# Mortar or grout?



## Vassago (Feb 27, 2008)

I'm getting ready to do my tank background and already ordered a variety of colored grouts and acrylic fortifier but now I'm beginning to wonder what the difference is between mortar and grout? To me it seems like mortar is thicker, holds it all together stronger, and is easier to sculpt while grout is much thinner and runny. So, if I want to add more depth and shape to the background rather than just covering it in a few thin coats is mortar the way to go or will grout do the same job? Thanks for your help.


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## Vassago (Feb 27, 2008)

Anyone know which would be better? Would it be alright if I used mortar for structural and then a few thin layers of various colors of grout grout over top so that I can sand it and blend the colors in?


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## defaced (May 23, 2005)

Enjoy:
http://www.dendroboard.com/parts-construction/topic22606.html


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## Vassago (Feb 27, 2008)

Hahha, that thread is what prompted me to make this thread in the first place. He used grout with his backgrounds and it looks amazing but I also saw someone making a 60 gallon (I think) tank background with mortar rather than grout. It seemed like the mortar was easier to build up and structure while the grout simply coated the shape beneath. I'm now wondering out of those two which would hold up better being submerged in water?


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## defaced (May 23, 2005)

The only way you'll find out is to try. I don't think anyone on this forum has done it yet.


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## haapapuro (Jan 17, 2008)

quick tip, though not directly in line with your question. Instead of buying all the various colored grouts, which are quite expensive, i just buy the big bag of white grout. Then go over to the concrete section of home dept/lowes, and get three colors of the powdered concrete pigment. They come in brown, red, and black. you can mix and match these to get just about any color you want, and at a lot less expense. for a colored grout, i priced it at apprx $10 a color. regular white grout is about $5 for a big bag of it. the concrete colors are $5 each. so, if you plan to do a mix of a variety of colors, it is much cheaper to make your own. when i work painting on the grouts, i have 5 colors of grout mixed up in cups, then daub them on in patches, giving it an irregular and natural look.

also, the grout can be very runny if you mix in a lot of the fortifyer. it can be as thin or thick as you want, depending on how much liquid you add to the mix. it sets fairly quickly also, so if you mix up a batch and its too runny, wait ten minuites, and it will be a lot stiffer and easier to build up.


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## haapapuro (Jan 17, 2008)

here is an interesting link that i think explains fairly well the differences between grout and mortar. 

http://www.maconline.org/tech/materials/grout.html

also note, you will want to use a sanded grout, as opposed to the non sanded grout. sanded grout is intended for joints larger than 1/8". sanded grout will have less problems with shrinkage, which can be signifigant with a non sanded grout. i learned this one the hard way.


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## Vassago (Feb 27, 2008)

I guess that I should have ordered the pigment instead of various colors of grouts but they're already ordered so I can't do much about that. I did order the sanded grout, however. The link was quite helpful and since no one has really experimented with grout vs mortar to see which holds better underwater I guess I'll simply go with the grout that I already bought and then let everyone know how it works. Thanks for your help.


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## Sundra (Mar 11, 2008)

Hi there,

I am brand new to this board, and use great stuff in my terrariums so cannot comment on grout/ mortar in terrariums, however I have used grout without mortar in mosaics and this experience might be helpful to you. I would recommend using mortar as a structural base and then mortar for color on top. I made a coffee table with only grout and in a short time the grout had cracked and was chipping off. I have some pieces with mortar and grout that I keep outside in the rain and snow and they have not been damaged by the moisture at all. 

Good Luck,
Sundra


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## Vassago (Feb 27, 2008)

Thanks for the advice. I've since decided to do 100% of the sculpting with the actual styrofoam background before applying the grout rather than also using mortar to help sculpt the shape of it. That way I can look over the background for a long time and determine if I should add/remove any other pieces and whatnot and THEN cover it in grout. I was a bit worried that the mortar would set quickly and would be difficult to remove if I didn't like how I sculpted it once i was all done.


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## bLue_reverie (Mar 2, 2008)

be careful with pigment though as too much may actually weaken the mix when cured. i would recommend you use a pigmented mix on top of a plain base. in general, mortar should be rather thick. if you make it thin, again it should make for a weak cure and break down over time. and again, only use potable water for any kind of mix. potable as in water you would drink.

can't help but to hear my construction teacher's voice ringing in my ears.


