How They're Made

We're proud of our stones. We've compared ours to many others we've seen, and we'll stack ours alongside theirs anytime, anywhere, and you'll see the difference. Literally. Just looking at the sides of our stones compared to those others, and you will see just how much more care we take.

Click on the graphic to see it enlarged and detailed.

We've also had many, many, many people tell us that they have looked at a lot of different people's stepping stones, and that THEY could see the difference in comparing our stones to those others. We've even had several people who actually make stepping stones such as ours compliment us on how much better ours are than even the ones they make. Now THAT's a compliment.

It's evident in the smooth, even sides as opposed to the chunky, uneven, and pitted sides that many of the others have. This comes from the special way we prepare the molds and the special way we go about pouring and working the concrete. We're not going to tell you how we do that, because we have to keep some of our trade secrets to ourselves.

Let's start with our reinforcing materials. There are many people who are using reinforcing materials such as chicken wire, hardware cloth, or other similar items. There's several problems with those, in our opinion. First off, we hate working with them - they are a pain, quite frankly - it's next to impossible to get them to lay flat, they work themselves to the top of the concrete (the bottom of the stone when they are in the mold), they're constantly poking & scratching you when you work with them, and they really don't add that much strength overall - only in the area in which they actually occupy space - they give no strength, for instance, to the edges of the concrete. Another problem with wire reinforcing is that concrete is wet (most of the time) and full of caustic ingredients like lime. That adds up to rust. And after a while, rust leaches through anywhere the wire is close to the surface or sides. That means a visible stain on the outside of the stone - something you don't want and can't get rid of. For a close-up of the image at right, click on the image And not only does the rust leach out and stain, but how much strength does rusted wire add, anyway? If you said "None!" you were right.

Fiber Reinforcing

Fiber Reinforcing Material

Compare that to our method - we use fiber reinforcing. Fiberglass and/or nylon shreds, as fine or finer than "angel hair," are added into the concrete while it is being mixed. These fibers permeate the entire structure of the concrete, binding it together totally. They don't look like much, do they? Contrary to their appearance, they give a lot of strength. We've had several concrete contractors tell us that using fiber reinforced concrete is (by their conservative estimate) 10 times as strong as regular, non-fiber reinforced concrete. There are several advantages other than just the structural strength. For instance - fiber doesn't rust. Imagine that! No rust to leach through your stone and ruin its appearance. It also is equally as strengthening in edges as it is in the center - unlike wire. It's much easier to work with, and actually less expensive than wire. All these add up to better stones for you.

Now let's talk about glass. Since the highlight of these stones is the glass itself (otherwise, they'd be boring old concrete stones, now wouldn't they?), we choose colors and textures that we feel are much more harmonious with the individual stone patterns than many of the other stones we have seen. We also use, in very high proportion to other types of glass, Spectrum glass. Spectrum has very high consistent quality, very wide selection of colors, and a large portion of their glasses are translucent to opaque as opposed to transparent - important on a stepping stone, because you don't want to see the concrete behind the glass - you want to see the glass. Even with all these other factors, Spectrum is also one of the least expensive glasses on the market, so again we can keep our costs down for you. 628TIPIRID sample

While we use Spectrum in most cases, we also use other manufacturer's glass when need be to make the stone look its best. For instance, the Kokomo 628TIPIRID glass at right that we use in our Trout with Lure stone is heavily rippled, iridized and transparent. Combine that with a white stone (made using white thin-set mortar instead of concrete), and you have a very impressive appearing stone... it looks just like rippling water with the shadows cast on the bottom of a stream. This is just one instance of our making sure we use the right glass to harmonize with the theme of the stone.

Now that we've talked about glass itself, what about the way we work it? We've seen many stones where there were huge, varying and irregular gaps between the cut pieces of glass, sometimes as much as 1/4 to 1/2 inch! And while that's all right for some, it would never do for us. We try to maintain just as tight a gap as we would if we were using lead came to make a window - about 1/8" gap between the pieces. While this does vary slightly, we think that the more accurate cutting and grinding gives an overall feeling of higher quality to the stone, rather than being slap-dashed together by someone in a hurry. You compare. Another fault is cutting the glass to fit too closely together. When that is done, no mortar can fill the gaps, so there is nothing to hold the glass - except some natural adhesion from the mortar on the back - and no wonder those other stones start popping their glass out after a winter or two!

Concrete is concrete, right? Wrong! There are varying strengths of concrete, dependent upon several factors: Ratio of ingredients, mixing consistency, setting (ambient air) temperature, and other factors influence how strong the concrete is when it is fully cured. The concrete you get when you order a concrete mixer to dump it in your driveway is stronger than that that you buy at the building supply center in bags. Why? Because they use a different mixture ratio. The cement mixer concrete is known (usually) as "5-bag" concrete (meaning that there are 5 bags of Portland Cement per cubic yard of concrete. The stuff you buy in the stores is (usually) "4-bag" concrete - one less bag of Portland Cement per cubic yard. Doesn't sound like much, but it makes a considerable difference. We've actually calculated the exact amount of extra Portland Cement to add to each bag of concrete we buy to make it into "6-bag" equivalent. We've also done the same for the mortar that makes up the layer next to the glass (see diagram below). Checking the instructions found in the various books and from various "helpful sources" at glass-supply shops has invariably been wrong - they've been off by as much as recommending less than 1/4 as much extra Portland Cement as needed all the way to recommending 5 times too much (too much also weakens the concrete).

