Hot lime mixing

[@benchippy8039]

I’m a carpenter but tend to end up getting drawn into covering other trades too and have come to the conclusion that lime mortar is so much better to work with than cement mixes, it makes me wonder why so many brickies are reluctant to use it

[@michaeljamesdesign]

I hear what you're saying Ben.

[@lordtop6847]

Hotlime miami? Carpenter but?

[@amyntas97jones29]

My conclusion too.

[@pc2753]

Really enjoying your videos, thanks for taking the time to show us Mike!

[@amyntas97jones29]

Hi Mike, Didn't the old way of making hot lime mortar involve covering the lime in damp sand and waiting twenty or so minutes before mixing?

[@michaeljamesdesign]

We still do that but not with powder.

[@amyntas97jones29]

@@michaeljamesdesign Glad I asked you. Many thanks.

[@colummulhern8865]

Thank you very much for making the effort to show this. Younger generations , and present ones, will need this valuable information.

[@michaeljamesdesign]

That's a very positive and upbeat comment. Thank you for posting 😃

[@christinebaker3293]

Thanks for the video! I just got my first two tons of quicklime for various projects in Arizona. Project 1 is a 10' x 20' cob shed on a rubble foundation. In the past, I used 10% Portland to fortify the adobe bricks for the bottom rows and a "good amount" of Portland for the earth mortar. It worked great. Now I need lime-based mortar on top of the rubble and I'm wondering whether we should just add about 10% lime powder in a bowl in a wheelbarrow and mix it with my cob? Mix the cob first, then add lime? Or make a different mix, lime, sand and ??? Appreciate any suggestions!

[@michaeljamesdesign]

Speak to Heritage Cob and Lime in Devon.

[@samarshi539]

Great video. Thanks . I also find Q & A very informative as well.

[@mw1460]

Hi,can you please share the way you do hot lime? What kind of CL 90 ? There is CL90-S or CL90-Q do you mix with sand and water? I‘m from Norway and have to order locally.

[@michaeljamesdesign]

the Q is quicklime because that's what you need.

[@mw1460]

@@michaeljamesdesign Thank you very much. Does it make a difference if I use CL 90 or CL-80. CL-80 is easier to get.

[@michaeljamesdesign]

@@mw1460 CL80 has less lime and so is less reactive. It may slake more slowly but it may also cure more quickly - depends on the ground. It's just a slightly different animal. Either is good. 80 has some impurities which is normal

[@mw1460]

Thank you! The only question I have is: What is the advantage of mixing CL-90Q pulver with sand vs CL-90S pulver with sand for plastering walls?

[@michaeljamesdesign]

@@mw1460 No idea.

[@quayd]

I have been trying my hand at hot mixing and came across your videos after I found my plaster was cracking shortly (30 minutes) after applying it but still fairly moist. It was still steaming and not very soft in the bucket, so I am thinking maybe I needed to either mix it more and use more water or let it cool off a bit before applying? You mentioned something about letting it sit as optional? I was under the impression applying it while hot would give it the best bond with the surface but not with this cracking I expect. It cracked very quickly more on thin edge areas but not much longer on some central areas that were no more than 1cm thick. Conversely, to soften some up I added more water until it was easily workable and sightly runny and this cracked a little after an hour or more of sitting but on thicker sections. I have tried to keep thickness around 1.2cm max but yeah maybe it was on slightly thicker sections for the wetter one that cracked. Been about 21 to 24 degrees Celsius inside and i have sprayed the surface to keep it moist a number of times. Brilliant sharing of your experience and knowledge of lime. Thank you.

[@michaeljamesdesign]

You've not mentioned types of sand or ratios etc. I'm guessing you're not a contractor otherwise you'd have got your gear sufficiently workable and trowelled out the cracks. More water will make it more workable but it won't impact much as far as cracks are concerned. Just float them out but make sure you include piles of horse hair or fibres.

[@quayd]

@@michaeljamesdesign thanks for the response. Great, so I am probably overly cautious about too much water after I read some things saying too much and it cracks and becomes weak. I am not a contractor just hobby renovating an old stone house in northern Spain and moving away from all the cement based plastering and pointing done here to protect the stones and to improve the properties of the house regarding high humidity and mold. Although, yes when I saw the cracks I wet it down and troweled it down a bit more which alleviated the cracks. But some reformed again and I was concerned repetitively doing this would weaken and in some cases detach the bond to the surface below. I have tried ratios of quicklime to sand of 1:3, 1:1.5, and 1:1. I am using sharp sand from the local hardware depot which seems to be 0.5 to 4mm graded, but probably consisting mostly of 1 to 2mm. I didn't use hair because I am worried of mold growing from organic material. Again high humidity mild climate all year around and mold is incessant in these parts. Thank you for your thoughts. Much appreciate your response already.

