Procedure for mixing Lime Mortar


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Old 08-19-05, 06:01 AM
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Procedure for mixing Lime Mortar

What is the best procedure for mixing a cement/lime/sand mortar?

Should I add the Lime to Water first and make the putty or can I add the lime to the sand, then add the cement and water to make the mix as I would just using sand and cement?

The purpose of the mix is to do some patches of repointing on an internal exposed brick wall so I'm going to make a number of 'swatches' up first to get the right match.

Any advise is appreciated as I've read a few conflicting article on methods.

Cheers
 
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Old 08-19-05, 05:45 PM
The Tuckpointer
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Ritchie, I dont know the definition of swatches, but if you mean you are doing this to try to match an existing color, you need to use mortar color. Adding you mortar mixture in different combinations will not change the color very much. The best way to mix mortar is with a mortar mixer, I throw all the material in mixer, let dry mix for a minute, then add water to till the mortar is like mashed potates, then it is ready to point, if it wetter, you can make a mess. On small jobs a hoe and wheelbarrow will also do the job, It is what I use on small chimney jobs.
 
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Old 08-19-05, 06:20 PM
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Thanks, so no need to make a putty with the lime then. Makes it easier. I only have about 50 sq.ft to point but bought a mixer for my drill as I'm lazy.

Your take on swatches was correct. So I need some mortar coloring then? Will check with my local builders merchant to see what he has otherwise I'll order some on line.

I also saved 30lb of dust I ground out to try and 'dirty' it up a little, is this a good idea?

Is there any treatment you would suggest afterwards, being as it's an internal wall?
 
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Old 08-19-05, 08:29 PM
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Ritchie, what is the color of existing mortar, gray? white? If you are trying to achieve light gray, or off white, no mortar color is needed, Just go to Menards or Lowes and get Sakrete, quikrete or pakmix mortar mixes, these are all good mixes that will work, I have used them all. Make sure you make your mud about the consistency of playdoy, I say this because if your indoors you may not be able to wash it with a acid to remove mortar smears. Dry mortar will hardly smear if applied the rite way. If your mortar joint is about 3/8 inch wide, use a 1/4 inch wide marshalltown flat tool to install, then use a concave brick striker to smooth mortar. Strike vertical joints first, then horizontal second, rake off excess mortar hanging off of mortar joint, then repeat until it looks finished, when mortar has partially dried, usually about 30 minutes, lightly brush off work with horsehair brush to seal joint. If you are able to wash down brickwork with acid, this can be dangerous, make sure you have plenty ventilation, with only 50 square feet you wont need more than a gallon of muriatic acid. Prewet wall with straight water, mix about a 1/2 gallon of acid to 5 gallons water, this will be more than strong enough, use rubber gloves and eye protection, breathing apparatus, after prewetting wall with water, use stiff synthetic brush to wash wall, then wash with straight water. Let it dry to see if you need to repeat. If you need mortar color, any local brickyard should carry any color you need.
 
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Old 08-20-05, 07:55 PM
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hi, I picked up some DCS Sandy Buff (#51) which seems to be somewhere near the sandy/white/yellow color of the older existing mortar. I have a little more prep work to do on the wall and I'm ready to go.

The bag of the colorant says 10%, is that 10% of cement volume or 10% of total volume? I was going to make a sample at 10% of cement volume and see how it dries before making the final mix. I went to the DCS website and it wasn't that good, also the desk jockey on saturday duty at the brick yard wasn't much help.

Part of the nightmare of prepping the wall has been removing the 'bodge it and leg it' stuff that had gone before, including some work with some acid based products (restoration cleaner) and some other paint strippers, etc. It's taking shape though and I think it's going to look good when it's done. I'm going to try and avoid having to use an acid 'post pointing' as it was quite a task to get everything sealed off and a vacuum hooked up and everything without jeopardizing the floors so I'm going to go for a 'stiffer' mix, mixing it up in manageable batches, using a small painters bucket as my measuring device to ensure batch to batch consistency.
 
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Old 08-20-05, 08:09 PM
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Procedure for mixing Lime Mortar

I would assume the pigment in the DCS is an iron oxide. Most concrete pigment is.

The 10% is related to the amount of cement in most concrete. With pure iron oxide, the maximum amount is 10%. I assume yours is relativelt pure with a minimum of other compounds, so the 10% rule should hold.

Dick
 
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Old 08-25-05, 08:53 AM
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OK, I'm around the last bend and on the home straight. With the best will in the world and a stiff mix I still got a few smears on some of the bricks.

I'm not going to need to give everything an acid bath but definitely some.

Would this be a good procedure?

1) Mix 1:10, Acid:Water
2) Wet wall in spots to be treated
3) Use brick brush to apply acid solution
4) Rub in
5) Wash off with wet sponge and towel

I don't want to spray the acid off as I'm worried about it running onto the hardwood floor.

I used some Light Duty Restoration Cleaner during my restoration of this wall and I couldn't keep all the water away from the floors, not even sealing everything with 6 mil plastic and duct tape and using a wet vac to suck the water as it fell was enough to totally keep the fluid off the floor, I'm worried the acid might be more damaging so I'd like to control the splashes and seepage.

I washed down last night with a hard surface cleaner which while clearing some of the light residue, left some of the heavier smears behind.

I picked up a gallon of acid at the brick yard on my way to work and plan to give it a clean tonight.

Also, after Iím finished, is it recommended I seal the wall with something? Itís internal so I donít need to worry about damaging the hydrostatic performance but should I seal it with something and of so what?

I had to strip off what would appear to be some kind of varnish, probably a polyurethane and thatís still on the top half of the wall, as that was in decent condition. If I wanted to give the whole wall a coating of poly for cosmetic purposes is there a sealer I should put on the Ďbareí repointed areas first and should I wait a period of time before doing this or should I avoid finishing it in any way at all?

Cheers, youíve been a great help.
 
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Old 08-25-05, 12:46 PM
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No need to seal an interior wall.
 
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Old 08-25-05, 12:48 PM
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If you are going to wash any part of wall, do it all or none of it, because the spots you wash will not match the rest of wall.
 
 

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