The most scientific way i can think of is to drill a hole in the center of each plate. Put a string through the center bottom to the top, tie a stick to the string so it will not go back through the hole. Each one needs to be in the same position. Put the first disk over parallel boards, boards the same distance apart, to the very edge of each plate as long as it is the correct thickness, with the string hanging down between them. Attach the hanging string to a fish weighing scale. Pull down on the string using the scale and note the pounds it reads before the disk breaks. If you kept the whole disk or plate the same thickness, say, 1/2", this test will work perfect. If your edges taper down, you will not know a thing. This would be interesting. Please keep us posted.

Jo

Jo I tried the fish scale with weights.
Too violent.:)
I switched to just filling a bucket with sand until the tufa breaks and then weigh the bucket.

The bucket of sand is a good idea. Just put the fish scale between the test piece and the bucket and you can get a reading off the scale. It might be violent and messy. How much more fun can a person have!

Laura,
I am unclear what it is that you are trying to test....
how much weight you can hang from a plate of mix
how much weight you can put on top of a plate

Have you thought about testing the durability by dropping the different thickness from different heights, or having someone step on just a small edge, with their cloddhopper shoes.
I am not trying to make fun, I am trying to understand why more clearly what and why?
If it is leaves you are making and want them to be thin (or thick)they still need to be treated with some care.
Happy casting,
At the very least you will have some interesting durable (maybe) charger plates.
Dena

Dena - I'm not sure what I want to test either. I am hoping some of you who have more experience can help guide me. (by the way, I love your terrific projects and am grateful for all the photos and directions!)

I read a lot about how to make the leaf casts "stronger" - admixes, fibers, various recipes, etc. When I make the leaves, I notice I admire my thinner ones more than my thick ones. So -- I would like to determine just how thick I need to make them to have a good chance they will not break if dropped from 12 inches into the dirt or bumped into the edge of a flowerbed or whatever natural accidents are likely to happen to concrete leaves.

Actually, the factor of leaf size is so tied to how thick the concrete needs to be that my "tests" may not tell me much. I just made a couple of elephant ear casts about 22 by 15. I used Quickcrete Quickwall (SBC) which I seem to have bought by accident but have loved using. I made the thickness under half an inch except near the main central vein where I built it up more. When I uncovered it after 36 hours I noticed a strange "hollow ring" to it that I haven't heard before. That may be the sound of "too thin" but it seems okay so far (day 4 of curing). I have lots of questions about all this but the exploration is a lot of fun.

Laura

Laura, That hollow ring you hear is a good thing. It means there are no cracks in your piece. That's how stone carvers test a piece of stone (tap with a hammer) to determine if it's OK. I'm not familiar with the product you used, but sounds (hollow....lol) like you got it right.

I just did a google of the product you used Laura and it seems you hit home run with your choice. I found several references to it in other forums for casting leaves. The Quickcrete home site tells you that it's a fiber reinforced product. That's exactly what you want. It will still need care in handling after a full 28 day cure, but dang girl, you did good!

Laura is it thin leaves you admire or is it the edge that you admire?
The leaves I have displayed knee height and lower are more vulnerable to someone or an animal stepping into the garden, or a shirt catching an edge and moving it off of it's base, not to mention kids toys, and balls being thrown. The edges of some leaves are tucked into or resting on the ground with only a porton of the edge showing, others are seated with the edges slightly elevated, and the detailed surface showing, hung on a fence or seated on a pedestal.
Those hanging are still seldom viewed overall,i.e. by picking them up, it is the surface and the edge, same for the ones that are on stands or pedestals.
I too am attracted to leaves where the edges are thinner, and turning over large leaves I have snapped a couple edge points as I accidently rested the piece on what I thought was a strong point, it snapped to where the stronged point was. I also relate the turning of the large leaves to how long they may have sat curing.
I honestly can not think of too many disasters for the ones I have that occurred after they were placed in the garden, or where they would be displayed. I do have lots of people through my yard, and I sheepishly say that I have also carried them haphazardly in my car.

The quickwall stuff sounds interesting. Were you using it by scooping portions out of the bag?
Dena

wow - I appreciate all the great feedback from everyone! I have taken 5 fast photos this morning to try to show the thickness of the leaves I am trying to make. This is very difficult to photograph but check out the 3rd album if you are interested. Forgive the awful photos. The other 2 albums have the "glamor shots".

Dena, in answer to your question about quickwall... yes I just scoop some out and add water and go. The white leaf in the thickness photos is the only one made of quickwall that I have photographed. I may switch to using it all the time but my test plates and the rest of my leaves have been portland/sand/fortifier.

Laura

Here is a link that might be useful: try this for photos

Has anyone researched Quikwall?
We don't have it here so I've never tried it, but it seems to me that fibers or not a mortar mix like quikwall will be weaker than concrete products like topping cements.
And Quikwall appears to be a low slump material and I would think a high slump material like a topping cement would be even better at picking up detail from leaves.

