decoupaging help...

[xduhx.livejournal.com]

first off i would express my appreciation for this awesome community- it has provided endless inspiration for many projects but unfortunately i have very limited access to a digital camera...

now onto the questions:

i recently acquired some flooring ceramic tiles- and i have been experimenting with modgepodge/decoupaging stuff- and i want to make coasters... and some potholders to put hot plates/hot pots onto instead of the counters or tables....
i read in the memories that polyeurathane could make modge podge surfaces waterproof... is this a spray or a liquid and where do i get this? and will it make it safe against high heat?

i also have old metal pieces of a stovetop (the part you place the pots/pans onto that conduct heat) and ive heard you can paint them and use them seperately as potholders also but is there a particular paint you have to use to ensure no damage to the paint?

in short... i just want to make my modgepodged tiles either waterproof or highheat proof.... any suggestions?!