Post by Ron Walker on Aug 30, 2022 19:31:39 GMT -7
Posted by: Ray Worthy Dec 19 2008, 03:18 PM
Dome Fabric
As I have stated before, the first fabric I tried , a white PVC.
, was in most respects , unsuitable. Physically, it was tough and
durable, ( It gave me six years with any wear and tear), but compared to
the stuff I used later, it was stiff and not sufficiently flexible. Its
downfall came when I was refused a licence to take it into schools
because of its lack of fire retardation. The fire brigade inspector who
wrote the report took a stopwatch and timed a class of children entering
the dome in single file. They took something like forty seconds. Now
this is a long time and the man envisaged the kids coming out through
the zip door on an occasion when the fire bell was ringing. I could
fully understand his point of view.
I explained to his superiors that , in an emergency ,
the kids would not get out that way; the dome would be pulled down in
three seconds and the class would simply walk away. They obviously did
not believe this claim. However, they set up a demonstration where I
could show what I meant. Not one of the high brass of the Fire Service
knew what an inflatable dome looked like so quite a number of them
turned up . I inflated the dome and they set up no less than three movie
cameras on tripods to catch all the angles. All the brass was having a
chin wag at one end of the hall. I went inside the dome and positioned
myself furthest from the zip. I shouted “ Are you ready?” The answer
came “Yes!”, so I bent down and pushed one hand as far underneath
the fabric as I could reach and pulled hard towards the centre of the
dome circle. At the same time , I pushed the fabric with my other hand
about a metre or so up the inside wall. The effect is truly amazing when
seen for the first time. The hemisphere of entrapped air seems to act as
a solid. The dome flies over and lands on the floor in a crescent. I
stood up to be greeted by a host of saucer like eyeballs as they stared
in astonishment at the place where the dome had been. I began to pack
the dome away, but the chief stopped me. He apologised and asked me to
repeat the demo. They had not even switched the cameras on. The upshot
of this demo was that I was told that the speed of exit was so
impressive that the only barrier against me obtain permission to go into
schools was the fire retardant quality of the fabric I used. Now, at
this point, I came across the old problem facing anyone who intends to
make a planetarium, fabric or otherwise, there is no market for
planetarium construction. It is the same as when one makes a home built
projector; nothing is made specifically for the purpose. The fabric
market is exactly the same. You can have just about any fabric you want
if you are prepared to order something like ten thousand metres of the
stuff; otherwise “Hard cheese”. I made an appointment to see the
fire officer who possessed the file on all the special regulations I
would have to follow. When it came to the crunch, there weren't any. The
concept of an inflatable fabric dome which enclosed a class of pupils,
quite simply had never been envisaged. We cannot blame the planners. I
explain all this to you because the fire authorities in each area seem
to be a law unto themselves. This dilemma always comes as a surprise
when the local man is faced with the problem. However, they seem
amenable to follow when one authority has taken the lead and I include
the United States in this. The US has its own system and the fabric has
to be tested by the national authorities, even though the fabric has
already undergone tests in Europe. The fireman was hunting around,
trying to find an applicable category, but without any success. The best
we could come up with was tenting fabrics and drapes in hospitals and
hotels. He looked up the records to find a hotel which needed a fire
retardant certificate for its drapes and found one not very far away. A
quick telephone call to the hotel manager and we learned where we could
buy some fabric. It had to be light tight and air tight. This was a
situation absolutely crying out for Google but the Internet had not
been thought of then. I soon learned that what the fabric people called
light tight and what I as a planetarian called light tight were not
exactly the same. When I was taken off the road , the date was the third
of a December , although the precise year escapes me. My bookings for
the following year began on the twelveth of the February. I was
desperate. The managers of all of the places where such work could be
undertaken simply laughed at my request. With Christmas coming ,
closely followed by New Year , they could make no promises. So, in the
end, the decision was made to do the work myself, that is myself , my
wife and one or two good friends. I converted a spare bedroom put in a
large work surface and got cracking. I did all the design work, cut out
the panels, made many mistakes and sewed them up. My wife was a music
teacher and a director of a large adult choir, I had been, amongst
other things a drama teacher with all that implies at Christmas time .
