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Sealant

We use sealant in two ways:

  • To make work waterproof. When the vase is glazed from the inside: treat it 1 time. When the vase is not glazed: treat it two times. Put the liquid in and immediately pour it out, then let it dry in chamber temperature for a few days and then treat it once again.
  • To apply polish to a work, for instance with pit-fire or primitively fired work. Apply a minute amount of sealant on a clean sponge, brush past your work and you will have polished it. Dilute the sealant with water, half water and half sealant for a more satin-like effect

Attention: Sealant is non-toxic, but may not be used in items that will hold food. The layer will come off when the work is washed with water hotter than 60 degrees.  Immediately wash your hands with water when you get sealant on your hands, for if you don’t you will get a plastic coat on your skin that is hard to remove. Preserve the sealant in a place that is free of frost. Even after use the possibility remains that a plastic layer will come loose when left outside in the frost.

 

 Terra sigillata

Read page 217 and other pages of our book Rakuvaria 2 for more information about terra sigillata. We have added  peptapon to the colour stains of the terra sigillata, this keeps the stains from sinking to the bottom. 

Tip: Terra sigillata can be added to unfired work as well as to bicque baked work. However, the chance of  peeling is higher with bicque baked work.

  

Peptapon

We mainly use peptapon for glazing, prepared with frit, usually 3 grams per 1 kilogram of raw material. For copper mat glaze we use 10 grams of peptapon per 1 kilogram of raw material.  

Thanks to peptapon the glaze does not settles or less. The glaze is easier to brush on and a glazed object will not be damaged when you pick it up.

Attention:

  • You will need no peptapon for glaze made of gerstley borate, because this glaze already attaches itself perfectly.
  • The qualities of peptapon may be lost when the glaze has been left in a liquid state for over half a year. In this case you will have to add peptapon to the glaze again.

  Dolaflux

Dolaflux is actually used as a tool to make casting slip. We use it to make terra sigillata. (more info in our book Rakuvaria 2, on page 217 and others.)

  • Making Terra sigillata: make the clay liquid first, then add dolaflux.
  • Making casting slip: dissolve dolaflux in water, then add the casting slip.

 

Temperature gauge

Complete temperature gauge up to 1200ºC. Including a thermocouple and battery. 2 year warranty. 

 

Turquoise/red

This glaze gives off many variations, 950 °C - 1000 °C.

You can create many colours with this glaze.

  • If you want turquoise as outcome: take the work out of the hot kiln and leave it to cool for a long time, then place the work on sawdust and don’t put any sawdust on the glaze.
  • If you want a coppery outcome: take the work out of the hot kiln and cool it for a short time, then place the work on sawdust and throw lots of sawdust on it.

Attention: it happens a lot that when you place your work in the sawdust too soon, the outcome will have raw glaze marks. The strong cooling transforms the liquid treacly glaze into a hard glassy layer. The sawdust will bite itself in the tough glaze when work is placed in the reduction barrel too soon. Raw spots will mostly be found in places where glaze comes into contact with sawdust.

 

Blue/lilac/copper

This glaze gives off many variations, 950 °C - 1000 °C.

  • If you want blue as outcome: take the work out of the hot kiln and leave it to cool for a long time, then place the work on sawdust and don’t put any sawdust on the glaze.
  • If you want a lilac, purple, coppery outcome: take the work out of the hot kiln and cool it for a short time, then place the work on sawdust and throw lots of sawdust on it.

Attention: it happens a lot that when you place your work in the sawdust too soon, the outcome will have raw glaze marks. The strong cooling transforms the liquid treacly glaze into a hard glassy layer. The sawdust will bite itself in the tough glaze when work is placed in the reduction barrel too soon. Raw spots will mostly be found in places where glaze comes into contact with sawdust.

 

Thermocouple, Ni-Cr-Ni 

The cheapest way in temperature measurement is: attach a thermocouple to a simple multimeter and measure the temperature in Milivolt. 1 Mv = 25 degrees. Most multimeters do not directly show the temperature in degrees Celcius, yet our multimeters do.

