The-Artistic-Garden's Blog

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 & Concrete Projects Tip
How to Make Embedded Items Stay Stuck!

I received an email from Julie asking me:

Hi, my friend and I made our first hypertufa batches the other night, using a couple of your recipes, and want to make more.

My question: I want to put some glass stones and other things like nails on the outside of some pots and balls but am afraid they will fall out. If I put a binder in the mix will that keep the stones etc. attached?

Thanks for all your help! Julie

My reply:

Hi Julie:
Thank you for contacting me and I can answer your question – you don’t really have to add a binder into the recipe. Most crafters don’t. They just push/squish their chosen objects into the wet hypertufa or concrete.

Most embellishments – stones, marbles, mirror pieces, etc. – will stay “stuck”. But nothing is 100% fool-proof, so if some do end up falling out, use a little silicone caulk (or epoxy glue suitable for your project – i.e. glass and concrete) to stick them back. Just make sure you do give each item a good “push” into the wet ‘tufa or concrete.

That’s all there is to it. Good luck!!

~~~

And hey everyone … check out this idea for your next hypertufa or concrete project!

I found this great project the other day while I was surfing around online, and I would encourage you to read Kathy Cano-Murillo’s instructions for her concrete coasters project.

She explains how to glue pictures onto the back of clear glass pebbles before embedding them into wet concrete. How cool! And how easy!

This crafty idea CERTAINLY can be used to embellish larger garden art items, like hypertufa or concrete troughs, spheres … whatever! But I love her coaster idea. As a matter of fact … I always encourage new crafters to mix up small batches of ‘tufa or ‘crete recipes, in order to get the hang of working with the stuff – to make sure they are getting the ratios of ingredients right, how long it takes to cure, things like that.

Kathy’s project would certainly be a great one to try with hypertufa, too. You could make coasters, or perhaps small garden plaques. That way, if you are trying a small test batch because you’re new to working with hypertufa (or concrete) … if you had success then you’d have a nifty item to put in your garden, or something to give away as a gift.

Anyway … making sure your embellishments stay stuck really isn’t a major concern. So go ahead, and try adding something fun or whimsical to your next garden art project!

What Kind Of Paint Can I Use For A Tuscan Look
On My Grey Concrete Planter?

Gabby emailed me asking:

Hello, can you help me find the right type of paint for a large concrete planter? It is grey concrete and I want to achieve a tuscan look. Also where do I buy this paint?

Thank you sooooo much … Gabby

My reply:

Hi Gabby:
I will be happy to help and answer your questions.

#1) For information on what paints to use and info on what I think will be an easy way for you to get a tuscan look, please refer to my article: Decorative Sponge Painting.

Note: in this article I do not mention concrete planters (but I should – think I’ll add that to the page) but acrylic OR latex paints will be fine for your planter. Follow the directions in my article and you ought to have a nice long lasting decorative paint finish for many years.

Getting the “Tuscan look” you want will of course rest upon your artistic abilities. If need be … practice on a large piece of cardboard to get the color combination and appearance right. Sometimes my color choices aren’t always the greatest after I see them applied together. I have to do trial runs myself sometimes!

#2) In the USA, acrylic craft paints can be found at stores like Michael’s Crafts, Hobby Lobby, even the Wal-Mart in my area has a huge array in their craft section.

Or, regular latex paint can be purchased at stores like Sherwin Williams (though probably pricier than what you need to spend), Home Depot, even Wal-Mart sells latex paints, or most large hardware stores. You do not need to buy the most expensive paints.

#3) Make sure to apply at least 2 or 3 good coats of clear sealant, too. There are matte, semi-gloss and gloss finishes. For a Tuscan look I will say a matte finish is what you should use.

In addition, I suggest you take a few extra minutes to read all the pages I have in the decorative paint techniques section of my website. You’ll get lots more helpful how-tos that will not only help you have success with this decorative paint project, but any others you decide to to try.

Best of luck in dressing up your concrete planter! A Tuscan-type technique really isn’t a too-difficult decorative paint project for even a beginner to try.