sign mask problem

[jim shula]

It's a 6"x60" sign with a flowing script font. Most of the letters are connected. I primed the extira and painted it with two coats of Ben Moore Aura, my usual paint I've used on hundreds of signs in the past. I masked the whole thing using the 15" wide yellow Gerber sign mask, then started carving on the shopbot. Instead of cutting the masking cleanly, it left real ragged masking edges and completely tore it off on some letters. It's like the masking wasn't sticking real well.

When I saw this happening I stopped the toolpath, tore off the masking up to where the toolpath ended and tried again. Same result. My first thought was a dull vbit. I ran out and bought a brand new one and tried again with the same results.

Now I have two possible causes in mind. Maybe the surface was stippled from the roller. Usually I'll buff between coats with a sanding sponge or scotchbrite pad. On this sign I didn't. Could this slightly rougher surface cause the masking to lift off too easily?

The other possible cause is that on the same work table the painted sign blank was sitting on last night, I sprayed some wd-40 on a microwave oven I was cleaning up. Could a little bit of overspray have settled on the sign and caused adhesion issues with the masking? Maybe this is a stretch, but the sign was about 3' away in the path of the spray.

Also, if I put new masking on a sign that has already been carved, can I expect the vbit to cut the masking cleanly?

[coryatjohn]

I just did a set of three signs (30x6) last week that I painted with a roller and the mask worked fine. I used a different mask but essentially the same type of stuff. No problems. So I doubt it was the roller. The WD-40 could be a problem for sure but cleaning the paint carefully should solve that.

[jim shula]

I put the second coat of finish paint on the new sgin blank last night, and today a small piece of test mask peels off it just as easily as the first one. Therefore I can eliminate the wd40 overspray theory. I'm going to let it cure overnight by the woodstove and try again tomorrow.

[Rick W]

Jim,

I've never used the masking you are talking about but I have heard stories of vinyl not sticking because of shelf life!!! (vinyl sitting around too long)

Rik

[knight_toolworks]

I have wondered about using a drag knife to cut the masking then you would not have to worry about a spinning bit tearing it.

[jim shula]

I let the new sign blank cure overnight by the woodstove and tried a test piece of masking. It still comes right off. Last night I buffed it down and sprayed on another coat of paint to get a smoother finish. We'll see today if it works any better.