Rough texture!? What am I doing wrong??
 

Hi, this is my first post ever , but also a cry for help! I work with a national torch with a m-11 tip. I've been working just over a year on this torch, and something that I have not been able to figure out is that more often than not, my glass comes out with a rough texture. I've had some pieces come out nice and clear and smooth but now more than ever I feel like, especially with colored glass, it comes out wrinkled looking. It's driving me crazy! I'll put a lot of work into something and feel like it's ruined before it's finished. I'm hoping someone here knows what I'm talking about and have a solution for me. Thank you for any feed back

Please post a few pictures for better understanding the issue. What type of glass are you using (soft/Boro)?.
I believe it might be the heat you're applying to the piece is not good enough to melt the whole piece, It's happened to me a few times; also, are you somehow shaping your pieces?, for example using molds or graphite tools?, sometimes they leave unperceptible wrinkles (when heat) and when they cool down you see them.
Sometimes when applying color you have to be carefull not to burn out the color, some like reds and yellows are pretty delicate, it's better if you hit them on the farest portion of the flame first and then move into the center.

Sounds like your manipulating the glass while its too cold. Boro takes a lot more heat than soft glass. Are you using tanked oxy? When i was using oxycons i had troubled getting a hot oxidizing flame on my national

It's devitrification. As the others said, you may be moving the glass at too low of a temperature.

The other possibility is that you cooked the snot out of it, which can also lead to devit, but more than likely is the first option.

Sometimes you can flame polish it out, but not always.

So would it have anything to do with pressure at the regulators or anything like that ?

Some of the touchier colors like reds and yellows "cook" and bubble really easily - is this 104 coe? Doesnt really matter, boro will do the same. It doesnt even take much heat to get them to bubble and roughen. Everyone always says work further back in the flame. I have found , that means, moving your glass further away from the torch head not a couple of inches, but for me, like 8 - 10 inches.... Just a couple inches never works for me- and then there's the whole patience thing with working further back. Also once the glass has devitrified and roughened from too much heat, some of that doesnt re-work back out very well, even in slow low heat. Perfect example is take a yellow and then bubble the heck out of it, right on the rod so that it devits, then try to fix and work back out - some of the bubble spots that have overheated and turned white so that it looks like coral wont blend out.

But like menty said if it looks wrinkly instead of the texture of coral, then its more than likely, devit from low heat because the surface of the glass has cooled before the inside while its still moving, rather than devit due to overheating. In that case, check your surroundings for drafts, room temp, etc. if your ventilation is really aggressive, it's possible its cooling the outside of the glass too fast.

My set up is out in like a back room/window room of the house, so the Ambient temp is going to be close to what it is outside. I am having trouble posting pics otherwise I would have them up already. I am really appreciating all of y'all's feedback tho thank you so much

I have toyed with the cadmium colors and stuff and I am getting better with working them without bubbling them. I have been assuming that the wrinkling was from too much heat. Or bad flame chemistry or something . As far as moving the glass after it has gotten too cool, I have thought that too, but I will get a piece up to really hot and try to let it cool slowly with no movement at all I feel like other than rolling and still have the same effect or if it is already there I can't work it out, no matter how hot it gets

If it's rough like frosted glass, that's devit. If it's pitted and scuzzy looking, you might be boiling it. Crayon colors are super easy to boil if you're not careful. Heat them slow out in the flame and once they're turning red from the heat you can bring them into the working area of the flame.

From what you described, it sounds more like devitrification. If you're having trouble flame polishing it out, you can try sprinkling a little coarse kosher salt into the flame to sort of "fume" the sodium back into the glass; sometimes that will help. It's really kind of a last resort though, and better would be to learn to avoid it.

If you can box in your bench to reduce the amount of space your ventilation is moving air from, you can help preserve what little heat you might have in the room.

I use an infrared heater mounted over me where I work to keep me warm, it heats me, not the air.

Ok, so in the past I have tried to use lower psi or a smaller flame but from what it sounds like I need to use a hotter or bigger flame for less time , sometimes I do feel like it takes forever to work something down or condense

Also, any personal opinions on national torches (you won't hurt my feelings) and possibly suggestions on a better torch if I were to decide to upgrade. I've bought a larger tip for this national but I still feel like I'm always wanting a bigger flame. I mostly make pipes and pendants, but feel kind of limited by flame size

if it were me, i'd find a Midrange with a premix topfire. i LOVED that torch. i just needed something hotter in the end.
i wish i'd never sold it.

Nationals are nice, but rough on color.

