LumberJocks Woodworking Forum banner

Need advice on premix concrete

2K views 22 replies 11 participants last post by  bandit571 
#1 · (Edited by Moderator)
I'm building a Kamado Joe (like Green Egg) table. I want to the Kamado Joe to sit on a concrete paver that will be on the lower shelf.

I can't find a pre-made one to suit my liking and size so I'm going to pour my own. I would like the texture of the paver to look similar to a concrete foundation block. One in other words I don't what large aggregate.

I made the form in the picture but not use what concrete mix to use.

Wood Countertop Cabinetry Hardwood Gas


Bathtub Plumbing fixture Wood Tap Floor
 

Attachments

See less See more
4
#2 ·
Of course you can tamp down the aggregate below the surface and use whatever texturing technique you have in mind. Given enough shaking/vibration/tapping/etc. the aggregate should also be sub-surface on the sides.

A more expensive solution is mix your own from a sack of cement and sand, no aggregate. Don't forget that the less water you use the better, especially if you want a texture.
 
#3 ·
You can use mortar or even concrete mix with aggregate. Just trowel it smooth and work the mix so that a fair amount of water comes to the surface. That will settle the gravel below the surface, if you have gravel in the mixture. As that water evaporates, you can sponge the surface with the texture you like.
 
#4 ·
Of course you can tamp down the aggregate below the surface and use whatever texturing technique you have in mind. Given enough shaking/vibration/tapping/etc. the aggregate should also be sub-surface on the sides.

A more expensive solution is mix your own from a sack of cement and sand, no aggregate. Don t forget that the less water you use the better, especially if you want a texture.

- splintergroup
Do you think plain mortar mix would work? think it wold be strong enough for intended purpose?

Rectangle Font Label Publication


Of course you can tamp down the aggregate below the surface and use whatever texturing technique you have in mind. Given enough shaking/vibration/tapping/etc. the aggregate should also be sub-surface on the sides.

A more expensive solution is mix your own from a sack of cement and sand, no aggregate. Don t forget that the less water you use the better, especially if you want a texture.

- splintergroup
 

Attachments

#5 · (Edited by Moderator)
As they ^ said, troweling will bring more cement to the surface-you still run the risk of exposed large aggregate on the sides or bottom, though. Quikrete makes a Sand Mix that doesn't have the large aggregate and might be more along the lines of what you are looking for.

 
#7 ·
Never done myself it but I have seen people (probably youtube?) mix cement, sand and perlite to make their own insulating concrete blocks. If I remember correctly, you mix the cement, add sand and then perlite, in that order, mixing each completely before adding the next one. The perlite sucks in some moisture from the mix, making it thicker and more moldable, so you just stop adding the perlite when you get the right consistency. The perlite will give it sort of a cinder block appearance, depending upon how much you add. I'll see if I can find where I saw this if you cannot find it yourself.
 
#11 ·
Thanks for all the replies. Let me throw in one more option/question. I have on hand a bad of quickrete fast setting mix on hand. If I could use this it would save me a 32 miles of driving. What is your thoughts on using this?

- AlaskaGuy
Well, if you already have that, just use it. Make sure to float the top a bit to get it smooth and get the big gravel down, and then you can use a brush to give it some texture. I have used a wallpaper brush to give it a nice rough brushed texture.
 
#12 ·
Thanks for all the replies. Let me throw in one more option/question. I have on hand a bad of quickrete fast setting mix on hand. If I could use this it would save me a 32 miles of driving. What is your thoughts on using this?

- AlaskaGuy

Well, if you already have that, just use it. Make sure to float the top a bit to get it smooth and get the big gravel down, and then you can use a brush to give it some texture. I have used a wallpaper brush to give it a nice rough brushed texture.

- SMP
Thanks for all the replies. Let me throw in one more option/question. I have on hand a bad of quickrete fast setting mix on hand. If I could use this it would save me a 32 miles of driving. What is your thoughts on using this?

- AlaskaGuy

Well, if you already have that, just use it. Make sure to float the top a bit to get it smooth and get the big gravel down, and then you can use a brush to give it some texture. I have used a wallpaper brush to give it a nice rough brushed texture.

- SMP
It'a done deal, I show results a bit later. I used what I had on hand
 
#14 ·
FWIW:
When using concrete adjacent to high temperature devices like BBQ, outdoor oven, or smoker;
Be sure to seal all surfaces of the concrete with acrylic masonry sealer.
Why?
Concrete can and will absorb large amounts of water. If subject wet concrete to high temperatures, it can/will crack, shatter, and/or deconstruct (occasionally with explosive forces created by steam).

Learned this lesson hard way:
Had a concrete counter top in an outdoor kitchen explode, shattering a 12" wide section between a smoker and BBQ running side by side; just after a rain storm. Gravel shrapnel damaged a window 15 feet away, and golf ball size chunks traveled several feet. No one was nearby when it happened, fortunately.

Another recommendation by insurance agent investigating the incident was kitchen builder should have put fiberglass wool pads at edges of counter top molds where concrete counter top was less than 1" from natural gas cooking appliance shell. This insulates the concrete to help prevent moisture induced heating issues. Covering the exposed concrete with (sealed) decorative glazed tile will also reduce moisture intrusion issues.

PS - In wet unprotected environment, concrete next to heat sources needs to be re-sealed every couple years, sort of like a wood deck, or un-glazed tiles/tile grout in a shower.

PPS - Refractory brick is better choice for anything near/touching heating appliances as it doesn't absorb water.

YMMV and Be safe, not sorry.
 
#19 ·
Bricks are made from clay. Different stuff.

Problem is conglomerate of materials that make up concrete determine water uptake. Not uncommon to have holes filled with water in poured concrete below water line, especially when has not been machine compacted or vibrated. If you can create zero holes, can reduce the problem to near zero. It's all about distance/temperature/moisture amount.

Throw a hunk of sidewalk concrete soaked in water for few days on bon fire and watch what happens (from a safe distance please). If it's thin enough, it hisses as steam is released from cracks. If thick, it goes boom.

as always, YMMV.
 
#20 ·
Fire brick / refractory is made from a specific clay. It was mined here in northern Illinois for decades. I did electrical jobs at the plant several times, so I got to see alot of it and learn some about it.
After forming, the bricks or other shaped go into a rotating kiln. After slowly heating, they are fired for several days, then cool as the table spins, and the bricks are almost cool enough to touch when removed. Refractoryy clay is nothing like concrete, that is why, when dry, will stand up to very high temps, even inside a blast furnace.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top