Mortar Mix Fails each time


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Old 03-30-15, 06:13 PM
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Question Mortar Mix Fails each time

I am having problems mixing mortar correctly. Each time I follow the manufacturer directions and the mortar is the consistency of peanut butter. Even though it looks perfect, it never sets up correctly. The following day it is not hardened and crumbles to dust. Basically I can dig it out spoon the next day.

What am I doing wrong? Am I mixing it too dry? Too wet?
 
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Old 03-30-15, 06:35 PM
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How old is the mortar? Try buying from a different store.
 
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Old 03-31-15, 03:38 AM
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Are you adding the sand or are they the ready mix bags of mortar?
 
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Old 03-31-15, 04:08 AM
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I agree. Is it "mix" or pure mortar (N) without the sand?
 
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Old 03-31-15, 04:15 AM
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Quikcrete premix mortar in 10 lb bag
 
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Old 03-31-15, 04:20 AM
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Just checked again, and the instructions on the bag say to just add water. Nothing about adding sand or anything else. After mixing, do you have to let it sit for a while before troweling?
 
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Old 03-31-15, 04:26 AM
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Do you still have frost, or periodic freezing conditions in Missouri ?

I'm just a Real Estate Broker; but I've seen a lot of crumbly concrete due to people trying to get it to set up when it's too cold.

I think it likes to be kept above 50F until fully cured.

I have one house where an addition was built on sonna tubes and in the beginning everything looked great, but now all that's left is the steel rebar . . . . the concrete has all fallen away.
 
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Old 03-31-15, 05:09 AM
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If the temperatures have been cool it can take a long time for mortar to harden. I've had mortar still too soft to brush down after 12 hours when it's cold. The same mix on a warm day is ready in a couple hours. Barring that I would say try a different batch of mortar.

Also, don't expect mortar to be rock hard the next day. It takes about a month for it to come up to it's full design strength. So, even properly cured mortar might be tender 24 hours later.
 
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Old 03-31-15, 06:43 AM
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All the rock/brick laying I have observed, the artisans added about two shovels of Portland cement to the bag of mortar mix.
When I asked why, I was told that it stuck better and hardened more because of the Portland.

FWIW

RR
 
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Old 03-31-15, 05:08 PM
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We do that when setting rock, and it does make it "stickier". Of course most purists will mix their own. I believe my guys use 5 sand to 1 N type mortar.
 
 

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