[@michaeljamesdesign]

@@quayd No hair, wrong sand, unsuitable ratios. Enjoy your cracks.

[@mohammedatif9560]

Is lime light renovation plaster ok for rendering internal walls?

[@michaeljamesdesign]

It's fine as long as breathability isn't required.

[@leechaplin7284]

Hi Michael great videos mate, I'm learning loads. For a repointing mix could I use nhl 3.5 with a washed sand and no sharp? Cheers Lee

[@reecemarriott5328]

Two soft sand one sharp sand so three to one, makes a good mix lee mate.

[@michaeljamesdesign]

Be careful because not all NHL 3.5 is the same. Some have a very low free lime content whereas some have high compressive strengths. What this means is that some perform very like NHL5 whereas others are closer to NHL2. So it's better to go for weak 3.5 or a strong NHL2. So read the data sheet before purchase. Personally, I mix strong NHL2 with two and a half parts sand. It doesn't really matter about aggregate size as long as the grains are sharp.

[@leechaplin7284]

@@reecemarriott5328 cheers Reece I'll bare that in mind 👍

[@michaeljamesdesign]

@@reecemarriott5328 1:3. Always specify binder first.

[@reecemarriott5328]

Is it a plasterciser in the water? Is it even beneficial to use a plasterciser with lime? Any information would be much appreciated.

[@michaeljamesdesign]

No plasticiser. The quicklime doubles in volume and the mortar becomes very workable because of the high free lime content. You need Nigel Copsey's book Reece.

[@ricdavid7476]

Mike suggested the Copsey book to me too and that was £15 down the drain its almost unreadable unless you are doing a degree in civil engineering. the blokes who used lime 300 years ago could in all probability not read. Hot lime seems almost cult like and and someone said to me that there is big money in the the lime and hot lime renaissance but very little evidence that that hot products are that much better than cold products. Mr Copsey seems to be one of the leaders of this movement. My book is still on the shelf and is never opened any more and i get most of my info from speaking to Conservation lime suppliers like Rose of Jericho and Mike Wye whom mr James seems to have had a falling out with but my experience of them is that they are only too happy to help. Also the internet is a good place to get info

[@stihl3826]

What mixer is that ?

[@michaeljamesdesign]

Just an ordinary twin paddle mixer. About 1800/2000 volts

[@tyremanguitars]

do you use a special bucket so that it doesn't melt?

[@michaeljamesdesign]

Yes!

[@amyntas97jones29]

These buckets are made from old tyre rubber. You can buy them online.

[@roymichaeldeanable]

I'm sworn to secrecy

[@lukenfoci]

Do you mind a question? Hot lime or hydrated lime for Victorian house repointing? Need to do quickly some repointing on my neglected by previous owner front, so would appreciate honest answer. Will be buying a book you mentioned in the comments but no time to read when weather permits external works :). Thanks.

[@michaeljamesdesign]

I rarely use hydrated lime.

[@lukenfoci]

@@michaeljamesdesign Thanks. I did more research and I need to go with hot lime.

[@michaeljamesdesign]

@@lukenfoci Nice in theory. Do you have brick or stone?

[@lukenfoci]

@@michaeljamesdesign Brick. ~1910 Victorian house with cavity walls. Thanks.

[@amyntas97jones29]

One more question Mike. Is it two parts water to one part lime, so for one bucket of lime one should you two buckets of water? Great videos.

[@michaeljamesdesign]

You can't gauge water as sand has a water content.

[@ashsmith5831]

Hi Michael. Brilliant video once again. So please advise me, i noticed that the quicklime was almost powdery? Was it not calbut which i think is more chunky? Also what was in the bucket before you added the quicklime? Was it just sand? Sharp or soft sorry for questions, also finally sorry did you add a pozzolan to speed up the carbonation process? Thank you kindly. Ash

[@michaeljamesdesign]

That'a powdered quicklime and the stuff in the bucket is just sand.

[@michaeljamesdesign]

I always add a small amount of pozzolan

[@tyfe]

@@michaeljamesdesign - hi michael - when exactly do you add the pozzolan? Pre-slaking dry to the sand, or post-slaking as a wet paste? So so much data, research, historical papers, books etc available on hot mixing, but so little experienced and historically/technically correct practical advice on mixing on site available. best wishes from portugal - great vids and work btw 👍

[@michaeljamesdesign]

@@tyfe Pre or post slaking as is. Depends on how quickly and how hard you want your mortar to set up.

