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Making Concrete Bar Tops - Page 2

post #31 of 189
Quote:
Originally Posted by mmeister View Post

I had several beers in me to loosen up the sore muscles and was half taking a drink when I read that.....beer on a laptop from your nose is never a good thing


HEYNOW- I use a sawzall aka reciprocating saw with the blade off. Place the guard against the form and pull the trigger. The vibration that is natural to the saw does a good job of releasing the bubbles from the side and bottom...then I take a hammer( or mallet) and give it some hard thumps on the bottom of the form just to make sure any stubborn bubbles released.

Brilliant!
post #32 of 189
Had this article in a spam e-mail from HGTV this AM. has quite a few linked resources on concrete counters and sinks.

http://www.hgtvpro.com/hpro/di_kitch...456203,00.html

The force must be telling me a concrete vanity is in my future for the basement.
post #33 of 189
I took out the shelving on the left side of the mini-bar BIG...so now I am thinking this is my bar counter since I just have a rectangle with a sink hole. That is unless I don't get a sick deal on some granite from you know where.
post #34 of 189
Thread Starter 
Quote:
Originally Posted by BIGmouthinDC View Post

Had this article in a spam e-mail from HGTV this AM. has quite a few linked resources on concrete counters and sinks.

http://www.hgtvpro.com/hpro/di_kitch...456203,00.html

The force must be telling me a concrete vanity is in my future for the basement.


Out of those links concreteexchange.com is the one I'd recommend and have used. They have a great calculator for amount of concrete needed and if you don't want to take the time to do as much diy as I've done they have pre-cast molds for sinks and faucets (for a price) as well as color and additives. Fossils too!!



24 Hours after pouring and the concrete is as hard as... well concrete. It has lightened up in color too as it dries. In the picture you can see the under-mount sink bolts that were pushed in the cement after the bubbles were taken out(bubbles on the lower right). You can also see the sink mold that sticks up about an inch from the cement. I know it looks rough and yes you could float and work the surface smooth but keep in mind this side is out of sight and the work doing that would be wasted.

post #35 of 189
Quote:
Originally Posted by mmeister View Post

Lee,

To get the look that I have you need diamond grinding pads and a polisher. An angle grinder will not work because of it's high rpm's. Harbor Freight is your friend for this tool as well as the hole saw if needed.

http://www.harborfreight.com/cpi/cta...105&pricetype=

This is the one I used. It's nice because it has a dial for speed control and it maxes out at 3000rpm's and you don't want to go over 4k when polishing concrete. The pads can be found on ebay at a good price also.

The more you grind with say your 50 grit pad the more stuff will show. This is optional and some people may just want a nice rock free look. I went for a happy medium on my first one. It's like a box of chocolate, you never know what your going to get

I'll take lots of pics during these steps. I plan on pouring the beginning of the week when I can get my buddies over to help- it's at least a two man job, three is better!

OK, that is what I thought. My experience is that the aggregate will not settle like that and that polishing was definitely needed to get that look.

You could also expirement with some colored marble chips in the mix as well if you wanted to get a different color aggregate. Of course at some point, you may as well just make terazzo. Speaking of which, I have seen a fair amount of glass chips and even some with bits of mirror in terrazzo lately. It looks super cool especially in countertops.
post #36 of 189
Quote:
Originally Posted by Lee L View Post

OK, that is what I thought. My experience is that the aggregate will not settle like that and that polishing was definitely needed to get that look.

Unless you've done something really wrong, the aggregate should be dispersed pretty uniformly thoughout the mix. The polishing takes the cement paste off of the surface of the aggregate.

As far as the rebar goes, I would recommend putting some in no matter what. Concrete is great at supporting compressive loads, but it sucks at tension. The 1/2" rebar is commonly referred to as #4 rebar and the 3/8" rebar is #3 rebar. #3 rebar is plenty for what you need.

Also, I would guess the reason that you'd want to add sand to make the mix more flowable rather than water is not really for the strength (3,000 psi is close to what we use for sidewalk and curb and gutter, which will support vehicle traffic), it's so that you don't get shrinkage cracking on the surface of the concrete if you are doing a larger span.

CJ
post #37 of 189
I guess it's time to get busy making counters. I now have the much coveted Wife Acceptance for making my own concrete counters. I've wanted to do this forever, but your thread helped gain the approval, and give me the moral support to tackle it.

Thank You!!
post #38 of 189
Quote:
Originally Posted by CJO View Post

Unless you've done something really wrong, the aggregate should be dispersed pretty uniformly thoughout the mix. The polishing takes the cement paste off of the surface of the aggregate.

.