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## Vassago (Feb 27, 2008)

I already have the pre-colored grout mixes, so I don't have to worry about adding pigments. HX told me that he's used grout-only in aquariums where it was constantly underwater and it hasn't broken down, so I'm not even going to bother with the mortar now.


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## Toad and Bun (Feb 11, 2008)

You could also use paint and forget the dye altogether... Much more forgiving (i.e. you can paint over "mistakes").

Do you plan to do mortar/grout on styrofoam??? The other post uses ethafoam which IME is difficult to locate. They made it sound as if the mortar wouldn't bind to styrofoam well, but I have my doubts...I'll be anxiously watching your results.

Matt


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## Vassago (Feb 27, 2008)

I was thinking about going with painting but, even though I'm quite artistic, I've never done very well with paints. I'm more of a sculpting or ink drawing sort of person. But, I could always touch up some parts with paint afterwards that I'm not happy with. 

Yes, I'm using grout on extruded styrofoam. It's the kind that cuts nicely and isn't made of a whole bunch of tiny styrofoam balls stuck together.


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## somecanadianguy (Jan 9, 2007)

im a brickmason marble and granite mason , you need to be aware that masonry products leach out efflorescents , these are a white chacky looking haze that comes from mineral deposits. using an acrlic additive {enriched thin set or a wellbond type of additive} can possible cause sever chemicals to be leach out slowly for a great deal of time. to avoid this use ro water or a cleaned water source contianing as little minerals as possible. if mixing a mortar dont buy a premixed one even if easier , buy a bag of portland type 10 { not masonry cement contians lime in a fair amount} and buy sertilized play sand {you wont be using a great deal of it so its not that expensive}and use a 15 to 1 raito of sand to cement { basically a rich dry pack}.in a dry and mouldable mix it would be very easy to create wild effects.for those that dont know masonry and concrete keep harding forever but the rate drops very much after 28 days. i personally would dry for a month , then saturate compleatly for a few weeks rinse out before adding plant or frogs.
craig 
i wont even get started on the chemical in tile grouts , read the labels or even scarier read the msds sheets {meterial saftey data sheets } or usa version of such.


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## Vassago (Feb 27, 2008)

I was going to spray it daily for about two weeks so it could fully cure and then rinse it many, many times in the bathtub for the next while. After that I'd leave it in the tank with water that will be occasionally replaced and keep testing the water until the pH is stable and nothing is detected. Basically, once the background has been grouted it will be over a month before I actually put my reptile in the tank with it.

I also have a sump beneath the tank so the total volume of water moving through the system will be about 60 gallons. I think that that will help to lower the concentration of anything that may still be leaching out. I also have a large canister filter that brings the water from the sump back to the main tank and cleans it wil it does so, so that will help. I'll also be doing small water changes once a week.


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## zachxbass (Apr 21, 2008)

I am in the process of doing the same thing w/ a 55 gallon. I decided to do this because although it takes longer to cure, i thought this would be easier than using a million tubes of silicone and coco fiber. The hardware store i went to sucked and didn't have any diff. colors than white and didn't have color to add so i am using food coloring to color the white grout. It seems to be working although the color seems to be coming out, in that i mean some parts are kinda red while some parts are kinda blue. We'll see how it turns out.


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## Toad and Bun (Feb 11, 2008)

painting it with acrylic craft paint, esp. diluted with water will work well and look very natural. It will take more coats, but it will look good.


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## zachxbass (Apr 21, 2008)

acrylic craft paint...that would be much better than my current method of using food coloring. no matter how much i mix it there is always somewhat of a rainbow effect.


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## zachxbass (Apr 21, 2008)

I got some acrylic paint, painted the mortar... one coat and it look very good... i jsut covered it with a very dark brown. then did some light grey/tan highlights. Looks very natural.


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## Vispilio (May 8, 2008)

After reading through this post I don't think the main question the original poster was ever answered.

"What is the difference between Mortar and Grout?"

The answer is they are both just about the same thing. Though some Grout contains Dolomite. Dolomite is the name of a sedimentary carbonate rock and a mineral, both composed of calcium magnesium carbonate.

That's it. Both Mortar and Grout are made of Crystalline Silica and Portland Cement. They both will leach minerals in the water if not completely cured.


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