The-Artistic-Garden's Blog

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.

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.

Let’s Learn About the Right vs. Wrong Way to Resurface
Existing Concrete Patio Surfaces

I received this email from Trisha asking me:

I have encountered a problem on my patio. After much research your website was the only one that made it clear there was a difference between concrete and cement.

We have a slab in our back yard (like a river rock slab), we wanted to skim it over with a smooth layer. We did so with what the hardware store told us to do it with, which was Portland cement. But it came out with lots of cracks and you can scratch your fingernail in it.

Is it because we used cement and not concrete?

My reply:

Hi Trisha:
First, thank you for telling me how you found my website. Glad my concrete-vs-cement page helped you.

Next … the easiest way to explain cement vs. concrete: cement is the dry, powdery product; once it is mixed with water and aggregate, it is called “concrete”. So no, your problem wasn’t in the terminology … your problem was a very ill-informed salesperson.

What a shame! You were given horribly wrong information!!! Even I know that you can’t put pure Portland cement onto a concrete (or rock) slab! And I’m no concrete expert by any means.

**First … I seriously suggest that you go back and confront the store manager about what happened because you’re not going to like my answer, meaning this isn’t going to be an easy “fix”, nor cheap. (Unless you clean off the crumbling Portland and forget about doing anything further.)

Let me tell you that the husband of a very close friend of mine was a professional concrete finisher and I picked his brain for you … and in a nutshell, here are some guidelines I can offer you:

1. Portland cement CANNOT be used all by itself in this situation! it needs some kind of aggregate added to it … so this was mistake #1;
2. You cannot just put a “skim coat” onto the slab … you need at the minimum a 2″ thick “layer” of concrete … so here was mistake #2;
3. The slab must be prepped with a “bonding agent” … this allows the new concrete to adhere to the slab … mistake #3;
4. There very well might be the need for the bonding agent to also be mixed into the new concrete;
5. The slab might possibly need to be wet down, before the bonding agent is applied;
6. You should use a 5-sack mix (called 5000 lb concrete);
7. The new concrete needs to be kept moist for 28-days – it will reach about 90% of it’s full cure (hardness) in that time frame – spray it down with your hose every day & night to dampen – this will help it to not crack and cure properly;
8. And then seal with a good quality concrete sealer after the 28 days.

And before any new concrete can be laid, you are going to have to THOROUGHLY clean/scrape off all the flaking Portland cement.

PLEASE NOTE: There could be other things to take into consideration before attempting this concrete project. I DO NOT know the particulars. There are many variables when it comes to concrete and the specific project.

***Bottom line … I suggest you call a reputable professional concrete company to add the smooth “layer” for you. Forms have to be built along the outside edges to hold in the concrete; expansion joints may need to be added into the wet concrete; depending on the size of the slab, interior wire “mesh” might need to be laid to help it not crack; the top must be finished off correctly to make it smooth, etc.

