Curing Too Quickly?

scroungerJune 3, 2009

I'm afraid that my first Hypertufa project is destined for failure. On 5/18, I attended a class and made a bowl shaped container using this recipe: 2 parts portland cement, 3 parts peat moss, 3 parts perlite and binding fiber. We returned the following nite to remove the form. Either I wasn't listening or we weren't told to do anything other than to keep the container "out of the elements for 3 weeks". The teacher said to put it on a covered porch or in a garden shed. Well, mine has been stored in my garage until today when I put it in my rather damp basement. I'm afraid that it has cured too quickly in the warm, dry garage.

Is my project doomed? What will happen to it?

Unfortunately, I just discovered your website. I wish I had read all of this great info earlier.

BTW - I loved the process and the end result and I'm hooked on Hypertufa!

Thanks for any advice you can give a beginner.

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billie_ann(6b PA)

Welcome to the addiction.
Were you having frost warnings back when you made the bowl. That might be what "out of the elements for 3 weeks" was about. You need temps above 50F for working with cement outside and for curing. If you read the "FAQ" here and any of the threads there are many thoughts on curing. For planters, I unmold in 24 to 48 hours, wire brush or carve and put in a water bath for a couple of days then plant. If your bowl is a planter, I would have had it planted by now.
I prefer the water bath after unmolding but I use to wet the piece and wrap it in plastic bags for a couple of days. The idea is to keep the piece moist for a few days. Your bowl will probably be fine.
Keep us posted on your next projects. A-a-a-a-a and you don't need fibers for small projects. Just adds to the expense. Billie

    Bookmark   June 4, 2009 at 5:37PM
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Thanks so much for the advice. I think we were out of frost danger by that time, but you might be right about the elements comment,even though that wasn't explained. Your system sounds so much easier - the thought of having to wait weeks is not appealing! Do you think I'm safe to plant in it?
Thanks again, Scrounger.

    Bookmark   June 4, 2009 at 9:35PM
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billie_ann(6b PA)

Yep, plant away!
In your first post you listed that you were in NY. If that's true then you would have still had a chance for a frost back when you made the bowl. I'm further south (granted not much) and my last frost date is May 15th. I'm pretty sure we had a frost after that date this year.
So what's the next project? Billie

    Bookmark   June 5, 2009 at 5:29PM
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You are so nice to answer my questions! I think for now, I'm just going to make some more bowl-shaped planters which I will give as gifts. I need to get a bit more comfortable with the product and have to learn how to mix correctly, etc. I'm very excited to try some of the projects that I've see on this site! I'm in the middle of a large backyard project which will take most of my time for awhile. I live in Rochester, where are you in PA?

    Bookmark   June 5, 2009 at 9:01PM
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billie_ann(6b PA)

The bowl shaped planters make nice gifts. You can do some great carving on the sides, imprint leaves, embed stones/tiles/mosaics. What are you using for molds? If you can find a mold with straight sides you can see the carving and such better.
I'm outside Philadelphia.
What's the backyard project?

    Bookmark   June 6, 2009 at 10:16AM
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I used a plastic bowl for the first project. I like the idea of a straight sided planter - do you have suggestions for a mold? I understand that it's more difficult to work with straight sides as opposed to bowl shaped - agree? BTW, I planted mine today and it looks sooooo nice.
I'm turning my backyard into a wildlife habitat, sans grass. There is a perennial bed, a veggie garden, an herb garden, a butterfly/hummingbird garden, a meditation garden and a 65' long dry creek bed. Some of the areas are fairly complete, others in various stages of completion. I've hauled tons of rock, mulch and wood chips, but it's looking quite nice.
So nice to chat with you!

    Bookmark   June 7, 2009 at 7:45PM
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Billie are a wealth of info..Thanks for sharing your experience.

I too am really getting into this hypertufa creations. Did my first projects of border stones last week.

I also want to do some straight sided projects and I am going to try to use one of those rectangle closet organizer baskets as the form. I thought I would cover it with plastic, and build/mold it on the outside. I figure I will keep playing with projects until I run out of supplies...:0)

These projects are endless!!!!

    Bookmark   June 17, 2009 at 10:03AM
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billie_ann(6b PA)

scrounger, For a straight sided mold you can use a square or rectangular plastic trash can, a plastic wash tub or even cheaper a cardboard box with a plastic bag liner. The cardboard box with plastic bag liner will give you a wrinkly exterior wall, can look like stone. Sometimes if you work the cement mixture too much it can embed the plastic liner in the mixture too far. If it's too far embeded, just let it cure and use a candle to melt/burn off the plastic that's left sticking out. Don't breath the fumes from the melting plastic. You can make a mold from rigid foam insulation sheets just cut out the size walls and bottom, use 8 or 10 penny nails to join the corners (butt joins) and bottom then wrap around the sides with duct tape. Put the wraps about 3" to 4"apart, for a 12" tall planter wrap at the bottom then around the middle then around the top. Hope that makes sense. Put some strips of duct tape across the bottom.
It's a little harder to work with straight sides when you're first starting out but it's not that hard. Work with a drier cement mixture and make patties. Yeah, patties. Fill the bottom of your mold (I like working on the inside of molds) and tamp the mix to get out any air pockets. Make patties to fill up the sides, blending them as you go around the sides. Most of the time I use vegetable spray (like PAM) for a mold release.
Yippee for the completed planter!
ijensen, Your welcome. Most people on here share. One of my first creations was on the outside of a cardboard box that I had stuffed with newspaper. I didn't realize that the wet hypertufa mix would be so heavy. I didn't know that the sides of the mold were collapsing in. It was a strange looking planter. That's one of the reasons that I usually work on the inside of molds. Billie

    Bookmark   June 17, 2009 at 7:16PM
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