500 coarser in grit than is 1000 or than is 1200... smaller the number the coarser the finish as in sandpaper nomenclature.
Mr. Surfacer can be thinned with Floquil Diosol also or Liquid cement but why?
Overall these three products are more for final finish paint surface preparation, small surface mars or minor seam filling.
The best thing for filling seams or flaws can be accomplished by me possibly sharing an article and discussion that I gave at an IPMS Convention in Atlanta some twenty five years ago now...
The answer is simply Testors Liquid Cement mixed with Squadron Green Putty in a mix of some one part liquid cement to five parts Green Stuff... this is a thick coarse mixture that can be applied and then pulled, scratched, stamped or tacked to give various looks or cast surface features and thess varied mixtures readily adhere or bind to the plastic's surface. It also lasts for months or years in the bottle without going bad or hardening up... simply shake and use. Simply put a couple of BB's if you wish into the jar and shake... I have some different consistancy mixtures laying on the workbench that have been used and added to or remixed for years now. I really prefer the old Testors low form square liquid cement bottles (that have the brush in the jar as they do not tip over like the new tall cylindrical ones now do) and I have saved my old jars for just this purpose built mixture.
The 'Green stuff' mixture can be made more thin with the addition of more liquid cement. The mix can also be made with Squadron White Putty (which is finer in texture) but the consistancy is a bit different and gives a less coarse texture finish than does the green putty version. You can color it with paint as well to derive different undercoat or primer colors to chip through the overlying paint to achieve great weathering looks for your paint.
Here is what can be achieved with this mixture for surface texture... and is simple to use and inexpensive...
Here are three forms (colors) of this mixture used in white, red and green to fix a flaw in the conversion and addition of a three piece transmission cover to backdate an Italeri 1/35 Priest... I actually primed nearly the entire surface of the rolled armor segments to add texture and pitting and then went back and fixed the minor flaws or problems found after 'priming'...
If you look closely you will see that I have an extra-fine version in pale blue and used it to correct a problem on the PE siren... using it just like Mr. Surfacer 1200 to fill minor imperfections.
The surface now has great 'bite' for paint application and shows any errors that can be addressed before final paint application layers...
Look to the surface texture that is also applied to the "Priest's front face" near the lights... as an example of what can be achieved...
Mr. Surfacer 500 is much thinner than this mixture I am proposing for readers to try but can be used directly on top of this ad hoc "green stuff" slurry.
Need more help contact me through... http://www.afrikakorps.org/ and then click link to Nacht... hope this adds to readers work benches for another method or tool to use when needed...