The ceramic coated Coil.
I have looked thru the very interesting threads "The Pyrex SS hybrid Wick" and "The Next Big thing.... Porous Ceramic Wicks" started by Scubabatdan. Here I'd like to discuss an alternative way to electrically insulate the heating coil from the SS mesh. I personally feel that this is somewhat of a Holy Grail for many average or beginner vapers, and even for experts, who use genesis-style rebuildable atomizers. The idea is to cover the Kanthal coil with a thin insulation layer. It should be noted that as the Kanthal wire (which is an alloy of iron, chromium and aluminum) is heated up at temperature above 1000 C (1830 F), it becomes covered with the aluminum oxide (Al2O3). This alumina layer has good electrical insulating properties but, unfortunately, it is too thin to ensure proper insulation. So, I'll explain how to coat the coil with high temperature insulation ceramics. The first post on this topic can be found here (in Russian):
http://www.e-cigarette-forum.com/fo...077-1079-1080-1089-1099-a-50.html#post8087838
My method of providing an electrically insulating ceramic coating on a wire includes the following stages: annealing the wire to clean the surface of the wire, depositing a thin film layer of ceramic material on the surface of the wire, drying the layer after deposition of the ceramic, and heating for the ceramic layer to form the resulting coating. At the first glance this is a little tricky, but as we'll see this is an easy-to-use approach to solve the problem, rather than a total reinvention of the system.
There are a wide range of ceramic coatings that can be applied to metals in order to make them excellent insulators. I describe below two approach based on (1) high temperature painting and (2) refractory cement:
(1) Very High Temperature (VHT) Flame Proof Paint Coating, an organic solvent-based dispersion, is widely used as a protective paint coating for many applications, where resistance to high temperatures is required. Typically it contains metal oxides (e.g. titanium dioxide, TiO2) and silica and is supposed to withstand heat up to about 1200 C.
(2) Refractory cement (RC) is a compound, odorless, water-based dispersible product. It can be applied as a substitute for fireclay mortars with a higher content of alumina. Any of a variety of mixtures, such as a refractory mixture of alumina-silica and high-alumina opening materials with chemical and ceramic binders, with a refractory range of 1400-1500 C (2600-2800 F), is used in high heat applications, including ovens, fireplaces, kilns and furnaces. When diluted with water, RC can also be used as a protecting coat.
In both cases, the methodology is as follows:
1. Coiling. Measure the length of wire and use a drill to twist the turns of the coil together tightly, making them nice and strong, but so as adjacent turns don't touch. Before coiling, it is useful to anneal the wire using a gas burner. Important: don't use a lighter; it gives carbon black and, as a result, the wire will be dirty.
2. Cleaning. It is important to ensure compatibility between the ceramic material and the Kanthal surface. Therefore you must clean the coil and let no oils/grease from your fingers touch it. To this end, the coil is again annealed. The best way is to plug your coil to a battery, letting the wire to be heated to red. The annealed wire is shown in Figure 1a.
3. Coating. In the case of VHT, dip the coil into a bottle of paint and dry for 5 minutes. This can be repeated several times until the desired coating is achieved. Then clamp the coil to the contacts of your atomizer. Note that there is good adhesion of VHT to the metal so that the coating does not separate when bent or otherwise disturbed. If you are using RC, first add water to the cement paste and mix with a trowel until it has reached the consistency of tomato juice or peanut butter. Then attach the coil to the contacts and deposit liberally the cement on the inner surface of the coil turns with a thin trowel, needle or toothpick, making a circular motion. With enough working, you can actually make a smooth surface to the cement.
4. Drying. VHT coatings will air dry in 15 to 20 minutes and if handled with reasonable care, may be put to immediate use (Figure 1b). When exposed to air, RC also quickly hardens. Due to the presence of chemical bond, high strength is obtained immediately after drying at normal temperatures. Because the loss of water, drying causes an increase in porosity.
5. Curing. To ensure maximum resistance and completely remove all volative compounds, the ceramic coated wires are heated several times to red hot temperatures of about 600-800 C in 10 to 15 seconds (Figure 1c and 2a). To do this, simply press the button of your BB.
6. Assembling. Insert a wick into the ceramic coated coil and align the turns. The heater is now ready for use (see Figure 2b). In principle, there is no need to oxidize the wick.
Figure 1. (a) Annealed Kanthal wire (0.2 mm). (b) VHT coated wire. (c) VHT coated wire after curing.
Figure 2. (a) RC-coated Kanthal wire after curing. (b) Ceramic coated coil.
The VHT paint comes in a spray can. To use it, direct the spray jet into a glass and then pour the paint into a small vial with sealed cap. I used the VHT SP-118 paint that contains titanium dioxide and silica. The refractory cement is supplied as a paste ready for immediate use. Available ready mixed in small tubs.
