3/4" x 18" Surface Conditioning Belts (Non-Woven), 16 PACK

Dynafile owners buy this belt to do the job the tool was designed for: reaching into a corner, a slot or a tube cluster and leaving a clean, blended finish there. A 3/4" x 18" non-woven belt fits the Dynabrade 40320 Dynafile II named on our original listing, and the Dynafile II contact arms that accept belts up to 3/4" wide. It deburrs, cleans weld discolouration and puts a linear satin on stainless, aluminum and titanium without cutting into the part.

Each pack holds 16 belts of one grade. Choose Coarse (brown), Medium (maroon), Very Fine (blue) or Ultra Fine (grey); the colour tells you the grade from across the shop. We convert them in Anaheim, California.

• Fits Dynabrade 40320 and 40352 Dynafile II arms rated for 3/4" x 18" belts
• Aluminum oxide grain in a nylon web: deburrs and blends, holds part dimensions
• Coarse, Medium, Very Fine and Ultra Fine cover 40-60 through 320-400 grit finishes
• Reinforced scrim backing survives the tight wheel radius on a file arm
• Reduced loading and heat build-up compared with a coated file belt
• 16 belts per pack; converted in Anaheim, California

Which grade should you run on a Dynafile?

The four grades share one construction and differ only in grain size. Pick by the finish you need on the part when the belt comes off.

• Coarse (brown, 40-60 grit equivalent): removing burrs from sawn and punched edges, cleaning scale and spatter next to a weld, stripping paint from a hinge line or channel. It is the one grade that will take measurable material if you lean on it, so ease off on thin sheet.
• Medium (maroon, 80-120 grit equivalent): deburring machined aluminum, blending the scratch from an 80-120 grit coated Dynafile belt, cleaning heat tint off stainless TIG welds. The grade most shops keep on the tool.
• Very Fine (blue, 180-240 grit equivalent): the #4-style directional satin used in food-service, architectural and pharmaceutical stainless. Also the right grade for matching a factory brushed finish on tube and extrusion.
• Ultra Fine (grey, 320-400 grit equivalent): a fine satin on aluminum, titanium and plastics, and the last step before hand polishing or buffing. Few converters offer this grade as a 3/4" belt; we do.

Working sequence for a stainless weld: coated 120 grit to level the bead, Medium to blend and clean, Very Fine to match the surrounding satin. On a machined aluminum part, skip the coated belt and go straight to Medium then Ultra Fine.

Grit guide: colour, grade and equivalent finish

The numbers describe the scratch the web leaves, not how fast it cuts. A brown non-woven belt removes a fraction of what a 60 grit coated belt removes; that is the point. Use the coated belt to shape and the non-woven belt to finish.

Which machines take a 3/4" x 18" belt?

• Dynabrade 40320 Dynafile II, named on our original listing, which runs belts from 1/4" to 3/4" wide by 18" long depending on the contact arm fitted.
• Dynabrade 40352 Dynafile II, which accepts 1/8" to 3/4" wide by 18" long belts.
• Other 18"-length pneumatic file belt sanders with a contact arm that carries a 3/4" belt. Check that your arm is a 3/4" arm: a 1/2" arm will not track a wider belt properly.

This is an 18" belt. The Astro 3035 and similar tools use 3/4" x 20-1/2", which is a separate product; measure the belt you are replacing if you are not sure. To mount, retract the arm, slip the belt over the drive and contact wheels with the seam running the same way as the belt you removed, release the arm and jog the tool to check tracking. Expect to touch the tracking screw when switching from a coated belt, because the web is thicker.

How to get the most out of a non-woven Dynafile belt

1. Slow the tool. Feather the throttle or turn the regulator down. Non-woven belts finish best below full coated-belt speed and last far longer there.
2. Light to moderate pressure. Let the web float over the surface. Pushing hard folds the fibres, builds heat and strips grain off the web. A light hand is especially important with Coarse.
3. Use the slack of the belt for contours. With the arm angled, the unsupported belt between wheels conforms to fillets, inside radii and tube intersections without flattening them.
4. Stroke in one direction for satin work. Long, overlapping, parallel passes give a #4-style grain line. Any swirl or cross pass shows on stainless.
5. Start from a 120-220 grit coated surface. Non-woven blends existing scratches; it will not erase 36-60 grit gouges.
6. Lubricate lightly on aluminum. A touch of oil or wax stops soft alloys smearing into the web. Run steel and stainless dry, and keep the tool moving.
7. Keep spares in the box. Store belts flat, away from solvents and sunlight, and let a cold belt come to shop temperature before running it.

Use it for / don't use it for

Use it for

• Deburring machined, sheared and laser-cut edges on stainless, steel, aluminum and titanium
• Cleaning heat tint, oxidation and light scale from welds in confined areas
• Blending coated-belt scratches into a uniform directional satin
• Prepping small areas for paint, powder coat or anodizing
• Finishing plastics, fiberglass and non-ferrous alloys without loading

Don't use it for

• Grinding welds flat or removing stock; that is a zirconia or ceramic coated belt's job
• Chasing out coarse scratches from 36-60 grit belts
• A mirror finish; go from Ultra Fine to buffing wheels and compound
• Full air pressure and heavy hand pressure, which shred the web

Specifications

Frequently asked questions

Related products and guides

• All surface conditioning belts, discs and flap discs
• 3/4" x 20-1/2" Surface Conditioning Belts, 16 pack
• 1/2" x 18" Surface Conditioning Belts, 24 pack
• 1/2" x 18" coated sanding belts for stock removal first
• Custom sanding belts made to order in about 3 days