I’ve posted a few things about my water damaged house and I want to say thanks to all those who gave me feed back! Now for something fun!
When we ordered our cabinets we were mistakenly sent a 30″ sink cabinet instead of a 36″. The cabinets were already installed in the home(modular)so we decided to bite the bullet and make due.
Looking through mags my wife fell in love w/farmers sinks……you know the $1000 ones. After much discussion about cost on my part I finally persuaded my wife that getting such a sink was a waste of money…..and we are getting it anyway!!!I guess I told her!!!
Being the tight wad that I am I thought about making my own from concrete. I think I have the form figured out,but was wondering should I use mesh or rebar in the sink to strengthen the sink?And do I need any additives in the concrete to protect it.
Finally should I grease the form, and with what?
If this does’nt work out I’m fine with losing a little money–sounded like a fun project!
Replies
I've been farting around with concrete counters for a many years now--did a couple poured in place with help from buddies in the know--then started casting in melamine molds a'la Cheng Design. Got the book, mixed from scratch for a 6-7 sack/5000psi mix with water reducers, fiber reinforcements, pigments, inlays, formed features like drainboards, grinding and polishing with diamond pads etc... I've done a couple for myself and several for clients with more and more success as I've gone along.
Here's what I've concluded about mixes, reinforcement for pre casting counters (assuming your form is not place and you will move the counter or sink into place after curing)
*Screw doing your own mix with a pile of sand, a pile of rock, additives, fiber reinforcement, etc. Home depot sells a "crack resistant" concrete mix, with water reducer, air entrainment, stealth-type poly fiber and a colorful crushed gravel that's about 1/2" minus for size. Problem I have with mixing your own has been that it's really hard to get the fiber to integrate properly, always gets clumped up even when added to dry mix in the mixer. Also I think aggregates have to be really clean to achieve strength in a counter down to 1.5" thickness. At 4.5$ a 80lb bag, this is easy, clean and convenient and it has yielded a very strong, plastic mix that seems wayyyyy stronger than the scratch mixes I've done from the above components. No piles of sand and gravel left over.. no multiple trips... No buying fibers/agents separately...
*If the counter is 3" thickness or greater, then it makes sense to use rebar. Less than 3" thickness, rebar will only create a weakness along it's length for the concrete to crack and the rebar can ghost through the surface of the finished piece. I've seen thinner counters crack all only where the reinforcement was. I have been using very minimal reinforcement in my counters--fiber that's already in the mix, and then pencil rod over only the length of the counter. So, up to 5 pieces of pencil rod lengthwise in a 24-5" counter. NO other reinforcement. It's the uninterupted strength through the thickness of the crete, with fiber netting it all together that makes a strong piece.
* The really low slump mixes don't vibrate well enough. I started with the really stiff mixes that hold form in your hand, stay in a ball when tossed into the air... BS--they don't vibrate and thus will be weaker despite the lesser water content, and be full of voids in the counter--and in the surface of the counter which is a real pain in the butt to fill. (I started using unsanded tile grout for filling voids and pits--pigmented with the same color as the counter--works wayyy better than making a slurry of cement and pig and it cures much faster) What I found is that a mix with more slump (don't ask me exactly what the slump is, I just know it's runnier than the Cheng book will rec.) and then VIBRATE THE HELL OUT OF IT!
*Form support and vibrating-- If you build the form away from the cabinet or whatever it will sit on, the counter will match the form and not the cabinet. If the form support is weak and there is bow or twist in the form when poured, that bow or twist will show up in the finished counter--then when the counter is placed, it will crack when settled on it's cabinet(s) To counter this, the cabs need to be solid(and underfloor!) and FLAT and LEVEL and NO TWIST anywhere... Now go build yourself a form table-- good sawhorses are fine for the base but build yourself a frame or cribbing out of 2x6 with sides longer than the counter, and crossmembers on 12" or 16" ctrs wider than the counter. Put it on the sawhorses and shim it perfectly flat and level. Screw everything together solidly. Now build your form on it and go. I build mine out of melamine 1" an 3/4" as in the Cheng book. With melamine, you don't need any form release and you'll get a perfectly smooth surface. To vibrate, palm sanders and hammers are rec. against the sides of the form or in the wet concrete; I say BS to that again! A palm sander works only for the sides of the form. he rest won't vibrate well... I have a Fein multimaster--I put a solid chunk of aluminum on it and buzz the sides with that works fantastic! Next, I have a small makita SDS rotary hammer. I put the chisel in it, put it on hammer only, go under the form and Ratatattat on the 2x6 cribbing that the form is sitting on and WATCH THOSE BUBBLES COME UP! Very satisfying and it does adequately vibrate. Fill the form half way, vibrate like hell to really get a smooth pock free surface, then place your pencil rod, fill the rest and vibrate again. Less the second time because the pencil rod WILL submarine down and end up in the face of your counter.