I don't use either as I make my own recipes and haven't started casting but I'm interested in why Quikwall is used over topping mixes.

Tufaenough - would you copy your post and add it to the quickwall thread?
I have no answers for your questions but I hope someone will!
I thought I was getting a bag of regular concrete with fibers added and I got home with this bag of quickwall. I didn't open it for a couple of months and can't even remember where I bought it now that I would like more. Or - maybe there is just some quality about it that I could mimic in my recipe.... adding fibers for example. I'm hoping the experts will help out.
Laura

Hi Laura
I posted to the other thread.
I am curious but regular concrete and mortar don't hold that much interest for me.
They are simply TOO heavy.
For some creations the weight overcomes the strength of the product.
My goal is tufacrete products that weight 1/2 as much or less than regular crete but are still very strong.
If it's light enough it's hard to break it by either dropping or bumping.
I have stuff so light you can drop it on concrete, it dents but does not break. But because it contains peat it will deteriorate over time.

So at the moment all my recipes contain Zonolite additives (either Perlite or Vermiculite or both) of different types.

It is fun to work with the light weight material.

ltd123, your leaves are beautiful! I love the colors you have acheived. They are so nice and thin. I really would love to know how they hold up at that thickness. They look so fragile, but they are lovely! Are you using any reinforcements other then the fibers in the quikwall?

Laura,
Your leaves and colors are lovely. Some so fanciful and inviting to look at. I like the panel of hosta and the rock fern too. I think that is a cabbage leaf in one of the albums, I have a savoy cabbage in my album 9new garden items), they really are fun with so much texture and the leaf peels right off.
With any of your leaves it should be noted they are works of art and should be handled as such, with care.
Happy casting,
Dena

gottatufa, you asked if I was using any reinforcements other than the fibers in the quickwall in my leaves. The answer is-- no-- but to make the situation a little more clear, I have only made a few leaves out of the quickwall. (all the ones that looked white were quickwall). The leaves that were painted have all been made from various recipes of portland/sand/water/acryllic fortifier. I guess the liquid fortifier (about 20 % of the total liquid I add) is a reinforcement but they did not have any other reinforcements or fibers.
Thanks for your input.
Laura

Dena, I loved your concept of leaf casts as fine art that needs to be handled as such! Laura

Laura, rather than testing your "plates" by another person's criteria, why not just test for YOUR needs?

When it comes to leaves, the trouble seems to be usually from too-thin concrete over the veins, not enough compressive strength (i.e., stepping on them when used as stepping stones), or likely damage to the fine, thin edges.

For the first problem, I would place your test plate half on a table or counter, half off. Then hold down the half that is on the table, and press down on the other half that is hanging off the edge. How much pressure is acceptable to you? How thick was the plate that didn't break, or the one that only broke under extreme pressure?

The second problem might be connected to the first. If the leaf is set on sand, then walked on, will it resist breaking? What happens if it has been placed on plain soil/rock, and water washes away some of the soil, creating a kind of shelf under the leaf, and a 200-pounder steps on it while it's kind of in a teeter-totter position?

The last problem, damage of leaf edges, was best answered by Dena.

Some people think because it's concrete, that it's invincible, and I think that's stupid. Every material has its limitations. Are you old enough to remember those large pots that people were making 20-30 yrs ago, that were wheel-thrown, and closed up all but a small, finger-sized hole and lip? I think they were hard to make well, and expensive. If you paid $3,000 for one, would you want your 15-yr-old son to dribble it down your brick steps? NO, you wouldn't. Would you expect it to break? YES, you would.

In my opinion, our work should be strong enough to survive normal use as it was designed to be used. It doesn't seem to me that we need to make it teenager-proof, bomb-proof and stupid-proof.

If it is made to spend winters outdoors, it shouldn't be susceptible to freeze-thaw damage. If is likely to be damaged under those conditions, the buyer should be warned that the object should be dried and put away until it is safe to be put out again, or only used indoors. If you said it is weatherproof and it isn't... you eat it/replace it, and apologize.

If you you make a (relatively) delicate decorative leaf (or whatever) that was designed as an art piece to be hung on a wall (preferably under shelter), and the buyer decided to use it as a stepping stone, the buyer can consider it a stupidity tax if/when it breaks, IMO.

Sue

Laura

you are a fantastic artist, I never seen so wonderful colors , ideas ( I loved the raised leaves), color combinations...etc. You are next to Little and Lewis, who are the gods of concrete leaves!

Can you post more pictures ? I would love to see more about your art.

Andrea

Andrea, thanks for the great compliment! I have been playing with concrete for just a few months and those leaves are about all I have done. I wish I was an artist but nothing I have ever painted or made before concrete leaves has satisfied me. These leaves actually look good to me and that is a big thrill. Still, it is pretty much an accident when one turns out great and I can't duplicate the result yet so I have a long way to go.
Laura