FreeShip- Reflective Glass Beads, Very Fine, 0.02 mm, Paint Additive, Resin Filler- (Prompt rebate on orders with 3 or more FreeShip items!)

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Not all quantities are pictured.

These are the "Very Fine", 0.02 mm Median Size, there will be size variations, see below.
We carry 6 sizes of reflective glass beads: "Very Fine", "Fine", "Medium", "Coarse", "Extra Coarse", and "Super Coarse".
The bead in this listing is the Very Fine. It has a "Median" or "Typical" size of 0.02 mm diameter (about 625 mesh or 0.00079"). The median is the size around which variations in size cluster, or the top of the bell curve in a plotting of size variations. The "Cluster" is 0.01 mm to 0.03 mm. The "Spread" is 0.005 mm to 0.035 mm. Read on to see the definitions of "Cluster" and "Spread". Also, you may question why are the very fine beads in this listing the color they are. See the bottom section for an explanation of that.

Different suppliers "grade" the sizes with differing methods and I've found that the labeled size of beads to be sometimes puzzling after I've actually measured the beads in a new batch from a supplier. Average, reasonably priced glass beads of a stated size are not all going to be that labeled size. But I've sometimes found the majority of measurements of a batch to be a different size than the labeled size. So, I've done my own sizing and set up my own system for defining sizes. I take 30 or so measurements of a given size (depending on how much variance there seems to be initially). This gives me a sometimes wide range of sizes, sometimes narrow range. It depends on the supplier and the size of bead. If you plotted the different size samples you would get a bell curve. I operate on that curve using the following definitions:
-The "spread" is the distribution between about 95% of the measured sizes. It will be given as 2 sizes, the smallest and largest within that distribution and is the distance between those 2 sizes. There will still be some sizes that fall outside the smallest size and largest size, but not many (~ 5%).
-The "cluster" is the distribution of sizes at the top 15% or so of the bell curve. It too, will be given as 2 sizes, the smallest and largest within that distribution and is the distance between those 2 sizes.
-The "median" is given as a single size that is at the approximate center of the "cluster" values. Another maybe better name for it would be the "typical" size.
Please note that measurements were taken with a very high quality digital caliper, not a micrometer. I don't think the end result would be much different if a micrometer were used. An optical comparator would be better than either.

In addition to the above description on size variations, note also that the beads are not going to be perfectly round. If you need precision glass beads they are available, at a much higher cost.
Visit the Potter's site (the largest producer of "glass spheres" in the world). Check out their "Premium Highway Safety Marking Spheres" description, which is here with an excerpt:
https://www.pqcorp.com/products/marking-spheres/premium-highway-safety-marking-spheres
"Our Premium Highway Safety Marking Spheres meet or exceed every adopted highway safety marking sphere standard in effect today for North America..... Strict quality control produces truly round spheres that optimize retroreflectivity. Proprietary coatings are available to resist agglomeration, ensure flotation for ideal embedment and improve adhesion for greater durability.....
Potters Premium Highway Safety Marking Spheres can be applied as drop-on spheres in all commercial applications—waterborne paint, epoxy, polyester, thermoplastic, MMA, polyurethane, polyurea and VOC-compliant paints. They may also be incorporated as an intermix into thicker binders, such as thermoplastic and MMA."

Please note that glass beads are like miniature ball bearings. If you spill them on a hard floor and walk on them, it's like walking on ice. I've almost crashed a couple of times when I've spilled them unknowingly on a concrete floor.