CJ

I meant that it would be very unlikely that the aggregate would settle nice and flat at the surface like that. It will definitely be dispersed as long as it is mixed well. I have seen some slabs acid wshed that does take the surface cement off the top and expose the aggregate, but it is not nice and smooth like that.
post #39 of 189
Quote:
Originally Posted by Tedd View Post

Hasesian, you crack me up. Good thing that popcorn is bottomless, watching concrete dry and all...

I am sure this is similar to watching a baseball game/watching the grass grow...
post #40 of 189
Thread Starter 
Quote:
Originally Posted by cane.mba View Post

I guess it's time to get busy making counters. I now have the much coveted Wife Acceptance for making my own concrete counters. I've wanted to do this forever, but your thread helped gain the approval, and give me the moral support to tackle it.

Thank You!!

Great! My wife said the same thing when I started the little trial top for the popcorn machine. After it was polished and waxed she whought it looked better than our granite tops in the kitchen. This is very much a DIY project if you follow the basic steps. You WILL get dirty and this stuff is very heavy and labor intense, but the end results look great and there is no limit to what can be done. When you get under way and help is needed shoot me a tell. I did not go over making a template for your molds as I didnt need any but can talk about that if questions come up. Monday I'm flipping the molds over and I'll start on polishing!
post #41 of 189
I'm sure I'll have many many questions. I picked up Cheng's book a year ago, so time to dust it off and do a little reading....
post #42 of 189
Thread Starter 
Quote:
Originally Posted by CJO View Post

Unless you've done something really wrong, the aggregate should be dispersed pretty uniformly thoughout the mix. The polishing takes the cement paste off of the surface of the aggregate.

As far as the rebar goes, I would recommend putting some in no matter what. Concrete is great at supporting compressive loads, but it sucks at tension. The 1/2" rebar is commonly referred to as #4 rebar and the 3/8" rebar is #3 rebar. #3 rebar is plenty for what you need.

Also, I would guess the reason that you'd want to add sand to make the mix more flowable rather than water is not really for the strength (3,000 psi is close to what we use for sidewalk and curb and gutter, which will support vehicle traffic), it's so that you don't get shrinkage cracking on the surface of the concrete if you are doing a larger span.

CJ


Most tops I've seen built use nothing more then wire mesh with re-bar around the sink area minus any overhangs. The sand is for flow and strength (you want 5000)in that if too much water is added the mix will be weak and cracks can happen and I would not recommend normal cement this unless maybe your a pro at this. They do have fibers to add to the cement to help prevent cracks also. I have seen 9000 psi mixes which you can buy on-line too. This is just my way of doing it that has worked for me. Try Chengdesign.com for more info and ideals. He is the one that started this whole idea in the first place and has a wealth of knowledge.
post #43 of 189
Thread Starter 
Quote:
Originally Posted by cane.mba View Post

I'm sure I'll have many many questions. I picked up Cheng's book a year ago, so time to dust it off and do a little reading....

Check your local library for his dvd that also has step by step instruction. Mine carried it here and was fun to watch.
post #44 of 189
Quote:
Originally Posted by mmeister View Post

Most tops I've seen built use nothing more then wire mesh with re-bar around the sink area minus any overhangs. The sand is for flow and strength (you want 5000)in that if too much water is added the mix will be weak and cracks can happen and I would not recommend normal cement this unless maybe your a pro at this. They do have fibers to add to the cement to help prevent cracks also. I have seen 9000 psi mixes which you can buy on-line too. This is just my way of doing it that has worked for me. Try Chengdesign.com for more info and ideals. He is the one that started this whole idea in the first place and has a wealth of knowledge.

There are two kinds of cracking that you are talking about- structural cracking and shrinkage cracking. Neither of those will be helped with increasing the strength over a nominal amount (say 2,000 psi). The rebar is there to help with the structural cracking. The shrinkage cracking is caused by the uneven curing of the top of the concrete with relation to the bottom of the concrete. The wire mesh (if properly placed) or fiber will help control the shrinkage cracking. Too much water will exacerbate the problem, but not because it weakens the concrete. Too much water can also cause crazing, which is spiderweb like cracks in the surface.

Personally, I would not purchase a 9,000 psi mix unless you absolutely need it from some reason. It will set very quickly and is very expensive.

CJ
post #45 of 189
Thread Starter 
Thanks CJ- I didn't talk about controlling the drying of the cement! Personally the tops I've seen with the spider webs I kinda liked the looks of it. Love your theater too, I've been quietly following along.
post #46 of 189
How did you get the specs in the table top for the popcorn machine? Did you add the specs or is that how the cement looked with the coloring?
post #47 of 189
For reference, I did a concrete countertop for my home bar - currently being finished. It is the fourth concrete countertop I've done on various projects around my house.

