Concrete benchtops

[Arron]

Well, my time is now more limited then I thought, so I havent had much chance to experiment, but here is an update on what I have done.

I made 4 trial-size moulds, about 400x400, and have cast them several times.

Most I have done using 'structural grout' rather then concrete. This is a wonderful material. It dries quickly and can be removed from the mould later the same day. Next day it is rock hard, with a fine-grained surface more like stone then concrete. It also has no shrinkage and minimal cracking - actually on these sample size trials it has zero shrinkage and zero cracking. It is hard and durable enough to be further experimented on even without reinforcing. Put lots of pigment in and when wet it behaves more like liquid rubber then concrete. I bought it at Bunnys but the downside is that it is $15 for 10kg bag. I believe that most of the proprietary mixes available in the US are really just this stuff relabelled.

I have done some in regular concrete - still wet and soft two days later, which may be OK in the finished job but not good for these tests.

I have tried different pigments - no issues there.

I have tried brass inclusions - rather nice.

I have tried grinding and sanding. Using a ROS and working grits from 60 through to 200 then polishing is a cinch. Just expect to use a lot of pads (good thing KMart has them on special here). Polishing is dead easy - just grind away any dags, sand flat with 60 grit and then carry on through the rest.

I have tried experiments with parting oil (unnecessary) and silicon (unnecessary as well).

I have tried trowelled surfaces and casting such that the mould side is the finish side. The latter works better, though my wife says it is dull.

I have tried pigment washes (looked good but lost when sanding) and rough surface infill. The latter is not working yet as the infill tends to be undercut too easily when finishing. Perhaps I should be wetting the block first.

I'm glad this thread is staying alive. Keep up the commentary.
Arron

[scooter]

Arron, might be worth getting your discs from an abrasives supplier, would probably work out cheaper.

If you have a diamond stone you may be able to use that to take down any rough spots first.


Good luck with the further experiments.......cheers........Sean

[Jill]

I'd love to see pics of your experiments, Arron.

I've been interested in poured concrete benchtops for some years now, after seeing a vanity bench top in an Owner Builder mag. made to look like sandstone. It was very well done & looked like real sandstone. The guy who made it used a steel ruler to carve the layering to simulate sandstone. He also made his lintels, cast in-situ, and one had a mouse 'carved' into it, along with other detailing. Inspiring work.

Cheers,

Jill

[Trav]

Hi there

Has anyone got any recent experiences with concrete benchtops? I am very keen, but keen to hear if others have had positive experiences. Particularly people in Australia - where did you get the mixes, grinding/polishing discs etc.

I am probably going to buy the book/DVD mentioned here and referred to earlier in this thread ( http://www.concreteexchange.com/catalog/1/)

Cheers

Trav

[tameriska]

Trav, check this thread out, In here somewhere Jill has a poured in place benchtop, it came up really well.

http://woodworkforums.com/showthread.php?t=25158

[encino_]

Can anyone recommend what sort of mix to use for pouring up for polished concrete?

I want to make a small hearth for my fireplace, probably around 1m wide, 70mm thick, and 200mm back.
I see that Cheng sells a pre mix stuff on his website, but it's expensive, and to get it shipped to Aus would cost heaps.

I want to do it on the cheap, but with a similar appearance to something like these :

http://www.customconcrete.co.nz/hearths.html

I like this style of ground finish better though :
http://www.instructables.com/files/d...K1M.MEDIUM.jpg


Can I just get bags of premix from Bunnings? Do I need to add stuff?
What about polishing on the cheap without buying expensive pads?
Anyone reckon if I used plastic or glass on the bottom of the mould, when I turn it over it would be basically finished and shiny without the need for polishing much?

[Metung]

An architect building around the corner from me has a free standing, polished concrete bath. Looks impressive but I imagine it would suck a lot of heat from the hot water.

[derekh]

I'm glad I ran into this thread. Only last night I was thinking about the feasibility of casting a base for an Cob Oven in concrete and moving it into place atop masonry blocks. Same principle as a bench top (I hope).

[Gra]

Well, my time is now more limited then I thought, so I havent had much chance to experiment, but here is an update on what I have done.

I made 4 trial-size moulds, about 400x400, and have cast them several times.

[encino_]

For anyone interested, this bloke gives a fairly good step by step... but again, I'm at a loss as to what materials people are using here in Australia, especially on the cheap.

http://www.instructables.com/id/Conc...--Solid-Surfa/

[solid art]

[quote=encino_;644157]Can anyone recommend what sort of mix to use for pouring up for polished concrete?

I want to make a small hearth for my fireplace, probably around 1m wide, 70mm thick, and 200mm back.
I see that Cheng sells a pre mix stuff on his website, but it's expensive, and to get it shipped to Aus would cost heaps.


[email protected]

I'm new here and new at blogin so be nice while I stumble through. I am in the concrete countertop biz having my own company for 5yrs. Here are some pic. for now, I have to go. I'll answer your ???? later.