Tag Archives: Sandblasting Abrasives

Number One Cause Of Premature Coatings Failure

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The most common cause of premature coatings failure is improper ANCHOR PATTERN.

What is anchor pattern?  It is a term used to describe the roughness (etch, or profile) that is created on a surface when sandblasted.  The Anchor Pattern is measured in 1/1000th of an inch, which is called a MIL.  Paint coatings are also measured in MILS as well, making it a term that is easy to remember.

Coatings require specific mils of anchor pattern in order to properly adhere to the surface it is applied to.  Each coating will have different requirements.  Therefore, you cannot simply sandblast a surface clean and then apply paint to it without technical information on what mils profile that particular coating requires (among other factors).  If you simply guess at what profile you need, you risk premature coatings failure.

If you have no access at all to the coating manufacture’s technical data and need to make an educated guess, you will want to consider the following rule of thumb:

The mils of anchor pattern you create on the surface to be coated, should be 25 to 30% of the DRY film thickness of the total coatings system BUT NEVER greater than the dry film thickness of the primer coat unless additional coats are to be applied immediately.

Also key to understand is that the wet mils of a coating will be different than the dry mils of a coating.  Many coatings shrink tremendously, depending on the percentage of solids contained within them.  Make sure that the anchor pattern you create when sandblasting is much shallower than the total coatings when dry.

Other factors that impact the development of anchor pattern include the type of steel you are blasting (including hardness and chemical composition), how the steel was formed, prior use of the steel, the type of abrasive you use to create the anchor pattern (including size, shape, hardness, and velocity), as well as what type of blast nozzle you choose to use and how you use it (such as angle and distance to the work surface).

The chart below is a crude approximation of abrasive size to anchor pattern, and should thus be used only as a starting point only for both centrifugal wheel and pressure blasting.

  • 1 Mil Profile = G80 Steel Grit, 100 Mesh Garnet, S110 Steel Shot, 3060 Coal Slag
  • 1.5 Mil Profile = G50 Steel Grit, 100 Mesh Garnet, S170 Steel Shot, 3060 Coal Slag
  • 2.0 Mil Profile = G40 Steel Grit, 3060 possibly also 80 Mesh Garnet, 36 Grit Aluminum Oxide, 3060 Coal Slag, 3060 Copper Slag
  • 2.5 Mil Profile = G40 Steel Grit, 3060 Mesh Garnet, 24 Grit Aluminum Oxide, 2040 Coal Slag, 2050 Copper Slag
  • 3 – 4 Mil Profiles = G25 Steel Grit, 36 possibly also 3060 Mesh Garnet, 16 Grit Aluminum Oxide, 2050 or 1230 Copper Slag, 1240 Coal Slag

 

 

 

 

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Using Crushed Glass To Clean Precast Concrete

Crushed Bottle Glass Abrasive For Concrete

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Armani Restoration Job SiteCrushed Bottle Glass Abrasive is used to clean and restore the exterior of this 27 story concrete building.  Using a proprietary wet and dry blasting system, the contractor dramatically changed the surface color of the building, as you can see in the photo.  The concrete surface of this building was not smooth – it did have a texture to it, so a medium grade was chosen.  The end result is a much brighter surface color to the concrete, without damaging the exterior.

Crushed glass sandblasting abrasive is the perfect choice for either light cleaning of precast concrete, or by using coarser grades, exposing the aggregate in the concrete.  A medium/fine grade was used for this job, as the customer did not want to damage the surface of the concrete.

Crushed bottle glass abrasive is a 100% recycled product, and is shipped from a variety of locations.  It contains no free silica, no heavy metals, is inert, and it blasts fast and clean.  Many times people will just leave it on the ground rather than clean it up (unless you are blasting off something toxic like lead paint or have local laws requiring cleanup).  This makes it great for blasting log homes and automobiles as it minimizes cleanup in areas where it can be left on the ground as a soil amendment.  Because this type of abrasive is shipped from all multiple points of origin, we will always try to find the closest location to your end job site when quoting.  NOTE:  If left on concrete it will be very slippery!

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Abrasive Grade Silicon Carbide – Uses Of

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Silicon Carbide Grit

Silicon Carbide Grit & Powder

The main uses for abrasive grade Silicon Carbides (Carborundum) are:

Due to the very hard structure of silicon carbide (silicon + carbon) , it has historically been used as an abrasive.  Today, there are many high tech uses for varying grades of Silicon Carbide such as electronics, brake pads, ceramics, LED’s, diodes, transistors, semiconductive research, heating elements, even jewelry.  Gone are the days when Silicon Carbide was known only as an abrasive.

How Is It Made?  Silicon carbide is  manufactured by mixing silica sand (SiO2) and finely ground coke (carbon) together, then they are put into a brick lined electric furnace and baked at high temperature, while at the same time, an electric current is passed through a conductor.  This process can take days from start to finish, with the end result being chunks of silicon carbide of varying purity.   The aggregate is then sorted, crushed, and graded.

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Cleaning Bronze with Glass Bead Blasting

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Here is a great video and article on glass bead sandblasting.

This company is using a fine glass bead to remove bronze patina from outdoor monuments, which restores them to their original state.  I would have liked to see some before and after photos of the monuments, but the article does contain a video clip where you can see (from a distance) the cleaned and uncleaned areas.

Workers from Sterling-based Mercer Lettering and Monument Works have been  sandblasting and pressure-washing the granite stonework over the past few weeks.  The granite stones also have been treated with an organic acid designed to  preserve the grass below while removing fungi from cracks in the stone.

On Thursday, they aimed nozzles at the bronze plaques and sprayed them with  fine glass particles. That removes the patina, or green and brown film, that has  developed on the metalwork over time without damaging the metal below it, said  Graeme Everson,  the company’s owner and a National Guard veteran.

“It brings back the shine of the bronze as it was when they put it up,” he  said.

The article does not discuss the size of the glass bead used, nor the exact machine they used, but the video shows the actual operator blasting.  You can therefore see the blast pot and the operator’s protective head gear which is useful for those just starting out and not familiar with protective gear.

To see the full original article by By ALISON SHEA of The Bulletin: Jewett City monuments gleam like new – Norwich, CT – The Bulletin http://www.norwichbulletin.com/news/x1474279320/Jewett-City-monuments-gleam-like-new#ixzz21poiW0in

© Copyright (c) ALISON SHEA The  Bulletin Originally Posted May 18, 2012

 

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Sandblasting Media: Welcome to SandblastingAbrasives.com!

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Offering a FULL line of sandblasting media, powders, and blast nozzles.

Silicon Carbide Grits 12 and 30 ANSI

Silicon Carbide Sandblasting Media

Having trouble finding a triple graded, Boron Carbide Sapphire Polishing Powder?  Or a very coarse Brown Fused Aluminum Oxide for anti-skid applications?  We offer the full line of ANSI & FEPA sandblasting media and powders, not just the most popular sizes!

Now offering a full line of Made-In-The-USA Sandblasting Nozzles, in both Boron Carbide and Tunsten Carbide.

If your order is 200 lbs or less, we encourage you to simply order online.  For orders over 200 lbs, please use our Request A Quote form, so we can provide a custom freight quote as well as wholesale pricing.

Most of our abrasives can be ordered online in small quantities, or ordered offline via a wholesale account.

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