Question and Answer Page (2) Questions and answers about lampworking equipment.
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* Updated February 14, 2004 *
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Following are some questions I have been asked about glass, along with my answers to them. If you have questions about glassmaking, you may post them on my Glass Discussion Board. Unfortunately, I no longer have time to answer questions individually via e-mail.
Q. What is the minimum equipment you need to have to produce blown beads? I see lovely hollow beads, usually ellipsoid shaped and often with a lovely trace line of color wound about. Is this glass different from Moretti and/or workable with a Minor Bench Burner. Do I need a Murphy Fire Bucket to make them?
A. Blown beads can be made out of any glass, although for beginners borosilicate may be easiest because it doesn't crack as easily as soft glass (Moretti). The easiest way is to start with a piece of tubing, heat it and blow (the short answer). It can be done with the same equipment used for making wound beads. However, blowing takes quite a bit more practice to learn than making wound beads - it is several orders of magnitude more difficult to control the hot glass. As far as the Fire Bucket, there may be some situations where it could be helpful, particularly if you are working out of a small furnace or making VERY large beads. But for anything normal, you don't need one.
Q. What is the minimum equipment you need to set up a useable lampworking shop?
A. This isn't a question with an easy answer. Here is my long-winded, yet still incomplete, answer to the question:
While opinions about the definition of "minimal" may vary, here is what I consider a decent minimal lampworking setup, primarily for working with solid rod. (Whenever I mention borosilicate glass below, I am referring to the type commonly used by lampworkers with a C.O.E. of approximately 33 x 10-7. This is called by different names depending on the manufacturer [Kimax KG-33/Kimble; Pyrex 7740/Corning; Duran/Schott]. While they each have slightly different working characteristics, they are all compatible with each other.)
Here are my personal preferences, in both low budget and slightly more expensive versions:
A small torch;
Low budget: National 3a blowpipe, (otherwise known as a National hand torch) with several different size tips - approx. $75-$90 w/tips
Better but more expensive: Nortel Minor burner or Bethlehem SGA hand torch $170-$200.
For tubing work, I consider a surface mix torch a must, because of its easy flame adjustability, so the National hand torch won't do. For larger borosilicate tubing work, a larger, i.e. far more expensive, surface mix torch is required.
I have (and use) all of these. In my experience, the National (with a multi-hole tip) is the best for working borosilicate glass rod. The Nortel is a good torch that works equally well with propane or natural gas. The Bethlehem doesn't work quite as well with propane, but has a tighter flame than the Nortel, and has the added versatility of using it as a hand torch. Both the Nortel and Bethlehem are surface mix torches (the gas and oxygen mix as they exit the torch tip, instead of inside it), which allows far more flame adjustment than an internal mix torch. With the National (an internal mix) one must change tips to adjust the flame much. Surface mix torches also won't backfire like an internal mix will.
If one is working exclusively with soft glass, a gas/air (instead of gas/oxygen) torch can be used. This eliminates the need for oxygen tanks and regulators. However, these torches are a little hard to come by, and one still needs a source of compressed air. They are most commonly used in neon shops. Check with a neon shop or neon supplier, if you can find one.
A VERY basic setup might use a Hot Head torch but, while it may be a cheap way to see if you like beadmaking enough to stick with it, this is not a setup I would recommend for anyone who is serious about lampworking.
Oxygen tank and regulator:
Oxygen tanks are available for lease at your local welding supply company. The cost varies depending on location, but tanks usually rent for $30-$50 per year, not including the security deposit of $50-$100, or the contents (oxygen). The large tanks (often called "K" or "E" cylinders) are more economical to fill (on a dollars/cubic foot basis) than the smaller ones. The price of oxygen also varies widely depending both on location and how much you use (quantity discounts). Expect to pay from $12 - $20 for a refill. Once the tank is empty, it is taken back and traded for a full one. If you are lucky, your supplier may also offer free tank delivery.
