Back to Basics: Cloth Sheets

Most abrasive products, like sanding belts and sanding
discs, are ready to use right out of the box. But other sanding
supplies--like sandpaper or cloth sheets and rolls, usually need
to be cut to size before you are ready to sand with them. And
some abrasives benefit from being “broken in” before sanding
to improve their performance. Here are some “tried and true”
tips for handling cloth sheets:

• Cloth sheets can usually be torn evenly along the weave of the fabric backing
  by ripping carefully across the sheet from one edge to the other. Otherwise,
  a utility knife cuts nicely from the back of the sheet. Common sizes are
  4-1/2” x 5-1/2” and 3-2/3” x 9” for power sheet sanders.
  a
•  When sanding curved or irregular surfaces, your cloth sanding sheet will
  benefit from a little additional flexing. Just pull the back of a 9 x 11 sheet
  over the edge of a benchtop or machine table. Then turn it 90 degrees and repeat.
  a
• Even if you choose the most popular name brand of abrasive, it won’t do
  you any good if you continue to sand with that cloth sheet once it’s dull.
  Change out your cloth sheet with a new one as soon as you notice it is
  no longer sharp. Dull abrasive sheets require more energy to remove
  stock, decreasing your productivity. In addition, they will contribute to
  a poor finish on wood.
  

Most cloth backed sanding sheets have a flexible, J weight fabric backing and
are available in grits 40-400. They are seen as a general purpose abrasive for
wood or metal and can be used by hand or attached to high speed vibrating
sanders. Abrasive Resource also converts custom-sized cloth backed sheets
for specific industrial or artistic applications. 

For more information on cloth sheets, visit the Abrasive Resource website 
or call us at 800-814-7358.

Sanding Diamond Willow

Tools that will do the job: Scrapers, chisels, knives (no folding blades though--it's too hard to see what you're doing through the blood) and of course, sandpaper. All sharp tools must be used in such a manner and direction that the hand not holding the tool is out of danger.

Procedure: Remove the bark from the diamonds. This can be done most effectively with a rounded blade such as a gouge chisel or a knife. Whatever the tool, do not cut too deeply into the diamond area. Traces of bark in the deepest recesses enhance the final appearance. If you prefer to remove all traces of bark, you must take care not to cut to a depth that exceeds the diamond's special coloration.

Next, smooth the overall surface to whatever degree practical using a scraper, rasp, block plane, broken glass (an old Boy Scout trick) or other tool that lends itself to the purpose.

Sanding follows and this is the most important element in creating a good-looking finish.

Sandpaper Recommended: You will need standard Aluminum Oxide Production Paper. Grits needed are 100, 120, 220 & 320. The paper should be tri-folded for easy gripping during use. 90% of the sanding has to be done with the 100 grit paper, so resist the temptation to go to the other grits until you have smoothed the wood to the greatest degree possible with the 100-grit.

Coating: This can be done with whatever finish you prefer except that polyurethane is not recommended. Tung oil finish works very well for everyone.

Submitted by Holace Nelson of Holly Industries

What is the difference between open coat and closed coat sandpaper?

CLOSED COAT







Closed Coat means that close to 100% of the backing on a coated abrasive product is covered in abrasive grain. Closed Coat products are more aggressive and cut faster because the grit particles are grouped more closely together.They also provide the best finishes because there are no gaps between the grains. You receive the full benefit of the work that the abrasive grain is capable of doing.


SEMI OPEN / OPEN COAT

Semi-Open and Open Coat means that there is more space between grain particles on the abrasive product. Semi-Open Coat usually refers to about a 30% reduction in the amount of grain on the backing and Open Coat usually means that there is about 50% coverage. Semi-Open and Open Coat products have less grain on the backing, which results in less cutting power per grit designation...they are not as aggressive as a Closed Coat abrasive product. In addition, Semi-Open and Open Coat products have gaps in their grain coverage, so the finishes they provide are not quite as even and will tend to fall on the coarse end of the finishing scale for that particular grit.

So what’s the bottom line?

