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-   -   Ready Mix Mortar Consistency / Performance Issues (http://www.diychatroom.com/f105/ready-mix-mortar-consistency-performance-issues-164335/)

Rapscallion 11-21-2012 09:58 PM

Ready Mix Mortar Consistency / Performance Issues
 
I'm at my wits' end :( regarding mortar Quikrete Type N mortar; no matter what I do, including letting it 'slack', adding more water, talking to it, gently rocking it in the wheel barrow, etc. it seems to amount to nothing more than very granular, grey, wet sand.

It starts out looking like a cement / sand mix, but on adding water the cement seems to almost disappear. In the end, its workability is non-existent. And forget about the creamy texture that I keep reading about - nothing creamy about it.

Over the last 5 years building small garden retaining walls I must have purchased several thousand pounds worth of 66 lb bags from different locations. It doesn't seem to be a bad batch issue, unless bad batches are typically shipped to Ontario ... lol!

What I hope members of this forum can contribute is
a) similar experiences with this brand of Type N mortar, so I don't start wondering about my water quality or sanity and
b) ideas about supplements for this mortar mix so that it actually becomes 'creamy' & workable OR
c) ideas on the exact sand & cement (3:1?) I should buy to make my own.

Building with reclaimed brick is challenging enough without having to also contend with questionable mortar.

Many thanks for any experiences or suggestions anyone can share or suggest.

Regards,
Jill-of many trades .. master of none ;)

dakzaag 11-21-2012 10:33 PM

I have probably personally used over 10,000 bags of Quickrete type N and have never had a single problem. You are just gonna have to face the facts and realize that this is not your garden variety DIY skill. If you want to confirm the consistency and creamy feel of real mortar, just buy a bag of Type N masonry cement and mix with mason sand 3 parts sand to 1 part masonry cement and add water to the necessary texture and compare. There is some difference, but not enough to really make any project impossible to complete.
This skill set is something that takes years to hone into productive efficiency. Knowing what portion of the process to adjust for the specifics of the job at hand is something that is counter intuitive and takes years of trial and error or a good mentor to figure out.

Your description sounds to me like your not using enough water. Mix for about five minutes and you should be good to go. Lime can be added and might be needed for reclaimed pavers but you really need lime putty or building lime, not just hydrated lime from a bag.

joed 11-21-2012 11:39 PM

Sounds like you might be adding too much water.

Daniel Holzman 11-22-2012 01:32 AM

If this is old mortar, it can absorb moisture from the air over time, and become useless. I have six bags of Portland cement in the garage that have hardened over the years due to absorption of moisture, of course they are worthless, but they are so heavy I haven't had the desire to take them to the dump.

dakzaag 11-22-2012 07:23 AM

Try another flavor of "Pre-mix"

Spec mix
Sackrete

Maybe that will help.

Kinda funny that two posts suggesting the opposite approach. Just love the internet...

concretemasonry 11-22-2012 11:35 PM

The brand has little to with mix. Because of the freight costs, the prices will be very similar in your area since local aggregates will be used and all the baggers of cement and preproportioned mixes have the same coice of other materials (cement and lime) to buy for packaging. Some cement companies have cement packed by others because it a low volume. The mixes are designed to meet the ASTM C279 requirements for volume proportioning for the various types of mortar. - In other words, there is a minimal difference in what is in the bag.

Mixing and amount of water and tining can be critical, especially with different local aggregates that are usually rounded, but the gradations can vary from harsh (coarse) to smooth (fine, very round), but all are very similar.

Mixing is very underated, except by very good masonry contractors the will pay a high premium for a good mud mixer (some more than a mason gets) that knows what the masons need for the type of masonry units.

Dick

Rapscallion 11-23-2012 11:47 PM

Thanks to all who have responded, especially those who are mix-masters by trade - sharing your wisdom with newbie DIYers is noble. If I could afford you I would, but I know that you wouldn't even bother to submit a quote on my 15' X 18" small perennial garden retaining wall ... so I have to muster it on my own :wink:

Update: I bought a brand new bag of Quikrete Mortar Mix (just add water variety) and mixed a 5-trowel batch in a tub in my kitchen sink with tap water. Hey - Don't laugh too much! Temperatures outside are hovering around 5 deg C. Seemed like the best way to ensure that the mortar was pre-warmed to some extent (P.S. I used cold water though). Haha .. ya, newbie, trying hard.

I made sure not to take less than 5 minutes and not more than 10 minutes to mix it (as recommended on other product websites) and I mixed it quite vigorously using my trowel; flipping, stirring, etc. to get some air-entrainment.

I also didn't attempt to estimate the 'right' amount of water given the 3.7L per 66 lb instructions; I don't have a scale on site. I went by creaminess and vertical hold test.

This batch was fantastic! Spreadable like butter :yes: Bricks basically leveled themselves ... it was actually fun!

I think the original problem was due to not adding enough water, as one commentor suggested; most DIYers are fearful of adding too much water given that this may be the only bag they have on-site.

I also believe that, the first time, I spent over 30 minutes mixing a full 66 lbs worth in a wheel barrow. Perhaps over mixing is a problem too?

Hope this helps others in my situation and thanks to all who chimed in encouraging me to try again :thumbup:

Rapscallion 11-23-2012 11:58 PM

Special thanks to the Chief Outhouse Engineer
 
Special thanks to the Chief Outhouse Engineer: Should you need some perennials to go with your outhouses, I have an abundance of beautiful multi-petal bright yellow Rudbeckia's (Golden Glow 'Hortensia'), more commonly known as the Outhouse Plant. Link deleted Seriously :thumbup:

Tscarborough 11-25-2012 08:57 PM

Concrete and mortar are not the same product, they just use similar ingredients. There is no such thing as a test for mortar that equates to a slump test for concrete, for example, because the most important characteristic of mortar is workability. This can change the actual mix by each batch, so you have to be able to "faire le mortier aime la truelle".

Normally a bagged type N mortar is going to be much harder to get right than a Type S, so buy Type S if possible.

Guywithskills 01-05-2013 12:04 AM

the overmixing messes with it trying to set up. Also avoid "shaking up" or remixing when starting to get stiff for same reason.


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