One of them by the way was a white countertop, using white portland cement and white marble sand for the concrete mix for my outdoor kitchen, barbecue/pizza oven/ sink

For my home bar, I did an experiment with coloring. I want it black ( for home theater purposes) and so added a quart can of black acrylic latex paint. Strangely, the color ended up looking lighter than without it. I could detect no difference in finish or hardness with the paint additive compared to concrete without it.

I have two suggestions, no matter how you do it. The quality of the bag concrete mixes varies quite a bit, even between the same brand and type number. I always add a trowel full of portland cement to each bag of mix I put in my mixer. As well, once you pour it in your form try to set up a vibration, either by borrowing or renting a concrete vibrator, or by making the mix on the wet side and tapping all around and under the form after pouring with a hammer (of course not hard hard enough to break your forms). for at least a half an hour straight after pouring. You will see the bubbles come up.

Anyway, I poured the top in place, as I did all the others, filled some of the holes and bubbles with a slurry of portland cement and water, and after curing, sanded it smooth with a belt sander. Then I painted the top with cans of gloss black spray enamel.

This can be done, is cost effective compared to almost any natural stone, but is labor intensive. And cleanup is a bigger job by far.
post #48 of 189
Thread Starter 
Quote:
Originally Posted by bfinn66406 View Post

How did you get the specs in the table top for the popcorn machine? Did you add the specs or is that how the cement looked with the coloring?


All the specs and stones you see are natural to the cement/sand mix. Everything gets stained dark when you add the color and then the diamond pads take the top layer away- 50,100,200. If I wanted a smooth rock free look I'd start around say 800 light. You could add rocks, glass, whatever to the bottom if you want.


Quote:
Originally Posted by Lone Cloud View Post

For reference, I did a concrete countertop for my home bar - currently being finished. It is the fourth concrete countertop I've done on various projects around my house.

One of them by the way was a white countertop, using white portland cement and white marble sand for the concrete mix for my outdoor kitchen, barbecue/pizza oven/ sink

For my home bar, I did an experiment with coloring. I want it black ( for home theater purposes) and so added a quart can of black acrylic latex paint. Strangely, the color ended up looking lighter than without it. I could detect no difference in finish or hardness with the paint additive compared to concrete without it.

I have two suggestions, no matter how you do it. The quality of the bag concrete mixes varies quite a bit, even between the same brand and type number. I always add a trowel full of portland cement to each bag of mix I put in my mixer. As well, once you pour it in your form try to set up a vibration, either by borrowing or renting a concrete vibrator, or by making the mix on the wet side and tapping all around and under the form after pouring with a hammer (of course not hard hard enough to break your forms). for at least a half an hour straight after pouring. You will see the bubbles come up.

Anyway, I poured the top in place, as I did all the others, filled some of the holes and bubbles with a slurry of portland cement and water, and after curing, sanded it smooth with a belt sander. Then I painted the top with cans of gloss black spray enamel.

This can be done, is cost effective compared to almost any natural stone, but is labor intensive. And cleanup is a bigger job by far.

Odd that the black latex paint didn't darken it up at least a little. I'd suspect there is not near the same amount of pigment as the colorant that is made just for quikrete and acrylic latex is an additive used in cement I believe to aid in stain resist and adhesion to a subsurface if I remember.

Did I read that right, you painted the cement?
post #49 of 189
correct, after the belt sanding ( a long process) I painted it with spray cans of gloss black enamel. My outdoor kitchen white concrete top isn't painted, but this one is. I like the look and if and wear or chips happen, it will be easy enough to fix with another can of spray.
post #50 of 189
Thread Starter 
Can you post some pics to share with the group

I'm always interested in seeing other peoples work/ideas!

I just checked my tops. They have settled at a dark grey color. I think the small amount of brown added is giving it a nice bump to the warm side. Tomorrow I'm going to remove the faucet plug and trim down the sink mold flush with the cement(I'll remove it after the flip)
post #51 of 189
Thread Starter 


Here we have the tops flipped over and all melamine removed. If this is the look you like then forward right up to the polishing pads at 1500 and polish away!



The tops look good. A few bubbles, but no major voids. If you have a defect in the tops you have 3 choices. Redo the tops, hide the defect if possible, or show it off as if thats how it's supposed to be. Myself, I'm an option C man. It's one of the things I like about using this material- you don't have total control over this stuff. If your a perfectionist then this is not the project for you. If your like me and like to go with the flow of the material then this is right up your alley.



