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

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

Concrete Pre-Mix Products vs. A “Make It From Scratch” Recipe

I received an email from “Stoner” asking me:

I have been using a regular pre bagged “sand mix” cement for my concrete leaves. Is there a benefit to using something that I mix together myself ? Thanks. Stoner

My reply:

Hi Stoner:

Well, not necessarily. I mean, if you are very successful with and happy with the results of using the premix … “if it ain’t broke, don’t fix it!”  But of course, mixing your own ‘tufa or concrete recipe(s) allows you to tweak it, so that the recipe accomplishes what you want it to “do”.

Such as – maybe you want a really thin, yet very strong leaf casting. In this case, you might want to use an even finer sand than what comes in your premix, etc.

And then of course, you might want to add reinforcing fibers or a bonding agent, but of course that could be added into your premix.

I guess the point is, “it all depends” upon your desired outcome.

And perhaps mixing up your own might be a cost savings … don’t know what you’re paying for premix versus non-premix.

Good luck with all your projects!

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.

Hypertufa or Concrete?
Will Peat Moss Be A Good Addition For My Recipe?

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! 

A Budding Concrete Sculptor Asks Some Questions

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