The-Artistic-Garden's Blog

Admixes? Liquid Fortifiers? Acrylic Strengtheners?
What Is Their Pupose and How Much To Add
To Your Hypertufa and Concrete Recipes

I get emails quite often asking me about “liquid fortifiers” and exactly what are they, what do they “do”, and how much should be put into a ‘tufa or concrete recipe. So, today I’ll share what I do know about using various types of admixes.

First, as is commonly referred to either here on my blog, or in forums that discuss hypertufa and concrete garden art recipes and projects, the term “admix” (or “admixture”) and “fortifier” and “liquid bonding agent” are usually synonymous. Basically, an admix is an acrylic liquid and is used as strengtheners to enhance the longevity of the cured object. Continue reading

A Frustrated Hypertufa Trough Maker Seeks Helpful Advice

I received an email this week asking me:

A friend and I tried one of your basic hypertufa recipes without adding the fiber mesh. Our results are very crumbly. I think we goofed by not using it, right? Where does one find fiber mesh? NewLearner

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My reply:
Hi NewLearner:

I hate to say it, but I don’t believe the lack of fiber mesh in your basic recipe was the cause for a crumbly failure. Sounds like the amount of water you used and/or wrong proportions of ingredients was your problem. Continue reading

Sometimes These 2 Ingredients are Hard to Get Your Hands On

I often get asked by many hypertufa and concrete garden art enthusiasts where to find “silica fume” and “poly fibers”, also referred to as “fiber mesh”. Depending where you live, it may or may not be very easy to lay your hands on this stuff. Continue reading

Be Aware Of How Portland Cement Or Mortar
In Your Recipe Will React To Various Metals

I received a question from a crafter who had read my post about using hypertufa to skim coat vertical walls. She has a metal shed that she’d like to use the technqiue on and wondered if it would work in her situation.

I told her I’d found and saved some information years ago about this very issue and would post it. So … here it is. Anyone who works with a hypertufa or concrete recipe and uses a metal mold, or has something else made from metal that will be embedded into the ‘tufa or ‘crete needs to be aware of this information.

Aluminum
Embedded aluminum roof flashing, aluminum water stops, aluminum electrical conduit, introduced aluminum powder (sometimes used to foam concrete), or embedded structural aluminum shapes may all corrode in concrete or mortar. In all cases, a reaction that forms aluminum hydroxide and hydrogen gas occurs, and may cause expansion and cracking of the concrete or mortar. The common use of calcium chloride (or other alkali compounds), and dampness of the concrete increases the reaction rate. Usually, coating the aluminum with bituminous paint, impregnated paper or felt, plastic, or an alkali-resistant coating will prevent or sharply reduce the corrosion.

Copper
Copper embedded in concrete and/or mortar is usually roof flashing. Embedded copper is practically immune to reaction with corrosive alkalis, even if exposed to constant moisture. Copper will not react with dry, hardened concrete and/or mortar. Rainwater leaching, however, may bring chlorides in contact with the metal. Corrosion may occur and result in a green discoloration or runoff. Consequently, chloride admixtures should not be used in concrete if contact with copper is expected.

Lead
Lead will always corrode when in contact with fresh concrete and/or mortar. The high pH from calcium hydroxide is the cause of the corrosion. Cured, seasoned concrete or mortar will not react with lead. Corrosion of embedded lead flashing in mortar joints will usually result in the production of a lead oxide, a white discoloration. A special case of lead corrosion, called differential aeration, occurs when a lead strip is partially embedded in concrete so that part of the strip is exposed to air. The embedded section has a different electrical potential than the section exposed to air. The result is that the strip will become polar in the presence of moisture. Gradual corrosion and disintegration of the embedded lead will then follow. In such a case, and in all other cases, the embedded portion should be coated with epoxy, varnish, asphalt, or pitch.

Zinc
Zinc is highly reactive with alkalies and will deteriorate to some degree upon contact with fresh concrete and/or mortar. The reaction is limited due to a corrosive film that forms on the outer layer of the zinc. It protects the underlying metal from further reaction. Zinc will not react with dry, seasoned concrete and/or mortar. Embedded zinc will react with moisture and calcium hydroxide to produce calcium zincate. Zinc corrosion may also occur when galvanized iron, in the form of flat or corrugated sheets and rebar, comes in contact with fresh concrete and/or mortar. Galvanized iron is coated with zinc, and will react with moisture and chlorides in the concrete and/or mortar to produce zinc chloride. The result is expansion and cracking of the concrete and/or mortar. The metal should be protected with epoxy, varnish, asphalt, or pitch.

Sculpting Hypertufa Into Realistic Rocks
For Use In Bonsai Landscapes

Jim wrote and asked:

I am an avid bonsai gardener. How do I make hypertufa into rocks with sharp edges so they will look like small mountains and fit well into my bonsai gardens? Also what recipe would you suggest for these rocks? Jim

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My reply:
Hi Jim:
Thanks for asking your questions.

First, as far as sharp edges, that is what one would call “artistic expertise”. Meaning, you’ll have to use some kind of tool (maybe a small paring knife; a screwdriver tip; or an appropriate “professional” carving implement) to scrape and carve away the ‘tufa in order to get the crevices, sharp points and such you’ll need to make in order to reproduce the look of real rocks.

