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.

You didn’t tell me the “basic” ingredients you used, nor the ratios. Too much or too little water is often the cause of failed hypertufa recipes. Sometimes too much of one of the dry ingredients can be the culprit. Since I wasn’t there to observe you mixing up the recipe, I can’t be more specific in figuring out the cause.

I suggest you (re)read this article: Hypertufa Recipe Mixing Guidelines.

About where to find the fiber mesh – you can check with commercial concrete companies if you cannot find it in retail stores that have a good assortment of concrete products. Fiber mesh can sometimes be hard to find in certain areas of the country. I also suggest you Google “fiber mesh for concrete” and many results will come up and you’ll find online sources.

Also read the blog post I wrote on just this subject: locating silica fume and poly fibers. I believe you’ll find it quite informative and helpful.

Remember … hypertufa “success” often takes a couple failed attempts. Really. Portland cement can be temperamental to work with. Most crafters really have to get the hang of the correct water ratio in relation to the portland cement, along with following proper curing methods. Keep trying your hand at small projects (less wasted materials) until you believe “you’ve GOT IT!”

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.

PLEASE NOTE! Silica fume is sometimes confused with fumed silica (also known as colloidal silica and pyrogenic silica). These materials have different derivations, technical characteristics, and applications. Silica fume is very fine like beach sand and completely black.

Silica fume and poly fibers are used as strengtheners, normally referred to as fortifying agents. They help make your cured hypertufa or concrete object stronger. Often, you’ll want to use one or the other for items such as stepping stones or very thin spheres. I do have some recipes sitting on my website that I’ll refer you to, in case you aren’t familiar with recipes and/or projects that utilize silica fume or poly fibers. Here are three of them:

Hypertufa Recipe Using Fiber Mesh (Poly fibers)  (refer to last recipe on the page)
Hypertufa Sculpture Recipe
Concrete Recipe For Very Thin-walled Spheres

How to Locate Silica Fume and/or Poly Fibers

My first suggestion is to call commercial concrete supply companies in your area. Many times they will have either fortifier, and will be willing to sell you a couple of pounds. (You don’t need much of either one in a recipe – unless I guess you’re making something collosal in size! ).

I’ve even read of people walking away with some for free, after explaining to the sales people what they will be doing with the silica fume or poly fibers. Seems the sales people get a kick hearing that Portland cement is going to be mixed with peat moss and water to make an odd concoction called hypertufa!

My next suggestion is to do what else … that’s right, find suppliers who sell via their online store. In doing a Google search today, I found EpoxyUSA.com carries poly fibers for a very reasonable price on the Fillers-Thickeners webpage. Note – I have no affiliation nor experience ordering from them. Perhaps you should contact them first to check shipping charges, etc. before you order. But I’ll wager a guess they are legitimate and probably fine to deal with.

Finding silica fume online seems to be more of a daunting task. I did find this link to the SilicaFume.org webpage. If nothing else, call them and see where you can purchase a small quantity online.

So, there you have it. I hope I’ve helped you locate two ingredients that do help make a difference in strengthening concrete and hypertufa recipes.

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.

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.

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!

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. 

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.

I received an email from Beth who asked:

I am just beginning in learning hypertufa, actually in the process of collecting my ingredients to get started. Anyway I have read a mixture of vinegar and water would speed up the curing process. Any truth to that or is it better just to wait the 30 days for the curing? Also how safe is it to handle once it has cured? Many thanks! Beth

My reply:

Hi Beth:
I have addressed the vinegar issue on my webpage: Hypertufa Curing Guidelines (look at the very bottom) and personally I wouldn’t use vinegar.

Most successful ‘tufa makers use good ‘ol water to leach out the lime. Refer to the information in my curing page and you’ll do just fine!

Also, hypertufa is safe to handle after a proper cure.

Good luck with your project!

I received an email from Ya’aneh asking:

Hi, i would like to make a water fountain. Large bowl on the bottom, then smaller bowl in the middle and smaller one on top. Could you tell me the recipe for the right concrete to use? I was wondering if a peat moss one would work? Thank you. Ya’aneh

My reply:

Hello Ya’aneh:
Thank you for contacting me and I’ll be happy to answer your questions.