Starting with 50 and then 100. These 2 pads have the most control over how much rock is going to show- followed by 200 and 400. Keeping the surface wet is important as well as keeping the polisher moving, never staying in one spot long. I give the surface a once over with the 50 then squeegee the surface to see what I have. Back and forth you go. By the time your done with the 100 pad the surface should look uniform, if not work any areas that need it. 400 is the last pad that will be grinding the surface as 800 and up polish.
Stop at 400 and allow to dry after the surface has been cleaned. At this point you have a choice. Leave whatever small bubbles are there or skim the surface with a slurry to fill in any gaps. This slurry can be a contrasting color or one to match.
The sides of the tops are hand worked with the diamond pads and water. The grinder is hard to work at this angle and throws the water straight up in the air.



Here is a macro shot of the top. I didn't add anything to this mix, everything you see was in the cement mix.



Next step- the polishing pads to give it a glossy finish. Thanks for looking!

**EDIT** The slurry mix I talked about is made up of portland cement and colored water. Add sand if the gap/hole is larger than 1/4". I found that my hands works best. With gloves on mix it up to about the thickness of mayo and work it into all voids and once you have it filled the way you want it take the squeegee and remove as much as you can. This stuff sets up fast so work quick!
post #52 of 189
Lot's of water and a cheap Harbor Freight electric polisher, somehow I can't see myself going that route. How about using a compressed air powered polisher?
post #53 of 189
Thread Starter 
Quote:
Originally Posted by BIGmouthinDC View Post

Lot's of water and a cheap Harbor Freight electric polisher, somehow I can't see myself going that route. How about using a compressed air powered polisher?

If you have a compressor big enough to handle it say 14-16cfm's and you can set the rpm's at 3000 then sure. Anything you use electric wise MUST be plugged into a GFI outlet as I did when dealing with water. The polisher I'm using works great and has done several tops without problem. If I was doing this as a business I'd defiantly want one either electric or air that had a water feed included.

Here's an air one!

http://www.concretecountertopspecial...gle%20Polisher

At day 10 I will start to polish the tops.
post #54 of 189
Very nice. Thanks for sharing.

CJ
post #55 of 189
mmeister,

Way cool - this is a great thread!
Thanks for posting and documenting
post #56 of 189
This is a GREAT thread.
post #57 of 189
Thread Starter 
Thanks for the compliments!

Here is a shot of the sink area 24 hours later. It's silky smooth and has a light coating of dusk on it from the grind. I'm working on a strip of stainless steel to go in between the two tops when they are joined together.



And the bar sink looking for a new home.

post #58 of 189
Quote:
Originally Posted by mmeister View Post

Thanks for the compliments!

This really is a terrific thread. These kinds of detailed, specific logs are great for sharing knowledge, and will help a lot of people duplicate this process for themselves.

One question - to remove the slabs from the mold, I assume you have to disassemble the forms? That you can't just "pop" the counter out? It seems like it might be nice to be able to quickly poor a second counter in the same form if there was a manufacturing defect, or if some problem cropped up later i the finishing process.
post #59 of 189
Thread Starter 
Thanks for the input Foosinho,

OK, a little about removing the tops from the mold. For this step I removed the sides, I found that when removing the sides it's easiest to lift up on the side pieces of melamine and then pull out-wards as opposed to try to just pull the sides out-wards.

These slabs weigh 200lbs each and it took two of us to flip them. We slide them to the side half off my support and pivoted them up and over. One of the tops broke free of the cement as we flipped them while the other needed to be helped free. Be gentle when pulling the melamine off. This is new concrete and it's still "soft". Don't use screwdrivers or wounder-bars to pry it off, take your time and the silicone will give.

The melamine comes off clean and would be easy to reuse, you would just have to redo the silicone. My buddy who is also finishing his basement with a bar liked my tops so much he wants to do them too. I'll do another step by step as we build his also as his has some different challenges in it.

If you want to tackle this project I would highly recommend building some 1' x 1' molds and experiment with color and additives so there are no huge surprises when you make the big ones!

Now on to the polishing!
post #60 of 189
Thread Starter 
This step takes as long if not longer then grinding with the 50 and 100. Same basic principal involved. Keep the surface wet and keep the polisher moving. It would be a good idea during these stages of grinding and polishing to have a disposable suit on- the $10 ones you find in the paint dept. to keep yourself somewhat dry. OK OK shut-up and show us the pics, I know the drill...





The can is there of course to show the glossy surface that can be had. The surface is still not totally cleaned and I have not put any kind of polish/wax on it yet.





Flash on looking down, kinda looks a little like Corian. Dont have a lot of time to write today but any questions please ask!

Thanks!
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