Kiln Wash or Kiln Shelf Paper – What’s the Confusion

A Picture of a Cartoon Man Choosing Kiln Wash Over Kiln Shelf Paper

I was sitting with a fellow potter, and we started talking about Kiln Wash and Kiln Shelf Paper and how the words wash and paper sounded like a 1930’s Gangster Movie about Counterfeiting Money.

One of the hardest things to figure out after buying a Kiln is the best way to protect the Kiln Shelves. Should I use Kiln Wash or Kiln Shelf Paper? I have done the research to clear up the confusion and tell you what the differences are and why Kiln Wash is the best method for protecting your Kiln Shelves.

Why Potters Choose Kiln Wash Over Kiln Shelf Paper

Kiln Wash is used for all forms of Pottery making. Kiln Wash is tried and true. It’s the best way to protect your shelves from those nasty meltdowns that glazes love to have.

Kiln Shelf Paper is formulated mainly for fusing glass and overglazes.

What Is Kiln Wash

Kiln Wash is a shelf primer. It is a thin liquid substance that is resistant to extreme heat.
When spread on properly and dried it forms a protectant barrier between your Kiln Shelf and the Dreaded Dripping Glazes that like to fuse to it.

Kiln wash is basically made up of 

  • Kaolin
  • Silica
  • Alumina Hydrate

Other ingredients can also be used in different combinations

  • Flint
  • Calcined Kaolin
  • EPK Kaolin
  • Ball Clay
  • Bentonite
  • Zirconium oxide
  • Zirconium Silicate

You can make your own, or you can buy it premixed.

My Favorite Kiln Wash and a few Others

Mayco Kiln Wash
Mayco Kiln Wash is one of my favorites. It doesn’t clump and brushes on smooth and easy. It is premixed, so you do not have to use a mask. Mayco has a well-balanced formula that does not crack or peel during firing and is ready-to-use.
Mayco Kiln Wash is AP certified (The AP (Approved Product) seal identifies art materials that are safe and that are approved in a toxicological evaluation by a medical expert to contain no elements in sufficient quantities to be toxic or injurious to humans, including children, or to cause acute or chronic health problems.)

Paragon Liquid Kiln Wash
Paragon Liquid Kiln Wash is very convenient. It’s easy to apply and remove. This formula is really nice to work with.

Paragon High Fire Kiln Wash (Mix Your Own)
If you prefer powder form, Paragon High Fire Kiln Wash is available. It has a very long shelf life like it will outlive you. It’s also easy to apply and remove. Just mix with water and brush on the kiln shelves.

Amaco Carton Kiln Wash (Mix Your Own)
Amaco Carton Kiln Wash is a convenient powder mix, just add water and mix well.  It is also AP certified nontoxic but only when wet. Label warning: Be careful not to breathe in power dust.

What Is Kiln Self-Paper

Kiln Shelf-Paper is a  lightweight, heat-resistant ceramic saturated paper. Kiln Shelf Paper can only fire up to 1600 degrees before it starts curling up and burning away. With that said, Kiln Shelf Paper is best suited for very low firing.
Cone 011 – 1582°F (861°C) to cone 022 – 1094°F (590°C)

Kiln Shelf Paper is used mainly  for;

  • Glass Fusing
  • Slumping
  • Overglaze decorations
  • Lusters
  • Burnishing
  • Enamels
  • Decals
  • Decorations

When Firing at high temperatures Kiln Wash is still the best line of defense for your Kiln Shelves from those darn drippy pieces of glazed pottery.

Kiln Wash Safty Tips

If you use Kiln Wash that comes in powder form and you mix your own, it’s suggested to use a mask or respirator while it is still in powder form. Once you’ve added water and mixed your kiln wash to liquid form, you can remove your mask.

You can scrape your old Kiln Wash directly into a garbage can indoors. If possible, it’s best to scrape it off outside. You may want to use a dust mask or a respirator when scrapping. Over time it could affect your lungs.

It’s also smart to wear safety goggles when scraping off the melted glaze. You may think you’re okay, but you never know when a particle would go flying up in the air and hit you right in the eye. You also don’t see the tiny dust particles flying around your head.

Here at Pottery Crafters, we like to practice safety. These are a few items you may consider when doing clean up or preparation.