For a concrete recipe for your project, I would suggest you read over my web page that has a recipe that will certainly work well for you: ‘Thinwall’ Concrete Recipe.

I would NOT suggest you use a hypertufa recipe (hypertufa uses peat moss as one of the ingredients). Because the peat moss will decompose over time, leaving pits and crevices and you might end up with “leaks” in your cured fountains bowls. Use a concrete recipe for your fountain.

To easily view all the “how to” pages to help you be successful with your concrete or hypertufa projects, please refer to my Site Map page. Look at the “Concrete” and “Hypertufa” categories … there are many pages of helpful advice.

If you have any more questions, please do not hesitate to contact me.

Good luck with your project! 

I received two emails from Eugen who asked (please note English is not his primary language  it isn’t because he is such a bad typist!):

I have a question – where from peat moss , and if that could be replaced by another material wayting for your suggestions, thank you in advance, yours, eugen

and …

I also find your site very interesting I’m a doctor gp pasioned by sculpture, I intent to build( create) few large statues in my garden with concrete, but still didn’t found some clear overview about waterproof methods. If you have any valid ideas about this, please answer me. Thank you again, eugen

My reply:

Hello Eugen:
Thank you very much for contacting me and as I received two emails from you, I will be happy to try and answer all questions here. Also, please appreciate I am doing my best to understand your questions, as your English is obviously not your native language (I mean no disrespect to you by saying this). It is just that I want to do my best to help you. 

You ask: “where from peat moss … and could it be replaced ….”

#1) Alright, if you are asking me where you can FIND or PURCHASE peat moss, here in the USA it is very easily purchased in garden supply stores. It comes in a compressed square-ish shaped “bale”, and is normally used as a soil amendment for garden beds. Since I do not know what country you live in, I cannot be more helpful at this time. The type of peat moss used for hypertufa recipes is sphagnum peat moss.

#2) “can it be replaced” …. NO. Hypertufa is not hypertufa unless it has peat moss as an ingredient. Any other type of cement based recipe (as hypertufa is), will be a concrete recipe … not a hypertufa recipe. But, that being said, I have a recipe on my site that utilizes coir in place of peat moss. Please refer to: Hypertufa Recipe Using Coir

#3) Or you can use plain soil as a replacement (note there is no perlite in this recipe): Garden Stepping Stones Recipe

Next, you ask about waterproofing methods for concrete statues. Why? As I am sure you are aware, if your recipe is prepared correctly, and you cure your sculpture properly, it should last a life time. However, if you wish to waterproof it as you are wanting part of your sculpture to be a water basin, as example, or maybe you want your sculpture to attain a glossy appearance, then here in the USA I would go to a store that sells cement supplies, and purchase a concrete sealant. Just make sure what you purchase says “Waterproof” as opposed to “Water Resistant”. You should apply at least 2 coats, 3 or more is better.

Or, here is a technique I have pulled from my files for you: For items such as birdbaths and such that will be constantly holding water, instead of using expensive and often questionable sealers…finish just the “bowl” portion of the item with modified cement. Plain old concrete does a pretty good job of holding water, but you can easily take it to the next level by mixing up batch of pure, neat Portland (no sand) and polymer admix to coat that area.

It can be plain gray, pure white (white Portland) or colored using integral color. You can even get a marbleized effect using multiple colors. Poly-modified cement is extremely dense and about as watertight as you can get. It can be visually interesting too since the surface can be as smooth as glass (with a little sanding & polishing) or textured to your taste. It bonds very well to lightly textured concrete. As an added measure, apply a light coat of Carnauba wax and buff it just to finish it off.

So … are these answers of help to you? Please do not hesitate to contact me for further clarification or help if needed.

Also, if you have not reviewed the stain and colorant information, please do. It is the best available on the internet, and though the brands mentioned may not be available in your country (or are you living here in the USA??), the application methods, etc. is valuable information: Colorant Charts For Hypertufa & Concrete

Good luck! I wish you much success with your sculpture project