*The Cure - Tent the piece, keep warm and moist for about 4 days. Unform What a wonderful surprise! You'll love it. Smooth as glass. Now you can grind and polish while still green if you want. You can expose as much agg as you wish. Just a little grinding takes the cream off and you'll see only the colorful sands. More gets you into the 1/2" minus gravel.
I know you're only doing a sink and I've kind of gone nuts on the whole process of counters, but despite the work, stress and craziness associated with doing these things, I keep coming back to them. It is such a creative process and the results can be incredible--so custom. You can really do anything you want with color/texture/size and shape/inlays/forms etc. You can really be an artist and that makes me a happy dirtbag carpenter
I hope this is helpful for you and any others.
Cheers,
Pat
I always thought about epoxy grout like five star, its self leveling, and about 8000 psi.“Ilsa, I’m no good at being noble, but it doesn’t take much to see that the problems of three little people don’t amount to a hill of beans in this crazy world”.
Yeah, that would be great. At the point you have to fill some voids, all you want to do is be done with the counter. Don't want to wait another 3 days so you can polish off the filler...
I have never tried it, that epoxy is prety wet, and its a black color, I dont know if it would have voids or not, just smething I was always thinking about.“Ilsa, I’m no good at being noble, but it doesn’t take much to see that the problems of three little people don’t amount to a hill of beans in this crazy world”.
The spectralok epoxy grout is white, and then you add the powder/color, to make it whatever color you want. Seems like it would work well for that.zak
"When we build, let us think that we build forever. Let it not be for present delight nor for present use alone." --John Ruskin
"so it goes"
<With melamine, you don't need any form release and you'll get a perfectly smooth surface.> One of the carps that works for me took the Cheng course last year...he won't use melamine because he says the surface is not perfectly smooth...it comes out textured like melamine.The stuff he does that really is perfectly smooth has been coming out of a plastic or laminate form.Are you wet grinding? Outside of the gates the trucks were unloadin',
The weather was hot, a-nearly 90 degrees.
The man standin' next to me, his head was exploding,
Well, I was prayin' the pieces wouldn't fall on me.
Yes, You're right. And I'm wet grinding. To expose aggregate I start with 50g and grind off all the cream to expose the sand, then go deeper if I want to see rocks... Then I go 150-300-500-1000 and sometimes finer for the fun of it. I got a set of 4" wet diamond pads on ebay, BTW, from a chinese manuf for less than 50$ including shipping. I dunno if he's still on but the pads have been great. I'm almost thru the 150 grit after 6 or 8 counter jobs.
I agree you should polish when they come out of the melamine forms. You could hit the coutners with 300-500 straight off and get a glassy surface easily. There's a closeup photo in the Cheng book showing how the concrete reproduces the melamine perfectly... I get my melamine as seconds from a local manuf. that sells 4x8 2 sided for 5$ I use 'em up, then toss 'em at the recycler for 2.5$ a yard along with my cutoffs and other wood waste.
Cheers,
Pat
Just to add to the others - you can sand the melamine smooth before you pour, or use the 1/4" cheap shower board stuff at the big box.
If you are polishing, the melamine is fine unsanded.
Treat every person you meet like you will know them the rest of your life - you just might!
If you are interested in doing it, look at the specs for Wilsonart and Formica laminates. They make gloss finishes, and degrees of matte finishes. For cast crete counters, you want the gloss.