  • Safety Goggles
  • Respirators
  • Masks
  • Gloves

Making Pottery can be Dusty and Dirty so protecting your Lungs, Eyes and Hands should be something to be thinking about.
Check out a related article, Pottery Clay Dust – How to Minimize it

6 Things To Watch Out For When Using Kiln Wash

  • Proper Application
    Before applying your kiln wash, wipe the kiln shelf with a damp cloth or sponge to remove dust. Kiln wash can be applied with a spray gun, sponge, or brush. Whichever you choose is fine, just make sure you apply a thin and even coat. If you use 2 or three coats, the Kiln Wash should be dry before applying the next layer.
  • Too Thick
    If your Kiln Wash is too thick, it will cause cracking and peeling. It should have the consistency of Whole Milk.
  • Too Thin
    If your Kiln Wash has the consistency of water, it is too thin and will not protect the shelf effectively.
  • Flaking
    If you leave the Kiln Wash on your shelf without checking for cracks or scaping it after each fire, the wash will start to flake.
    If you made a bad batch of Kiln Wash, it might also flake, and you will have to throw it away and make a new batch.
    The flakes will then fly around the kiln and land on your pottery leaving marks. The flakes can also land on your heating elements causing damage if not removed.
  • Wash build up
    If you apply too many coats or reapply new wash without removing the old, the Kiln Wash will start chipping, peeling, and or flaking.
  • Kiln wash placement
    Kiln Wash should only be applied to the top of the kiln shelves. If applied to both sides the Kiln wash could flack off and onto your pottery and leave little marks on your glaze.
    Keep kiln wash away from the heating elements. The ingredients in kiln wash are harmful to the heating elements and can cause them to fail.

Different Types Of Kiln Shelves Require Different Amounts Of Kiln Wash

Not all Kiln Shelves are the same. Your type of Kiln Shelf will determine how much Kiln Wash you will need to apply.

  •  High Alumina Kiln Shelves
    Solid pressed clay with high alumina for stability. These shelves are the most common and least expensive. They are considerably porous; therefore at least two coats of Kiln Wash are highly recommended.
  • Corelite Kiln Shelf
    These are hollowed core clay shelves. Because Corelite Kiln Shelves are also porous and few coats of Kiln Wash is highly recommended for protection and less scraping and chiseling.
  •  Silicon Carbide Kiln Shelves
    A thinner and lighter shelf made from a Nitride-bonded Silicon Carbide. These Kiln Shelves are a bit more pricey and less porous than clay shelves which make glaze clean up earlier. These shelves don’t need Kiln Wash unless your using porcelains you may need a light layer of kiln wash.
  • Advanced Formula Nitride Bonded Silicon Carbide Kiln Shelf
    The lightest and thinnest shelf. These Kiln Shelves are the most expensive. They have a smooth glassy surface resulting in significantly less porosity. Because glaze drippings remove easily, you may only require a thin layer of Kiln Wash if using porcelains or heavy glazing.
    There are a few other ways to protect your Kiln Shelf, see related article; How To Protect Your Kiln Shelf From Melting Glaze

How To Remove Kiln Wash From Shelves

Because it is called Kiln Wash, one would think you could just wash it if off after each firing. That would be wonderful if you could, but no such luck. Any loose kiln wash will have to be scraped off before it starts to flake. That’s why it’s important to scrape your kiln shelf after each firing and reapply any bare spots.

A three or four-inch heavy duty paint scraper works the best. Although a six-inch scraper may seem better because it covers more territory and you think it will take less time. The six-inch scapers tend to be more flexible and don’t get the wash off as easy.

Melting Glaze Removal
If you happen to get glaze on your shelf, it’s essential to get it off before you fire again. The glaze will continue to eat away at your self and subsequently ruining your shelf. You want to be careful not to dig into your Keln Shelf while removing the melted glaze. Digging too hard could damage the shelf. It’s worth taking the extra time to prevent damage.

Properly Disposing Of Kiln Wash

When disposing of your Kiln Wash that has been fired in the kiln, it should be placed in a tightly tied up trash bag and disposed of into your trash can. While the Kiln Wash may not be toxic, the dust particles may still be harmful to your lungs.
Due to Dust and Contamination at some point and time, you may have to dispose of your old unused Liquid Kiln Wash.
We dispose of our unused Liquid Kiln Wash exactly the same way we Dispose of our Glaze’s.
See our related article; Properly Disposing Of And Recycling Glazes

POTTERY CRAFTERS THOUGHTS… Kiln Wash increases the working life of the Kiln Shelves. It is well worth the time and Saves Money in the long run.

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