You should always use a Closed Coat abrasive unless there is a reason for you not to. The main reason to switch to an Open Coat abrasive is that the material you are sanding or grinding is soft or gummy. Soft materials are soft woods like Pine, Fir, Spruce, Larch, Cedar, Cypress, Redwood, Tamarack, and Yew. Soft metals include Aluminum, Brass, Bronze, Copper, Magnesium, Titanium, and Zinc. When you attempt to sand these types of materials with abrasives manufactured with a closed coat, the areas between each grain will load up with sanding swarf. Eventually it will load up to the point that it’s taller than the grain and will completely cover the grit. If you continue to sand with a “loaded” abrasive, you will burn both the belt and most likely your workpiece. This is where Semi-Open and Open Coat abrasives are most useful.

By spacing out the grains on the backing of an Open Coat material, you create room between individual grains which will help to reduce the amount of sanding swarf stuck between the grains. You can then use compressed air, a rubber cleaning stick or even the movement of the running sander to help dislodge the swarf from the abrasive. This will enable you to sand soft materials for longer periods of time and with better results.

Woodworkers that only sand cherry, oak, ash or other hardwoods usually don’t experience any problems sanding with an Open Coat abrasive, but you would benefit from using Closed Coat abrasives for your hardwoods and reserve Open Coat materials for soft woods only. You sacrifice life, speed and quality when you use an Open Coat abrasive product on a bare hardwood finish for no reason. This may not be practical for smaller woodworking shops that work with different wood varieties every day, but certainly something to consider.

Prepping A Car for Finishing

Body Shop Business published a great article about car refinishing a few years back. The mindset that car refinishing is easy seems to be spreading throughout the industry. But there are no shortcuts to perfect paint jobs, and thorough prep work is essential to a lasting, quality repair.

No Scuff ’n Shoot Here
by Nathan Tarr

Clean, Clean, Clean
Many times I’ve observed a refinish tech pull a job into the paint shop, pull out a DA and go to town on the car. And I cringe every time I see it. Why? Because they’ve violated what I consider the golden rule of prep work: Always work with a clean surface.

There are many contaminants on a car’s existing finish, and every paint company makes several types of cleaners to get these contaminants off. The first thing all refinish techs should do to any car they work on is spray it down with their chosen paint company’s waterborne cleaner. Wipe off the cleaner using clean towels, making sure you’re actually cleaning the panel and not just smearing around the gunk. These waterborne cleaners are designed to rid the panel of nasty stuff like bird droppings, bug guts and grubby body tech fingerprints.

You’ll also want to use some solvent-based cleaner on the panel and clean it again. When you just start sanding on an unclean surface, you’re just grinding all that wax and gunk into the paint, which will ultimately result in a repair that just doesn’t last.

R-E-S-P-E-C-T
Technicians generally don’t have to deal with customers, so we usually don’t have a personal connection with the cars we’re working on. As a result, it’s pretty easy to become thoughtless with other people’s property. But as professionals, we all need to treat these cars in a professional way. Before you go slopping up a customer’s interior, close the windows and cover up any openings that allow dust and sanding goop to go where it doesn’t belong. It’s also a good habit to protect the panels next to the ones you’re sanding with masking tape instead of relying on your extreme skill with sandpaper. The extra time you spend protecting the customer’s car will be nothing compared to the time it’ll take you to fix an extra panel you damaged after zoning out.

Inspect the Damage
The car is clean and protected, but you’re still not ready to get on with this “scuff and shoot” just yet. Now is a good time to check over the body technician’s work. I make sure the repair looks right and is finished in the appropriate grit. Most primers are made to fill 180 grit scratches, so an 80 grit repair is unacceptable in my mind. Yes, my primer will fill the coarser grits, but only for the time being. In most shops, it isn’t standard operating procedure to take care of primer shrinkage three months after the car is delivered to the customer. Now is the time to give the body tech a second chance to finish his repair…

To read the complete article, please visit Body ShopBusiness.com

Why do some woodworking shops use Silicon Carbide paper wide belts?

