I use the same product Tim talks of in his video, same formula as his new distress glaze. He's so right it really goes a long way, I purchased an extra container when I discovered it would no longer be made and still haven't had to open it. I find it indispensable when stamping on envelopes to be mailed, and anytime I want to seal water based ink or paint. I even use it on my professional watercolor paint projects. Although it can be used as a resist, I haven't used it for this purpose. I highly recommend this product!
I love using this as a resist medium (Search on YouTube for Distress Glaze Resist) AND for sealing my ink smooshing when I use alcohol ink paper (smooshing with Oxides OR alcohol ink). It seals beautifully and then it makes the layers of color just magically pop. WOWWEE!!