don’t slam me for no pics…
but heres what i’ve worked out for …. what i think is as fast as i can build a form and make concrete countertops…
since I’m casting them for 19 units… and each unit gets 3 to 6 seperate castings… this is the best i’ve come up with… so far…
no templates… i make a rough sketch with measurements with a piece of carbon paper face up under the page i’m draw’n on… since i cast them face down… this gives me the reverse image i need without thinking…
i have a couple “cast tables” set up outside with a tarp for an awning about 20ft long on 12″ i-beam leveled off… painted 3/4″ osb… then 1/4″ waxed lexan which the concrete is cast on giving a very smooth surface right out of the mold… I’m casting them 1.5″ thick… for form material I’m using 1.5 x1.5 x 1/8th angle iron this is cut & screwed down through the lexan… using angle iron screwed down lets me skip any backing for my forms and is very easy to keep things lined up and real easy to pull and reuse…
i cover all the surfaces of the angle iron with clear packing tape leaving 1/4″ to lap onto the lexan giving me a very clean smooth finished corner right out of the mold… for corners i do the same thing with a small piece of tape makes a nice finished outside corner… I’m use’n 3″ tape so the rest gets folded over the angle iron make’n it very easy to clean and reuse the steel plus i use it to cover the screws so they don’t get clogged with spilled concrete… for easy clean up and remove’n the screws…
I’m use’n stainless undermount sinks that i’m casting in place … face down leave’n the flange exposed on the finished top…. i place a 1/8″ think x 1/2″ wide strip of foam tape around the sink flange before i place t face down in the mold… i then secure the sink in place with a flange screwed to the form and a piece of allthread come’n up through the sink drain hole… where i clamp it down with an old sawblade a washed and a nut… (2 of these on double bowls) this clams the sink down and seals it to the mold… and when removed from the form it recesses the exposed sink flange about 1/8″ below the surface of the countertop… somrtimes i cast the hole for the faucet if i know where i want it or sometimes i’ll just drill it later… all sink tops get rebar front & back of the sink…
simple sand rock and portland mix…. 1 bag portland three 5 gallon buckets of fine white sand… one bucket of small jagged rock… 2lbs of carbon black… 1qt latex bonding agent (can’t tell a difference with or without) a fairly wet mix since i’m portland rich… this makes an almost jet black mix…
i place the mix to within 1/2 inch of the top of the form… vibrate like crazy with my hammer drill until i see no bubbles … this takes a while more than i usually vibrate… i then place whatever rebar i need in the form… push it down into the fix and then fill the form and screed… vibrate a little… hit the surface with a mag float..ie will be the bottom but needs to be smooth so it sits on the counters well… clean up the edges.. clean as much spilled concrete as i can… and wait… maybe 45min… hit the bottom with a steel trowel… get it pretty darn smooth… make sure the edges up against the angle iron forms are clean with the same trowel… and let sit for a min of 48 hrs…
pull the forms… one long piece of angle iron always stays screwed in place on the casting table this is almost always will be back/wall edge.. the rest gets moved around…. if i’ve done my job the edges will be very smooth… i then flip the castings on edge (the back one) and we carry them to saw horses where they are laid face up…… again if i’ve done well they will need nothing they will be smooth and ready for sealer… after a quick water bath and remove’n the foam tape from the sink edge… i use a semi gloss concrete sealer that penetrates into the concrete and drys to recoat in about 5 min… which i do… then about an hour later i put on a 3rd coat… this is out in the sun and the surface get too hot to touch… so i’m pretty sure it’s “baked” on…
no two are the same but pretty standard sizes so i keep my metal cutting down and reuse the angle iron … most are 24.75 deep or 25.75 deep most are less than 9ft long… anythin less than 4ft i can move alone pretty easy.. we always take alot of care with the weaker sink units… but other than that if it wasn’t for the “cure time” i could do 3-4 a day… as it is the i’m down to 1 every 2-3 days depending what else i’m doing that day… i use my bobcat to move all the materials around… so it takes about 20-25 min total to load the mixer mix and place the mix.. have another guy clean’n everything up while i’m finish’n the bottom side and cleaning up around the forms…
I’m also casting some back splashes… and a few bartops at the same time… i usually have enough room on my casting tables to at least get one piece cast for the next unit… so that adds up… one “mix” will do most of the smaller kitchens (about 11-12 running feet of countertop) i have enough cast table to do about 16ft of counter and 12ft of bartop plus some back splash… or 2 full mixes…
no labor… just materials… i have about $20 in each kitchen…
even this is slower than i’d like so i might build another 16-20ft casting table…
just one of the things i’ve been doing…
:)p
Replies
Cool beans.
We won't slam you for no pics but we should!
pretty much akin to torture is what it is
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Edited 7/9/2009 11:36 pm ET by rez
You are a hoot Ponytl. I gotta get up to Memphis to see this condo project. I bet it's da bomb!
Pictures PLEASE!
