Lower fired pieces can be repaired and a second a second time
Gloss glazes will give a high sheen and Matte glazes with give a satin sheen.
Metallics are intended to go over a fired glazed item, but may also be used on prepared, fired porcelain bisque. The final results will have a matte, antique, burnished look.
Cleanliness is vital. Clean the item with acetone, using a soft, lint-free cloth. Take care not touch it and leave finger prints. Do not get it on your fingers as it will leave traces on your item even if you have cleaned your hands.
Use a small, dry, clean soft bristled brush, have one brush per lustre. Remnants of other chemicals will cause contamination.
DO NOT shake or stir the metallic.
Applying too little is better than applying too much. A thin application can be easily fixed with a second application if the first firing was at cone 022, but it is not easy to fix a heavy application or if the firing was at cone 018.
Test firing a small piece is recommended to ensure your technique is correct.
Allow gold to dry for 24 hours, fire it to cone 018 (unless manufacturer recommends a different temperature). If you want to be extra cautious and want to see if there are any repairable errors, you can soft fire your piece to cone 022. This will reveal the gold, but it will be soft and it can be wiped off. You can repair thin spots by painting on another thin coat of gold as well as remove errors more easily with a gold eraser.
This soft firing can also create a unique effect in that you can cover a detailed area with gold, soft fire it and then scrub off the gold from the high points giving an ‘antiqued’ appearance. After you check your item and are satisfied with the application, you will then want to re-fire it to a hotter temperature/cone to permanently affix the gold.
Purple colouration instead of gold indicates the gold is too thin. Fix by removing unwanted purple or applying another thin coat of gold.
Drips, cracks or crazing in the gold – gold has been applied too heavily. These things are easily repaired if fired to cone 018. The over application is not as easy to repair when fired to 022.
Clean your brush with gold essence or mineral spirits and mark it in a manner that will prevent it from being used for any other purpose. If you clean brushes by swishing them in the bottle of essence, do not use the same essence for other over glazes. Contamination will result and compromise future applications and firings.
Do not fire gold/metallics in the same kiln as lustres. Fire the gold first and then the lustre next - usually one cone cooler (cone 020 or per instructions on your lustre)
Metallics and Lustres create fumes during the firing process which conflict and contaminate each other. After their first firing, there are no further issues with contamination.