The repair grade. Where 1000 and 1200 are for priming a surface you've already got right, 500 is for fixing one you haven't. It carries the largest pigment particles in the Mr. Surfacer range, which gives it real body — enough to fill the scratches, unevenness, pinholes and gaps that modification work leaves behind, rather than shrinking into them and showing the flaw straight back at you.

That makes it the grade for anyone who cuts plastic rather than just assembling it. Scratchbuilt panels, conversions, kitbashes, sanded-back putty joints, resin castings with surface bubbles, the trench left where you removed a moulded-on detail — all of it disappears under a coat of 500 and a sanding stick. Mr. Hobby also point out it makes a good base before brush painting, since the slight tooth gives brushed paint something to grip. 170ml.

• Coarsest grade in the range — genuine filling power
• Eliminates scratches, unevenness, pinholes and modification marks
• The grade for conversions, scratchbuilding and repair work
• Good tooth as a base before brush painting
• Sands back cleanly, wet or dry

Tip: Work in stages. Spray a coat, let it cure properly, sand it back flush, and look again under raking light — deep flaws usually take two or three passes rather than one thick one, and a heavy coat takes far longer to cure than it looks like it should. For anything that's genuinely a gap rather than a scratch, use putty first; a surfacer is for the last tenth of a millimetre, not for structural work.

Don't use it as a general primer. This is the one mistake worth avoiding with 500. Those large particles that fill so well will also bury rivets, engraved panel lines and fine surface texture if you coat a whole model in it. The professional sequence is 500 to fix the damage, sand it flat, then a finer grade over the top as your actual base.

Understanding the numbers: the grade is coarseness. 500 is the heavy filler — this can. 1000 is the standard working grade for general priming. 1200 is finer, for a smoother base under gloss and metallics. 1500 is the finishing grade where any texture would show. Lower number, more filling; higher number, smoother surface.

Which one do I need? 500 when you've been cutting, sanding or filling and need the surface repaired. Mr. Surfacer 1000 (B-519) as your everyday primer once the repair work is done. 1200 (B-515) for a smoother base under gloss. If adhesion on resin or metal is the issue as well, Mr. Primer Surfacer 1000 (B-524) handles both.

Specifications

Brand: Mr. Hobby (GSI Creos / Gunze Sangyo)
Item No.: B-510
Type: Lacquer surfacer — heavy filling primer, aerosol
Colour: Grey
Grade: 500 (coarse)
Volume: 170ml
Suitable for: Styrene, ABS, resin, putty and filled areas
Sandable: Yes — wet or dry
Use in: Well-ventilated area; wear a respirator