> Problem I have with mixing your own has been that it's really hard to
> get the fiber to integrate properly, always gets clumped up even when
> added to dry mix in the mixer.A trick for mixing anything with anything: When adding a small amount to a larger amount, first mix the small amount with another small amount of the larger amount. (Make sense?) Eg, when adding a half ounce of additive to a gallon of paint, first mix the additive with about two ounces of paint, get that blended real well, then add that to the gallon.Further, if your mix has several components, some components will likely mix with the additive easier than others. Eg, if I had separate sand/cement/gravel I'd probably mix the fiber with sand first, then slowly add some cement to kind of get it all coated, before throwing everything together. Or, if I was working with a bag mix, I'd consider screening a bit of it to separate out just the sand/cement, and mix the fiber with that before throwing it all together.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
Thanks for the great info.
Is the bag mix at HD gray?
And what type of coloring do you use? how much to use per bag of concrete mix?
Does anyone have a pic of the sink being talked about?
BrantWell, Guess I have to learn how to do THAT, now!
Here ya go . . .
View Image
Buddy is right down the ol' 101 from you. Mix, admixtures, colorant, advice, coolness, and whatever else you might need. Check him out at http://www.buddyrhodes.com
WOW...very cool...definatly gets bookmarked! Seems they give workshops not far from me but $500 for two days is kind of steep. I will keep it in mind and I have contacted them.
Thanks...
"Revolution is not something fixed in ideology, nor is it something fashioned to a particular decade. It is a perpetual process embedded in the human spirit." Abbie Hoffman
http://WWW.CLIFFORDRENOVATIONS.COM
I'll post a picture of the sink in a couple weeks.
You're welcome. The HD bagged mix is gray. Add powdered pigment to it. That stuff is had bagged to mix per cubic yard. Do the math for your counter and you'll find it's 2-3 cu ft max. Then break that into bags, OZ's of dry pigment, etc. Get a kitchen scale what reads in oz's and lbs.
Good luck!
I would use mesh to reinforce the sink, unless you're making it really thick.
Also, what about using a waterproofing admix, like xypex? I think it might affect the finishing stage a bit. I'm not sure how much in this sort of project- I'd do a test batch.
Post some pictures if you do it.
zak
"When we build, let us think that we build forever. Let it not be for present delight nor for present use alone." --John Ruskin
"so it goes"
you have alot of good information already.... I agree with the dry mix being BS... i do make my own... useing portland very fine white sand and 3/8 & under sharp rock (no round pea)
for counters I get a form bent to my specs at the sheet metal shop... i've used some over 50x and no issues... i do back em up with plywood & 2x... and i always cast on a dead level metal frame or table...
i do use rebar... or what i use alot of... is 3x3 1/4" steel grid... i get if from old store displays and from pallet rack...
i also like to cast on lexan... super smooth zero grinding required... (old store sign faces)
i have never cast a sink... but i do cast ss sinks into my tops... face down...
i use alot of johnsons paste floor wax... in the mold and in corners to soften the edge some...
good luck
p
<Concrete Farmers Sink>
Can't help you with that interesting problem, but I liked your title.
Sounded like a headline about some dumb farmers' misfortune with a new crop, posted to get a chuckle from our resident concrete guys and farmers.
Forrest
I gotta get back to work so I'm not reading all of these posts and don't know if anyone suggested using KERDI and topping it with whatever...
"Revolution is not something fixed in ideology, nor is it something fashioned to a particular decade. It is a perpetual process embedded in the human spirit."
Abbie Hoffman
http://WWW.CLIFFORDRENOVATIONS.COM
> and topping it with whatever...D-mix
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
I top my Kerdi with a wonderful desert topping I make in my Bass-O-Matic.
Yummy!
I prefer whirled peas.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
And if you don't like it there's always the Slegde O' Matic
"Revolution is not something fixed in ideology, nor is it something fashioned to a particular decade. It is a perpetual process embedded in the human spirit." Abbie Hoffman
http://WWW.CLIFFORDRENOVATIONS.COM