Next, about a good recipe – since I know this project is for use in your bonsai garden, I don’s see why a very simple hypertufa recipe that does NOT have perlite or vermiculite in it would work. After all, these are very small rocks, and because of that perlite or vermiculte would not give them a realistic look (at least not in my opinion).

So, you could use either of the recipes found on the following page, but you wouldn’t necessarily need to use the fortifiers: Hypertufa Sculpting Recipe.

And, for something as small as what you’re making, a “final layer” would not be necessary.

Really, any ‘tufa recipe can be carved, in essence. These recipes as you’ll note don’t have the perlite/vermiculite which allows a smoother surface. (The peat moss will give you enough texture.)

OH … I would highly suggest to really sift and/or pulverize the peat moss to a very very fine texture. Again, with such small objects as you’ll be crafting, you don’t want a huge chunk of peat in your recipe!

Hope this helps get you pointed in the right direction. Good luck with all your bonsai garden projects.

Though Peat Moss Is An Important Ingredient
In A Hypertufa Recipe
Will Wood Shavings Prove To Be
An Acceptable Replacement?

I received this email from Sandy who asked:

Hi: I was so excited to find your site. Years ago I read a small article in a magazine about making hypertufa planters. I am so glad I didn’t get around to trying it until now. I wouldn’t have had a clue about half the stuff your website has explained!!

I do have a question for you. In one of your articles you explain about using coir in hypertufa recipes. Is it possible to substitute wood shavings (like the kind for small animal bedding) for the peat moss ? I know it wouldn’t be “true” hypertufa but do you think the results would be satisfactory ? Thanks, Sandy

My reply:
I’m glad you found my site. I hope you will find my projects and recipes to be of great help.

About the wood shavings, I’ve never personally used them myself, but am aware of others doing so. Their success came from what I will share here with you. There are some things to keep in mind when using them, so make note of the following:

—yes you can substitute the shavings for the peat moss–just do not use both in a recipe

—I’ve seen more mention of folks using sawdust as opposed to shavings

—it is suggested to NOT use perlite or vermiculite in a recipe using shavings or sawdust as these also absorb water (which can cause recipe failure)

—do NOT used treated lumber!

—your “shavings” cannot be too large … think of the consistency of peat moss. Many people even go a step further to sift down the peat to use only the finest siftings. Other folks use a blender to pulverize the peat into very very fine pieces if they don’t want one single little lump. So, what I am getting at is you can’t use big shavings. Then again (don’t remember right now the size of pet bed shavings), I highly suggest you first experiment with a recipe using shavings.

—remember that the whole idea of using peat moss is that it decomposes over time, leaving the pits and crevices that real Tufa rock has. The shavings will also decompose over time … so again I come back to the fact that large shavings MAY (notice I say “may”) ultimately leave holes that are too big and ultimately your object will fall apart.

—be very mindful of the ratio of water due to the fact the shavings will absorb a lot of water and in the long run this can goof up the cure and your object will more than likely fall apart . Refer to my page about mixing and such: Mixing Guidelines

—write down your hypertufa recipe’s ratios, etc so that you can see what was correct or what wasn’t correct (successful project versus failure). Keeping notes is really a good idea.

And please review my curing instructions – the correct curing procedure is as vitally important as a properly concocted recipe: Successful Hypertufa Curing Instructions

As I mention all over my website … practice first on smaller objects! And “patience is a virtue”!! You might be successful with your first attempt and then again, you might have to experiment a number of times.

That is about all I can think of right now to share with you for your hypertufa recipe’s success. Good luck!

Where Can I Find Recipes & Instructions
To Make An Aged Looking Trough?

I received this email from Stephen who asked:

Dear Artistic Gardener: This is from Sheffield England. Please could you advise me on the “wooden former”, concrete mix, possible wall thickness and dimensions and possible type of chicken wire as strengthener to make a concrete “aged type trough”?

I am referring to what was used as animal water troughs in England long ago. I want to make mine to hold plants. Yours sincerely,
Stephen

My reply:

Hello Stephen:

Thank you for contacting me. I believe the information you want can be found on the 4 Basic Hypertufa Recipes page and the instructions for How To Make A Hypertufa Trough.

I guess you overlooked that information on my site. I have many more pages of information that will be of interest to you about working with hypertufa.

Please go to my main hypertufa page. And then go all the way to the bottom of the page – you’ll see links to all the other pages of information. Note that the very last link is how to age troughs with moss.

I sure hope this helps. Good luck with your project. 

Tips When Adding A New Layer Of Wet ‘Tufa
Over A Dried Layer

I received an email from Regina who asked:

Can we add fresh hypertufa to an existing, partially cured layer that also has a few cracks on the top half? And should we use bonding agent? Thank you, Regina

My reply:

Hi Regina:

Yes you sure can … it is advisable to dampen the existing ‘tufa, then paint on the bonding agent and then add your fresh ‘tufa. Many crafters certainly will also add some bonding agent into the new hypertufa. Just make sure to adjust your liquid ratio accordingly.

And please know that the cracks you are getting aren’t a “bad” thing … in projects like large spheres, you will almost invariably get cracks. And that’s OK. That is why most people figure on doing at least 2 layers.

Hope this helps. Sounds like you are having some success now  Keep me posted.