together) and it is surprisingly efficient. A lot easier to clean up than a mechanical mixer, when making lots of small batches you have to consider the time wasted in setup/cleanup each time.

Mixing hoe:
https://www.speedcrete.co.uk/masons-mortar-hoes.html

Plasterer's Bath:
http://www.toolstation.com/shop/Han...16/Plasterers+Polyethylene+Mixing+Bath/p64497

In some ways it's less fatiguing than a hand held mixer with tub, i find that really hard work with lime because of the sharp sand and how heavy/fatty the mortar is by nature. I've often had the mixer trying to spin the tub round!

There is no way i would attempt 70sq/m without mechanical help or someone mixing for you.

The Baron mixers are fantastic, on a training course i was told you really must use a forced action mixer with lime and it did make beautiful, consistent mortar very quickly. On some of the high profile jobs he worked on eyebrows would be raised if a mason was seen using a drum mixer. He said drum mixers are really for concrete, (hence the name concrete mixer) and he wouldn't even mix cement/sand mortar in one - but that's a professional stone mason talking.

In America and many European countries even your average builder uses a forced action mixer by default for brick/stone laying mortar.

I was considering a much cheaper Baron clone if decide to tackle my render job myself:
http://www.pwm-sales.co.uk/Details_options.asp?ProductID=176
In my opinion the Baron's are for hard use by professionals running them all day - simply not required as a DIY'er and cost is impossible to justify.

 

[Andys]

The bath/hoe method looks most useful for my kind of jobs, a nice relaxing scraping and squishing action. On seeing my benchtop micro-batch method our carpenter said 'you want a Larry Box for that'. I nodded wisely and wandered off thinking about lambs before working out this is what he meant.
A nice dryish consistency of lime putty mix would all stick to the inside of the drum of a standard cement mixer wouldn't it? And there's nothing to squash it about, unless someone put a rock in there with it(?)
Having used a paddle mixer a few times for things like (the optimistically named) self-levelling compound, I wouldn't want to use one to mix mortar for fear of doing myself a mischief or scaring the neighbours - either the mix leaps out of the bucket, or the bucket makes a run for it or the mixer takes control of its scrawny operator like Wile-E-Coyote on a pneumatic drill.

 

[MDE]

Thanks mr-squirrel (red or grey?). I hadn't thought of that. Looks like a back-saver. Do you use a short-handled hoe with the bath on a table, or a long handled one with the bath on the ground (and if so, how do you stop it from moving around?).

 

[livias]

Wow thats the first time I have ever heard a plasterers hoe called a larry ... which is the right name for it, but I have never met anyone who has ever heard the term, even traditional tool dealers, who you would expect to know

 

[Andys]

Maybe that's when you know you've hired the right conservation tradesman - when you're paying the hourly rate for the work and the anecdotes and feel you're getting your money's worth of both.

 

[chuckey]

I have mixed about one ton (or should that be tonne?) of St Astier NHL5 with 2 1/2 parts sharp sand in a drum mixer. Not saying this is right , just what happened. Put in sand, then lime, turn over until even colour. Put in water slowly, mix starts to "ball", slowly add more water until it just starts to slurp and amalgamate. Leave turning over for 1/2 hour (per St Astiers instructions). Now mix seems too wet. Put in bucket, within 5 minutes the mix has started to "set", excess water seems to disappeared? However its still a bit on the wet side when used for pointing. So the first 15 minutes or so, just fill joints then go back and tool them off.
In general the mix is too fast after 2 hours its useless. The results are just about acceptable.
To the OP, why not counterbalance your mixer? - hang it on Bungees?
Frank

 

[MDE]

To the OP, why not counterbalance your mixer? - hang it on Bungees?

Hadn't thought of that. All sorts of Heath Robinson ideas now come to mind. Followed by visions of the Sorcerer's Apprentice, but with buckets of mortar!