Glass blowing demo at St Marks Square Venice

never heard of this on San Marco.

I have. I went there on an RS tour. As you face the front of the Cathedral it is on your left in the area near the big clock.

TBH I hated it. It was hot (well they do have a huge furnace going, lol!) The demo took about 10 minutes then you wandered thru the shop trying to find your way out and trying to avoid the sales people.

Rick's tours are known as NOT having shopping stops but I felt like this one was sort of in that category. No one was obligated to buy but the length of the demo was not worth the time spent getting in and out.

No idea about charges but I'd suspect there is no charge because they expect you to buy. No idea about reservations but they run people thru in groups, you sit in a bleacher type area, watch the guy make a horse or something, then exit to the showroom.

After all these years in Venice, I constantly learn something new! Thanks for teaching me something to avoid!!! I'll keep wandering around the non-tourist neighborhoods.

I love glass. I collect glass (in a small way). I will travel out of my way to see a glass museum. For me, glassblowing falls in the "If you've seen it once..." category, and I am reluctant to spend precious European vacation time tracking down glass-blowing demos. Some people (including a friend of mine) seize every opportunity to visit a working hot shop, so YMMV. I'm sure you can find demos on YouTube. That might give you an idea of whether it would be worth it to you to run the gauntlet of the Venetian salespeople.

The best Glass blowing demos are on Murano and when you are done you can walk the Island,nice place to go.
Mike

The shop in Venice we stopped at on the RS tour did not have pushy sales people when we were there.

Do not recall seeing anything that indicated there was an admission charge. Our group made up a large part of the audience for the demo, but there were other independent travelers there as well.

After the demo was done there were so many people willingly shopping that we had to wait to make our purchase. There was so much business the staff didn't have the need or time to be pushy.

I used to blow glass in a small way and also love hot shops and glass museums, but Venice glass scene has become so commercial with so much glass sold that is made elsewhere, it is hard to trust you'll find a good experience.
Seeing a guy demoing making a glass horse can be seen anywhere. Finding a hot shop that still works making Venitian glass chandeliers that allows you a peak in would be rewarding. They are bound to be off the tourist path.
I think most shops listed in travel guides are open to draw tourists for anticipated sales. They will demo short simple items. Consider that glass is hot and dangerous, so a gallery needs to be constructed for numerous viewers. The viewers will have a short attention span.
Alternatively, try to sus out where the fulltime blowers have their hot shops, wander down the street and hope they have a window or open door you can watch through. It's like making the time to trek over to the one working gondola shop left in the city.
Ultimately, if you have never seen it done, then maybe seeing it demoed in Venice is the quintessential location and experience.
There is always 'Blown Away' on Netflix, or maybe there is a glass place near you where you can do your own glassblown item.

Alas, just because it’s conveniently located does not require that it be authentic or worthwhile.