There are two basic types of oxygen regulators - single and two stage. Without going into detail, the two stage regulator is the one I recommend because it delivers a more constant pressure. The drawback is that it is more expensive than a single stage. A new oxygen regulator will run from about $65 - $130 (check for used ones at your welding supply store).
Some personal experience with brands: I own a few different regulators which I have acquired over the years. A couple of Harris, Victor, and several Airco. The Harris, and Victor brands are the ones that have seen the most use. They are also the only ones that still work (one of the Aircos was just two years old when it died). Draw your own conclusions about quality...
Propane tank and regulator (only necessary if you do not have access to natural gas):
Propane (also known as LP gas or LPG) is commonly used for glassworking torches when natural gas isn't available. A 20lb. propane tank from a gas grill works just fine for torch work, as does the small regulator that comes with a grill, although a propane regulator capable of handling higher pressure and/or volume may be necessary if one is using a large torch. An acetylene regulator can also be used (with an adapter). See above for brands. You can look for these at your welding supplier, or the gas company store (if you have one in your area). Make sure your connections are leak-tight. Check all connections for possible leaks with soapy water or propane leak detection solution - if bubbles form after this is put on a connection, you know there is a leak. (The leak detector solution can usually be obtained from your local propane dealer.) In most places it is illegal to keep a propane tank indoors, check local laws and safety rules for using propane (or anything discussed here). Propane is heavier than air. If there is a leak, the propane will accumulate at the lowest nearby point. This can lead to a puddle (or pond) of propane, with obvious unwelcome consequences if ignited. I don't want to make anyone paranoid - just aware. Many people use propane with no problems. Just be sure to use it safely.
Hoses:
The safest hoses are heavy rubber welding hoses. Be aware that there are different grades of welding hoses. For gases such as propane, natural gas, or MAPP gas, ask specifically for "Grade T" hose, which is a different type than the standard hose (grade "R") that is normally used for acetylene. Grade T hose is rot resistant when exposed to the fuel gases normally used for lampworking, while Grade R hose will deteriorate when used with them. Your welding supplier should be able to help you with Grade T hose since propane is often used as the fuel for cutting torches. Although I personally use surgical rubber tubing (1/4" x 1/2") because of its flexibility (I like to be able to move my torch around), I can't recommend it from a safety standpoint. If surgical tubing is used it must be checked on a regular basis, as it eventually rots and develops leaks (usually at the connections first). It is also much less durable than welding hose. Surgical tubing should never be used in a classroom situation with beginners because a hot piece of glass accidentally laid on the tubing will burn right through it.
Annealing oven:
If you are working with soft glass you will probably want a small annealing oven. Annealing removes stresses that build up in glass as it is worked, and keeps additional stresses from forming as the glass cools. Working the glass properly can reduce the introduction of these stresses, and cooling it slowly will also help, but neither works as well as proper annealing. Small annealers are available from various lampworking suppliers. If you are so inclined, you can build your own out of insulating firebrick or fiber, and heating elements. You don't have to have an annealer to work with small soft glass, but it helps. Due to its lower coefficient of expansion, borosilicate glass is less likely to crack when not annealed.
For those into accuracy -
Annealing glass IS NOT the same as tempering glass. In fact, it is exactly the opposite! Annealing removes the stresses in glass by bringing it to a temperature just below the softening point and then cooling slowly enough that very minimal permanent stress is introduced as it cools. Glass is tempered by rapidly cooling it, which introduces a large amount of stress into the surface of the glass. Done correctly, this stress actually strengthens the glass.
So remember, while they are both done with the hope of keeping glass from breaking, they are NOT the same - annealing REMOVES stress and tempering INTRODUCES stress. (If you haven't figured it out already, one of my pet peeves is hearing a self proclaimed "glass expert" incorrectly refer to annealing as tempering.)
Some basic lampworking tools:
Good stainless steel tweezers, maybe10 inches and 6 inches long. If you have a cooking supply store nearby check with them first, that's where they are usually cheapest. They should run about $10.
