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dreamie_gw

curing questions

18 years ago

As previously mentioned, I am a newbie to making hypertufa. I have searched the site and found answers to most of my questions but I am still not clear on curing.

First of all, how do you know when a piece is done curing? Is there some magic formula that tells you? Do pieces have to be KEPT wet or just be wetted down from time to time?

I have seen instructions saying to cure pieces out in the weather and others saying to cure pieces in water? Which is best? Curing under water could be a problem I think, if a picee is large. Do they have to be submerged entirely?

Is making hypertufa pots and troughs something that can be done indoors? I live in Michigan where it may freeze or frost for a long time yet. Do I have to wait to do this outside till after the danger of freezing is over? Can curing be done indoors? I do have a basement that I could work in. I want to be able to use anything I make this year so I need to start soon. I am excited and I feel like time's a wastin, lol.

Any input you can give is greatly appreciated.

Chris

Comments (7)

  • 18 years ago

    Hi dreamie, you can make items in your basement but it's not advisable because of the cement dust. Some items like large Hypertufa containers and pots can get very heavy to carry outside, these need to be almost made on the spot you want them to be placed. Smaller pieces can be water submerged completely, but if you water mist daily and cover tightly with plastic this works well also. Curing can be accomplished inside-if you mist daily. During hot summer weather the easiest way is to carefully place a relative new piece that is solid plus misted for a couple of days, (don't move to soon) in a black garbage bag and place in full sun, very tightly closed, I like to place a wet rag in the bag also; this method will create condensation to help the curing processes, after five to seven days you can remove the item, and use with care. Never attempt to move anything that you can make a scratch in. Always wear plastic gloves and YOU must use a mask while mixing the dry ingredients. Hopefully someone else can jump in here and give you some more advise. wendy

  • 18 years ago

    thank you for your answer Wendy.

    Can I start making items while there is still danger of frost? (around here that could be July 4th, haha)

    if the weather is cooler, does that lengthen curing time?

    I am realistic... I do not like cold weather and I know I am not going to be outside doing anything till it's at least slightly warm but I've got the bug bad!!!

    Chris

  • 18 years ago

    If this is your first time working with tufa, you can certainly start now in your basement. Start with small items like flower pots and Gnomes. Drying in the basement will be fine, like elephantear said. Rig up a work table at a good height for you. I used a large piece of scrap lumber covered with heavy plastic and placed over two saw horses. I stapled the plastic on. Cement dust can be a big problem in an enclosed place. Maybe not so much if you are mixing small amounts and handling carefully. One more important thing. Don't use your laundry tub to clean your bowls. Cement is not good for drains.

  • 18 years ago

    Shirleywny said:

    One more important thing. Don't use your laundry tub to clean your bowls. Cement is not good for drains
    ****

    ya know, as smart as I think I am sometimes, I did not think of that. I can imagine what a problem that could turn out to be, ugh.

    As impatient as I am to get started, I think I am going to have to wait till I can do this outside. I have a bad knee and trudging up and down the basement steps with heavy pots is probably not a good idea. I can still collect potential molds though :)

    Chris

  • 18 years ago

    About curing: the curing is caused by the chemical reaction of the concrete caused by the water. So, after you have made your tufa item, wrap it up in a plastic bag or cover it with a big sheet of plastic if the item is too heavy to lift, etc. for 36 or so hours for the first "cure", then unmold it and either (i) put it in a sealed plastic bag (sealed to close in the moisture), or (ii) you can completely immerse it in a tub of water, or partially immerse and put a lid on the tub to hold in the moisture; or (iii) if it's warm outside, put it in a shady spot where the moisture/dew will get on it and go by with a garden hose every day or so and wet it down.

    You don't want to put it in a plastic bag and put it in the hot sun, as the internal temperature of the bag is way too hot for curing and will make the pot/trough weak.

    In the winter, I work in my garage. The routine I've come up with (after one winter of working in the cellar and making a mess that still isn't completely cleaned up) is to mix my dry ingredients in a cement mixer (or tub) which I push outside so that the dust stays outside. While this is going on I use a propane heater to knock the chill off the garage and set up to make the trough. Then I dump the dry ingredients into a mortar tub and using hot water (which makes it mix easier -- concrete experts out there tell us why !!), make my item and put the finished item in a plastic bag and put it in the cellar. I try to unmold it in the garage after the first cure as the scraping, etc. makes a dusty mess, too. I am not neat enough to work in the cellar and the furnace doesn't need the dust in any event. Anyhow, then put the item back into a plastic bag and let it "cook" in the cellar until you are ready to use it. I've left troughs in sealed plastic garbage bags for months and they still have moisture in them when opened. The longer you let your tufa cure, the stronger it will be. I've found that although not necessary with smaller pieces, the larger ones need the extra strength and do better with the 28 day cure.

    There are also some mixes you can get from the local masonry dealer which can help accelerate the curing when concrete has to be worked with in cold weather.

    Just some ideas, and they've been working for me. Haven't had any of my customers return a broken trough yet and they stay outside in the Northeast which can get pretty cold!

    So, the rules of curing concrete/hypertufa are pretty basic and there's no need to get too fancy or worried :)

  • 18 years ago

    I love working with hypertufa. I have a spare room I work in and it seems to be working out great. I am working where it is warm and I just cover the floor with an old shower curtain to protect the rug and away I go. I use a mask until everything is moist. I am stirring with a drill motor with a long sheetrock mud mixing auger I bought at a pawn shop it works good. I usually can carefully unmold in 24 hours. Using a mask again and safety glasses I take a wire brush to rough the sides. DO NOT PICK UP BY THE SIDES UNTIL WELL CURED. I keep in plastic garbage bag to cure. Sometimes I spray and re-seal sometimes not. I love the results you get with hypertufa. The bigger troughs Ill have to wait to make until Spring. The ones I made last year came through the winter great. We get down to zero here. The nice thing about making troughs through the winter is by Spring they are ready to plant.

  • 18 years ago

    Yes by all means don't pour the cleaning water down the basement drain. After the clean-up my DH carry the dirty water outside in a tall bucket and pour it on a piece of waste ground. In the basement I only make a couple of smallish pieces at a time, even the large hollow spheres are considered a small batch of mix as it's just one layer at a time. Just waiting now for the outside temps. to warm-up.

    club 53, I've never had a problem with anything breaking while sun curing items in a tightly closed plastic bag, got this info from some pro's here-but I'll take your warning and keep a check on this. Also some of my exposed items have been outside though two Iowa winters with no cracks. Of course the birdbath basins are covered tightly. Wendy

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