Whether you are an experienced fuser, or a novice, it is likely that at some point in your career you will get your glass stuck in the mould.
This is not always the end of the line for the glass, or the mould, as there are lots of ways to rescue things depending on whether your mould is ceramic or metal.
Pendant Pods with holes
(Image from www.warm-glass.co.uk)
These are notorious for people getting things stuck on them! They're fantastic if you can get them to work for you.
If you got it stuck in the first place, it's possible that you didn't use enough kilnwash / boron nitride spray / zyp / primo primer, or whatever separator you normally use, or that you fired it too long or too hot. Some separators don't hold up to casting temperatures so do check the information to make sure you are using the correct product for what you are trying to achieve.
That said, these make fantastic pendants and are well worth the effort. These often get stuck around the little round bit in the middle, because glass shrinks more than ceramic and so it hugs the centre part as it cools.
You can start by folding a towel and putting it on the worktop, then putting your mould upside down on top and giving it a few good taps (not enough to break it though!) - a rubber mallet can help with this if you have one. Sometimes this will dislodge the pendant.
If that doesn't work, then put it back in the kiln, upside down, suspended on little shelf posts and do a tack fuse - that should enable it to drop out.
Heating these in the oven doesn't work, as there is ceramic in the middle as well as outside so you're trapped both ways!
If any little bits are still stuck on the mould, you can remove these with a dremel tool (with a diamond bit, use it wet!) or with a bit of wet and dry sandpaper.
If you have managed to break off the little bit in the middle you can use fibre paper or a piece of chalk to replace it, just use a new one for each firing.
Stainless steel drape vases:
(Image from www.warm-glass.co.uk)
If you slump or drape something over one of these, or a cocktail shaker, or other similar vase, sometimes if you over-fire it can get stuck. These are normally fairly easy to release, as metal shrinks more than glass, so wait until it's cooled down properly and then pop it in the freezer for a bit. Often this is enough to shrink the metal enough to release it from the former.
If you can't get it off, then pop it back in the kiln upside down and it should release at slump temperatures. Keep an eye on this as you may be able to loosen it just enough to keep your vase too!
If you want to get more kiln wash on it before you start, heat it up in the oven (or with a hairdryer) and then spray kiln wash on it. The evaporation will help more of it to stick. If you have one, you could also rough up the metal with a sandblaster or some wet and dry sandpaper.
Stuck in a ring?
(image from www.fusionheadquarters.com)
The new metal casting rings (for pot melts / screen melts etc.) are brilliant, but you need to make sure you line them with 1/8 inch fibre paper (NOT thinfire or papyrus - they're not thick enough) so that when the metal ring shrinks around the glass it won't trap it.
If you've trapped your glass, try popping it in the oven first to see if that will release it, as metal expands more than glass.
If that doesn't work, you can support the ring on kiln posts and take it up to slump temp and wait for the glass to drop out.
Ceramic drape vases
These are not recommended, because there's a high possibility your glass will get stuck and crack. This is because glass shrinks more than ceramic when it cools, so it will hug your vase very tightly and not want to come off without a fight.
If you do want to have a go, for instance if you're on a budget and using a terracotta plant pot, it's a good idea to put a big circle of fibre paper over your mould, as well as kilnwashing it, as that way there is some space even if the glass shrinks. Be generous with the fibre paper so that you know it will reach all the way to the ground around your pot in case you over-fire.
If you are on a budget, it's better to keep an eye on your local charity shop and get hold of a second hand stainless steel cocktail shaker!
Don't use things which are smaller at the bottom than at the top. These are a recipe for disaster!
If you get one of these stuck, remember you can put it in upside down and take it up to slump temp again - it should release - just keep an eye on it so you can keep a vase shape rather than a puddle!
Stuck drop ring vase (ceramic)
This is one of my pieces, which cracked on the way up and wrapped itself round the drop ring! I tried the freezer but it wasn't having any of it...
I set it up in the kiln, upside down, supported on kiln posts with a couple of posts on the top to counterbalance the weight of the glass. I also put some thinfire on the top of the ring in case it decided to flop down the other way instead. Then I full fused it.
As you can see, success! The glass came free and only the very tiniest bit of glass remained on the drop ring, and that was easily removed.
I'll use this glass in another project (or for practicing on my tile saw!)
I hope you have found this helpful. Please do add your hints and tips in the comments.
Disclaimer: These are some things which have worked for me, they may or may not work for you. Always fuse responsibly.