Putting these reports on the Web should facilitate distribution, and will make it unnecessary for me to send out overly long email messages. It also provides an automatic archive.

Just before the NCECA conference this year, I was privileged to take a workshop with Ruthanne Tudball, who came in from England. Her work is entirely different from mine, and it was a real trip to watch her and talk with her.

Ruthanne spent most of her first eight years as a potter self-taught, in a tiny basement workshop that barely had room for a wedging table and a wheel, so she was unable to fire her work. She’d make something, and put it into the scrap bucket so she could recover and reuse the clay. She couldn’t afford to get attached to any of her pieces. I find the whole business kinda staggering.

NCECA itself took place in Baltimore, in March. As always, it was very good. I got to talk with some extremely knowledgeable people, and picked up good information on several subjects. I also donated pieces to two of the benefit auctions, and participated in

» Read the rest

(22 May, 2005)

First, however, a small note: I have been thinking about bringing up one of our old pulsed YAG heads, using an etalon to narrow the bandwidth for reasonable coherence length, Q-switching it for reasonably brief duration, and jamming the output through a doubling crystal so I can do some pulsed holography. The Q-switch will probably have to be passive; I wonder about coffee (which can apparently Q-switch ruby, according to one story I’ve heard from before my time with lasers) or perhaps a thin slice of brown beer-bottle glass… have to do some testing, I guess, to see whether either of those has any potential for use as a saturable absorber at 1064 nm.

Here are two pieces I fired to about Δ 10 today in moderate reduction:

Both of them are glazed with Joss Research “New Blue”. The little bowl warped pretty severely, but the colors are really sweet, and it’s kinda cute despite the warpage, or perhaps partly because of it. The platter is a bit heavy, but them’s the breaks; it

» Read the rest

(22 June, 2005)

Having spent the weekend at a conference on European Cooking from Rome to the Renaissance, I return to these issues refreshed and burping contentedly. (Actually, there was very little I could eat; but it all smelled nice, and I learned quite a bit.)

A long time ago, Doug (founder of the Joss Research Institute) handed me what looked like an excimer laser head, made of two pressed brass electrodes, with pairs of doorknobs down the sides. It was pin-gap preionized, but oddly: the electrode profiles are very tall, and the pingaps were between the doorknobs of a pair. (I’ve already taken it apart, and I’m not finding the picture I thought I had, but perhaps I can take some photos of the parts. If so, I’ll post them here.)

                       

(If you want the full pixels for the first one, drop the “u” from the number in addition to changing “8c” to “22c” in the filename, but be prepared for blurriness. For some » Read the rest

Just about anyone who really wants to build a nitrogen laser of one sort or another can do so: it isn’t hard. Building a high-performance nitrogen laser, however, is a different story. (For the purposes of this discussion, I will establish arbitrary criteria for low-pressure nitrogen lasers, as follows: a low-performance nitrogen laser works, but cannot provide more than, say, 100 kW peak power. A mid-performance nitrogen laser puts out more than 100 kW but less than, say, 0.5 MW, or has poor pulse-to-pulse uniformity and cannot be depended on to put out at least 0.5 MW every time or nearly every time it is fired. A high-performance nitrogen laser routinely puts out well over half a megawatt.)

Please note that these criteria are for low-pressure nitrogen lasers. It is a relatively straightforward task to build a room-pressure nitrogen laser that puts out peak power in excess of 1 million watts, but such a laser need produce only

» Read the rest

(September, 2009, ff)

This page details the construction of an improved (I hope!) head for the nitrogen laser that is initially described on the previous page.

I need a nitrogen laser for a project or two. I have removed the head from my most recent design in order to rebuild it; but that is a lengthy and complex project, so I decided to put this laser back on line first. When I tested the head, however, I discovered that it leaked considerably more than I wanted. In the process of trying to find and fix the leaks, I found that some of them were easily localized, but some were distributed along the sidewalls. After a bit of thought and some grumbling (after all, I started on this because I thought it would let me accomplish a project or two without having to do any major rebuilding) I decided to construct a new head, using plastic walls instead of wooden ones. (I also intend to rebuild the wooden head, because I still think it’s a great » Read the rest