We’ve been supplying sanding belts to the woodworking industry for 29 years now and the “traditional” belt recommended for wood sanding has always been an aluminum oxide, open coat belt.  It is the most common, all-purpose woodworking abrasive, and for good reason. It is the only abrasive mineral that fragments under the heat and pressure generated by sanding wood. This characteristic is called friability and is highly desirable. As you sand, aluminum oxide renews its cutting edges constantly, staying sharp and cutting much longer than other minerals. Aluminum oxide is also a relatively tough abrasive, which means that its edges won't dull much before they fragment. Its friability and toughness make aluminum oxide the longest lasting and the most economical mineral for wood sanding applications.

But sometimes life or price isn’t the determining factor.  In recent years, higher end woodworking plants have started to incorporate Silicon Carbide paper-backed belts into their wide belt finishing line. Why, you ask? Well, here are some of the properties of a silicon carbide paper belt that are beneficial to woodworking:

1. Different types of abrasive minerals will stain differently. The same grit belts of Silicon Carbide will stain differently than Aluminum Oxide, with a lighter color gradient than when sanded with the traditional Aluminum Oxide belts.
   
2. Silicon Carbide is sharper than Aluminum Oxide, and is effective at removing the “hairs” that is the result of the wood fibers being bent instead of cleanly cut by an Aluminum Oxide belt. These fibers then “stand up” after staining and contribute to a blotchy finish.  Common practice is now to belt sand with Aluminum Oxide in your coarser grits, and then switch to Silicon Carbide for your finer grits to eliminate any fuzziness that was created by sanding with the AO belts.
3. Paper backed belts have a flatter substrate, so the grain height is much more exact over the whole surface than cloth backed belts.  All of the grit starts and ends at the same height—you don’t have the potential for variation like you do when some of the grain sits on top of the cloth threads versus in between the cross-hatched woven cloth threads.
4. Finally, paper belts run cooler—they dissipate the heat more effectively than cloth belts. And less
   heat=less glazing of the mineral as it wears down & higher quality cutting, which contributes to a finer finish.

Basically, it comes down to finish. Silicon Carbide belts may not last quite as long, and they usually cost more than Aluminum Oxide belts—but they are the preferred wide belt for final finishes in a lot of professional cabinet shops and furniture manufacturers!

Interested in ordering sanding belts?. Just give us a call at 800-814-7358 or contact us through our website.

Are you interested in grinding welds with a flap disc?

Overlap flap discs grind like a depressed center wheel and blend like a fiber disc all in one operation, reducing production time and lowering costs.

Premium closed coat blue Zirconia abrasive flap discs are the best all-around overlap disc capable of fast cutting, long life and superior finish. Backing is made from non-flexible consumable fiberglass.Choose from either standard density or the thicker, high density Xtreme disc. Use in place of a grinding wheel or fiber disc on a right angle grinder for stock removal, grinding and blending of welds, castings and other metal finishing.

Choose from Type 27 flat discs that are designed for finishing on flat surfaces and used at up to a 15 degree angle or the Type 29 conical discs, which are to be used at a 15 - 25 degree angle and are the best choice for speed and maximum stock removal.

Please go to the Overlap discs on our website and find the size that works for your grinder.

Please watch this great you tube video by Kevin Caron on how to use these flap discs . . .

You can "Reclaim" your used Resin Fiber Discs

Are you tired of paying $2.00 and $3.00 for a 7" x 7/8" zirconia or ceramic fiber disc and only using the outside inch or two in your shop? It’s such a waste of money…

Don’t you wish there was an easy way to cut them down so you could “reuse” the disc on a smaller 4-1/2” or 5” grinder? Less waste and better for the environment…

Now there is a way! Abrasive Resource will laser cut your used fiber discs into smaller sizes and ship them back to you so you can reclaim them for another grinding cycle…

          ~  Most heavy grinding occurs on the outside periphery of a 7 x 7/8 resin fiber disc.

          ~  After this “first” use, discs can be boxed up and sent to Abrasive Resource to be laser 
              resized with Laser Blade technology to 4-1/2” x 7/8” or 5” x 7/8” grinding discs.

          ~  Your reclaimed discs are shipped back to your plant within 2 weeks—freight paid.

          ~  Cost is based on order volume and starts at $.50 a disc with a 1000 piece minimum 
              order.

 For more details or a custom quote, give us a call at 800-814-7358.