Problems:
1. Ceramic troughs have corundum growth and poor flow from dross buildup. Also, inclusions in the metal as well as trough life and maintenance are problems.
2. Auto-Pour Ladles are wearing out rapidly. Also, aluminum skin builds up with the traditional coatings, leading to mispours from the shot size being reduced and/or the lip area being obstructed.
3. Permanent molding of complex castings with low-draft, high-drag regions results in poor surface finishes and high scrap rates.
4. Casting tables have refractory deterioration from corundum growth and also have dross buildup
5. Wear (oxidation/erosion at the air-metal interface) occurs with graphite rotors / stators used with degassing units.
6. Metal troughs are rapidly corroding.
7. Ceramic Staulk Tubes have porosity that inhibits their use.
8. Metal Staulk Tubes are rapidly burning through.
9. Hand ladles are "burning up" rapidly.
10. Transition plates for Wagstaff Billet Casters require a smooth, non-wetting coating.
11. Dross sticking to the press hea is interfering with Dross Press operation.
12. The white boron nitride coatings are difficult to distinguish from the ceramic surface.
1. PROBLEM – Ceramic troughs have corundum growth and poor flow from dross buildup. Also, inclusions in the metal as well as trough life and maintenance are problems.
1. SOLUTION – Boron Nitride LUBRICOAT® or Boron Nitride LUBRICOAT-BLUE® offers the very best release / non-stick properties with good adherence and erosion/wear resistance when applied to most ceramic bodies-- extending refractory life 2 to 5 times. These coatings reduce the number of costly rebuilds and downtime, stop the damaging corundum growth, improve metal flow, and virtually eliminate the use of lime, bone ash, red clay mud, ...etc. therefore reducing the risk of inclusions. The removal of the skin or skull is made to be very easy without damaging the ceramic. Additionally, BN LUBRICOAT¨ eliminates the need for trough maintenance after every drop -- thereby saving time and money.
Need for coating maintenance: when sticking of the skin or skull occurs, it is necessary to re-coat/touchup the coatings. With LUBRICOAT-BLUETM, the need for coating maintenance is more easily indicated by the diminishing of the blue color. Also, LUBRICOAT-BLUETM makes spot touch-ups much easier to observe and virtually eliminates over-application of the coating that can cause flaking defects and inclusions.
The lifetime achieved prior to the need for coating maintenance is dependent mainly upon the degree of wear or erosion.
Application and coating maintenance is described in detail in our Painting Instruction Guide: apply like housepaint. Note: do not apply over other types of coatings such as bone ash, red mud, ...etc. without priming the surface with Z-Primercoat [described along with coatings for Wagstaff billet casters]. For brush application, the surface must be below about 170 F to avoid defects.
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2. PROBLEM – Auto-Pour Ladles are wearing out rapidly. Also, aluminum skin builds up with the traditional coatings, leading to mispours from the shot size being reduced and/or the lip area being obstructed.
2. SOLUTION – Boron Nitride LUBRICOAT®¨ or LUBRICOAT-BLUE®is recommended for this use because of the superior Teflon¨-like release properties -- very important for auto-pour ladles. In order to maintain excellent performance, pull the ladle from service when the aluminum skin begins to adhere tightly to the ladle and/or when the blue color of LUBRICOAT-BLUETM begins to fade due to the coating wearing away. Strip the ladle of all old coating and recoat as outlined in the Painting Instruction Guide.
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3. PROBLEM – Permanent molding of complex castings with low-draft, high-drag regions results in poor surface finishes and high scrap rates.
3. SOLUTION – RELEASECOAT or easy-to-use RELEASECOAT-BLUE® provides unsurpassed Teflon¨-like mold release and mirror-like ("COSMETIC") surface finish for permanent mold/low pressure die casting. A thin coating of RELEASECOAT is applied as a topcoating over the usual insulating mold coating and touched-up as needed. It is very important that the RELEASECOAT be applied over the usually used mold insulating coating, since Boron Nitride is a good thermal conductor. RELEASECOAT is typically applied by spraying onto the hot molds without stopping production. To maintain, operators merely have to re-apply by air-spray onto the warm mold a thin layer of RELEASECOAT when sticking / dragging is first observed.