A graphite paddle: 3"x 5" is a good versatile size for small work. Available at lampworking suppliers.
Stainless steel mandrels (if you are making beads): Use uncoated stainless welding wire (rod) in whatever diameter you like (1/8" and 3/16" are good starters) and cut it to approximately 1 foot long pieces. Make sure to deburr the ends after cutting it or you'll never get your beads off the mandrels. You can get enough wire for a bunch of mandrels for just a few dollars.
Bead release: To coat your mandrels so you can get the beads off when they are done, plain old kiln wash works ok, but there are some commercial bead releases available that work better.
Last but not least - SAFETY EQUIPMENT!!!
Fire extinguisher (just in case) - I have never needed mine, but...
First aid items for dealing with cuts and burns - You WILL get cut and you WILL get burned! Be prepared beforehand. I like aloe gel for burns. Ice is good too, if you have some nearby.
High quality tweezers for removing slivers of glass from various body parts. Mine have a very sharp tip which I sometimes use to dig out deeply embedded slivers. A good magnifying glass can help too.
A mirror: In case you get something in your eye (one hopes not glass!).
Safety glasses - Safety glasses are a MUST!!! Didymium glasses are the type most commonly used by lampworkers because they filter out the yellow glare from the sodium in the glass. Be aware that they DO NOT filter out much more than that. They are better than nothing, but not by much. They should DEFINITELY NOT be used for furnace glassblowing. For bead making and working with soft glass they should be okay. For higher temperature glasses, like borosilicate, they provide very little protection from the infrared energy generated. Aura Lens Products makes an alternative - AUR-186, which is far better than standard didymium at filtering infrared (and other wavelengths) and does a better job at filtering the wavelengths didymium filters, as well. Unfortunately, I find the pair I have to be somewhat uncomfortable to wear due to their weight (they use a two part laminated lens which is fairly thick). But since I bought my AUR-186's Aura has introduced these lenses in smaller frames to lessen both the weight and the cost, and those I have spoken to who use them say they are comfortable. Aura has some very good and detailed information about eye protection on their website, including spectral absorption/transmission charts for their various lens materials.
If you think that safety glasses make you look dorky and you can't learn to live with that, my advice would be to find another hobby other than glassworking (although Aura offers much more stylish frames than standard safety glasses). Broken glass in the eye is no fun - particularly if it is near 1000 degrees Fahrenheit.
(A personal opinion about glasses - I have my reservations about any glasses that FILTER infrared. My personal feeling is that once the lens absorbs enough infrared, it heats and reradiates IR at your eye, kind of defeating the purpose. Although that is still better than no glasses at all, I think a far superiour solution would be a durable coating that would allow one to see the color variations in the glass as it heats, but that would REFLECT IR away. Unfortunately, there appear to be technical problems with making a practical coated lens for glassblowing and I don't know of anyone currently making glasses like this, so until then... can you say "glassblower's cataracts"?!?)
For anyone making colored glass in the flame using various chemicals, the dangers increase exponentially. Many of the chemicals used to do this are quite hazardous just to handle. If one decides to take the risk of mixing color in the flame (and I strongly recommend against it), extremely good ventilation and proper chemical handling procedures are an absolute must!
Okay, that's enough for now. This is in no way a comprehensive list, but is good enough to get someone started. There are probably a few things I have overlooked, but I think most of the basics are there. If you want more info, a good book to take a look at is: "Contemporary Lampworking" by Bandu Scott Dunham. It has lots of good lampworking info in it. Have fun!
Oh yeah, a table with a fire resistant top, and a good comfortable chair will help too. I like a nice, adjustable height office chair on casters.
My little weasel clause: The advice above is only meant as a guideline. Improper use of the equipment and tools mentioned can be dangerous to life, limb and property. Seek professional advice on safety procedures and equipment before beginning. And if you do something stupid and get hurt, don't sue me. I don't have anything you'd want, anyway. (If you want my glass, it will be much cheaper and easier to just buy it.)
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