I have looked thru the very interesting threads "The Pyrex SS hybrid Wick" and "The Next Big thing.... Porous Ceramic Wicks" started by Scubabatdan. Here I'd like to discuss an alternative way to electrically insulate the heating coil from the SS mesh. I personally feel that this is somewhat of a Holy Grail for many average or beginner vapers, and even for experts, who use genesis-style rebuildable atomizers. The idea is to cover the Kanthal coil with a thin insulation layer. It should be noted that as the Kanthal wire (which is an alloy of iron, chromium and aluminum) is heated up at temperature above 1000 C (1830 F), it becomes covered with the aluminum oxide (Al2O3). This alumina layer has good electrical insulating properties but, unfortunately, it is too thin to ensure proper insulation. So, I'll explain how to coat the coil with high temperature insulation ceramics. The first post on this topic can be found here (in Russian):
http://www.e-cigarette-forum.com/fo...077-1079-1080-1089-1099-a-50.html#post8087838
My method of providing an electrically insulating ceramic coating on a wire includes the following stages: annealing the wire to clean the surface of the wire, depositing a thin film layer of ceramic material on the surface of the wire, drying the layer after deposition of the ceramic, and heating for the ceramic layer to form the resulting coating. At the first glance this is a little tricky, but as we'll see this is an easy-to-use approach to solve the problem, rather than a total reinvention of the system.
There are a wide range of ceramic coatings that can be applied to metals in order to make them excellent insulators. I describe below two approach based on (1) high temperature painting and (2) refractory cement:
(1) Very High Temperature (VHT) Flame Proof Paint Coating, an organic solvent-based dispersion, is widely used as a protective paint coating for many applications, where resistance to high temperatures is required. Typically it contains metal oxides (e.g. titanium dioxide, TiO2) and silica and is supposed to withstand heat up to about 1200 C.
(2) Refractory cement (RC) is a compound, odorless, water-based dispersible product. It can be applied as a substitute for fireclay mortars with a higher content of alumina. Any of a variety of mixtures, such as a refractory mixture of alumina-silica and high-alumina opening materials with chemical and ceramic binders, with a refractory range of 1400-1500 C (2600-2800 F), is used in high heat applications, including ovens, fireplaces, kilns and furnaces. When diluted with water, RC can also be used as a protecting coat.
In both cases, the methodology is as follows:
1. Coiling. Measure the length of wire and use a drill to twist the turns of the coil together tightly, making them nice and strong, but so as adjacent turns don't touch. Before coiling, it is useful to anneal the wire using a gas burner. Important: don't use a lighter; it gives carbon black and, as a result, the wire will be dirty.
2. Cleaning. It is important to ensure compatibility between the ceramic material and the Kanthal surface. Therefore you must clean the coil and let no oils/grease from your fingers touch it. To this end, the coil is again annealed. The best way is to plug your coil to a battery, letting the wire to be heated to red. The annealed wire is shown in Figure 1a.
3. Coating. In the case of VHT, dip the coil into a bottle of paint and dry for 5 minutes. This can be repeated several times until the desired coating is achieved. Then clamp the coil to the contacts of your atomizer. Note that there is good adhesion of VHT to the metal so that the coating does not separate when bent or otherwise disturbed. If you are using RC, first add water to the cement paste and mix with a trowel until it has reached the consistency of tomato juice or peanut butter. Then attach the coil to the contacts and deposit liberally the cement on the inner surface of the coil turns with a thin trowel, needle or toothpick, making a circular motion. With enough working, you can actually make a smooth surface to the cement.
4. Drying. VHT coatings will air dry in 15 to 20 minutes and if handled with reasonable care, may be put to immediate use (Figure 1b). When exposed to air, RC also quickly hardens. Due to the presence of chemical bond, high strength is obtained immediately after drying at normal temperatures. Because the loss of water, drying causes an increase in porosity.
5. Curing. To ensure maximum resistance and completely remove all volative compounds, the ceramic coated wires are heated several times to red hot temperatures of about 600-800 C in 10 to 15 seconds (Figure 1c and 2a). To do this, simply press the button of your BB.
6. Assembling. Insert a wick into the ceramic coated coil and align the turns. The heater is now ready for use (see Figure 2b). In principle, there is no need to oxidize the wick.
Figure 1. (a) Annealed Kanthal wire (0.2 mm). (b) VHT coated wire. (c) VHT coated wire after curing.
Figure 2. (a) RC-coated Kanthal wire after curing. (b) Ceramic coated coil.
The VHT paint comes in a spray can. To use it, direct the spray jet into a glass and then pour the paint into a small vial with sealed cap. I used the VHT SP-118 paint that contains titanium dioxide and silica. The refractory cement is supplied as a paste ready for immediate use. Available ready mixed in small tubs.
A Merry Christmas to ALL!!!!
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