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Hypertufa not setting up (newby)

Posted by Ronh4 none (My Page) on
Thu, May 30, 13 at 22:46

Some of my first efforts at pottery Hyper- failed to set up, they never got hard. I was wondering if I kept my mix too dry? At first I thought mix like cottage cheese but mine was way too dry, I did not want it to slump. My last batch was a bit more wet and so far the pots seem to be setting up much better.

Any comments would be appreciated.
Last question, is it a good idea to soak the pots in a bucket of water for several days to remove the lime before using the pot for flowers?


Follow-Up Postings:

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RE: Hypertufa not setting up (newby)

What ratio are you using for the mix itself? this has more of a bearing...the more cement/sand the stronger the item the finer the detail...peat moss, perlite or vermiculite less if you want strength. It's a balancing act . Cover the item with some plastic to slow the curing down a tad...makes for stronger.


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RE: Hypertufa not setting up (newby)

When you say "pottery Hyper" are you using clay in your Hypertufa mix? Cottage cheese consistency is okay. What Hypertufa recipe are you using? Did you thoroughly mix the dry ingredients before adding the water? How long did you leave them in the mold? If you can give more details it would help.
Yes, you can use a water bath. After you unmold the hypertufa, clean up the piece.....wire brush or carve, then place the piece in a bucket/tub of water to leach out the lime. Change the water every day. You need to do this for about 3 days. Do NOT use bare hands in that lime water, use rubber gloves.


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RE: Hypertufa not setting up (newby)

I am using 1 part cement to 1.5 parts peat and 1.5 parts pearlite mixed completely by hand before adding water. I left the mold on for several days.


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RE: Hypertufa not setting up (newby)

interesting mix, personally never tried a mix with so much perlite. I forgot to add the importance of mixing thoroughly which billie suggested this is very important. If the mix is not mixed thoroughly you can get areas that have no cement for example and no bonding consequently. I mix by hand too :). Try this mix : 1 part cement ,1.5 peat ,0.5 sand, 0.5 perlite.. I often experiment with mixes as it gives results you would not expect! Don't be afraid to experiment :)


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RE: Hypertufa not setting up (newby)

Themes, I will use your mix this week, picked up a bag of sand yesterday. Will comment later when I have finished a batch.


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RE: Hypertufa not setting up (newby)

You should always have some sand in your mix.


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RE: Hypertufa not setting up (newby)

something to look forward to. I've done no sand mixes before and they came out fine but it depends on what you are making what purpose and the thickness of the item. For your purposes you will need some sand


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RE: Hypertufa not setting up (newby)

I've used that ratio: 1 cement, 1.5 peat and 1.5 perlite lots of times with good results. I leave it in the mold for 1 to 4 days depending on how fast it sets up, which can depend a lot on the temperature and the size of the mold. It's still soft enough to carve a bit when I demold them, but the pots get covered up and kept damp for a month after that to further cure the cement.
Lately I've been using less peat and more perlite for a 1:1:2 ratio and it still works quite well. I also love vermiculite.
I use enough water so that when I squeeze a clump in my hand, it will not crumble but stay together when I toss it lightly from hand to hand, and a little bit of water squeezes through my knuckles.


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RE: Hypertufa not setting up (newby)

intrigued as I had never considered using so much perlite. Don't get me wrong I see the benefit namely the weight decreasing. My concern or reason was concerns about longevity, most of the thing I am making are structural or need to take weight at the moment at least. Can you elaborate further regarding the size of the items your making and the purpose? thanks


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RE: Hypertufa not setting up (newby)

Mostly pots. Some of these have lasted quite a few years and none have broken so far. Here's a picture of last year's second crop.

FWIW, I took a class a couple of weeks ago at a local nursery to see if I could learn some more finishing techniques and was surprised that the teacher used the same ratio ,1:1.5:1.5, yet some of her pots are really huge.
The only thing I really got out of the class was the use of a large "b" file for carving and shaping, but that was worth knowing. (Garden web won't let me post the name of the file because it could be construed as profanity, even though it really is the name of the file.)


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RE: Hypertufa not setting up (newby)

tt, I think you can get creative if it blocks you. How do you carve with a ba*tard file? It's flat, has teeth on 3 or 4 sides. I like to use a wood rasp for a rough finish and carving.


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RE: Hypertufa not setting up (newby)

The teacher was using the "B" file for smoothing and rounding the tops of the large thick walls of her pots. On some pots she used it to get this really nice smooth flat top. It was the coarsest "B" file I've ever seen.
I would think a wood rasp would work better for a lot of carving. So off to Harbor Freight I go!

I've been using a stiff wire grill brush for texturing the outside of my pots to get rid of the wrinkles left in them by the black garbage bags I use to line the molds.


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RE: Hypertufa not setting up (newby)

I just use my hands to round the top. You mound the mix above the top of the mold then use you hands to smooth and round the top.
What kind of molds are you using that you are lining with garbage bags?


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RE: Hypertufa not setting up (newby)

cool pots :). Food for thought. You may have solved a problem for me with a project I am doing. Thank you.


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RE: Hypertufa not setting up (newby)

Well I made some mud today 1 cement .5 sand .5 perlite and 1 part peat. Added just a wee bit more water so that a handful shed a few drops if squeezed. Things went well, three pots are wet and in the bag until late tomorrow or so.


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RE: Hypertufa not setting up (newby)

leave them to cure longer so not as to damage them


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RE: Hypertufa not setting up (newby)

I looked at the pots I made yesterday, they are looking good, will keep them in a misted bag for a few days.

Made another batch this afternoon using the same mix, things are looking much better. Thanks for all the help on this form. Will take pictures soon.


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RE: Hypertufa not setting up (newby)

OK, I really appreciate all the comments. Two batches made, keeping them moist and they are looking good.

Time I posted some pictures for comments.
These are pots I made over the last few weeks, nothing special.

Here is a link that might be useful: stuff I have made


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RE: Hypertufa not setting up (newby)

Haven't figured out how to do more than 1 picture so will make another post: Here is an orb I made using a glass for mold, smeared some paint and my wife liked it. It is sitting on a wood chair with seat cutout for a planter that I am working on.

Think that will add something to a yard? This is fun stuff to work with.


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RE: Hypertufa not setting up (newby)

I like the effect of the blue paint in your last pic. I'd be tempted to glue fake gemstones too :)


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RE: Hypertufa not setting up (newby)

this is a planter i made recently, with just sand and cement a 50/50 mix.


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RE: Hypertufa not setting up (newby)

That's an unusual green! I like it. Is it due to your climate? when I get growth on my tufa it's darker green and less fine. typical mossy growth...not as fine as yours.


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