RELEASECOAT-BLUE®can have an advantage because of its easy-to-see blue color that shows up well against most insulating coatings which are white.
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4. PROBLEM – Casting tables have refractory deterioration from corundum growth and also have dross buildup.
4. SOLUTION – BORON NITRIDE LUBRICOAT-BLUE® coating is engineered specifically for casting tables used in Wagstaff Billet Casters. BORON NITRIDE LUBRICOAT-BLUETM is an easy-to-see blue color that provides Teflon¨-like release that is so good that even mispours can easily be lifted out. BORON NITRIDE LUBRICOAT-BLUETM extends refractory life, stops refractory deterioration due to corundum growth and avoids inclusions that are a problem with other coatings such as bone ash. Application and coating maintenance is the same as described for Ceramic Troughs. See our Aluminum Billet Producers (Wagstaff Casters) Data Sheet for more information.
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5. PROBLEM – Wear (oxidation/erosion at the air-metal interface) occurs with graphite rotors / stators used with degassing units.
5. SOLUTION – COVERGUARD and/or MW-50 Paste extends the life of the graphite by 2 to 3 times. Typically, COVERGUARD is applied over the entire graphite surface for both the rotor and stator. At the air-metal interface, MW-50 Paste (a fiber reinforced paste) is built-up as a thick (about 1/4 inch) layer so as to provide longer-life protection. MW-50 Paste can also be used to repair worn shafts and to repair cracks and breaks. In one field test, a shaft that was reduced in diameter by over 50% was repaired to original dimensions and placed back into service. The life of the repaired shaft was 2 1/2 times longer than that normally observed for a new shaft. It should also be noted that fiber-ceramic stator guards can also be protected and their life extended between 2 to 3 times by coating them with COVERGUARD.
One other area should be mentioned – the COMBINATION coating of COVERGUARD as the initial coating for oxidation/wear protection followed by a topcoating of Boron Nitride LUBRICOAT¨ in order to achieve the very best nonwetting surface to the molten aluminum. This dual coating leads to unsurpassed protection against graphite oxidation and also a totally nonstick, nonwetted surface to molten aluminum and drosses. Of course, it is more trouble to apply two coats, so this dual coating will not appeal to everyone.
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6. PROBLEM – Metal troughs are rapidly corroding.
6. SOLUTION – Boron Nitride HARDCOAT® provides superior wear/erosion resistance, protecting the metal trough from burn-through due to metal attack and allowing easy removal of the skin or skull using gloved hands or pliers. The Boron Nitride HARDCOAT is easy to apply by brushing onto metal surfaces and has excellent adherence to metals.
The lifetime achieved prior to the need for re-coating (coating maintenance) is dependent mainly upon the degree of wear and erosion. Typically, 5 to 10 days of operation is observed. The need for maintenance is indicated when skin or skull begins to stick. Quick touch-up maintenance can be performed when needed, usually by air-spraying a light touch-up coat where needed onto the hot trough after removal of any skin or skull. Brush application is also OK, but the trough needs to be below about 170 F for this method. Only rarely is it necessary for the trough to be stripped clean and recoated.
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7. PROBLEM –Ceramic Staulk Tubes have porosity that inhibits their use.
7. SOLUTION – Boron Nitride HARDCOAT® or MW-50 Paste can adequately seal the porosity that exists in ceramic staulk tubes. Which product to use is primarily driven by shop practices. Boron Nitride HARDCOAT is applied to both the inside and outside of staulk tubes using either standard brushing or dipping methods.
MW-50 Paste should only be applied by brushing to the outside of the staulk tubes. Unlike Boron Nitride HARDCOAT, a thick (about 10 mils or more) coating is recommended. Of course, these thick coatings require a longer time to thoroughly dry; and, if not thoroughly dry before use, the coating can flake during use. Many users employ a drying oven.