With all the info out there i'm curious to know what resources you used to bone up on your methods. I'm also curious about reinforcement- do you use rebar only in the sink tops? No welded wire mesh? No other steel? Pics would be great but we'll pardon you for the time being. Sounds like they look swell, though...
resources? here mostly i float ideas... I build alot of tools.... since i have a full steel fab shop on site... so i'm always welding up something to do something.... and i think i have a grasp on the natural order of things... ie what has to be done in what order to get from a to b
I all but never make a proto type.. i think it out and the first one gets used about everytime... I refine each one after... at the end i might have made 20 and they all trun out well but the method used for the first might be nothing like the method used for the last...
case in point... the countertops... i was use'n some 1/2" x 1 1/2" plastic material i had for forms... screw'n it down with 2 1/4" screws... and backing it up on long runs and i was putting latex caulk in the corners... this worked but it took to long and i had to wait on the caulk to dry or set... use'n the same material i started using the packing tape in the corners and edges... resulting in an almost shine on the cast surface... plus the forms were easy to clean after... just pull the tape... then i went to the angle iron i still have my 1.5" thickness but no backing required... i can use 3/4" screws and less of them... i now not only cover the iron with tape on the casting side but on the other side also... 30 seconds to tape... 5 seconds to pull it off vs... several minutes scrap'n set up concrete otherwise...
yes 1 rod 3/8" on each side of the sink tops... they are usually about 6-8ft and only 2.5 in front of the sink and about 4-6" behind (wall side) so i put one rod front and one rod back.... i use all thread since i mined about 200 8ft sticks out of a dumpster... i say rebar but it's all thred...
now if i have an over hang or a small ELL going around a corner... i'll find some scrap short rod to toss in... but no mesh... no fiber... if it looks like something won't be supported i'll put some rods in...
the only reason for the rod in the sink units is so i can move them into place... they don't need it once set in place...
I will work on some pics they really do look pretty nice...
i cast a set late today... put the mix in the molds/forms @ about 3:30pm... finished by 4:30 and we did 2 full mixes even cast some 5/8" thick back splashs... which is a first for me to cast that thin... i added about 20% more portland just in case... and i liked the mix... just seemed "smoother" so i might be doing that on all my future mixes.. ups the cost of a set of counters by $2.20... so... :)
thanks for asking
P:)
The more you write about those lofts the more interesting they sound.
A couple of questions:
What kind of sealer are you using?
Can the cast in sinks be replaced or are they in there for good?
yes the sinks are cast in place... no replace'n em... you might could cut em out and use a surface mount sink in the hole... but yes they are one with the counter.... make'n a form and leave'n a hole in the casting and then mounting a sink would one ... i think make a weaker casting... and TWO... take way too much time and labor...
i ended up with a few cases of some kind of "concrete sealer" i really have no clue who makes it or even where i got it... I'll be sad when i run out... it says safe for dairy use... so if it's good for milk i guess it's safe for food...
I'll look and see exactly what it is... i know this... mineral spirits won't clean the brush... it takes Xylen (sp) or at least thats the only thing i had that would clean a brush that had started to dry with it on it....
p
so on the front and sides ,where you screw the angle down.
on the next one lets say it's different,how do you deal with the holes from the last one?i would guess fill them with something but i would think it would be hard for them not to show.
i was thinking a little squirt of hot glue ,then cut them off for the next one.
the older i get ,
the more people tick me off
you are good.... yes holes... and all are drilled through the plastic so it doesn't crack... but careful not to go into the wood under the plastic .. if you do then no bite for the screw...
dealing with the left over holes... first i tried small dots of packing tape... which wasn't bad yes you could see them on the finished product BUT since i try to keep the front edge form constant... meaning i have angle iron all the way down 2 edges of the lexan and leave it in place and work off of that edge/corner each time i make a new form..... the other edge is pretty constant( which i try to make the wall edge on the finished counter)... meaning the most counters are 24.75" wide or are 25.5" wide... with a 1.5" leg of the iron scewed down it usually covers or reuses previous holes on that side... if not the holes are so close to the wall side the tape works because the reflection it leaves is almost nil... so i'm only usually moving one form edge in or out for how long the counter will be... on these i've shifted beweeen the tape and filling with paste wax ... once out of the form/mold if they show they are easy to take a 800 grit diamond polishing pad to (pad are for a 4.5" grinder but i just use em in my hand) and a light scuff before sealing and you don't even see em... i use this same pad across the front bottom exposed edge to knock off the "edge" i have about 60 seconds of this on each counter...
i like your hot glue Idea because there are a few holes that end up where i'm dealing with em on every countertop...
on the back/wall edge I'm dealing with some exposed 12" heart pine posts that protrude into the room past the surface of the finished drywall... usually by 1"... for these i just place a block in the mold/form and do nothing but tape it in place...
the most tricky are the corners where there is a lazy susan... and one leg is 24.75 and the other is 25.5... makes the corner 37 wide x 36 wide in the mold... with an 11 x 11 inch "notch" for the exposed inside corner...
thanks for the hot glue tip/idea
P :)
If I am ever anywhere near Memphis I have to stop in to see you. How far out of the way from Cleveland to OC Maryland would it be?
I refuse to accept that there are limitations to what we can accomplish. Pete Draganic
Take life as a test and shoot for a better score each day. Matt Garcia
it's on the way... I always have ice cold lemonade... hell the only way i get pics posted is if someone from here drops by and takes em :)
P:)