April, Home Depot should have all the supplies you need for hypertufa. For planters/troughs I have a preference for the recipe of Portland cement, sand and peat moss in equal parts. Substituting perlite will give you a whiter look and vermiculite will give you a whiter,sparkly look. I always have some sand in a recipe. I'm not a fan of fibers or admixes. Accelerators make you mixture "set-up" faster. In your heat they'll set-up fast enough. I have troughs that are 15 years old without reenforcement or admixes. Just makes your piece more expensive. There's someone on this forum called the olddutchman that lives in Arizona. Try doing a search on his name. He's been making planters for a couple years and could let you know what he's done.
Cardboard boxes need to be lined with plastic, dry cleaning bags work. Just make sure you don't work the mix too much when placing it in the box or the plastic bag becomes embedded in your mix. You don't need a mold release for plastic bags. Regarding reinforcing the cardboard box, it all depends how thick the cardboard box is. For good measure you can wrap the outside of the box with duct tape. If you get larger than the 18" square that you mention then you need to reenforce the cardboard box with wood frames.
Plasticware works well for a mold just spray with PAM baking spray for a mold release. Make sure you clean these as soon as you unmold. The hypertufa will etch the plastic and harden and be very hard to remove.
You shouldn't need reenforcement in the mix for an 18" square.
You can add feet during the molding by putting a "cross" made out of styrofoam on the bottom of you mold. The empty spaces in each corner will be the feet just like in the picture on the Hypertufa forum home page. You can add feet after the fact by making feet from whatever mold you pick and cementing them on with a mortar mix. You can also add drain holes if you forget to put them in when molding by drilling with a masonary bit after the piece is cured.
Good luck. Billie

My HD doesn't carry fibers. Your best source is your local concrete company that has those big rotating barrel trucks. They come in a paper bag that is quite delicate (designed to be tossed into the big barrel & it disintegrates) & costs about $10 per bag. One bag is good enough for a cubic yard (3ftx3ftx3ft) of concrete, so you'll just need a pinch for small projects.

Wire mesh or hardware cloth is in the fencing or concrete area.

One technique that is useful for cardboard boxes is to tape all sides closed, not leaving an open side. It can make a real difference.

If you're wrapping with plastic it won't stick directly, but you must tape closed ALL folds or gaps, or the concrete will work underneath and trap the plastic, & you'll have to pull the plastic out in chunks, and it looks tacky.

I've never used acrylic admix, so it may make the concrete set up faster. I prefer latex polymer (specifically Hornweld from commercial building supply companies), and it usually seems to slow down setting, at least here in the PNW, even on warm days.

WARNING: Don't build with concrete or tufa on days where temps are expected to be over 90F -- your work will practically be guaranteed to crack. (Want to ask me how I know?) And keep your setting or curing project out of the sun.

Yes, Vasoline will work as a release, but don't goop it on thick. A thin film is all you need. So will a thin coating of Pam or other non-stick spray, motor oil, etc. Just keep it thin.

Got some old PVC pipe or wooden dowels lying around? Cut it into short lengths for drainage holes in pots: be sure to put them in place as you're building the pots. Oil the dowels so you can twist them out after the concrete has set. It's easier to put the holes in when you're building than to drill them when the concrete has set.

TIP: If you will possibly have to move your project, build it on a piece of motor-oiled plywood. The oil will help it release, and the plywood can be picked up and moved without having to shift the concrete.

Since you say the outside doesn't matter, I would be inclined to omit the peat and replace it with perlite. Peat is porous and perlite is less so. Since you're going to tile the surface, I think you would want minimal porosity so water doesn't work under the tile and pop it off. But if you are in a part of AZ that doesn't have freezing temps AT ALL, it would probably be less of an issue.

BTW, most working methods that apply to concrete will apply to hypertufa, mostly with the exception of porosity & strength. And freeze-thaw problems in some areas.

Good luck!

Sue

Thank you Sue and Billie for the replies.

Especially about the heat, I should probably try this at night. I never thought of the temps. and the days here are hot.

I think I have my list all set. I was going to toss out an old table that has been weathering on the patio, but now I am glad I didn't.

Guess all I need to do now is go shopping....

April

Hi Y'all,

I came across some really neat looking objects for planter molds. They were changing out industrial lighting at our plant and had quite a few old reflectors for high-bay lights. Over the years there had been many different styles of lights installed so there is a variation in the sizes and shapes. About half of them are fluted on the sides. Their large open end dimensions range from about 14" to 24" and heights of 14" to 16". All aluminum. These are like stadium light reflectors.

