The adhesive manufacturer's warranty the adhesive properties of their products (glues and tapes) for one year, from the date of activation. Therefore, it is unlikely to find a manufacturer who will warranty belts or sticky back discs for more than one year after the invoice date on the product they sold. It is our recommendation to buy no more of these items than you can turn over in six to eight months, but we do warranty them for a year after invoice date. We also recommend storing them somewhere that is heat and humidity regulated, as both those factors can adversely effect the adhesives, as well as the backings.

How to Store and Handle Abrasives >>

Dynabrade recommends a 1 drop per minute setting when using an F-R-L (filter-regulator-lubricator). If this is not feasible, it may be best to:

1. Place 2-3 drops at the coupler before using in the morning.
2. Place 2-3 drops before using after lunch.
3. Place 2-3 drops at the end of the day.
4. After that, run the tool for 20-30 seconds to distribute the oil in the air motor, then it will be fine to let it sit overnight.

Warping and curling are usually signs of variations in or exposure to heat and humidity. Contact customer relations at 1-800-645-5555 to request our Woodworking Reference Guide, or visit our reference page to read about storage and handling.

How to Store and Handle Abrasives >>

We recommend to never skip more than one grit when working up through a grit sequence. If done, the finer grit is overworked by asking it to remove a scratch it is not designed to remove. This can result in burning of the workpiece, belt and lower abrasive life.

The recommended PSI for our wide belts is as follows:

• 45 – 55 PSI for paper
• 55 – 65 PSI for regular cotton cloth
• 65 – 75 PSI for polyester

There are instances when poly belts are used to plane or dimension metals or wood with a PSI over 70. For these types of operations, this is acceptable. Paper belts should never be used for these types of applications.

Recommendations are as follows. If you are thinking about going outside of these parameters, please check with our technical department first.

For all portable belts, #4 is 1st choice and #3 is 2nd choice/ for glass belts.

All Dynafile belts only use #4 joint.

Intermediate belts (This includes backstand grinders and lever stroke sanders)

• Cloth: #4 joint is 1st choice and T joint is 2nd choice if #4 joint fails/fine grits
• Paper: #4 joint is 1st choice and #1 joint is 2nd choice for fine grits only

All pump sleeves only use #1 joint.

Mold sanders use #6 as first choice and #5 as 2nd choice.

Edge Sanding uses #4 joint as 1st choice, #2 joint as 2nd choice*, and #5 joint as 3rd choice.

*2nd choice is an option for fine grits only. Designations are based on grits 150 and finer.

See also: Belt Joints >>

For blending the welds we would recommend the SMT Flap discs. If it is hard aluminum, the SMT627 is fine. If it is soft, try the SMT630. If the welds are too large for these discs to take down in a timely manner, do the brunt of the take down work with the A46N Supra regular grinding disc. Then, go to the flap discs for the actual "blending" portion of the work.

After the welds are blended, use either the regular PS33 or the non-woven discs to try and even out the entire surface. The grit would be determined on what product your working on, but 80 grit would be a good place to start with the PS33 and perhaps the medium density on the non-woven.

There is nothing on the market that you could spray on a belt that would deter glazing due to loading. If the belts are polyester (inherently waterproof) or if they have been chemically treated to be waterproof, try to wash them and clean them out. Some shops are using a product called "Purple Power®" that is available at any retailer. It's ecologically safe so disposal is not a problem, and does seem to buy them some extra life on their belts.

When sanding soft, gummy or resinous woods, it is recommended that abrasive belts are Open Coat. This means that 50-70% of the grain has been removed from the backing so that as you sand and particles get packed up in the grain, they will have room to fall back out.

Closed coat abrasives have 100% of the backing coated in grain and should be used for hard woods or metals only. They offer the best cut and finish because there are no gaps in grain coverage, but if you load the belt up before it's completely used, less life and finish will occur.

You can use a fiber disc on a right angle grinder for the actual cutting. That would be the quickest. Also depending on how deep you need to go, probably start with 80 grit and then adjust up or down based on removal rate.

The only suitable products we have with a Hook & Loop back are paper products, and therefore may not last as long as a cloth backed item would. However, if you would like to try, we would recommend our PS11 which is a wet dry silicon carbide paper.

As for the grit range, that is a hard call for me to make not seeing the surface, but I would think if you started at 80 and went to 150 or so, you should end up with a fairly nice looking top. You can always sand finer if you decide you want more sheen to the concrete.

Please check KLINGSPOR's grit chart, located on the back page of our catalog. This grit chart will list all of our products that have been chemically treated to be waterproof (i.e. they will have a WP or “waterproof” designation on backing) and all our polyester backed products which are inherently waterproof.