Bubbles in blow in

[Cerberus]

I did my first blow in and have a couple of bubbles. Is it safe to use or should i just trash it? Won't bother me to toss it, I prefer not to have it pop in my face if there's a good chance of that.
Chinese black in chinese clear with silver filings, i have no idea what to expect from this piece.

[Jackass Glass]

Bubbles are fine. People intentionally put large bubbles in space tech all the time.

[snoopdog6502]

Heat the shit out of them bring them to the surface pop them with tungsten. Get it hot and go for it. you made it rather then toss it you have nothing to lose.

Once you get it hot you will have round bubbles and are not as bad structurally.

[H1JACK3R]

You can pick it open with a punty, then fill in the gap or heat and pull out that whole section if you want

[SavageGerbil]

I'm with these guys, heat it up and yank the bubbles. The best practice you can get is the pieces you wouldn't be heart broken to toss. You can practice your recoveries with that, they're skills that'll pay off time and time again.

[Michael]

In the future if you preheat the cup more & go slow on the blow-in you can laminate the two easier. The last pic I posted in fresh kiln whatnot is a blow in with Chinese black behind fume.

[Cerberus]

In the future if you preheat the cup more & go slow on the blow-in.

Yeah I figured the clear wasn't hot enough. I was using a point with a really short handle and my hand couldn't take the heat so warming got cut short.
Thanks for the replies, I'll pick out the bubbles. There's enough glass to make two blanks from it so I'll make something from it if the bubbles don't come out clean. I'm getting much better at salvaging errors and minor fails, not as good as getting it right at first but better than all going in the bucket.

[James M]

It was suggested to me to make your blank a bit of a bubble before opening one end. That way when you blow in it will fill the bubble and then the sides. I have not tried this yet but it makes sense to me. I usually end up separating the bubbled sections and using that for something different than the final piece.

[snoopdog6502]

I plan for a little waste on the ends, bubbles have to go somewhere unless you get a little lucky.

On striped wig wags those ends even with glitches are bitching to make pendants and marbles from.

[Cerberus]

Honestly i was excited that it worked at all. I do expect to lose the ends on blanks and thankfully I waste less as i gain experience. I'll do more of these for sure, maybe a little smaller next time.

[Michael]

Start small for sure, once ya get the hang the only limiting factor is how much heat your hands can take. My advice would be make a thickerish shoulder that has a 45 deg taper or more. Otherwise you trap a ring when color hits other end. Blow in color, pause then heat shoulder where color stoped & blow color thro. Now you'll have two open blow tubes. Plug blow in side, condense/ stretch. Another tip is whatever is being blown in, tilt slightly on your final heat & let gather thicker on end. This will give you even coverage as the blow in travels the length of your clear vs the blow in popping prematurely & leaving ya with an uneven mess.

[Michael]

Forgot, you asked about the silver filings... skip that for a bit & try laying some light fume at first. Some amazing colors can be achieved by flame striking fume prior to blow in. My fav is burning away select spots of silver when striking & layin gold over. That's all that last pic I posted is. Can prep MASS amounts of glass so fast once ya get the hang. Good luck!

[CheeseNip]

A word of advice that you didn't ask for.. Lol. When using China black, or really any color, but ESPECIALLY China black, when you encase it in clear, whether via blow in, vacuum, whatever, get it way hotter than you did this one. The black really needs to be heated quite a bit in application like this in order to really make those two layers "one", per say. If it is not heated enough, when broken open you can clearly see 2 defined layers where the clear kinda sits on top of the black, rather than being made one with the black. If you have this happening, they are MUCH more likely to break days, or even weeks later, or even while you are working on the piece. If those bubbles are that "unrounded", it definitely was not brought up to a high enough temp to really "meld" those layers together.

[Cerberus]

Thanks cheesenip. These blanks were both definitely not hot enough but I had to take it to the end.

[CheeseNip]

No problem, but to clarify, I was talking about after you do the blow in or encasement, when you are giving it a good melt down and pre-shaping your blank or prep tube. Not during the initial blow-in or encasement. Well, then too, but yeah.. Lol.