I originally bought glass beads as an experimental filler in casting resins and cements. Glass beads are relatively expensive which is not so much a factor if you're using them for their reflective properties by incorporating them into a coating. But if you use them as fillers for castings either to add weight or translucency to the cast part, the cost starts to matter. There is another form of glass that is much less expensive and that is crushed glass, but it has some disadvantages. All the properties of glass beads except weight and some degree of translucency are not present in crushed glass. The particles are irregular in shape and may not be as transparent as glass beads depending on the supplier and the separation of glass grades they used. Also, you probably won't get as great an increase in weight because the resin viscosity increases much more than with the spherical shape of the beads. If you want to try crushed glass we do have 3 mesh sizes and you can get to the listings with this link:
https://www.etsy.com/shop/NorthernWestStuff?ref=hdr_shop_menu&search_query=crushed+glass

If you're making smaller castings, the expense of using glass beads diminishes. Referring to the Potter's site again, they list these advantages when using them as resin additives or fillers:
-Fewer defects: excellent mold flow, uniform dispersion, improved surface appearance
-Very high filler loading: precise geometry for uniform dispersion, better surface wetting, closer packing
-Dimensional stability: reduced molded part shrinkage and warpage; improved part flatness
-Improved product characteristics: higher flex modulus, better abrasion resistance and surface hardness
-Available uncoated, or with coupling agent coatings designed to optimize performance in specific resin systems
-Partial replacement for expensive fiberglass
Visit this Potter's page for other uses and types of glass beads:
https://www.pqcorp.com/product-search/?Category=58376ba0-e74c-412a-a709-efc203b0fb26

For additional uses, here are some I've gathered from the internet in general and discovered when experimenting with them:

--In paints to give interesting reflective properties to the paint coatings when dry. Glass beads are what give road signs and those reflective stripes and lines on roads their reflectivity at night. Technically it's called "Retroreflectivity", and there's a nice Wiki article on how it works:
https://en.wikipedia.org/wiki/Retroreflector
There are lots of articles on the internet about Retroreflectivity. YouTube also. I even saw a webpage where someone had made a retroreflector tuxedo. Most people who are buying glass beads are buying them to make retroreflective (or lets just call it "reflective") surfaces by mixing them with different paint materials. You see a lot of application these days on safety clothing. Bicycles use it and bicyclists use it on straps and clothing. They are being used in the arts increasingly for interesting effects. Artist's paint suppliers Golden and Liquitex both have versions of acrylic mediums premixed with glass beads

--As a "weight" material, since glass is heavy, it's used as a filler in dolls and other items. Glass beads make whatever you fill with them into a neat "squishy" soft bag, that's made more interesting by its weight. They can go into any casting material to add weight. They're not cheap though, so small projects would be a more appropriate use. {Steel shot makes for a heavier "weight" filler, which we also carry and can be added to the glass beads for whatever weight you want: https://www.etsy.com/shop/NorthernWestStuff?ref=hdr_shop_menu&search_query=steel+shot }.

--As a filler in resins and plastics, since glass beads are very low-friction, mobile, and free flowing (except for the smallest sizes), they can add weight to a resin while maintaining relatively low pouring viscosities. And since they are clear glass, if their refractive index matches a clear resin, they give a relatively clear, filled, casting. It is difficult to find that right combination of matching RI's, however.
If they don't match, there are still other interesting effects besides just reflection. At a minimum you'll get a translucent, filled resin that is way more translucent than the standard filler used to make so called "Cultured Onyx", namely ATH (Alumina TriHydrate). Glass beads are much more expensive than ATH, though. {We also carry ATH here: https://www.etsy.com/shop/NorthernWestStuff?ref=hdr_shop_menu&search_query=ATH }.

--As a shot peening media used in a sand blaster. Glass beads leave a smoother finish than sand, more of a cleaning and brightening effect than abrasion because they are not removing much material like abrasives used in sand blasters do. Peening a surface is more complex than just cleaning or smoothing it. It creates a compressed layer, each round particle acting like a ball peen hammer. If done correctly it can harden metals by surface compression, protecting against stress cracking from surfaces by relieving tensile stresses in surface layers. In general it can be thought of as providing an outer layer of protection to the metal. There's a good Wiki article on the subject:
https://en.wikipedia.org/wiki/Shot_peening

