Watch Your Scotchgard

Previously, I had been suggesting the use of strong water repellents like Scotchgard to seal paint. It is a convenient alternative to traditional sealants. However, I have recently noticed several problems. The waterproofer is much more corrosive than it initially appears to be. Unless sprayed liberally over most acrylic paints, no adverse effects are apparent. Also be careful of the following:

• It discolors. Some mild yellowing is visible, especially with lighter colors.
• Bleeding- it also causes oil-based inks to bleed through any layers over it.
• And again, corrosion. It can dissove thin coats of paint and eat through lightweight materials such as tissue paper.

This is, of course, just what I've gathered from personal experience. I have done no experimenting and cannot decisively determine precise effects.