I work with a redmax that I'm rather fond of. They get a lot of flack for being inefficient with the oxygen and they put off a bit of radiant heat, but for the money it's one heck of a workhorse.

Thank you all so much ���� yeah I have shopped the red max and like those a lot. I really really wanted a phantom but just don't know if I'm ready to drop that kind of money yet on something that is just a past time right now.but I still might get a wild hair when I decide to buy. And just to help clarify , when I said colored glass I was mainly referring to the tubing , like cobalt and green or Amber, but also clear. I don't have too much trouble with the rods as far as the texture and over working. Just when I am trying to get the final shape or condense something hollow is when I get the rough texture

If you have never worked the material, why answer the question?

When you say "wrinkled" does it look like tiny ripples on the surface of water just suddenly froze or does it look like teeny tiny bubbles and grey or white hardened foam on the surface? It sounds to me what I call "mechanical devitrification" I know that is not really a term but it appears like devitrification although it is caused as others have said by manipulating the glass while it is too cool. It should not have much to do with ambient temperature although your piece will cool down quicker obviously if it is cold in your studio.

Try an experiment, heat a section of glass up until you think it is hot enough to bend, twist or manipulate in some way. Instead of manipulating it, take quite a bit more time adding heat to the same area then manipulate it a bit. Just once and then pop it in the kiln.

Next, take an identical piece, some color, shape, size and heat it up until it is barely able to move, manipulate it in the same manner as the first piece but do so knowing it doesn't have quite enough heat then pop it in tbe kiln.

After they have cooled, compare the two. If the piece that you gave extra heat to is smooth and the piece you did not heat enough has that "wrinkled" appearance you are talking about, then you know that you need to add heat before you manipulate your glass. Going back over the glass with the flame in areas you have heated and manipulated will also help to melt in the mechanical devit.

Otter

Right, but suggesting using a fork when someone asks how to eat soup because your gut tells you the fork is the right thing to use despite never having seen soup isn't as helpful as you might think.

I get that you're trying to be helpful, and instead of jumping on you for potentially giving wrong answers due to inexperience, I'd encourage you to get some clear boro and go try it. 6 mm rods should melt easily enough with your setup and you can try some sculptural work. Transparent boro colors tend to melt and move easily as well and shorts are a good way to experiment at a lower cost.

One of the reasons I stock 104 and 90 in my shop despite being boro focused, is that by working other types of glass I can get a better understanding of how the material moves overall and can relate that experience better to my preferred glass.

Like the title above says, "Borovangelist". Go forth, create. THEN come back and share your missteps to aid others.

ok, what if it's "wrinkled" looking ( your ripples on the water description is perfect) but will NOT polish out in the flame?

every time i break the 2" mark on a marble...i get these ripples along the equator where the lens meets the color backing...the rippling is on the clear.
no amount of flame polishing fixes it. i have a feeling that it's "phase seperation" (idk if that's even the proper term) from cooking the snot out of it.

any ideas?

Could be, but it could be from when you joined the two glasses they were different temperatures and you froze the ripples. Make sure you work the join better and keep aware that colored glass will move differently than the clear glass (and opaques will move differently than the transparents).

One tricky bit with marbles is that you're moving glass on the outside, but if you don't have the glass under it hot enough it won't move along in a harmonious way. Think of it like tectonic plates, they move independently of the core of the planet, but not always quietly.

You can heat the outside of the glass all you want, but if you don't heat the glass under it, you'll have issues in shaping and getting a clean surface. This is where building a good heatbase by going in and out of the flame to let it soak all the way to the core can be crucial. If you maintain that heatbase, you'll shape more efficiently too.

As Tom said, clear will move differently than color, opaque different than transparent. Since you are having this issue at a boundry layer AND you say it is when you reach a particular size threshold, I would agree it is a heat issue. As we start working larger projects, we may not understand the heat base needed deep inside must be increased geometrically. The outside may move the same as smaller marbles and we believe we have the same heat base when in fact we don't have enough heat. So if you are having trouble moving upward in size/scale of your projects try deep heating the core of your marble. Good luck.


Otter

strange thing is...i don't see it until final rounding.

It's possible that your final punty was on the lens (it's clear...easiest to clean up, right?) and when you put it in the kiln there was still enough heat in the glass that it was soft enough to wind up with an impact related chill mark.

