proculation - 13-9-2023 at 02:57
Hi,
I have this Dean-Stark trap that I got some times ago. On arrival, it had that "star break"-like cracks (images following).
I successfully used it to extract some essential oils at low heat once to test it but I would not use it for it's real purpose until repair.
I have some knowledge and experience with glass working. I'm wondering what would be the best way to repair this piece of glassware: can it be
repaired by just heating the specific area + around until the cracks are gone or I would have to anneal the whole piece afterward ?
Yours truly,
P.
Edit: it would be better with the images 
[Edited on 13-9-2023 by proculation]
BromicAcid - 13-9-2023 at 03:40
One question is what are you going to gain out of it? If you are not running under vacuum then the chances of catastrophic failure are cut and
considering you're not messing with pyrophorics from what it sounds like then the danger of said failure is also somewhat low.
That being said, this is the sort of repair that chemists have been tackling on their own for the better part of a century. Though there is a very
real chance you could ruin the glassware. There have been times I've attempted this sort of repair and upon heating the crack spreads. Other times
I've head sufficiently but the crack will not come together. And at other times I have had success. There is a bit of technique to these smaller
repairs of wafting the torch over the are to bring it slowly up to temp and then slowing the cooling by doing the same to give it an 'annealing
blessing'.
Again, you might be able to keep using as is, I think the greater risk will be trying to fix it in your case. But honestly I would probably give it a
go just to get the experience so long as you know what you are getting into.
Chemetix - 13-9-2023 at 15:02
I've done a few vids on glassblowing for the absolute beginner, and aimed at those who need to repair small cracks like this in their glassware.
I focus on using techniques that don't need any more equipment than just a bunsen burner and a few low tech hacks. It will be limited in what you can
achieve with this technique but your problem seems a perfect example of when to use it.
Healing a crack
Glassblowing with a bunsen burner
I can answer any questions you might have about set ups and techniques