Posted by Mike Jackson on November 09, 2003
PatrickI read through Rawson and Evans first patent last night. It is pretty interesting reading...if you are so inclined. I was curious!
According to Samuel Evans patent, for the stencil in this process, he used heavy document manila paper, soaked in oil and let dry. The pattern material could be stacked and cut in groups of 8 to 20 stencils at on time us a sharp knife. This was done off the glass. The glass was cleaned, then coated with a layer of soap solution (one variant of the process calls for an under layer of asphaltum) and the stencil material was applied over it. The panel was then frosted with a sandblaster. According to the patent info, the warm glue was brushed onto the panel.
Now, the interesting part. While the glue was still very soft, they quickly pulled the manila pattern off the glass, leaving only glue in the frosted areas. I've never really tried that exactly, but in the Bob Mitchell process, you had to hand cut around all edges and remove the stencil. It is similar but Rawson and Evans didn't have adhesive stencil. The patent uses the work "quickly" a couple of times...so maybe there is something related to the speed they pulled the paper, or maybe that is related to the timing after the glue was applied.
The double chipped glass is mentioned and described in relation to this patent. From the best I can understand, once the first chip is done, they simply coated the entire glass piece with glue again. The asphaltum would still be there along with the thin layer of soap solution (dried by now but still there). The combination of asphaltum and soap would prohibit the glue from gripping the glass.
If anyone else cares to read the patent, maybe we can glean additional bits of information or clarify anything I am missing here. It seems one of the tricky parts in their process would be aligning all the manilla sheet patterns on soapy piece of clear glass. They probably had a large sheet of layout paper underneath it. I suspect the soapy glass allowed a certain amout of sliding and adjusting, too.
Just guessing here, but a lot of their designs were perfectly symmetrical either in one axis or even both. They may have been able to fold the manila paper to only have to cut one side or one quarter of the shape, then unfold it onto the glass.
Also last night, I tried searching around on Google to see if I could find any information about sandblasting equipment they might have had back at the end of the 1800s. I didn't find anything right off, so if any reader has access to any related information, please post it. We pretty much know there wouldn't have been an Ingersol-Rand compressor and an Empire 300 lb pressure pot lying around at the plant at that time. It doesn't take much pressure to frost glass, but some sort of equipment had to be around at the time.
Mike Jackson
Mike JacksonAbout twenty or so years ago I had a manila stencil from the Rawson and Evans shop. It had been used and in very fragile condition. I recall that it said "remember to buy mirrors". It was a heavy parchment type of paper , stiff and resembling rawhide, about as thick as a credit card. The fonts were rather crudely cut out by hand with a knife. The centers were fixed in place with lenghts of wire held by small dobbs of glue.
It was semi transparent like brown mica and stiff as though it had been soaked in turps or a shellac to make it tougher. The sandblasted area where the letters were was left a darkish gray from the exposure to the sandblast. This small stencil had to have been blasted with a hose and nozzle method. It may most likely have been only a syphon system as they were cheap and easy and usually required only to frost the glass. I read somewhere years ago that Samuel Morris (telegraph) invented the first steam powered sandblaster. I have heard accounts from old glass men that sand was shoveled through tubes in the ceiling to fans that blew air directed at the glass to frost it. Then it was moved to a room with a wooden rack were it was acid washed with hydroflouric acid. I saw an actual b/w photograph of the washing set up, odviously before OSHA.
I don't know how early pressure pots were used to apply sand to glass. I imagine that the steam powered one credited to Morris was probably invented to remove rust and scale off steamers in the shipyards. Maybe THEY discovered deep sandcarved glass after hitting a couple of portholes at 200PSI with 20 grit silica. :^)
Hi Patrick,
Sounds like you have, or had, a nice little treasure. The patent mentions soaking the manila sheet in oil, but it didn't say exactly what kind of oil. Turps would probably dry hard after a period of time, and the soaking might render the manila material a bit on the transparent side. Of course, the original patent might have called for manila sheets the they might have found better materials as the years went along. It the stuff was as thick as a credit card, it would be hard to image them cutting up to 20 sheets at a time, even with the sharpest #11 X-Acto!
Maybe a few people who are currently chipping quite a bit will have a chance to try the patented method, using a manila sheet and soap cover glass.
Thanks for the note!
Mike Jackson
Kent Smith
Robare M. NovouFYI - Western Sandblast had a decomissioned steam powered blaster that Willie showed us on that last visit there.
Mike JacksonWhose Willie? and are you referring to Western Sand Blast of Chicago. I dont think that they are in business anymore.
RMN
Kent SmithThat would probably be a hoot to see working. It would be nice to try to get a photo of it...Kent, do you think you could arrange that?
Thanks in advance,
Mike Jackson
Yes, Western Sandblast Co., Clinton and Jackson Streets, Chicago. Willie was the last employee whom we met when we were there many years ago. I left my camera in my car and rode into visit with Rick G. and Joe Balabousko. They were cleaning the place out since Mr. Pine had recently died. Rick picked up a few souveniers as did I, mostly popcorn wagon and railroad. Rick posted Willie's photo on the Letterville site last fall when this topic came up, don't remember the date. I have no photos but it was a room sized behemouth with a huge boiler. I suspected that some of the piping was still in place since the building was much more damp than other buildings in the area. We wondered at the time how they were able to chip in that environment, Willie said they heated an area of the shop "extra hot" which had extra radiators for the steam heat, I suspect maybe from the same boiler. It was a good brick building so it retained the heat well and probablly would stay dryer once heated.
Mike Jackson
Kent SmithHi Kent,
Was this during the event at Pheasant Run in St. Charles around 1988? One night we all went out to dinner and it seems Rick had mentioned going there and he had one of the zinc stencils as one of the souvenirs. At the dinner, I can remember you and Judi, Rick & Lola, Ellis Doughty, Mark Klein, Lynn Rogers, David and Suzie Butler, Terry Hopkins, and Darla and myself. There were a bunch of other people at the other table.
Your description above just rung a bell.
Mike
That is the right bell.
Denver Chapter of the Letterheads