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This is the first time I've encountered this problem. I was putting kiln wash on some new molds tonight. One of the molds the kiln wash beads up. These are ceramic molds like all the rest that I have. I mean it kinda sticks but I can brush it off in areas. It's like there's something on the mold yet I can't see or feel anything. What is the problem? Help help.

There might be some oil or residue on the mold.

Perhaps firing it in your kiln to a low temp might burn the oil off? Washing it with soap and water might work as well.

i would fire it to 1000f or just put it in with whatever firing you do next. if that does not help then what you have is a result of how the mold was poured. the clay can be compressed in an area and less able to easily hold kw.

If it's still doing that after firing you can sometimes fix it by sanding the area. I use a coarser grade of sandpaper and bear down a bit. That gives the area a little tooth so the kilnwash can adhere. Doesn't always work, but it's worth a try. Any marks you make on the mold will be filled in with kilnwash, so it doesn't affect the texture.

Thanks for the suggestions. I will give them a try!

When they make molds with a "pour slip" method….where the slip hits is called a hard spot. It usually may look like it does not have kiln wash on it but it probably has some. I would lightly sand it or put it on a hot kiln, try again, and then use it!