Both of our sons were members of singing groups. You can imagine the
kind of parties that went on downstairs. One minute I would be
performing on the drums or reciting and singing, the next minute, I was
racing up the stairs to get on with the next job. Naturally, many guests
found their way upstairs to gape at what was going on. My workshop
seemed to be part of the Christmas Tour. It was a miracle that the whole
job was completed, the licence obtain and I was back visiting schools by
the middle of February. There was only one postponement of a booking of
a week. This was the turning point of the business. It was but a short
time until I was receiving requests to make domes for other enthusiasts.
In that bedroom, Josie, my wife and I even made an eight metre negative
pressure dome for a friend up in Helsinki, Finland.
--------------------------------
Have you ever noticed that hindsight always gives one
twenty- twenty vision? So it is in this case. At the time, the main
driving motif was my February deadline. I simply bought the necessary
material and got on with the making up and sewing. The fabric was
called by some in the trade, a sandwich. There were at least three
layers. There was a matrix of some kind of open weave lint like
material. This was covered in one pass in the mill with a black
substance. There were two more passes in the mill. On one side was a
smooth covering and on the other was a kind of flock deposit. The basis
of the material was a kind of acrylate . It was the flock side which I
intended to use as the internal screen. As a step up from the PVC fore
runner this was great, especially because it came with a fire retardant
certificate. I do not know whether it was the best the trade had to
offer, but, at the time I was very pleased with the fabric. It was only
later that certain aspects came to light. Having a scientific background
and forever pushing the bounds of my knowledge, I began to explore what
was known about this fabric. I was met with a brick wall. I wished to
discuss things with the technical staff of the manufacturers. After all,
I was going to put this fabric to a use never heard of before. When I
made enquiries at the place where I bought it, I was met with programmed
obstruction. Even the girls on the telephone had been instructed not to
discuss the topic with me. This went on a long time. All documents had
been tampered with me to keep the place of origin secret. At the time, I
was mystified, but I had other matters to keep me occupied. Then, one
day, I requested details of the washing instructions and I found that
all the management's efforts had been in vain. There, at the bottom of
the document, in microscopic print was the fax number of the wholesale
supplier. Down to the local library I went and did some detective work
with the telephone directories. I knew the town and half an hour with
the Yellow Pages pinned down the wholesale company. It was then that I
discovered why this knowledge had been denied me. My supplier had put on
a hundred percent mark up. Now you can appreciate why I am telling you
this. It could save you a lot of money.
Next; Making the dome dark.
RAYMOND WORTHY
Dome Fabric
As I have stated before, the first fabric I tried , a white PVC.
, was in most respects , unsuitable. Physically, it was tough and
durable, ( It gave me six years with any wear and tear), but compared to
the stuff I used later, it was stiff and not sufficiently flexible. Its
downfall came when I was refused a licence to take it into schools
because of its lack of fire retardation. The fire brigade inspector who
wrote the report took a stopwatch and timed a class of children entering
the dome in single file. They took something like forty seconds. Now
this is a long time and the man envisaged the kids coming out through
the zip door on an occasion when the fire bell was ringing. I could
fully understand his point of view.
I explained to his superiors that , in an emergency ,
the kids would not get out that way; the dome would be pulled down in
three seconds and the class would simply walk away. They obviously did
not believe this claim. However, they set up a demonstration where I
could show what I meant. Not one of the high brass of the Fire Service
knew what an inflatable dome looked like so quite a number of them
turned up . I inflated the dome and they set up no less than three movie
cameras on tripods to catch all the angles. All the brass was having a
chin wag at one end of the hall. I went inside the dome and positioned
myself furthest from the zip. I shouted “ Are you ready?” The answer
came “Yes!”, so I bent down and pushed one hand as far underneath
the fabric as I could reach and pulled hard towards the centre of the
dome circle. At the same time , I pushed the fabric with my other hand
about a metre or so up the inside wall. The effect is truly amazing when
seen for the first time. The hemisphere of entrapped air seems to act as
a solid. The dome flies over and lands on the floor in a crescent. I
stood up to be greeted by a host of saucer like eyeballs as they stared
in astonishment at the place where the dome had been. I began to pack
the dome away, but the chief stopped me. He apologised and asked me to
repeat the demo. They had not even switched the cameras on. The upshot
of this demo was that I was told that the speed of exit was so
impressive that the only barrier against me obtain permission to go into
schools was the fire retardant quality of the fabric I used. Now, at
this point, I came across the old problem facing anyone who intends to
make a planetarium, fabric or otherwise, there is no market for
planetarium construction. It is the same as when one makes a home built
