This guide covers every stage of automotive refinishing from body filler to clear coat — with the correct grit range, disc type, and hole pattern for each step. Use it to build a stock list that covers your workshop's full repair sequence without gaps or over-stocking.
Each stage is matched to an SPX product route so you can move from the guide directly into the right buying page without searching.
Use this as the quick visual before the detailed stage notes below. The goal is to keep the repair sequence clear: ceramic where the work is heavy, then finer discs as the finish standard rises.
This page is strongest when it stays practical. The proof layer below keeps the guide anchored to first-party signals from the current 150mm products, plus one internal P320 case study that shows the cut-versus-finish balance buyers care about in mid-stage prep work.
Across the current products surfaced as part of this 150mm automotive system.
From approved reviews on matching 150mm product lines.
In the SPX joinery paint shop, a 150mm SPX ceramic disc in P320 was run through black guide coat on Varen Legno 2K polyurethane supplied by Paint Holdings using a Festool ETC-5. Recorded sanding pass: 50 seconds.
P320 is the kind of stage where buyers want both cut speed and a controlled finish. That same balance shows up in automotive primer and guide-coat work.
This was not an automotive panel test. It is still useful first-party proof of how the SPX 150mm ceramic behaves when the stage demands both control and throughput.
"Very quick response and delivery. Great service"
James • SPX 150mm Ceramic Sanding Discs - 40–80 Grit (50 pcs)
Automotive refinishing follows a defined sequence. Running the wrong grit at any stage means extra passes, rework, or a visible scratch pattern under the topcoat. Use this section as your reference for each stage of the repair.
A quick-reference table covering every stage from filler to clear coat. Use this to confirm your stock list covers the full sequence without gaps.
| Repair stage | Grit range | Disc type | Key objective |
|---|---|---|---|
| Body filler shaping | P40–P80 | Ceramic | Shape the repair quickly, establish the surface level before primer stages. |
| Blocking & levelling | P120–P180 | Ceramic | Remove coarse scratches, refine the surface before high-build primer. |
| Primer surfacer sanding | P240–P320 | Ceramic (volume) / Standard | Level primer, establish a flat surface, apply and read guide coat. |
| Guide coat & final primer | P400–P600 | Standard or film | Remove guide coat, final flatting before topcoat application. |
| Pre-paint & blend prep | P800–P1200 | Film disc | Scuff adjacent panels for blend, reduce gloss before clear coat. |
| Clear coat flatting & denib | P1500–P3000 | Film / wet-dry | Flat runs, nibs, and overspray in cured clear before machine polish. |
Most workshops make the mistake of over-stocking fine grits and under-stocking coarse. The reality is that P80, P120, and P240 are the highest-consumption grits in most panel shop environments — filler and primer work accounts for the bulk of disc usage.
A practical stock approach is to hold larger quantities of the coarse and mid tiers, and smaller quantities of the fine finishing grits. Ceramic grain on everything from P80 through P320 reduces overall disc consumption and gives operators more consistent performance through each stage.
Match your disc hole pattern to your backing pad. A mismatched pattern blocks extraction ports rather than opening them.
| Decision point | Best fit for | Main advantage | Watch out for |
|---|---|---|---|
| 7-hole | Festool Rotex RO 150, older DA sanders, and shops already standardised on 7-hole pads. | Widely stocked, proven in heavy automotive use, simple to reorder. | Not interchangeable with 15-hole pads — will block ports on a 15-hole system. |
| 15-hole | Fixed-pattern 150mm sanding setups already standardised on 15-hole pads. | Straightforward fitment and reorder logic when the workshop already runs 15-hole. | Must confirm pad pattern first — the benefit disappears entirely on a mismatched pad. |
| Multi-hole | Mirka DEROS, mixed-machine workshops, and buyers needing one disc across multiple DA brands. | Broad compatibility — useful when a workshop runs multiple pad systems side by side. | Not optimised for any single pad — may underperform a well-matched 7 or 15-hole disc. |
Ceramic grain earns its premium most clearly where the disc is under sustained load. At fine finishing stages, scratch control takes over as the priority.
P40–P320 work puts maximum load on the abrasive grain. Ceramic self-sharpening makes the biggest difference here — standard discs glaze out quickly on filler and dense primer, adding changeovers and inconsistency.
P400–P600 is lighter work. Ceramic still performs well but the self-sharpening advantage is less pronounced. Standard discs are usable at these grits in moderate-volume environments.
P800 and above is about scratch pattern control, not cut speed. Film backing gives a more flexible, consistent finish on curved panels. Ceramic is available at these grits but the disc-type choice matters less than the grit accuracy.
The useful way to compare abrasive cost is by repair stage or by car prepared, not by packet price alone. The most important stages to watch are usually P80 or P120 filler work and P240 or P320 primer work, because that is where disc changes and slowing cut rate become visible fastest.
Track how many discs a technician uses to finish the same stage, whether the cut stays stable near the end of disc life, and whether the scratch pattern is still clean when the disc is close to being changed out. That gives you a much stronger benchmark than comparing packet prices in isolation.
The SPX internal P320 case study above is useful here because it shows the kind of cut-versus-finish balance buyers are trying to measure. Once a workshop logs the same checkpoints across filler, primer, and guide-coat stages, the cost-per-car decision becomes easier to defend.
Use the page that matches your next buying question. Each one is built around a specific decision — size, material type, fitment, or supply structure — rather than a generic product listing.
Start here when you need the complete grit range guide, hole pattern overview, and buying options for the 6-inch DA format.
Use this when cut speed, disc life, and cost per job are the main comparisons. Includes ceramic vs standard and cost-per-job analysis.
Use this when sander compatibility and extraction fitment are the priority. Includes the sander compatibility table and dust extraction guide.
Use this when the question is about repeat supply, volume pricing, and setting up a trade account for the workshop.
Products matched to the SPX automotive system. The grid stays inside 150mm, stage-relevant products so the guide and the product block stay aligned.
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Each page below handles a specific part of the buying decision. Use this guide as the starting point, then follow the link that matches your next question.
Full grit selection guide, hole patterns, and ceramic vs standard overview.
Performance page for buyers comparing cut speed, disc life, and cost per job.
Dust extraction guide with sander compatibility table and stock plan.
B2B route for workshops, panel shops, and trade buyers ordering at volume.
Already weighing SPX against 3M, Mirka, Indasa, or Norton? These honest comparison guides walk through cut, dust extraction, fitment, and cost per job for Australian panel shops.
Ceramic cut against Cubitron, plus the real cost-per-job maths.
Dust extraction, 15-hole vs net, and life without tool lock-in.
Two value brands compared on cut, supply, and restocking.
Refinish focus versus a broad industrial catalogue.
Use the 150mm page for the full grit range, or open the wholesale route if you are setting up a repeat-order account for a panel shop or spray booth.
