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Concrete Countertop Series #1: 1st Entry

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Blog entry by Siegel_KenEvil posted 11-15-2010 01:41 PM 3539 reads 11 times favorited 15 comments Add to Favorites Watch
no previous part Part 1 of Concrete Countertop Series series Part 2: No progress, just gathering information »

After two years of pondering, I finally started a concrete counter-top. This will be going in a master bathroom. I have the mold construction complete. Next step is to radius off the corners and fill the small voids using caulk and/or bondo.

I’m ordering a new product from Lowes by Quikrete called “Countertop Mix”. (http://www.quikrete.com/productlines/CountertopMixPro.asp) I’ll need two 80lb bags costing about $11 each. I calculated the finished weight to be about 130 pounds.

Here is a great video on how I’m going to properly reinforce the concrete using #9 ladder wire.
http://www.youtube.com/watch?v=wZOVvj0UnNE

I also need to decide on a color and technique. One technique I liked used a not-so-fluid mix of concrete, hand packed like a baseballs, then placed in the up-side-down mold. When complete, the underside looks like a typical concrete pour but the top side will have a bunch of voids that need to be filled with a complementary color concrete mix. This gives a marbling effect. I’ll post the link to this video if I find it again.

Here’s a great video about how to make concrete flow without adding more water. http://www.youtube.com/watch?v=naRoDinbbdc

You may notice I have a huge undercut in my mold. I’m not sure how I’m going to remove it after the pour. I’m experimenting with using water to break up the MDF. I’ve even considered burning the MDF out. I don’t have a good solution yet but I expect many hours with drills and chisels ahead.

-- Scott



15 comments so far

View Howie's profile

Howie

2656 posts in 1677 days


#1 posted 11-15-2010 03:36 PM

This promises to be very interesting.
One thing…don’t try burning out the MDF. Wet concrete(even though it appears dry) explodes when a lot of heat is applied.
Keep us posted.

-- Life is good.

View sras's profile

sras

3947 posts in 1883 days


#2 posted 11-15-2010 04:21 PM

Definitely an interesting project! I like the creative sink design. The undercut will be a challenge. How about drill out some of the area and re-filling with wax? Might be a little stressful given how nice your form looks. You could go so far as to replace the undercut with a solid wax piece … A nice little mind puzzle there – drill & chisel should work also, just don’t rush it.

-- Steve - Impatience is Expensive

View botanist's profile

botanist

152 posts in 2292 days


#3 posted 11-15-2010 04:25 PM

What about using a release agent on the mold like they do for other concrete forms?

View Howie's profile

Howie

2656 posts in 1677 days


#4 posted 11-15-2010 06:09 PM

Maybe styrofoam block. Would be easy to remove that way.

-- Life is good.

View RexMcKinnon's profile

RexMcKinnon

2593 posts in 1949 days


#5 posted 11-15-2010 08:34 PM

Cool, I’ve been waiting for someone to try this as I am interested in this also. Going to keep a close eye on this project.

Thanks

-- If all you have is a hammer, everything looks like a nail!

View rivergirl's profile

rivergirl

3198 posts in 1592 days


#6 posted 11-16-2010 12:52 AM

On youtube there is a video about a release agent that some hillbilly sells. Looks like good stuff. Forget the name though- but you will know it if you just think “hillbilly” when you check out the videos. I want to do a concrete pour over river rocks for a table top. Spring time though- too cold to do it now.

-- Homer : "Oh, and how is education supposed to make me feel smarter? Besides, every time I learn something new, it pushes some old stuff out of my brain."

View dakremer's profile

dakremer

2492 posts in 1845 days


#7 posted 11-16-2010 03:33 AM

looks awesome so far! I’ve always wanted to try something with concrete! It looks fun. I’ll be waiting for the next blog! Can’t wait to see how it turns out – the design looks awesome!

-- Hey you dang woodchucks, quit chucking my wood!!!!

View botanist's profile

botanist

152 posts in 2292 days


#8 posted 11-16-2010 06:55 PM

I just remembered that an episode of This Old House had a demonstration during the show about the construction of concrete counter tops. I believe it was two seasons ago for the house that was prefabricated. Thought that might be of some use.

