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I usually apply dilute kiln wash by spray onto a hot stainless steel mold and it sticks great. However, I am now firing into a 48" bowl mold and it is just too large to remove when hot and spray with the kiln wash. Does anyone have any ideas of how to get the kiln wash to stick to a cold (room temperature) mold?

pre heat the mold and brush it on in the kiln. I have never sprayed kiln wash I would not want the particulates in the air. Air brush particles can remain airborne and breatheable for an hour.

Kevin does it the way I do it. Heat mold to 300F, then brush on. You can usually do that in the kiln, but it make take more than one heating to get enough on.

I'm not sure -- never tried it -- but there are a number of pre-mixed kiln washes on the market (Paragon makes one, as do others). They're thicker, so don't run when applied to non-horizontal surfaces. Made for pottery, but might work.

Boron nitride is the main alternative I can think of, but it's much more expensive.

Thanks guys. I will try brushing it on. I used an HVLP sprayer before and it does work well if you can get the mold out of the kiln. It doesn't put much particulate into the air only steam.

every particle of steam has something to condense on....one of those particulates.
Want it thicker, mix a thicker batch. Want it to stick more add more clay. Your glass may stick too.
The answer is heat, coat with brush, heat again and coat until the coating is to your liking.
got brush lines? just gently swipe your hand on the mold and they will be removed. Don't try that at high temperature!
I heat to 5 or 600 but your kiln may be different. I find the temperature drops fast enough that I don't get cooked and I can apply a couple of coats instantly sizzle drying before having to reheat
It can be hard on the brushes. might want to wear gloves etc to protect from possible steam burns and be sure the power is off before sticking parts of yourself in the kiln.

I use a propane weed torch head from harbor freight and an air gun. One hand uses the torch, removes it and the other hand sprays kiln wash

Thanks for the suggestion, I might use it in the future. As it is, I am just using the kiln (a bell kiln) lowered to just above the mold to warm the mold. I then roll out the trolley floor with the mold and apply the kiln wash.

Hello! I joined this board specifically because I need some advice on a recent problem involving kiln wash. I have a Paragon Pearl kiln and have been using Bullseye's powdered kiln wash on the shelf for over 10 years. Each time I sand off the previous kiln wash by hand, clean it off and give it a long time to completely dry out (usually overnight), then mix up the new stuff and apply 5 coats as Bullseye instructs. It's always worked great and I've never had a problem until now.
I have a film on the shelf side of part of the glass after a full fuse...not ever after a tack fuse or anything at lower temperatures. Often it's around the edges of the glass piece and, on a couple of occasions, some glass is stuck to the shelf...a tiny amount at the edge or corner of the piece.
I'm trying to work through what could cause this. Is the kiln older and isn't firing efficiently? Do I need to adjust the firing schedule? If so, in what way?
Is the shelf old and no longer holding the kiln wash? Do I need a new shelf?
I'm assuming it's not the glass, since I'm using Bullseye compatible glass as I've always done.
I don't believe it's vitrification because it's on the bottom of the glass.
The kiln wash is a new bucket from Bullseye, which I'm mixing at the prescribed percentage.
Can anyone help me trouble-shoot this?
Thank you so much!

It looks like you're firing a bit too hot. Try reducing the top temperature 10 degrees or so.

Thank you--I'll try lowering the top temp and see what happens!

All of the above right but old technique works the best. I use stainless steel molds over twenty years with single coat of RUST-OLEUM HIGH PERFORMANCE ENAMEL ALUMINUM spray # 7515. no pre firing , dry in ten minutes and at the end of the slumping wash it of and do it again. use it to slumping temps only!!! old is gold