Questions re concrete cast leaves.

21 years ago

This is a duplicate post of one at the hypertufa forum. Wasn't sure where to ask these questions.

Mom, kids 9 and 11, grandmother and a friend cast concrete leaves yesterday for the first time and are awaiting "unveiling" tomorrow. During the course of our experiment, several questions arose and I hope someone can answer.

The recipe we used was 1 part portland to 2 1/2 white sand. I'd heard that adding Elmers glue can be added to strengthen the concrete. Elmers permanent or school glue and when do you add it? How much to perhaps a gallon ice-cream bucket of mix? How to test mix for enough water? I think ours may have been too runny. Or perhaps we didn't wait long enough before applying it to the leaf backs. Small cracks seem to be developing in one of the leaves. Anyone have any idea why this happened? We did use fiberblass tape to reinforce.

The completed casts were covered with saran, then newspaper to keep the sun off. Would hot sun have been bad or good? The castings were misted several times since completion and will get more til we uncast the leaves. Can we continue to mist to "cure" them? Or should we leave them in a bucket of water for a week or so to cure before painting? (We have two that are too large for buckets.)

Next comes the painting. I need recommendations on how to proceed. I think we'd like to use several colors blended together. We have oodles of Apple Barrel acrylic craft paint. Can we dilute this and use on the leaves? I understand we can also use water-based house paint. Is this correct? Do we do the veins first? Then what? Can you seal as soon as the paint is dry or should we wait for a day or so?

I've seen so many great leaves on links to this forum, I'd really like our project to have a happy outcome and a positive reinforcement, especially for the kids.

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Comments (3)

billie_ann
21 years ago
Elmer's glue isn't necessary for leaf castings.
Cracks can be caused by too much water and drying out too fast. Cure them in the shade; not under newspaper in the sun.
I unmold most of my leaves in 24 hours, small leaves can be unmolded in as little as 8 hours or less, large leaves can take up to 48 hours. I'll mist and wrap them back up in plastic for a day or two to "harden" them before putting them in a water bath. You run the risk of breaking the leaves by handling them too much when their still green. The water bath is for leaching out the lime and to finish curing. Wear your gloves when handling fresh made leaves, even when putting them in and out of the water bath. Change the water every day and the lime should be out in a few days. The lime will take the skin off your hands until it's leached out. Not everyone has the same reaction. The ones that are two big for your bucket can be hosed down a couple times a day but this can take awhile to leach out the lime. If you have a wheelbarrow, mortar pan or kiddie pool that will work. Until the lime is leached out, every time you touch them and they are wet or you have a wet hand you'll get a skin burn.
You can use craft paint or exterior latex house paint. I paint a base color on first then accent the edges or high spots. You can paint the veins first or last it's up to you. I don't seal so can't help you. Cajunmist gave me a tutorial on dry brushing and that really works well on leaves.
What are you going to do with your leaves? Billie
Fleur
Original Author
21 years ago
Thanks for the information regarding lime. My large leaf still has leaf debris flaking off. I actually like how it looks with that stuff on, sort of fossil-like. I haven't put it in any kind of waterbath yet. Can I still do it after the leaf stuff flakes off or should I have done it immediately after unmolding? I don't have the answer to that one yet.
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billie_ann
21 years ago
You can put them in a water bath to leach the lime out at any time. If you do it shortly after unmolding your doing two things at once. Curing under water and you don't have to worry that the piece isn't getting enough moisture during the initial curing stage. You're also leaching the lime out at the same time. It can take a long time for the leaf debris to flake off.