We are able to offer a superb baked enamel on our Cast Alloy bathtubs. The name Slow Baked refers to a process baked slower at a much lower temperature (around 400-425F) than traditional Vitreous enamels, it is Baked rather than Fired. We use a high solid dry powder style process similar to the origins of enameling (that is virtually chemical free) rather than the modern wet system which produces a thinner coating and contain more harmful chemicals.
We have already discussed the ‘Prep’ to get the tub ready for Enamel so we start below from where we left off...
The sanded and smoothed tub takes a long hot bake. This serves two purposes, it heat treats the alloy which increases its strength and durability and it anneals the casting.
Once fully annealed to remove any impurities the first Ground Coat Powder can be applied, it is baked to thermally fuse the metal and Ground Coat. Next a second Ground Coat is applied and baked.
Once cooled the Ground Coat is sanded smooth preparing the surface for the next step. Sanding will smooth the underlying coat but also promotes mechanical in addition to chemical, thermal and molecular bonding. We then apply two coats of Porcelaine White, again in a powder form, which are slow baked to melt the powder and allow bonding and flow for a smooth glass like appearance
Next comes two coats of a high gloss clear. The tub is then Slow Baked one last time until the tub interior is hard, bonded and glass-like. This process allows for a thicker, tougher coating which has the appearance of Porcelain. For a final step, because we want each tub to be as beautiful as it can be we gently hand sand the surface with an ultra fine sandpaper. The Enamel is then compounded, polished and glazed before being ultra glossed (hand rubbed) to achieve a truly glass like finish. All in all its take just over a week of solid work usually over the course of 2-3 weeks to get the interior to the completion.
Slow Baked Enamel Facts & Specifications
- Color Permanence - A permanent lifetime finish is provided through SB & V enamel.
- Gloss - SB & V enamel offers a high gloss finish but not Ultra Gloss. Depth of the gloss is from within not a surface reflective finish (like acrylic).
- Finish - SB & V offer a smooth finish. The look achieved is smoother than traditional antique enameling, but it contour to the casting to produce a more original look and feel whilst allowing the original character to show.
- Cleanability - Smooth and Glassy SB & V enamel is easy to clean, usually only a mild detergent and mild rubbing. The high solid surface is a barrier against odor and bacteria. As with all enamel surfaces scouring agents are not recommended.
- Thermal Properties - Abrupt and severe temperature changes do not affect SB enamel. SB enamel has high elastic properties, these were designed to flex with the casting in expansion and contraction. V enamel coated iron (applied at correct thickness) will also flex with the metal providing resistance to mild stresses or expansion and contraction.
- Acid resistance - SB & V enamel offers excellent corrosion protection against mild aqueous solutions of alkalis, salts and most acids.
- General chemical resistance - SB enamel is formulated to resist the chemical reactions which may occur during normal use. It is resistant to mild chemical reactions. V enamel contains relatively inert inorganic oxides to provide an impervious surface that is highly resistant to most chemicals.
- Hardness, Abrasion & Wear Resistance - SB & V enamel show excellent wear resistance and frequently provide better wear and abrasion resistance than metals. V enamel has a hardness ranges from 3-6 on the Mohs scale of mineral hardness, and is comparable to plate glass. SB ranges from 3-4 on the Mohs scale. Both out performs normal Poly & Acrylic Urethanes in abrasion tests.
- Adhesion - Adhesion is increased ten fold due to the use of a sophisticated Ground Coat, the baking process creates what is known as Fusion Flow; a thermal, mechanical, physical and chemical bond to the underlying substrate. Neither will flake away from exposed edges or damaged areas. Rust however can become a factor over exposed iron substrates. In Adhesion and submersible tests our both SB & V enamel out performs normal Poly & Acrylic Urethanes.
- Impact Resistance - SB enamel has a high solid content which creates a much stronger and more durable surface. V enamel will usually not fracture due to impact unless the base metal is permanently deformed. SB enamel in minor impacts due to its elasticity it can deform with the base metal rather than fracture. Both out perform normal Poly & Acrylic Urethanes in all impact tests.
- Thermal conductivity - SB & V enamel are not a thermal insulator, but are a relatively good heat conductor when applied to our metal bathtubs. The Alloy itself is the main factor and unlike Iron which pulls heat from the water, the Alloy does not.