So what's the deal, just add water and stir, right? No way. First of all, the drier the concrete is mixed and poured (to a point), the stronger it will set. But if you get too dry, it just crumbles. Add to that the fact that every bag of cement has a different moisture content already (from being stored in various places), and you can't just add X amount of water and be done with it. It takes a special "feel" for when the mixture is right. And don't forget that the more large air pockets you accidentally trap in the concrete, the more chance that they can hold water, which expands when it freezes and may crack the stone. However, small air bubble actualy give freeze resistance to the concrete. It's easier to get the large air pockets out of a wetter concrete, but a drier concrete is stronger, plus you don't want to remove all the little bubbles. See the challenges? We've developed some special techniques and equipment to meet these challenges, and have spent many an hour with concrete experts discussing the best methods and additives. We use 2 different additives to cut the amount of water required, and another one to fill the gaps in the stones and do other good things, and yet another one to slow down the initial set (this is a good thing, too). We also initially cure our concrete at room temperatures, which allows for better curing and stronger concrete than curing them out back in the shed or in the garage. All these factors combine to strengthen our stones.

In addition to all that, as of April 2001, we are also using a brand new shrinkage-reduction admixture in our concrete. Whoopie!, you say? So what? Well, while this additive adds no additional strength, the one thing that, over time, can cause the stone itself to crack or to cause the glass to crack on its own is the stresses involved in shrinkage. Shrinkage happens to virtually all concrete - take a look at your concrete floor, driveway, sidewalk, or other areas - see all those tiny cracks running through it? Those are caused by the concrete shrinking as it dries out. The problem is worse in concrete that is poured too wet, but all concrete suffers from it. This new additive cuts shrinkage in concrete by up to 80% - which, in the case of the stones, leaves only microns worth of shrinkage - far less than can do damage.

All in all, we have improved our concrete formulation four times with additional additives to strengthen our stones or create other benefits, but we're not done yet. We are continuing to lead the way in finding newer and stronger formulas of concrete, while still keeping our prices the same. Unwilling to be satisfied with even the current stronger stones, we are committed to continue finding new ways to improve our stones even further. While our stones have always been strong enough to walk on, we believe that it is our responsibility to you, the customer, to continue to try to improve them.

So how strong are our stones? Well, the highly scientific (snicker) tests we have run (i.e., having a 250+ pound guy jump up and down a foot and a half on the edges of an 18" hex with a 1/2" iron pipe under it, and which took 3 jumps before it broke) say they are pretty darn strong. If that's not technical enough for you, then here's the actual numbers: From testing and calculations by the concrete experts and additive manufacturers, our concrete runs approximately 250% compressive strength of regular concrete (that's two and a half times as strong), or approximately 7000 to 7500 lbs. PSI compression before breaking, as compared to approximately 3000 lbs PSI for regular concrete.

One more little extra thing we do... because we know you will love your stone and want it to remain yours, we add a security measure to every stone. Many people have asked us "What if someone just walks off with it?" or said "I'd be afraid someone would steal it." So, to counter this challenge (we've never heard of a stone being stolen, but a challenge perceived is a challenge indeed), we do something no one else that we know of does: we add two anchors on the back side of the stone. While these could be used to hang the stone from a wall or fence, their real purpose is to allow you to install two stainless steel eyebolts in to them, and run a cable through the eyebolts to a post, pillar, rock, buried deadman, or other immovable object so that your stones stay secure. No one else that we know of does this for you.

OK, OK, so our stones are good, we say - what you really came here for was to find out just how in the heck they are actually made, right? Right. Well, first we have to select a pattern. Sometimes that's tougher than you might think. We have dozens upon dozens of existing patterns already. Which to choose, which to choose... We want to make things that will sell (we know, for instance, that the Haystack Rock, Majestic Heron, and Mr. Treefrog patterns are sure to sell - they are among our most popular. But we don't like always making the same thing - we, like you, like variety. This is where some of our new patterns come in - just because we got bored with making the old ones over and over. But that's good for you - because you have an opportunity to buy things that no one else has. New patterns can come from any or all of several sources - there are always new commercial patterns being produced - and everyone who makes stones can make these. Then there are existing stained glass patterns from other sources to be adapted. Not too many people (casually) are doing this, as adjusting them is sometimes more challenging than you might think - but with the aid of scanners, computers, and printers, there's not a lot we can't do with a pattern. Then there are the true custom patterns - the ones we make ourselves, like the ones listed on our Custom Stone page - often, we use photographs, our scanner, and Photoshop® to turn the photos into patterns. The Haystack Rock, Cape Meares Lighthouse, and Terrible Tilly (Tillamook Rock) Lighthouse are some examples of these. Or we could use a combination of things - take an existing pattern, scan it, modify it, move things around, add parts from other patterns, resize, adjust, and play - and poof! - there's a new pattern to play with.

