After going back and reading a thread on another forum let me answer a question. I use and offer discs for the woodturning market. As you talk around to other turners you will come to know the Blue Flex discs are a big favorite with wood turners for a number of good reasons. More importantly let me address a recent question and share some information talking about the make up of discs and what makes a quality sanding disc!
There are basically three components making up a sanding disc. They are the backing, glue, and the abrasive itself. There are also coatings but we will not get into that at this time. Generally it is these components that make up a sanding abrasive.
The backing generally is made up of 3 different materials…Paper, Cloth, and Film. Wood turners have been use to mostly paper over the years but that has changed over the last few years with the introduction of technology to the abrasive industry.
Paper can provide a very good backing when given the correct thickness of paper. It can allow sanding to a fairly high grit range with even grit consistency such as 800-1000 grit. The issue with paper backing is when the paper backing begins to wear it begins to tear. When the disc begins to tear the abrasive begins to separate from the disc and you have a break down in the disc itself.
Cloth backing offers a more durable backing not tearing up quite as easily. However, because of the crisscross mesh in the cloth backing you will find that you are not able to find cloth backed abrasives in the higher grits. Generally you can find cloth backed products up to only grit 220. Cloth backing tends to last longer than paper backing but you sacrifice then grit range you had with the paper backing. Make Sense?
Then we have film! Film is a fairly new process that has been introduced to the abrasive market. Mylar Film offers a number of advantages:
- Film tends not to tear! Because the backing is film is does not tear like paper you will get a longer life from a film disc over a paper or even a cloth backed disc.
- Film backed discs tend to be more flexible and hold a shape better then paper or cloth backed discs. So for coves and other shapes this can be very useful.
- While there is not much talk these days of people wet sanding film backed discs allow you to wet sand your project if you care too. You can place these discs directly in water breakdown to the discs.
- Film backed discs when manufactured correctly offer a superior grit consistency allow you to sand to a very high grit range. Understand this… abrasive used to be applied to the backing simply by gravity. Manufactures would simply dump abrasive grit on the backing as it rolled underneath it. The focus was trying to control grit particle size. However with the introduction of technology to the industry most quality products are no longer use simple gravity dumping techniques but rather a process involving electro statically charging the abrasive backing so as the grit is applied to the surface the abrasive grits stand straight up. Imagine footballs all standing on their ends standing straight up.
Before using the gravity system there was less control and the grits fell and lay where they will. You did not get a tight grit pattern lay out. Remember the idea of taking your disc and running it over an edge to knock off the high edges??? No more! Quality manufacturing allows for this process to be controlled and the user benefits by having even grit consistency and a tighter grit pattern lay out. I hope this provides useful information for you. Thanks, Vince
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