Test Spot Guide
Summary: An explanation on how to do a test spot, a necessity before every attempt at polishing
Are you unsure on what polish to use, and what kind of pads you’ll need? Want to preserve as much paint as possible whilst also getting a good finish? You’ll need to do a test spot to make sure you have the right combination of pads and polish. This saves from having to do the entire vehicle several times over and makes the best use of your labor.
Test Spot Supplies
- 1 pad in each hardness (finishing, medium, heavy). A wool or microfiber pad is optional in case the heavy pad doesn't cut enough. You can always order it later.
- All the polishes you want to try (finishing, medium cut, heavy cut)
- Paint inspection light
- Panel prep spray (PPS)
- Towels for polish removal
Test Spot Expectations
Firstly, we should only want to look for defect removal. For some deeper scratches it’s better to leave them in as removing them would take away too much clearcoat and burn through the paint layer. It’s just not worth the risk. Chasing perfection is extremely difficult, so a goal of removing 60-90% of swirls and defects is much more realistic. An older vehicle that’s never been paint corrected will often have some permanent damage, so don’t chase perfection. Even removing 60% of the swirls and scratches will make a daily driver’s paint pop!
Test Spot Location
For your test spot, you should choose somewhere that is a good representation of the average condition of the overall paintwork. If you have a few places that are much better or worse, do another test spot on them, with the aim of preserving as much of the clearcoat as you can. The same goes for panels that have been resprayed: they also need a separate test spot as they can behave completely differently to the factory paint. If in doubt, do an extra test spot.
Steps to Perform a Test Spot
Start the test spot process with the least aggressive combination: finishing polish on a finishing pad.
- Prime your pad with the chosen polish. Follow the bottle instructions. If it doesn't mention how much to use, start with 3-4 pea-sized drops.
- Working in left-to-right passes then repeating with top-to-bottom passes, go over the test spot area.
- Wipe the area dry with a clean microfiber towel.
- Remove the polish residue from the paintwork using the PPS on a microfiber towel.
- Judge the test spot and repeat the process with a different combo of polish/pad if necessary.
Judge the Test Spot
After you’ve done a test spot with one combination, assess the results and judge how it turned out. Check the finish and see if there’s haze still left. Was most of the swirling removed? Are there just a few of the deeper, unfixable scratches left? If it looks good, you’ve found your combo for doing the entire vehicle!
Making Adjustments for Best Results
If you’re not happy with the result and there was little change, you’ll need to make adjustments, which can include changing out the polish, swapping pads, or raising/lowering the speed setting of your polisher. All of these factors affect “cut” level, or how much clear coat you’re removing. Most of the result comes from the polish choice, with the pad choice being fine-tuning. Follow this progression:
- Start with a finishing polish on a finishing pad. Step up to medium pad then heavy pad if necessary.
- Try a medium polish with finishing pad. Step up to medium pad then heavy pad if necessary.
- Try a heavy polish with finishing pad. Step up to medium pad then heavy pad if necessary.
- Nothing worked? Repeat the medium polish on a wool or microfiber pad for heavier cut.
- Still showing scratches? This is beyond normal detailing and needs wet sanding or a repaint 😭
Learn from Experience
As you become more familiar with your vehicle’s paint and doing paint correction in general, you’ll become a better judge of what elements are needed to remove swirling.
A professional can often do one test with a specific combo of products and land on exactly what’s best for the vehicle with their own skilled movements. You’ll get faster, better, and more accurate the more you practice. Check out the Paint Correction Guide for more technique tips.
Need extra help?
If you need some visual help with your test spot, feel free to hop into the questions forum on the HTAD Discord. Sometimes another set of eyes on your before/after sections can help with judgement.