I just got this last night. Anyone who knows how this works? How long must I set it before applying paint? How long before I remove it after painting?

Thanks!

Just push the stuff into the shape you need and stick it on. No need to wait. Just put it on and paint.
As with any mask I would let the paint dry some before removing.

Working on that StugIII, I presume?
Depending on the paint used, don't keep blu-tac on longer than necessary, just to be sure. Testing it out before use wouldn't probably hurt.

I've been using Pritt's sticky-tac (pretty much the same stuff, only white).
Xtracrylics' thinned with water and airbrushed dry to a flat coat (unless sprayed on heavily), which gets darker if I let sticky-tac or masking tape stay on too long. So far, I don't remember other paints reacting like this, but I don't want to find out the hard way.
But don't worry, that has happened to me like after several days to a week.

I've found it most convenient to first roll the tac into a "saugage", place it on the model, and then fill in the rest with masking tape. On small models like 1:72 tanks, I normally use tape only 'tac (easier to cover small areas with, when compared to cutting masking tape into suitable shapes), but with larger subjects, it saves blu-tac.

You can also get different demarcation lines by varying the thickness of the "saugage" (make it thinner and press flatter to get a sharper edge), and spraying at different angles against the mask.
Removing is as easy as pulling it off (be careful around PE and other small parts). If small amounts of tac remain, you can use another piece to remove it. I don't know of the regular blu-tac, but that sticky-tac something leaves slight whitish marks, which can also be removed by touching them with a piece of tac.

Eetu, ack! You've read my mind Yep. I suppose I really need this stuff badly for future hard edge camo (I feel a lot coming along). Wonder how it will react with paint thinners since I use enamels all of the time.

To the best of my knowledge it won't react with enamel thinners.

Andy

Now that's a relief. Thanks for the info!

I've used a simular product and have had no ill effects. I shoot enamels thinned with lacquer thinner. As already stated though, I wouldn't let it set too long just to be on the safe side. The camo pattern on this BMP was done using this technique and shot with enamels/lacquers. "Q"