Scratch that...you mentioned the final rounding, so pre-kiln.

yes. It is due to the difference in viscosity between the colored and most likely stiffer backing and the softer clear lens as others have already suggested. My standard designs are 2.25" or so and I used to get this on larger marbles that needed lots of trips into my mold. The glass is being overworked and the damage, permanent devit, is showing up where its worst at that interface. It gets progessively worse so it is not surprising that it shows up at the end. I fixed it completely by reducing the amount of mold time to a minimum. When this was happening I was using the mold throughout the three hours or so it takes me for most of my marbles. Now I only use the mold for the final shaping. I keep them mostly round throughout with just heat and gravity. This is really pretty common. Why is it worse as the marbles get bigger? Not sure, but in my experience, everything gets harder and more critical as the mass grows. Also, be sure you clean your molds regularly. I use denatured alcohol to clean mine every day. You may be amazed by how much this will increase the clarity and luster of your lenses.

LarryC, some excellent points. And to the OP, I apologize for turning this more and more into a marble thread. Perhaps we should copy some of the information here to a new thread about general marble information?

A quick word about using molds and their potential effects on glass. I am adressing graphite molds or rings specifically but it could apply to all manner of marble shaping devices.

As Larry said, reducing the time the marble is in contact with the mold can help a great deal. Even after you have used your marble mold a few times to shape your marble and it is "hot" it is still relatively cool compared to the heat in the marble. This can lead to chill marks where the graphite is in contact with the glass. The graphite acts as a huge heat sink. But the marble isn't just a flat surface, it has depth and an unbroken spherical surface.

If you induce chill marks in one area, the glass has cooled and contracted rapidly. The consequences can basically be thought of as there is an equal and oppisite reaction (to a degree). So if the skin contracts on one hemisphere, all that tension goes somewhere. This may lead to distortion on the opposing hemisphere or distortion deeper in the glass. If you have two layers with divergent viscosity, this may also be where the distortion manifests. As Larry C said, this may be where clear and a backing color are next to each other or opaque and tranparent layers join. If the layer that deformed is deep enough in the marble there may not be a lot you can do to repair the distortion. Or you may be able to but you have just added a lot more time to your marble.

When working a marble, or any piece, remember the effect of rapidly cooling a portion of the piece will affect a change in other areas. It may simply be you have just induced a lot of stress or it may distort the opposing side or some other area prone to distortion for whatever factors are present. I have seen issues on the opposite side of my marbles where I attach my punty. A punty will act as a heat sink as well.

One other point Larry C made that really needs to be considered no matter if you are making marbles or sculptural pieces or Some other type of piece. "Everything gets harder and more critical as the mass grows". Part of this may be our familiarity with a specific size/mass produces habits and a skill and information set we rely on. As the mass/size increases the skill set and knowledge may not be the same and we do not always adjust for that. Part of it may simply be your torch has practical limits. Not to say you cannot make monster pieces on a small torch, I know for a fact you can. In terms of practicality though it is a different story. You may be trying to work in the same way you have for smaller pieces and moving up in size is not practical and you have to change many of the techniques you used on smaller pieces. There are a variety of reasons but I agree with Larry, mass complicates matters and certain factors become more critical.

Otter

One of the factors that I think contributes to the size vs. difficulty issue is the temperature differential of the core vs. the surface on large pieces. This gets much greater as you increase the mass and you have to spend more time out of the flame allowing the surface to skin up and the heat to sink in so the core can get hot. If you dont, these kinds of devit surface defects and boil can really become a problem. This is where large hot torches like my mirage really pay for themselves quickly. A good practice for me is to never going into the mold right after coming out of the flame when the surface is not skinned. Always give some settling time before working the glass. When I was working on fixing this a while back I came to the determination that it is not just one thing I had to change but my whole strategy and concept of how to make these. Feels like I learn more and more every time I work.

wow thanks Larry! that's a boatload of good info right there. next time i'll try and use gravity/surface tension (hot glass wants to ball up it seems?) to round it out until the very final finishing.
and i'll report back. thanks again LarryC :)

oh btw i do clean my molds before each use (and during if needed..sometimes i get a crusty piece of boiled glass that scratches the mold....like when i'm melting in white dots).

i also thought that it had a lot to do with the difference in heat between the core of the mib and the surface.
i also think that i'm working too close to the torch face and am burning the shit out of the clear.

i've never once had this happen on a flower compression marble....just clear and whatever color stringers were used.

and a mirage (or Kobuki if i can sell a kidney) is in the near future for me. i can justify the cost as i usually make marbles...almost no blown work, and a larger torch will increase my productivity (to a point anyway).

Mirage is a lot of torch for the money. I think its the sweet spot in GTTs product line.

i was thinking the same. if i sell my phantom, i only need come up with $400 or so. if i want the kobuki...i'll have to sell my soul.
i love the idea of having three different flame widths....but i don't like the idea that the foot pedal needed for a 3 stage is like $700 iirc.