Once a pattern is selected or created, it's even tougher sometimes to choose the right glass(es) to go into the pattern. There are so many choices! It has to harmonize, look right, and above all else, be quality glass (there's a lot of cheepo glass out there you'll never find in our stones).

So, once the pattern is laid out, we cut and grind the glass to fit the pattern. This can be accomplished several ways (and we use all of them at times). Normally, we cut it using a quality glass cutter (no $5.95 hardware store specials here - they ruin more glass than they save in money). Actually, a glass cutter does no such thing - it merely scores (scratches) the glass. Then we use glass-break pliers to break the glass along the score lines. The next step (or should we say "The Next Step"?) is to use our glass grinder to grind it down to the precise pattern size and shape. We prefer Glastar® glass grinders - they are durable and have only failed us twice - and Glastar's 5-year unconditional warranty had that one back and running in 4 days both times while we used a backup older model Glastar®.

However, there's times when even the most careful cutting/grinding combination can't do what you want. For that, we use our Gemini® Taurus II.2 Ring Saw. Its 1/8" square blade lets us cut in any direction, and allows us to do things like the interlaced white and brown feathers on the Bald Eagle and the cutting work it takes to put the lure in the Trout with Lure without cutting several surrounding pieces. So if it's so slick, why not use it all the time? Because it's a higher maintenance and expense tool than a grinder. Blades cost around $90 and last about a hundred hours. Grinder heads, on the other hand, cost about $25 and last many times as long. But there's times when you just have to use a saw to do what you want to do.

Of course, there's also the old fashioned way of "grozing" - you use a pair of "grozing" pliers to nibble away at the glass. It's messy, time-consuming, breaks lots of glass (unintentionally), and is generally a pain in the backside. We don't use this method very much, as you can guess. Click on the picture of the tools at right if you want to get a closer look at them.

Once the pieces are all cut, ground, cleaned and dried, they are laid out on the pattern in the exact position they will end up in, and a layer of adhesive-backed vinyl (clear contact paper, for you non-technical people) is used to hold them all in position. The vinyl is cut to the shape of the mold or the glass outside edges (depending on a couple of factors). This is then placed face down (eventual exposed glass surface down) in the prepared mold. We told you we weren't going to give away our secrets on preparing the mold, but since you've read this far... we still aren't going to. Ain't we stinkers?

The molds are generally made of ABS plastic, and are commercially available, although we can use almost anything of any shape to make a stone. For instance, we were using a 9" nonstick cake pan to make the round 9" stones long before the 8" round mold was commercially available.

The next step is to get our hands dirty (well, we wear gloves, of course, but they still get dirty - and dried out and cracked from exposure to the concrete - that's on top of all the glass cuts, ground down fingernails, and other hazards). Wearing a dust mask to keep the concrete dust out, we mix a batch of mortar to our "special recipe" and pour it into the mold over the glass (which, if you will recall, is held in place with that high-tech contact paper) to a thickness of about 1/4" to 1/2". This is worked into all the joints and cracks between the glass (we've developed some special equipment to do this). Then the remaining space in the mold is filled with the fiber reinforced concrete (we don't use fiber in the mortar, so that the fibers don't end up sticking out through the glass joints, as they could). If we are making a colored stone out of mortar/concrete, it is very important (and somewhat difficult) to match the colors between the mortar mix and the concrete mix. Alternatively, if we are making a stone out of thin-set mortar, no initial layer of mortar is poured - the whole stone is done in one pour. and consequently we don't have to worry about matching color. We pour a portion of it in for the first layer, add the fiber reinforcing to the rest, then pour it in on top. At this time we also place the anchors we install on every stone (for use in hanging them or securing them to the ground (see Tips & Techniques: Security)

So now we have what, for all intents and purposes, is a concrete and glass upside-down-cake. The stone is cured for a specified amount of time (far different than the instructions you get in the books and from the glass shops, but we've got this down to a science, and can have our stones out in as little as 10 hours - but we know how to handle them that "green"). When the stone is turned out, the remaining joint lines that did not get filled are grouted by hand, the stone is cleaned up, cured for a couple more days before moving it, and then scanned (for the pretty pictures you see here on the website), photographed (for our album) and stacked with protective material in-between them, waiting for transport to a show or for sale. The resulting stone is constructed similar to the diagram.

Custom & Special
Stones

How They're Made

Construction is an important part of quality

Custom & Special Stones

How They're Made

Construction is an important part of quality

Custom & Special
Stones