--A use I discovered while experimenting with CA liquids (like 'super glue', CyanoAcrylate, or just CA), is that some of the glass beads I had would cause CA to harden, like it does with several powdery fillers (the main one now going around the internet is baking soda- there are several others, such as the above mentioned ATH), and if you find just the right combination so that the CA doesn't almost instantly harden like it does with baking soda, and has time to soak into the spaces between the beads, you can make small castings in silicone rubber by dumping some glass beads (of the correctly found type) into the silicone mold, then squirt some CA onto the beads until the mold is "full". I only got it to work with small objects because it's tricky to match it to the CA so that it sets up, but not too soon (if it sets too soon it will also discolor the CA, causing it to "whiten"). Both the type of glass bead and the type of CA can be variables. You can also alter the timing of the cure reaction by altering the surface of the glass beads yourself, making the surface pH lower or higher. Another possibility is to prevent reaction between the CA and the glass beads and cure the CA by raising the temperature of the mold and its contents. Go a step further and replace the CA with a very low viscosity resin? No, there is no commonly available resin that has viscosities in the single digits, with the exception of MMA or EMA monomers (which are more difficult to use and which have crazy shrinkage percentages [but now that I've mentioned them, I'd like to try them for this!]. Here's a link on MMA: https://en.wikipedia.org/wiki/Methyl_methacrylate ). The size of the glass beads used with this idea is pretty crucial. CA is more expensive than the glass beads so if you used larger beads you'll have to use larger amounts of CA because of the bigger spaces between larger spherical objects. Use beads that are too small and the spaces between beads becomes so small that the CA won't readily penetrate the bead mass. I used this as a guideline: try using beads that are very small but are still free flowing. If the CA won't penetrate, go up a size.

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You may notice that the color of the beads shown in the pictures varies between close to white, grayish white, to greenish. This is partly due to the type of glass the manufacturer used. Common soda-lime glass has a level of iron in it (which comes from impurities in the silica sand used). The iron is actually beneficial in the manufacturing process for making sheets of glass, but it does tint the glass. Manufacturers can use "low iron" soda-lime glass which eliminates the green tint. There's also "flint" glass which is a purer glass used for optics and other application where a "water-white" glass is needed. See the bottom paragraph for more on "flint" glass.

Besides the color of the glass used to make glass beads, another factor is at play in the apparent color when you view glass beads of the same glass type but of different sizes: seeing them without lighting conditions to make them retroreflective, the larger beads transmit more light and thus appear "clear", but as the beads get smaller their size causes more reflected light from their outer spherical surfaces to hit your eyes (not light entering the bead and bouncing back from the rear interior of the bead), making them appear "whitish".

If you investigate "flint" glass you will find inconsistencies in descriptions of what it is. The best general explanation for today's glass is that it is any glass that is colorless. Flint glass actually has no flint in it. A quote from { www.gpi.org/learn-about-glass/what-glass/glass-colorization }: "To offset the yellow/green when making flint (or “colorless”) glass, other colors are introduced by adding selenium (for red) and cobalt (for blue) in proper proportions to yield a gray glass that appears colorless, hence the term “decolorization.” Historically, it's more complicated, and more interesting. This is paraphrased from a Britannica page: https://www.britannica.com/technology/flint-glass elaborates:
The term "flint glass" originated around 1675 in England when George Ravenscroft, searching for a way to make colorless glass used calcined flint as a base, thus the "flint" is explained. It was a flawed product however and he went on to use lead oxide to produce a heavy, crystal-clear glass (what we call "leaded", "lead", or "crystal" glass today). The name "flint" stuck and became synonymous with lead crystal glass (at least in England).-

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Reviews

Reviews (17)

Average:

Aug 3, 2024

Fast shipping. Great product. Quick response to questions. Awesome experience! Thank you!

Clifford

Apr 11, 2024

Great customer service, item is as described, easy to work with.

Tane Ko

Dec 14, 2023

Quality product, Excellent services, Quick seller responses

Scotty Guilbeaux

Jan 23, 2023

Taylor b

Nov 29, 2022

Petra Warwick