projector; nothing is made specifically for the purpose. The fabric
market is exactly the same. You can have just about any fabric you want
if you are prepared to order something like ten thousand metres of the
stuff; otherwise “Hard cheese”. I made an appointment to see the
fire officer who possessed the file on all the special regulations I
would have to follow. When it came to the crunch, there weren't any. The
concept of an inflatable fabric dome which enclosed a class of pupils,
quite simply had never been envisaged. We cannot blame the planners. I
explain all this to you because the fire authorities in each area seem
to be a law unto themselves. This dilemma always comes as a surprise
when the local man is faced with the problem. However, they seem
amenable to follow when one authority has taken the lead and I include
the United States in this. The US has its own system and the fabric has
to be tested by the national authorities, even though the fabric has
already undergone tests in Europe. The fireman was hunting around,
trying to find an applicable category, but without any success. The best
we could come up with was tenting fabrics and drapes in hospitals and
hotels. He looked up the records to find a hotel which needed a fire
retardant certificate for its drapes and found one not very far away. A
quick telephone call to the hotel manager and we learned where we could
buy some fabric. It had to be light tight and air tight. This was a
situation absolutely crying out for Google but the Internet had not
been thought of then. I soon learned that what the fabric people called
light tight and what I as a planetarian called light tight were not
exactly the same. When I was taken off the road , the date was the third
of a December , although the precise year escapes me. My bookings for
the following year began on the twelveth of the February. I was
desperate. The managers of all of the places where such work could be
undertaken simply laughed at my request. With Christmas coming ,
closely followed by New Year , they could make no promises. So, in the
end, the decision was made to do the work myself, that is myself , my
wife and one or two good friends. I converted a spare bedroom put in a
large work surface and got cracking. I did all the design work, cut out
the panels, made many mistakes and sewed them up. My wife was a music
teacher and a director of a large adult choir, I had been, amongst
other things a drama teacher with all that implies at Christmas time .
Both of our sons were members of singing groups. You can imagine the
kind of parties that went on downstairs. One minute I would be
performing on the drums or reciting and singing, the next minute, I was
racing up the stairs to get on with the next job. Naturally, many guests
found their way upstairs to gape at what was going on. My workshop
seemed to be part of the Christmas Tour. It was a miracle that the whole
job was completed, the licence obtain and I was back visiting schools by
the middle of February. There was only one postponement of a booking of
a week. This was the turning point of the business. It was but a short
time until I was receiving requests to make domes for other enthusiasts.
In that bedroom, Josie, my wife and I even made an eight metre negative
pressure dome for a friend up in Helsinki, Finland.
--------------------------------
Have you ever noticed that hindsight always gives one
twenty- twenty vision? So it is in this case. At the time, the main
driving motif was my February deadline. I simply bought the necessary
material and got on with the making up and sewing. The fabric was
called by some in the trade, a sandwich. There were at least three
layers. There was a matrix of some kind of open weave lint like
material. This was covered in one pass in the mill with a black
substance. There were two more passes in the mill. On one side was a
smooth covering and on the other was a kind of flock deposit. The basis
of the material was a kind of acrylate . It was the flock side which I
intended to use as the internal screen. As a step up from the PVC fore
runner this was great, especially because it came with a fire retardant
certificate. I do not know whether it was the best the trade had to
offer, but, at the time I was very pleased with the fabric. It was only
later that certain aspects came to light. Having a scientific background
and forever pushing the bounds of my knowledge, I began to explore what
was known about this fabric. I was met with a brick wall. I wished to
discuss things with the technical staff of the manufacturers. After all,
I was going to put this fabric to a use never heard of before. When I
made enquiries at the place where I bought it, I was met with programmed
obstruction. Even the girls on the telephone had been instructed not to
discuss the topic with me. This went on a long time. All documents had
been tampered with me to keep the place of origin secret. At the time, I
was mystified, but I had other matters to keep me occupied. Then, one
day, I requested details of the washing instructions and I found that
all the management's efforts had been in vain. There, at the bottom of
the document, in microscopic print was the fax number of the wholesale
supplier. Down to the local library I went and did some detective work
with the telephone directories. I knew the town and half an hour with
the Yellow Pages pinned down the wholesale company. It was then that I
discovered why this knowledge had been denied me. My supplier had put on
a hundred percent mark up. Now you can appreciate why I am telling you
this. It could save you a lot of money.
Next; Making the dome dark.
RAYMOND WORTHY