 

Raku-tongs

Our raku-tongs are really light and easy to use, because we make them out of heater tubes. They are flexible and will therefore not easily crush work. We pull most work out of the kiln with the small raku-tongs, which is only 67 cm long and weighs merely 500 gram.  We use tongs with two rings especially for sphere-shaped work  that is hard to grab.

 

Prop 

We saw the props from kiln brick JM26. These provide more stability compared to normal props. 

Tip 1: You can easily saw kiln bricks for yourself by means of an old handsaw which has become too blunt to saw wood.

Tip 2: We use the props in 4 ways when stoking raku:

  • As props
  • To create an expansion in height, which enables you to put in more work in the kiln.
  • We throw in a hot block when not enough mass ceramic is in the sawdust cask.
  • To avoid smoke nuisance. when your work is still on the ground awaiting its temperature shock, throw a hot prop, that comes straight out of the kiln, into the sawdust. The dry sawdust will now flame and not smoke.

 

Burner set

We have been working for decades with one type of burner with a capacity of 15 Kw. This burner can sufficiently heat an kiln made out of a large oil drum + props with a 150 litre capacity.

Benefits of this burner are:

  • Compared to a burner used by roof tilers this burner does not make much noise. 
  • This burner can also heat an kiln with a content of only 20 litres.

Caution: The ceramic burner head is sensitive to fracture! It will not break from heating, but from dropping it or bumping into it when it is hot. The burner head  has got a screw-thread built in which makes it easy to replace. You can keep heating when you see a fracture on the burner head. Yet, stop heating when a part of the burner head falls of. 

 

Insulating bricks JM 26

These insulating bricks are highly suitable for building a raku kiln. We also saw kiln supports out of these stones. Type 26 means that the brick can withstand a maximum temperature of 2600 ºF = 1425ºC. You can easily saw the bricks by means of an old saw or a jigsaw More information about how to build a raku kiln out of bricks features on DVD1 Rakuvaria.

 

Liquid glaze

All the liquid glaze that we sell is made with glaze G1 as a basis (G1 = 50 % gerstley borate and 50 % nepheline syenite) The advantage is that this glaze never goes bad. When using the glaze after, for instance half a year it is wise to first filter the glaze before usage. 

So, why didn’t we follow the basic recipe with with Alkalifrit (G3 recipe in Rakuvaria book 2 chapter 13)?

  • Because liquid glaze with a basis of Alkalifrit can get solid during transport. 
  • The reason for using Alkalifrit in our book is mainly due to its availability in the whole of Europe. We had rather used gerstley borate for all our experiments in chapter 13 of our book, yet this raw material is unknown in many European countries. (Rakuvaria2 is published in 4 languages).

There is a big difference in end result when using gerstley borate instead of Alkalifrit, the difference is:

  • You will get turquoise or copper when you add copper oxide to the Alkalifrit.
  • You will get green to copper when you add coper oxide to gerstley borate.
  • You could for example compare recipe G30 with G56 in chapter 13 of our book!

Attention: Don’t fire work with a coloured glaze too quickly. It often happens the colour disappears completely or slightly when firing too hard. A yellow glaze can for instance become white as an endresult.

 

Ceramic knots

Tool for attaching the insulating blanket to the raku-cask. With ceramic knots we apply the insulating blanket to the metal wall and cover of the cask. The knots are made of light ground clay and bisque baked on 900º.

 

Crocodile skin glaze

This technique is explained by Stefan Jakob (Zürich) on DVD1 Rakuvaria.

This technique in short:

  • Glaze is made quite thick, like pancake pastry.
  • A thick glaze layer of 3 to 5 mm is applied.
  • Work in wet condition is placed in a 150 degrees kiln.
  • By means of quick drying the glaze is already crazing.
  • Fire up to 900 to 950 degrees, depending on the expected result.
  • Then put it in sawdust, like with raku.

