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Re: phosphors
>Dear John,
>There are mainly three different binders for fluorescent powders, namely the
>binder for the sponge technique, the glass-beads technique and the liquid
>technique we call the PHILIPS suspencion technique.
>We never use the technique here in Europe that you tried out, infact I don't
>even know how it works. We call that the cold cote no bake technique, so using
>this technique it's not neccessary to have an oven. But it's just the use of a
>bake- or annealing oven which make the neontube superior to other tecnique's.
>Even when we use pre-coated tubes we still bake the tubes out for making them
>more clean and hydro free. What you actially do is sinter the fluorescent layer
>to the glasswall (again) especially important where the tube is bend. Anneled
>glass is three times stronger then before, so speaking about quality every
>bender must consider the use of an oven. I am convinced of the fact that this
>procedure is not more costly because there are less failures or thermal
>breakage
>(from the thermal tension in the bend) then not using an oven. The lifetime of
>your pump-medium is more then doubled and the pollution of your manifold is
>minimized. Doing merc repairs is vey easy when you bake out the glass
>first. All
>block out paint is vanished from the glass and the merc is sucked out from the
>tubing out of the closed oven by a fan when the temp is about 350 C. The
>exhaust
>merc polluted air is simply lead through a waterbed so that there is no merc
>vapour in the environment. Afterwords (when is neough merc) the merc can be
>triple distilled under vacuum and used again. That triple distilled is not
>a big
>deal. The unit you need for that is very simple to build from a roughing pump
>and a diffusion pump. I have blue prints of such an installation, so if you
>think that it is interested to you I can post them. It's realy an easy to
>handel
>operation to distil old merc, saving money and it's god for the environment.
>Back to binders.
>The binder for the sponge technique has a strength of 4 to 5 % and for the
>glass-beads technique a strenght of 3 %.
>The binder is never made with a component like camphor in it, we us ethat for
>other purposes. The binder is made from Aceton, spiritus Phortior and a glue
>like Phosphorus Pentoxide like P2O5. Make sure that the aceton (and all the
>ingredients) are chemical pure. Never use the cheap technical pure solvents.
>The solution for making a liquid suspencion is different from the dry powder
>binder. This solution is made from Spritus Phortior, Amelis Acetas and a
>nitro-cellulose in a specific concentration. Selling this solution through
>Western Europe you must forgive me not to publish the exact percentage's of the
>different ingredients. Preparing a liquid suspencion you must mill the dry
>powder in a milling vessel with ceramic balls inside for about 24 hours
>with 110
>RPM. So the vessel must do 110 RPM and not the machine. Using thing bars
>(like 5
>cm) the bars must do about 750 RPM. The ceramic balls have a diameter of 15, 20
>and 25 mm and the vessel must be filled halve with balls. When you have a
>powder
>with a specific gravity of 1 you can make halve a litre of suspencion from
>halve
>a (European) pound of dry powder. The viscosity of the liquid must be about 10
>or 11 Zahn seconds for the powdering bend tubes, and the viscosity mmust be
>about 17 Zahn seconds for straight tubes before bending. So for Brilliant Blue
>you can make 550 ml with 250 grams dry powder and for standard blue there is
>only 390 ml suspencion. The reason for that lies in the fact that standard blue
>has nearly (whatever the brand is) a specific gravity of 2 and BB is lighter
>then 1.
>All nitro-cellulose is vapourising at 350 C so at that temperature there is a
>build in fan in the oven sucking out the NC vapour with a hysteresis of about 3
>minutes. Then the tempearure is rising again to the annealing point. For
>us only
>using soda-lime it is 480 C so just under the aneealing point to prevent that
>the glass wil have other curves then before. These temperatures are continued
>with a hysteresis of about 5 minutes. The cool down period of neon tubing
>is 1 C
>m E -1. Following this procedure your glass is completely annealed and
>therefore
>3 times stronger. All ovens are heated by electrical power. We never use other
>sources any longer as these are old fashioned and unreliable. Men can regulate
>electricity so perfect with a narrow band of hysteresis that other sources or
>procedures are inferior compared with this one. The dimensions of an oven are
>mainly 3 mtr long 1 mtr wide and 1 mtr height. The installed power is then
>about
>14 kVA or as you say 14 kW. The maximum capacity of an oven is about 40 to 50
>pieces of tubing to heat in one time., so all neonshop are using the oven every
>day and are heating up overnight (nite?) when the cost of electricity is halve
>price. Your puming procedure and pumping time is shorter when the glass is oven
>annealed and baked and your manifold will stay cleaner for month. So please
>consider the use of an oven. Your work will be more brighter with a much higher
>light output and stay longer in the right original colour than before.
>Hope that this is enough fuel on the fire, like you asked me,
>is signing with best regards
>dirk a. boonstra.
>
>PS: John if you think that it will be a help for me that you correct my letter
>in proper English, please do. But don't put it on the list, so mail it
>direct to
>my adress.
Dirk, your english is very good. I don't think anyone will have problems
understanding you. Thanks for your very informative note about phosphors,
and for your participation on the list.
-John
______________________________________________________________________________
John Anderson
Mega Volt Neon, Inc. - Austin, TX
dead@netcom.com
Host: Internet Neon Mailing List