[@tyfe]

@@michaeljamesdesign thanks for the fast response. So pre-slaking (pozzolan mixed with sand before water is added to the lime) will make a less hard set or a harder set? I understand of course that the amount and type of pozzolan is a factor too.

[@olly1803]

Hi Michael how are you getting on with the mixer? What brand is it?

[@michaeljamesdesign]

Love it for quicklime mortar: www.amazon.co.uk/TECHWORK-Plaster-Paddles-stirrers-Plasterers/dp/B07B7LGV3W

[@michaeljamesdesign]

Mummy not teach you to say thank you?

[@reecemarriott5328]

Hi Michael, like I said great videos mate, just another question, what is your experience with the brand Hanson? 3.5 hydraulic lime?

[@michaeljamesdesign]

It's OK but I've yet to find out the eventual compressive strength or the free lime content . if you find out then do let me know. Thanks.

[@reecemarriott5328]

Definitely, that's great thanks.

[@jordancox3291]

Morning, big fan of your work. Do you always recommend using a paddle mixer for mixing lime?

[@michaeljamesdesign]

Paddle or pan mixer.

[@lazycarper7925]

can you do it in a cement mixer

[@michaeljamesdesign]

Not really.

[@reecemarriott5328]

Hello Michael, could you recommend a brand of powdered hot lime? The builders merchant don't stock it in my area, so would be ordering of the internet. After watching your video I'm going to give it a try.

[@michaeljamesdesign]

As long as it's CL90 or ML90 it makes no difference Reece. Calbux is an early slaker and most people are OK with that first time.

[@reecemarriott5328]

That's brilliant thank you much appreciated. I have always used hydraulic 3.5 some brands are almost like nhl 5, it seems like they use other powders as fillers to bulk up the weight. Can hot lime be knocked up the next day?

[@michaeljamesdesign]

@@reecemarriott5328 Yes it can. Just treat it like putty.

[@matte999me]

@@michaeljamesdesign Hi Mike could you please explain the difference between CL90 and ML90? Tried researching it but don't seem to be able to locate any information. Thanks in advance and great videos by the way 🤙

[@michaeljamesdesign]

I'd go with that. All I'd add is that the two are from different types of rock.

[@tomlewendon4563]

Where's this

[@michaeljamesdesign]

Tom!

[@tomlewendon4563]

Hello

[@tomlewendon4563]

Hot stuff

[@tomlewendon4563]

🔥🔥🔥🔥🔥🔥🔥💥☄️

[@DRJMF1]

Thank you, hot lime is catching on, albeit slowly, why ? Can you mix hot lime in pellet form into the aggregate using a Refina roller mortar mill ? Or will the heat generation destroy the expensive roller mixer ? I prefer hot lime in pellet form as breathing the dust ain’t good for you ? How do you know when the hot lime is ready as a internal plaster ? Can it not be thrown on while it is quite hot I’d when at its stickiest ? What are the benefits of adding your secret ingredients to the hot lime mix eg white pozzolan ? Is there any point in copying your method with the secret ingredients, so why produce the video, after all people need to learn themselves how to make a good lime plaster finish ?

[@michaeljamesdesign]

Of course you can. You don't use kibble for plastering. Yes you can harl it. See Nigel Copsey's book on traditional mortars - all 'secret' ingredients are there for you. Once you've tried plastering in lime you'll realise why it's often best left to the pros. Good luck.

[@reecemarriott5328]

Your videos are brilliant. But why have secret ingredients?

[@michaeljamesdesign]

For the same reason Coca Cola recipes are never shared.

[@reconciliation8491]

reece, ancient man made his mortar from fire pit materials.

[@andy199121]

I agree, while his videos are interesting to those looking to learn about stone work, tries to make out that pointing is like some kind of dark art, ridiculous really

[@michaeljamesdesign]

@@andy199121 I'll gladly share my knowledge. But you must cross my palm with silver first. A trade takes years of very hard work to learn. As I'm sure you know. And because of this, one does not give it away for free. I would argue that you're being disparaging because it's ridiculous of you to assume that I'm going to throw trade secrets away. Many years ago, parents would pay a master craftsman good money to train a boy. Now you all want a freebee.

[@corindoyle]

Because mortar mispecification is the main cause of damage to old buildings. It depends on the type of stone, exposure level, aspect, height etc. What works in Cornwall destroys buildings in Dorset.

[@charleejay4777]

I got the opportunity to mix up 3 batches of just lime with a mortar hoe(6 sacks/18 5 gal buckets each). I have a couple videos on it

[@michaeljamesdesign]

Good. Well done you😁