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CONCRETE OR MORTAR

billbla's picture

I have made several concrete wedge shaped plinths for a slate memorial plaque which will sit atop a concrete flagstone in a garden. The finished concrete although smoothly finished shows many pieces of aggregate around the perimeter and does not look good. A slate plinth will cost around £100 from a local quarry. Could I use mortar instead in order to get a good looking finish?

Bill (post #207153, reply #1 of 11)

How big are these things?

In the US, we have sand mix-more a cement very coarse sand as aggragate thing.

We've also have some bag mixes that have very small stone.

 

Also, by tapping the form after filling, you might be able to drive the stone back away from the forms, then break apart the form b/4 it sets completely and rub with a sponge float to fill the voids.

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Remodeling Contractor just outside the Glass City.


http://www.quittintime.com/

 


There are several different (post #207153, reply #2 of 11)

There are several different types of concrete finish you could apply to your pieces to achieve a smoother, more uniform finish.  Plain old thinset tile mortar works quite well, though the color is a bit off.  But there are purpose-made products you can purchase as your local lumberyard that work well and have a more "natural" color.


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

PLINTH SIZE (post #207153, reply #3 of 11)

The plinth is 43 x 25 cms in plan and 10 cm down to 6 cm in elevation.

 

I'm gonna put the onus on you bill (post #207153, reply #4 of 11)

What's that in US measurements?

A Great Place for Information, Comraderie, and a Sucker Punch.

Remodeling Contractor just outside the Glass City.


http://www.quittintime.com/

 


Google "43 cm to inches". (post #207153, reply #5 of 11)

Google "43 cm to inches".


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

of course, (post #207153, reply #6 of 11)

But this is a forum that resides in a country of feet and inches, therefore I can wait for the poster's translation.

I do know that those dimensions are not big-so easy answer-sandmix.

A Great Place for Information, Comraderie, and a Sucker Punch.

Remodeling Contractor just outside the Glass City.


http://www.quittintime.com/

 


concrete or mortar (post #207153, reply #8 of 11)

So this sand-mix is really a ready mixed mortar in a bag> ok thanks for all your info,

Slan go foill Bill

Yes Bill (post #207153, reply #9 of 11)

in a bag.

I've used it to repair concrete-it'll work.

There's no stone aggregate in it.

Take a look here-

http://www.sakrete.com/products/detail.cfm/prod_alias/Sand-Mix

 

See if the spec's will work for your application.

 

But, if you tap your forms to knock the stone back in the mass, then break the forms apart after it's semi set, you can use a sponge float to tidy up the area that was against the form.    That's if you need to use regular redi mix.

A Great Place for Information, Comraderie, and a Sucker Punch.

Remodeling Contractor just outside the Glass City.


http://www.quittintime.com/

 


concrete or mortar (post #207153, reply #7 of 11)

Hi calvin   In old UK momey the approx sizes are 17" x 10" and 5"x 2".

Cheers Bill

You will always have some aggregate at the surface. (post #207153, reply #10 of 11)

It really isn't possible to keep it off the surface at the forms, and if you are cutting to finish size you will cut through it..  As others have said you can use a mix design with smaller coarse aggregate.  That minimizes the impact, but you still have the coarse sized aggregate showing at the surface. 

My approach would be to use the coarse aggregate is a design feature.  White, (or other colored), concrete with crushed glass, marbles, or color selected stone that either contrasts with or complements the cement paste color looks good. 

Proper vibrating will bring (post #207153, reply #11 of 11)

Proper vibrating will bring the "cream" to the surface of the form and push the aggregate away from the form.  Generally not possible to eliminate all voids, but a better job can be done than the picture shows.

But I'd just take the existing pieces and resurface them with some sort of concrete surfacing mix.


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville