Getting a nice lip or edge

scoutycat · #1 2011-03-10, 4:33pm

Hi all! I'm a boro and tubing noob, I've been trying to make some little necked jars and stuff and they all have crappy looking tops. I've been pulling the neck out of my bubble, like you would pull a point, then heating where I want it cut and blowing it out really thing and flame cutting. Is this a bad method for getting a nice even edge? Do i need to do something after that before I flare it? All attempts at evening it out after I cut it off seem to result in abject failure. I'm not sure if I need more practice, a different tech, or I'm missing a step. I'm going for a shape kind of like this, with out foot or handles. Help!

http://www.vetriglass.com/Anfora/M/B003FJW3ZI.htm

gmkcpa · #2 2011-03-10, 4:46pm

Excellent question. I'd like to improve my mind by having someone explain to it what techniques they use. Thanks in advance.

Bunyip · #3 2011-03-10, 7:20pm

Ruffling the top hides a multitude of sins - It's also good for making wonky goblet feet look good. My suggestion to you, however, is to get a pair of cup shears and trim the top even after you blow it out and flame cut it. It works remarkably well with a little practice.

rckeyes · #4 2011-03-10, 7:42pm

Jen,
Heres a youtube video by Robert Brown AKA "acroduster" Robert has abandoned his torch for other ventures but he has left the lampwork community with a wealth of knowledge. This video should help you out some.

http://www.youtube.com/watch?v=d_Udv...AF1C01969EE741

scoutycat · #5 2011-03-10, 7:56pm

To use cup shears, do you flare first and then trim?

and thx for the vid link! looks great! and I see he's got a bunch of other stuff, sweet

I love his 'open source' concept!

evolvingBeau · #6 2011-03-11, 12:55am

As you've figured out, blowing out a thin bubble leaves a lot of room for lobes of glass you don't want.

For a small flared opening like the vessel in your link, decide where you want the edge of the vessel to be then heat the circumference evenly before drawing it out nice and thin from the lip-to-be. Puff and pull, puff and pull to thin out the glass from next to where that lip will be.

There are a couple ways you can go from there.

You can melt off the handle leaving just a thin point and nip it with disc cutters before going in with a pointed reamer and carefully opening it.
Or you can pull off the handle and keep heating that thin membrane left over the hole until it pooches out from the expanding air, as you do this (while turning evenly) take a small rod and start to wind that glass up like you would twirl up some cobwebs with a webster.
If all goes well you'll suddenly be left with a sporty smooth opening.

Trick is to keep the heat only on the thinned out glass or he hole won't pop because the expansion will be diluted into a larger area and this will whack out the possibility of a straight edge.
If you need to tamp the opening with a marver to square it up, get the edge fire polished, ream it just round and do it then, thicken it a little more if you like, ream it round and do it again before the final flare.

Nice openings usually start with relatively small holes. A little 1/8th or 1/4 inch hole is a good place to start for a 1 inch opening. Not rules just suggestions.

If you find the need to use shears, you'll generally shear first and flare second.

scoutycat · #7 2011-03-11, 8:29am

Thx Beau!

Cosmo · #8 2011-03-18, 8:07pm

For lips on jars, vases, goblets, etc. I use diamond shears. Shape the piece, then heat the spot where the opening is going to be. Use your diamond shears to crimp the piece, and then tap it to break it off. That will give you a nice, clean, even lip. Then heat and flare as usual.

The smaller the hole you can open, the better the lip will usually be.

ginkgoglass · #9 2011-03-18, 8:19pm

Quote:

Originally Posted by Cosmo

For lips on jars, vases, goblets, etc. I use diamond shears. Shape the piece, then heat the spot where the opening is going to be. Use your diamond shears to crimp the piece, and then tap it to break it off. That will give you a nice, clean, even lip. Then heat and flare as usual.

The smaller the hole you can open, the better the lip will usually be.

Nice summary of how to do it with diamond shears. I have some and have been too chicken to use them. I usually just blow a thin bubble, blow a hole and then tear it off in the flame. This is probably not the proper way to do it, but it has worked for me.

Cosmo · #10 2011-03-18, 8:28pm

Quote:

Originally Posted by ginkgoglass

Nice summary of how to do it with diamond shears. I have some and have been too chicken to use them. I usually just blow a thin bubble, blow a hole and then tear it off in the flame. This is probably not the proper way to do it, but it has worked for me.

That works, but it's hard to get the lip nice and even.

If you take a look at Steve Sizelove's video, he does it the way I described it.