I was confused by the design so my original reply doesn’t make sense. Soaking the mdf would probably make it easier to remove and probably wouldn’t harm the concrete. Burning the mdf would not be a good idea because it could crack the concrete, or as Howie said, could cause it to explode.

View Siegel_KenEvil's profile

Siegel_KenEvil

114 posts in 1592 days


#9 posted 11-16-2010 07:49 PM

Thanks for all the advice. Fire’s out I guess but it would have been fun.

I’m also going to use a release agent of some kind. I think PAM is ok or maybe WD40. Before that, I’m going to seal the MDF with a primer or something. Any advice on that would be great.

-- Scott

View rivergirl's profile

rivergirl

3198 posts in 1592 days


#10 posted 11-16-2010 08:18 PM

Here’s the release agent I would use… This is that hillbilly guy. Also, his other tips are really pretty cool and more simplistic than say Buddy Rhoades or the guy on Concrete Network.

http://www.youtube.com/watch?v=Q2xQd7D5_Co&feature=related

-- Homer : "Oh, and how is education supposed to make me feel smarter? Besides, every time I learn something new, it pushes some old stuff out of my brain."

View rivergirl's profile

rivergirl

3198 posts in 1592 days


#11 posted 11-16-2010 08:22 PM

Also for coloring concrete you can use gardening supplies like copper sulphate etc. No need to buy the Buddy
Rhoades stuff. For examples see below: and A REALLY GREAT SOURCE FOR MAKING YOUR OWN CONCRETE STAIN- EASY TO FOLLOW IS HERE:
http://www.stainedfloor.com/

• Iron Sulphate. This is one of easiest ways to stain concrete and doesn’t require any acid. Combine ¼ cup of iron sulphate, also called Copperas, with 2/3 cup warm water. You can see from these results the copper-colored end product. Seal when done to protect the integrity of the color.
• Copper Sulphate. If you want to create more of a blue or blue-green color, then this mixture of copper sulphates will do the trick. Mix ¼ cup of copper sulphate (also known as root killer) with 1 cup of warm water.
• Copper Sulphates with Potassium Dichromate. To achieve a more orange or green appearance, you can alter the copper recipe by adding potassium dichromate to the mix.
• Manganese. Want to achieve rich tones of brown and black? Then follow this recipe using different portions of manganese. Mix ¼ cup of manganese carbonate, 1 TBSP or potassium dichromate, and ½ cup + 2 teaspoons of muriatic acid

-- Homer : "Oh, and how is education supposed to make me feel smarter? Besides, every time I learn something new, it pushes some old stuff out of my brain."

View Siegel_KenEvil's profile

Siegel_KenEvil

114 posts in 1592 days


#12 posted 11-16-2010 09:38 PM

Thank you thank you

-- Scott

View rivergirl's profile

rivergirl

3198 posts in 1592 days


#13 posted 11-16-2010 09:56 PM

Very welcome! Can’t wait to see your project. Wish I could do it too. :)

-- Homer : "Oh, and how is education supposed to make me feel smarter? Besides, every time I learn something new, it pushes some old stuff out of my brain."

View jm82435's profile

jm82435

1281 posts in 2496 days


#14 posted 11-23-2010 08:51 PM

Styrofoam (dense blue kind) as mentioned earlier is not a bad option. Pour in some acetone when you are done and it is dissolved, leaving the void. Mold makers use it all the time…

-- A thing of beauty is a joy forever...

View SCOTSMAN's profile

SCOTSMAN

5594 posts in 2339 days


#15 posted 11-23-2010 09:19 PM

I should think any of the releasing agents would work well inc one I used to use when I was in dental othodontics for 30 years, anyway that was for plaster should work fine on concrete.So mix some gasoline a little will do with ground up candles wax of any kind,or kerosene might work too.Please do this needless to say well out doors leave this mix in a large jar till the wax melts then paint it on where you expect a problem or overall. Then the kerosene gasoline evaporates leaving a very fine film of wax onto the surface to be treated.This can be boiled off when finishing. This usually leaves a very fine finish Alistair

-- excuse my typing as I have a form of parkinsons disease

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