With this technique the crazing happens inside the kiln and not while taking it out at highest temperature.

  • A rectangular result occurs when fired at 910 ºC
  • The glaze will spread more roundly when fired at 950 ºC.

 

Naked Raku

You work with 2 layers when using naked raku:

  • Layer 1: quartz / kaolin layer
  • Layer 2: a layer of glaze

The tric is that the glaze (layer 2) cannot attach to the clay, because layer 1 is in between.

Tip: For layer 2 we often use recipe G1, (gerstley borate 50 / nepheline syenite 50) The naked raku-glaze layer, which we also sell, see page 170 of Rakuvaria 2, gives slightly different results as opposed to recipe G1. Make sure that you liquidise as much as you think you will need, for this glaze in liquid form will start to crystallise after a week. 

 

Copper mat glaze

Complete, 1000°C. Mentioned as G60 in our book "Rakuvaria2" This is a ready-to-use powder for the copper mat technique, all you need to do is add 1 litre of water and sieve it. Avoid glaze contact with the skin and dust, do not inhale fumes.

Tip: The copper mat glaze is well applied on your work hen you can see the clay through the glazing. Therefore you should apply it thinly, thinner than with normal glaze.

 

From our shop

Rakuvaria 3 (Dutch)

Rakuvaria 3 (Dutch)

Rakuvaria 3! (Dutch) Attention! Rakuvaria 2 is the basis, Rakuvaria 3 describes new techniques! In Rakuvaria 3 many unusual techniques and experiments are again explained step by step. In 13 chapters are described various smoking techniques with the help of, for example, milk, flour and plant extracts, crocodile glaze and many variations thereof, 70 new glaze recipes, ways to save on energy during raku firings and various unusual firing techniques. It is also to be noted that most subjects are explained using homemade YouTube movies. 2014, format 17 cm x 24.5 cm, hard cover, 192 pages, 9 graphs and 384 colour photographs. Shipping costs + €5 are charged for shipment within EU countries. Rakuvaria 2 = no blah blah, but AHA! Rakuvaria 3 = much more AHA!!!

Rakuvaria 2, German

Rakuvaria 2, German

Rakuvaria 2, German.

A publication by Ine and Ed Knops

The most complete and concrete Rakubook.

Over 300 pages, 34 chapters, step-by-step descriptions clarified by use of 470 pictures in colour of e.g.

Raku, Naked-raku, Copper matt, Terra sigillata, Sagger firing, smoking-techniques, stoking Raku in a 
microwave, sawdust oven, Pit-fire, Aluminium foil technique, charcoal oven, glaze recipes, Raku oven 
building, stoking Raku without smoke nuisance, etc.

A complete full-colour hardcover book printed on firm paper.

Price € 57

Shipping costs of + € 5 are charged for shipment within EU countries.               

First published in March 2003

Rakuvaria 2 has also been published in French, German and Dutch.

This book can be directly ordered on this website.

Rakuvaria 2, Dutch

Rakuvaria 2, Dutch

Rakuvaria 2, Dutch.

A publication by Ine and Ed Knops

The most complete and concrete Rakubook.

Over 300 pages, 34 chapters, step-by-step descriptions clarified by use of 470 pictures in colour of e.g.:
- Raku
- Naked-raku
- Copper matt
- Terra sigillata
- Sagger firing
- Smoking-techniques
- Stoking Raku in a microwave
- Sawdust oven
- Pit-fire
- Aluminium foil technique
- Charcoal oven
- Glaze recipes
- Raku oven building
- Stoking Raku without smoke nuisance
- Etc.

A complete full-colour hardcover book printed on firm paper.

Price € 57,-

Shipping costs of + € 5 are charged for shipment within EU countries.               

First published in March 2003

Rakuvaria 2 has also been published in French, German and Dutch.

This book can be directly ordered on this website.