Don't need the thick putty, but how to thin it?


Active Member
I am using the generic white putty in a tube - so generic frankly I don't recall the name - but it skins quickly and is fairly thick. I need to seal up some tiny pinpricks and would love to be able to paint this stuff on or find an alternate.

Does anyone have any ideas about a thin paintable putty to fill an inch or two square spot of pinprick bubbles? Or how to make a thicker putty thin enough to do it?
If you're using Squadron brand putty or Bondo glazing putty, you can thin it w/ some acetone or nail polish remover. I usually spread the area w/ the putty, then force it into the pinholes using a Q-tip dipped in acetone. The acetone thins the putty pretty well.

You could also use Liquitex matte medium applied w/ a brush, then using a damp finger force the medium into the holes. This might take a couple of applications.

Of the two, I prefer the first one. I can get to sanding the area fairly quickly that way.
You might be able to thin it with acetone. Depends what type it is, try it and see. You can also try Tamiya liquid surface primer, it's like a thick gray paint that will fill small pin holes. It comes in a jar with a brush in the cap. I sometimes use a toothpick to apply it.
All good tips. Squadron putty thinned with acetone will do the trick. I also use the Tamiya surface primer in the jar for tiny imperfections. And for those jobs where you might need something in between those two options, there's another brush-on japanese hobby primer called "Mr Surfacer 500." It's like a super thick version of the Tamiya stuff. Though I think the Mr Hobby stuff is getting hard to find in the US.
Ive used talcum powder mixed to primer for pinholes, worked very well, and its very light, so easy just to kiss off as not to open up any more holes.

Excellent - I have a couple of options now! Thanks for your help. I can see using at least two or three of these techniques, and maybe see if I can get Mr. Surfacer next trip to Buffalo. Acetone, the second most useful solvent in the world!
In the UK I use Holts car body putty (in a tube, from Halfords) and thin with acetone as required.

Consistencies from soft putty to creamy liquid all work well, but the thinner it gets the more acetone is in the mix, so test on scrap material before dissolving your model !

Use acetone, not nail polish removers which may contain all sorts of undesirables..... " Yes, yes, yes, the filling is pretty bad, but just love that fresh apple aroma !":lol
If you're building a styrene plastic kit you should be careful about using solvents to thin the putty. To much can melt the plastic, use alcohol instead. But whatever thinner you use will reduce the density of the putty, making it shrink more as it dries, so a second application may be needed.
The Tamiya worked for most, with thinned Milliput to cover the rest. I think I'll bookmark this thread, though, for future reference!

Thanks again, folks.
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