Alpha® PlasterKing® Backer Pad — 6-1/2" Soft, M10-1.25 Reverse Thread
Soft-edge hook-and-loop backer pad engineered for Alpha® PlasterKing® pool plaster polishing on curved surfaces — corners, coves, step radii, and bowl bottoms. The 6-1/2" working face and softer perimeter let the diamond polishing pad flex into contour without flat-spotting the plaster. The M10-1.25 reverse-thread (left-hand) arbor mates directly with gas-powered weed-cutter spindles — the industry-standard drive for pool-plaster polishing — so the backer self-tightens under load instead of unthreading. Pairs with Alpha® PlasterKing® 7" diamond polishing pads (PS070050 #50 yellow, PS070100 #100 red).
Features
- 6-1/2" soft-edge backer — designed for curved surfaces, corners, coves, and bowl bottoms
- M10-1.25 reverse-thread arbor — direct fit to gas-powered weed-cutter spindles
- No special connector or adapter needed for installation
- Eliminates spin-off risk from incompatible threads — self-tightens under load
- Hook & loop face for fast pad swaps between grits
- Wet or dry use — suited to real-world pool-plaster polishing conditions
- Pairs with PlasterKing® 7" diamond polishing pads (PS070050, PS070100)
| Part No. | Diameter | Thread | Use | UPC |
|---|---|---|---|---|
| PK710SH | 6-1/2" | M10-1.25 Reverse | Soft — curved surfaces, corners, coves | 749173480232 |
- Thread the PK710SH onto an M10-1.25 reverse-thread (left-hand) weed-cutter spindle. Snug by hand — the working load will tighten the connection.
- Center a PlasterKing® 7" #50 (yellow) or #100 (red) hook-and-loop polishing pad squarely on the backer face.
- Wet the plaster surface. Begin polishing curved sections — corners, coves, step radii, bowl bottoms — where the soft edge can flex into the contour.
- Hold the polisher at or below 5,500 RPM with light, even pressure. Let the diamonds cut.
- Switch to the flat-surface PK710HH (7" hard) backer for floors and walls; use PK710SH only where curvature requires flex.
- After use, rinse the backer and polishing pads with clean water and air-dry away from heat or direct sun.
6-1/2" — Hook & loop face — Soft Hook & Loop Backer Pad — PK710SH
| Part No. | PK710SH |
| UPC | 749173480232 |
| Size | 6-1/2" |
| Type | Soft Hook & Loop Backer Pad |
| Attachment | Hook & loop face |
| Thread | M10-1.25 Reverse (left-hand) |
| Max RPM | 5,500 RPM |
| Recommended For | Soft backer for curved pool-plaster surfaces — corners, coves, step radii, bowl bottoms |
| Packaged Weight | 0.35 lbs |
| Package Dimensions | 7 in × 7 in × 0.5 in |
| Commodity Code | 3926.90.9989 |
| Country of Origin | China |
| Property | Detail |
|---|---|
| Application | Wet or dry pool-plaster polishing on curved surfaces |
| Working Diameter | 6-1/2 in (165 mm) |
| Hardness | Soft — flexes to follow contour |
| Arbor Thread | M10 × 1.25 reverse / left-hand |
| Pad Attachment | Hook & loop |
| Max RPM | 5,500 |
| Recommended Drive | Gas-powered weed cutters with M10-1.25 reverse-thread spindle |
| Companion Pads | PlasterKing® PS070050 (#50, yellow), PS070100 (#100, red) |
| Country of Origin | China |
What is the difference between PK710HH and PK710SH?
Both run on M10-1.25 reverse-thread weed-cutter spindles for pool-plaster polishing, but they differ in hardness and diameter. PK710HH is a 7" hard backer for flat surfaces (floors, walls). PK710SH is a 6-1/2" soft backer engineered to flex into curved areas — corners, coves, step radii, and bowl bottoms — so the polishing pad keeps full contact with the contour.
Why a reverse-thread (M10-1.25 left-hand) backer pad?
Pool contractors most commonly polish plaster with gas-powered weed cutters, which use an M10-1.25 reverse-thread (left-hand) spindle. The reverse thread lets the backer self-tighten under load. Using a standard right-hand backer on a reverse-thread tool will cause the pad to unthread mid-cut.
Do I need any adapter or connector for installation?
No. The PK710SH threads directly onto an M10-1.25 reverse-thread spindle — no adapter, washer, or special connector required.
Which PlasterKing® polishing pads fit this backer?
The Alpha® 7" PlasterKing® polishing pads — PS070050 (#50, yellow) and PS070100 (#100, red) — attach to the hook-and-loop face. The 6-1/2" backer is intentionally slightly smaller than the 7" pad so the pad overhangs and can flex into curves without the backer rim contacting the plaster.
Can I use the PK710SH for flat floors and walls?
It will work, but the dedicated 7" hard backer (PK710HH) is the right tool for flat work. PK710SH is purpose-built for curvature where the soft edge is an advantage; on flat work it is less efficient than the hard backer.
Is this the same as the MP758HL backer?
No. MP758HL is the 5/8"-11 right-hand-thread backer for standard rotary polishers. PK710SH is the M10-1.25 reverse-thread variant for weed-cutter drives.
Wet or dry use?
Either. The backer itself is rated for wet or dry pool-plaster work. The polishing pads attached to it should be used per their own instructions — PlasterKing® diamond pads are wet-use.
No product-specific videos are currently available from the manufacturer or DST.
⚠ WARNING: Cancer and Reproductive Harm — www.P65Warnings.ca.gov. Always wear appropriate PPE.











