Concrete Anchors

Concrete/Threaded Masonry Fasteners

The Concrete Screw has been sold under many variations and brand names for many years. The most recognizable of these being the Tapcon Brand, patented by the ITW Buildex Company. The Tapcon was, and still is, a remarkable invention. It actually cuts threads in a concrete hole drilled to a specific dimension and is used to anchor a wide variety of items to the concrete. It does the job really well.

The thing that enables a Tapcon to cut the threads into the concrete has also been the main drawback to using a Tapcon for many applications, that being Corrosion Resistance. This problem, however, has not been solved.

By design, a Concrete Screw must be made of a hard carbon steel so as to ensure that it has the strength required to actually stand up to the very abrasive job of cutting threads in concrete. Hard carbon steel does the trick, but it also tends to rust very easily. Eventually the anchor will fail due to the rusting condition.

Over the years, manufacturers of a few brands of Concrete Screws have tried to overcome the corrosion problem in several ways.

The most obvious of these ways was to coat the screw with a high quality ceramic or epoxy based coating in order to shield it from moisture. This works pretty well but the coating will also eventually degrade. The most recognizable brand coating is Stalgard, which is patented by the Elco Company, and was first used, in the UltraCon Screw. Now, this was a pretty good stop-gap measure for preventing corrosion, but the main problem was that as the screw grinds through the concrete while cutting threads, it is compromised by the high abrasion and thus, the unseen part of the screw below the surface was usually attacked by moisture in the concrete. The anchor would usually fail to hold long before corrosion showed on the exposed head of the screw.

Another popular solution for the problem of corrosion was for companies to begin making the screws out of stainless steel. Two types of stainless have been used and both helped to a certain degree. The 410 series stainless had improved corrosion resistance but on the downside, it is still high in carbon content and it would also rust out eventually; it just took longer than a coated screw. The 300 series stainless screw was then developed as the ultimate answer to corrosion, because it has no carbon steel content. The big problem with 300 series concrete screws, however, is that it is a relatively soft metal and it will not cut the threads properly in the concrete. To overcome that problem, the manufacturers supplied an oversize drill bit with the screw to make the hole larger and easier to penetrate. This dramatically reduced the holding power of the anchor because the thread engagement was quite shallow.

The best and final answer to all of these problems came a couple of years ago with the invention and patent of a concrete screw called the Aggregator. This amazing fastener comes in two diameters – 3/16” and 1/4”.

The Aggregator technology is also found in the larger diameter anchors called ConFlex. This anchor also comes in two diameters – 3/8” and 1/2”.

Although there are many Masonry and Concrete screws and anchors on the market today, the Elco Company is the only brand that has overcome the hydrogen assisted embrittlement problem that has plagued these types of fasteners right from their inception.

The Elco Flex Technology Product family is a true revolution in concrete and metal fasteners.