Chlorine test: Difference between revisions

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Chlorine test (view source)

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→‎Procedure

Corbin.uhl

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 [[Laser Cutter|Back to Laser Cutter]]
-==In Brief==
+==Intro==
-The laser can successfully cut many materials that are damaging to the laser when cut. Do not think that just because the laser can cut it, it is acceptable to do so.
+The laser can successfully cut many materials that it shouldn't.
+In particular, materials containing chlorine (like PVC) release vapor that will corrode the laser's parts and also your lungs.
-In particular '''chlorinated''' materials create fumes which destroy laser components, primarily the optics. These are very expensive to replace. '''All unknown or unproven materials must have a sample tested for chlorine prior to cutting them in the laser'''.
+A simple test can determine if a material contains chlorine.
-Burn copper wire with a torch until green flame stops. Continue heating copper wire red hot. Jab still-hot copper wire into sample piece away from flame (below flame works best). If green smoke or flame ensues, there is chlorine in the piece and it cannot be used inside the laser cutter.
+==Procedure==
+Do this outdoors or under the welding hood when possible.
+You will need:
+* Thick copper wire (A tube of these is in the Trotec PC drawer)
+* Pliers
+* Propane torch (Usually found in the welding area)
+* A small sample of your material
+. Use a pair of pliers to hold the end of the wire in the flame for a few seconds
+. Stab the still-hot wire into a sample of your test material - try to get a decent amount of it melted on there
+. Put the wire back in the flame
+* If the flame turns emerald green, chlorine is present in the material and it must not be used in the laser cutter.
+* If the flame remains blue or orange your sample does not have (much) chlorine.
+This does NOT automatically mean that it is safe in the laser.
+With any new material, proceed with caution and watch carefully for fire, thick smoke, or sputtering.
 ==Known Materials==
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 * Acrylic plastic, clear or colored
 * Wood & wood veneers
-* Laserable Rubber (Jeremie)
+* MDF
-* (Incomplete List)
+* Cardboard
+* Leather
+* Fibreglass cloth (no resin)
+* Glass (etching only)
 Unacceptable:
 * PVC plastic. PVC = "'''P'''oly'''V'''inyl '''C'''hloride". The "chloride" means it has chlorine.
-* Speedball Speed-Cut Easy (blue). (Jeremie)
+* Sintra
+* Composites (fibreglass, carbon fibre)
 * (Incomplete List)
-==Introduction==
+==Trivia==
 The Beilstein Test: Screening Organic and Polymeric Materials for the Presence of Chlorine, with Examples of Products Tested
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 The test is based on the reaction of chlorine with copper compounds at the high temperatures found in burner flames. These conditions produce excited, green-coloured copper atoms or ions that cause the normally colourless (or very slightly blue) flame to flare brilliant green (or sometimes blue-green).
-==Procedure==
-Use a copper wire thick enough not to melt too quickly (e.g., I2- or 14-gauge copper wire, stripped of its insulation, that is used for wiring houses). Heat the copper wire to glowing red in the flame of a Bunsen burner or propane torch.
-Continue heating until no colour (other than the nearly invisible, slightly blue torch flame) is visible. There should be no green colour in the flame. Wash the wire intermittently with water and dilute nitric acid (10%) to remove materials that cause unwanted colouration. If washing fails, try a new wire. Once it is clean, take care to avoid touching the wire with fingers or objects other than the test material. When the flame is colourless, the test can proceed.
-The test is best carried out in subdued lighting so that the colour of the flame can be seen easily. Vapours, fumes, or smoke from the sample must envelop the hot copper wire in the flame so that reactions between the tested material and the hot copper can occur. This can be accomplished in several ways:
-# Heat the wire to red-hot, then quickly touch a fragment of the sample to it and immediately return the wire to the flame. A plume of green is a positive test for the presence of chlorine. Do not touch the entire sample with the hot wire. Some plastics (e.g., cellulose nitrate, Celluloid) may burst into flame. (This reaction is usually considered a positive test for cellulose nitrate.)
-# With the wire red-hot and still at the edge of the flame, bring a fragment of the sample near the flame in the vicinity of the wire until the fragment chars and the smoke produced envelops the wire. A green flame is a positive test for the presence of chlorine.
-# With the red-hot wire in the flame, place a fragment of the sample near or into the flame until it starts to char. Quickly move the smoking sample to the air intake at the base of the burner so that the smoke is drawn in with air and is intimately mixed with the flame gases. A green flame surrounding the copper wire is a positive test for chlorine.
-# Heat the wire to red-hot. Then immediately touch the wire with a piece of the sample held beside the air intake at the base of the burner or torch, so that some of the fumes produced are drawn into the flame. A green flame is a positive test for chlorine.
-The fourth method described is the most sensitive. It is also the best method to detect the presence of a volatile chlorinated material — perhaps a solvent such as methylene chloride.
-==Discussion==
 The Beilstein Test has been used for many decades to analyze organic and polymeric materials (Shriner et a1. 1964; Vogel 1966). A very similar test is now used by refrigeration technicians to detect and localize leaks of freon-type refrigerants (i.e., chlorinated and fluorinated hydrocarbons). This test has also been recommended for detecting PVC coin storage products (Sharpless 1980).