Does this overview of things-to-do help you? I hate to hear of problems like this. If nothing else, you deserve all your money back for whatever supplies and such that you bought for this project!

~~~

Trisha wrote back:

Thank you very much Claudia. Your info is extremely helpful!

We must be on the right track because yesterday we bought that same 5000 concrete mix and blended it with the Portland cement. It made a smooth finish like we wanted. It does not have the best appearance but it bonded and it is concrete. HA!

It is just a small 16 x 20 fenced in back patio, so anything done to the slab is better than what it looked like before.

Again thank you for all your info.

How Temperature Caused a Hollow Sphere Project to Literally Blow Up!

I received an email from Sue, who wanted to share with me this rather interesting bit of info:

You are my hero! I’ve been after the instructions on duplicating Little & Lewis spheres for a year!

I did some on my own and they exploded on my driveway (cold ball from house, 90 degree day= mess.) I just had to tell you about this recent disaster – maybe others can learn from this.

Sue

My reply:

Hi Sue:
Well, gee  Thank you for the compliment. That was very kind of you to take the time to say thanks!

Ummm … the only thing I am confused about is that you say you’ve been “after instructions” for a year to make hollow concrete spheres?? Did you search on the internet?? Because my hollow sphere articles have been available much longer than that. Maybe you mean you were thinking about it, because you just sent me into a panic that my Google rankings had dropped. But no, they are still at the very top! My rankings are:

how to make hollow concrete spheres — #1 and #2
how to make hollow concrete spheres — #1 and #2
how to make hypertufa hollow spheres — #1 and #2
concrete hollow spheres — #1 and #2
concrete spheres — #1
hypertufa spheres — #1 and #2

So you see, my instructional hollow sphere how-to pages are sitting up there at #1, waiting to be easily found.

Anyway … please know my information and how-tos should point you in the proper direction. And I am glad you found my site.

Wow, exploding concrete spheres!!  Now that’s a new one on me! If you had the video of the actual explosion, I’d be begging you to let me put it on my website so we could all learn from it, and maybe get a laugh, too?? (I’m not laughing at your mishap … just the mental vision of the sphere blowing up! ha ha)

But this incident goes to prove that temperatures CAN have a huge influence on the outcome of projects that use inflatable forms and Portland cement – both in the curing and otherwise, as your explosion proved! And this also proves that when making a hollow sphere the temperature of the air INSIDE the inflatable ball needs to be the same as the temperature in the area where you’ll be curing it.

Thanks again for sharing your concrete hollow sphere escapade!

A Reader Asks Construction Questions About A
Decorative Cast Leaf Fountain

I received an email from Jan R. asking me:

Hi there, I want to make a hypertufa leaf or concrete leaf fountain. After the leaves are made how would I form the fountain and to what? Got any ideas? Thank you for your time.

Sincerely, Jan

My reply:

Hi Jan:
Thank you for contacting me about making a concrete or hypertufa leaf fountain, which is a fun project to do. The answer to your questions will be rather difficult ones to answer at this point, as you’ve not told me how the leaves are to catch and/or collect the water; how many levels you want; or what sort of base you want the fountain to set on, to name a few.

Make sure you read through the ins and outs of working with hypertufa and concrete for leaves. Here are a couple of articles on my website that will be of help: Leaf Casting with Hypertufa: Tips for Success, and Concrete Leaf Casting: Super Tips From the Pro’s.

There are many variables I’d have to know in order to walk you through this, but basically here is what I believe will help you think this project through:

• Most crafters make two or three leaves set in a tiered fashion, and at angles to each other, which allows the water to spill over the edge(s) and finally collect in the bottom leaf.
• Joining all the pieces can be accomplished by mixing up a fresh batch of your recipe with bonding agent included in it and some bonding agent also painted onto the areas of where everything will be joined for good measure. (You would have to wait until the leaves were cured enough to be handled before you start joining them.)
• You need to seal the concrete or hypertufa leaves with a water-proofing sealant.
• You need to know how to install a simple pump in order to get the water flowing back up to the top-most leaf; you also need to get a pump that has the right GPH rating to effectively keep the water flowing.
• Another consideration – WHERE are you going to hide the pump and cords? Inside the base, or …? I wouldn’t think you want the pump and connections visible.
• You will need a GFI electrical connection available to plug in the motor for the pump. **There’s no side-stepping this requirement – water + electricity do NOT mix!

To learn about GPH and GFI, read this article on my website. Skim about half-way down: Garden Spitters Installation: GPH & GFI Considerations.

This is as specific as I can be for you at this time as I’ve no clue as to what actual shape/form you want your fountain to have. Nor how large you foresee the thing to be. What kind of leaves do you plan on using? Huge gunneras or something medium sized?

But, I do hope these tips help get you to thinking and sketching your ideas out on paper. Though not the easiest project, it is quite doable. Obviously your creative skills will really come into play with a project like this!

Good luck. I really hope you are successful with this leaf fountain project … personally I think there’s nothing nicer than the sound of trickling water in my garden.