If you like bowl shaped planters and want some large ones this might be a good direction in which to look for molds. Your local industrial lighting contractor may be able to get some of these for you... if you can get them for free. They are quite expensive to buy new.

David

Everything and anything can be a mold. Never noticed lots of things until I fell in the mud hole.
Paws

Okay, got everything but the perlite and gloves, but located perlite at Lowe's so I can get that today.

Took my husband to the HD, and that turned out to be very expensive by the time he got stuff. Next time I am going alone. He says " You thought this was a cheap hobby, we spent alot"...it would have been cheap had he stayed home.

I also have some wire mesh he feels I need, he can cut it for me.

Hoping to get started tomorrow.

April tell that man of yours to "Pound Sand"! :-)
$25 worth of Portlands, Peat, and sand can create $500 or more worth of items for your yard.

This can be a very inexpensive hobby.

I've seen woodworkers turn $150 worth of hardwood into $3 worth of firewood.:) ME!

Sorry I forgot all about the tools.
A wooden spoon and a brick...and you really don't need the Spoon.:)

I am assuming the wooden spoon is to stir, but what am I to do with the brick? Threaten my husband with it when is laughing at me about this endeavor? :)

It would have been a way cheaper shopping trip if he hadn't bought maglites and who knows what else.

I found the perlite today, I will try it tomorrow evening.

I decided the 18 X 18 planter would be too small on the inside, so going with a bigger box set up. Good my husband insisted on me buying the wire mess, after all.

Is the reinforcing on the boxes with duct just a few wraps around the box, or am I covering the whole thing with duct tape?

I have got about everything I think: perlite, peatmoss, an 80 lbs bag of premixed cement, and a really big cooler pad that is made of some shredded something that my husband has decided would be good to try too. For all his ridicule, he has alot of opinions on how I should be going about this. Then my MIL has a bag of some sort of cement she is bringing to donate to the cause. I was worried I would run short on supplies midway threw whipping it up, but now I think I need more molds.

So, now I have another question: If I am using the wire mesh to reinforce the planter, do I make it go all the way around the planter and across the bottom? or am I just reinforcing the length of the corners?

April

Even if you should run out of supplies you can always wet the existing piece and apply more tufa on top.
Paws

April,

Listen good to these guys and follow their instructions well. I did not and I have about 50 lbs of material filling a low spot by the garage!

They told me that concrete has an affinity for metal and it will stick. I said, 'Okay', and figured that a coating of silicone spray on my aluminum light reflectors would keep anything from sticking. WRONG! What a mess!

I'm looking for a source for latex now. Some of us have to learn the hard way.

Anyway, the folks in this forum truly love to see you succeed. Good luck with your first project. I hope your planter turns out well.

David

Hi Folks;

Three quick comments before I head out to the mudhole:
The brick is harder than 'tufa, so it is an ideal shaper when the 'tufa is on the dry side.

I line metal molds with plastic recycling bags, using them over and over. I like the "artistic" etchings, and claim to put them in on purpose. I unmold on the green side, at about two days, and the plastic pulls away easily.

Watch out if you are using premix instead of straight portland. The pre-mix has aggregate in it already, so if you use it, say, 1:1:1 with peat moss and perlite, you'll have a very small amount of cement to hold the pot together. Seeing as you've got the premix already, try adding maybe, 1/4 peat, and 1/4 perlite. The premix has nice angular aggregate in it already for the portland cement to grab to so it should be okay.

What do the rest of the "mudhole"ers think?

Mercedes (on batch # 186 and still learning!)

David-for latex,try Smooth-on.It should be easily available to you in the States.Also,I use metal bowls as molds all the time and I use Cresset Crete-Lease.I have to tap the bowl to release it,but it does release.I've been using the same stuff for my plastic molds and its fine as well.Go REAL thin on your application;lasts longer(not cheap!)and fewer bugholes.
cheers

I should go : 2 parts premix, one part peat and one part perlite? Do I need another 80 lb bag of premix or should that do me?

Just over 18 x 18? You should have enough. Try putting all the supplies in the mold. Like a dry run. Premix still in the bag, and measured peat and perlite. The cement (portland) in the mix and the water you add will not take up space. I don't have experience with premix, but if the supplies competely fill the mold, you can be pretty sure that you have enough, with a little left over.

Blooming

Bump