Several people in the past couple of days have e-mailed and PM’d me with questions about their own situations where either their significant others or landlords have not allowed them to cut holes in walls or ceilings to allow ventilation. They still want to work safely and have asked me to help them resolve this issue. Continue reading
From one of my e-mail correspondents:
So, once again, thank you! There is nothing like a great teacher, and confidence in design to motivate a person to do it the right way… without this it is so tempting to set up something you hope is “adequate”. I have learned a lot along the way! I am normally a total researcher, figure-it-out-myself kind of person, but given my life situation right now I just couldn’t go there, and you gave me the tools and the confidence to get ‘er done! I am going to send you pictures right away!! Please excuse the mess around the ventilation system… I haven’t gotten that part accomplished… but even with the mess I think it is truly beautiful!!!! Yea!!! Happy!!
Many people, some of them fairly influential in the glass-working field, have publicly stated that it is difficult, if not impossible to work in a properly ventilated public studio. These same people have said that it is “OK” to open some windows and doors and use some box fans to move air around, but to also take frequent breaks. As this paper will show, this thinking is short sighted, and ultimately dangerous to the uninformed (especially new students).
This failure to take the initiative in presenting a united front for studio safety has led me to research one of the principle reasons glass-working studios MUST properly ventilate their work areas. That reason is NOx. The chief “bad actor” (as Stan Wolfersberger calls it) of the NOx family is NO2, nitrogen dioxide. Continue reading
By popular request, I’ve added a new page that gives the links to the three articles I’ve written on ventilation. This will make it easier to look up the basic ventilation principles and formulae.
Thanks for writing!!
Due to a state of overexcitement, I kept a beautiful bead in the air too long and it cracked during annealing. I want to save it by turning it into a cabochon, but will I have to re-anneal it? Thanks for your wonderful blog, keep up the good work!
The answer is yes, but not in the way you normally think of annealing. Pretty much what you are doing when making a cabochon (or cab) in the kiln is a partial slumping — you heat the kiln up to the point where the glass starts to move, hold it there for a period of time, then drop back. The “drop back” is where your annealing is going to kick in. For example, if you are using Moretti/Effetre glass, simply bring the kiln down to 950 F, hold it for an hour or two, slowly cool it down to 850 F over the same time period, then allow the kiln to cool normally back to room temperature.
The slumping process does create movement in the glass, so you do need to re-anneal the glass, but it is done as part of the whole process, not as a separate process.
Thanks for writing!!
This isn’t rocket science, people!
I just called the welding supply shop that we got ALL of the equipment from (except the HH)…the brand spanking new tank, the brand spanking new hoses and proper fittings that were required to run the torch and spoke with THE owner…who has been in business for 40 years now. They are the best known and most respected welding supply here in the Tampa area. I told him the size of our shop/warehouse, the size of the office box, the size of the exhaust fan in the warehouse and in the office. He knows what torch is being used and what size tank and lines are running.
According to him (and I *think* that he might know what he’s talking about), it is NOT illegal [to keep propane inside]. They are used every day in many shops for all kinds of applications. He said the only time he’s seen any ‘rules’ about using one is in the situation of a jeweler in a mall or retail shop. And as for the insurance thing, he said that would be like telling someone they could not use their gas barbecue….that if something happened they would not cover it. Myth busted…..
Like many materials, glass has different forms, depending on temperature. It can be solid, it can be liquid, and at high enough temperatures, it will break down to its constituent components and turn into a gaseous state.
I like to think of glass as being similar to water. Because of its lower temperature transitions, we can easily see water in all three states: solid, liquid, and gas. At temperatures of 32 F and below, water is a solid. At temperatures between 32 and 212 it is liquid. At temperatures above 212 it is in a gaseous state (vapor).
I’ve never understood why people have to think glass is any different.
And no, glass does not move, or at least in any time frame that humans can see. Perhaps molecular movement may occur over tens of millions of years, but if anyone ever tells you that the reason old glass is thicker at the bottom is because the glass flowed that way is full of crap. Old glass was usually poured out in molds, and the installers always put the thickest part of the pane at the bottom simply because it was easier to handle that way.