Performance data suggests that the MW-50 Paste is best at sealing the porosity; but, of course, skin and dross will adhere -- unlike what would be observed with the Boron Nitride HARDCOAT. Some users will top the MW-50 with BN LUBRICOAT¨ (See COMBINATION coating like for COVERGUARD)
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8. PROBLEM –Metal Staulk Tubes are rapidly burning through.
8. SOLUTION – Boron Nitride HARDCOAT (similar to its use with metal troughs) offers superior wear/erosion resistance and adherence and easy brush application to metal surfaces. Boron Nitride HARDCOAT protects the metal from burn-through due to metal attack and allows easy removal of any adhering dross or skin. Staulk tube life is typically doubled, leading to greatly improved cost savings. One firm saves over $400,000 per year by using BN HARDCOAT to protect their staulk tubes.
When coating the metal staulk tubes, it is best to coat both inside and outside. A paint roller or sponge attached to the end of a long pole works well toswab the inside of the tube.
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9. PROBLEM –Hand ladles are "burning up" rapidly.
9. SOLUTION – Boron Nitride HARDCOAT is the product of first choice because of the high wear and abuse experienced with this use. In addition to providing Teflon¨-like release, Boron Nitride HARDCOAT saves money since the coating lasts about 7 times longer than the traditional coatings. Also, BN HARDCOAT is less expensive to use, since the coverage is much better: about 1 gallon of BN HARDCOAT replaces 20 gallons of traditional paints. Also, because of the Teflon¨-like release, dross build-up is eliminated -- allowing for cleaner pours and the elimination of mispours. BN LUBRICOAT® or LUBRICOAT-BLUETM is sometimes used because of the superior Teflon¨-like release properties; but, of course, the coating must be maintained more often. "Burn-through" of hand ladles is a major problem at many shops. This is caused by a break-down of the coating. Ladle life can be extended to years rather than days if proper coating maintenance is performed.
However, few shops will do this maintenance; and their decision not to maintain ladles comes at a cost in lost ladles that far exceeds any cost associated with maintenance. To maintain, pull the ladles from service when dross/skin begins to adhere tightly to the ladle. Strip the ladle of old coating and recoat using standard methods as described in PAINTING INSTRUCTION GUIDE .
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10. PROBLEM –Transition plates for Wagstaff Billet Casters require a smooth, nonwetting coating.
10. SOLUTION – Specifically engineered for use with Wagstaff Billet Casters,
T-Kote is a state-of-the-art, water-based, easy-to-see [aqua-blue color tinted], pre-diluted, ready-to-use coating. After application and drying, this coating is readily polished with a soft cloth or paper to yield an ultra-smooth surface finish.
Also see our Aluminum Billet Producers (Wagstaff Casters) Data Sheet.
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11. PROBLEM –Dross sticking to the press head is interfering with Dross Press operation.
11. SOLUTION – Boron Nitride LUBRICOAT® is an excellent choice to prevent dross/skull from welding to the press head. Boron Nitride LUBRICOAT® provides protection and release for 40 to 50 cycles before re-coating is needed. In field trials, LUBRICOAT¨ provided longer lifetime than any other coating available.
Application to press heads is specific for this application (Dross Press)
1. Clean the press heads of any dross, dirt, ...etc.
2. Preheat the press head (gas burners) to about 400 - 600 F.
3. Air-spray onto the hot press head a coating of LUBRICOAT¨ between 5 to 8 mils in thickness. This is thicker than normal!
4. For maintenance, when dross/skull begins to adhere, any skull and loose coating is removed usually by wire brushing, and fresh coating is applied as in Step 3 above.
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12. The white boron nitride coatings are difficult to distinguish from the ceramic surface.
12. SOLUTION - Our BLUE coatings have become industry standards to solve this problem. ZYP Coatings manufactures several paints using a permanent Blue ceramic colorant (with full stability with molten aluminum and other non-ferrous metals), whereby users can easily visually determine which areas are coated or need re-application for proper maintenance. Select from:
BN Lubricoat-Blue®
BN Releasecoat-Blue®
BN Aerosol Brushable Blue
- not available online
BN Lubricoat-Blue®ZS
BN Lubricoat-Blue®ZV
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