Stewart FURINI

Demonstration of Colouring Techniques
Thu, 15^th May 2025 at MWCC Club Night

Having previously looked on the Club's website, Stewart warned that tonight wasn't just an opportunity to watch paint dry, but rather to demonstrate different ways to colour wood because the Competition for next month was a "Furini inspired coloured" piece.

The wood varieties Stewart tends to use for colouring are Beech, Sycamore and Maple.
In order to allow more time for colouring tonight, he would be working with prepared flat-ended cylindrical blanks of Beech rather than wasting time turning a bowl or platter shape. The procedures would be exactly the same as if he was working on a shaped surface, but this allowed him to create an effect and then start the next by taking a simple straight cut off the decorated surface with a gouge.
The first such blank already had a thread for attaching to his Screw Chuck and had originally been 4" thick.

There are two types of stains; Spirit and Water-based.
 Spirit Stains are alcohol based so will dry very quickly, but the colouring will highlight every bit of torn grain, tool mark and bump left after your turning by accentuating these imperfections because they draw more stain into the grain. Consequently, prior to applying any coloured spirits, it is best to sand the bare surface down to 240 grit.  Any finer and the stain tends to sit on the surface and doesn't penetrate as deep. They are also easy to keep equipment clean using white spirits/meths etc.
 Water-based Stains take considerably longer to dry before additional coats can be applied and even then, the next coat will wet the undercoat and are likely to run into each other with variable intensity. If equipment is not cleaned soon after use, the stain can dry out and be very difficult to shift any clogging.

   Dabbing
The first demonstration used simple tools; preferably paper or else rag and some precautionary preparations as Stewart was going to work with Spirit Stains on his blank mounted on a lathe.
  ♦ Protect the lathe's rails with a nonporous cover (eg shower curtain);
  ♦ Wear eye protection and disposable gloves.

There are several suppliers of Stains but a good starting point is Chestnut Spirit Stains Mixed Pack of Rainbow Colours (about £23 as of May 2025) which includes 9 bright colours of 25ml while the alternative is to buy 250ml bottles of individual colours (about £11 each as of May 2025).

Application is via folded paper kitchen roll while the surface is at rest on the lathe using the following methods :
  ♦ Spot Dabbing - paper is scrunched up into a finger shape before trickling some stain onto it and flat dabbing onto the wood randomly leaving bare areas which were subsequently over-lapped and covered with other colours.
  ♦ Line Dabbing - paper neatly folded into a smaller narrow pad.
  ♦ Rolled-up Tubular End Dabbing - paper is rolled up tightly into a tube shape and its end dipped into a reservoir of stain. This also works well with paint which results in depth and texture.

He started off Spot Dabbing with a pale blue, added a darker blue and a contrasting red to cover the remaining bare wood. Applying the pale blue again enhanced the pale colour and softened the edges of the darker colours giving a sense of depth and movement.  Because these stains are transparent, areas which receive more dabs will build up an intensity of colour.  Stewart would normally apply 10 or more coats of stain, which might sound extravagant but each application uses very little liquid.
The example above right had 5 or 6 applications for each dabbing sample in order to give us an idea of the process; it would look a lot better with twice that number because the coats start to reactivate with each other to draw stain up to a puddle effect with outlined edges, especially if you set the piece flat and allow 30 to 60 minutes between later applications - but that would add another couple of hours to the demonstration!
(click on blue bowl to left for clearer view)
It also helps to frame colouring with crisp edges; for example cut back to wood around the outside/inside or even just with a black painted line. This example has been sealed and lacquered.

Line Dabbing starts off looking very uninspiring but it will transform after patiently building up with colour. The sample above was applied radially but a basket weave effect can result if interspersed with perpendicular dabbing. To add some drama, Stewart sparingly included some black line dabbing.

Tubular End Dabbing builds up a very different pattern and will require Spot dabbing to cover all the bare wood.

Stewart admitted that his usual 'get-out-of-trouble' colours were yellow or black.
 

(click for close up view)

   Airbrushing
Airbrushing is a very creative way of decorating due to so many shape options available but there are additional precautionary preparations to be made.
  ♦ Work space must be well ventilated;
  ♦ A1 standard Vapour Filter Respirator covering face & nose is now essential when using aerosol solvents;
  ♦ An Airbrushing Spray Booth to contain paint being flung off rotating pieces and incorporating a filtered extractor hood to collect overspray;
  ♦ A low noise compressor able to supply 20psi and with an inline moisture collector.
NB Stewart assured us that he took all these precautions within his workshop but as the Respirator precluded any chance of narrating, he considered it would be safe to not wear it because the Hall was many times larger than his workshop and the Spray Booth extractor would be on.

Stewart briefly outlined the many types of airbrush systems and how they worked but it would have taken a whole evening to discuss them all. Suffice to say that he has now invested in 'Gaahleri' individual syphon-fed airbrushes permanently fitted to each coloured stain bottle and with its own quick connect fitting to his airline.

With the lathe spinning at about 200rpm, basic principles of airbrushing is a combination of controlling the distance away from the surface, the thin/thick flow rate of colour coming from the nozzle and the speed of moving the nozzle over the surface.
A light thin spray just 1cm from the surface provides a crisp & controlled coverage with additional coats creating a stronger colour.  Darker shades will require even more thin coats to obtain a uniform colour.  Allowing a thicker spray so close will result in uneven, soft-edged & patchy coverage.
Spraying 10cm from the surface provides a softer gradient from weak to strong coverage of a single colour and useful for providing a smooth transition from one colour to a complimentary other colour.  Several colour mixes result in a muddy combination.

Fortunately, there is a Colour Wheel that can tell you which combinations work well together.
(Click the photo to read the guide instructions)

Stewart mounted a large platter sanded to 240 grit for the demonstration which he planned to hollow out in the middle after decorating.
Before every change of colour sprayed, he aimed the nozzle at the centre to gauge his distance from the surface and the weight of colour were correct for what he wanted to produce next before he would direct it onto the work area.  It was important to keep his nozzle movements smooth to avoid getting blotches of colour along a spray line.

The art of airbrushing shapes is to interrupt the spray pattern by :
   using an edge to create a crisp area of strong colour that fades further away;
or
   around or through bespoke stencils;
or
   using masking tape to change the available work areas.

① Torn Cardboard Template
A long random ragged cardboard edge is moved away from the previous spraying using a different section of edge for the next spray. Remember that more shapes can be obtained by turning the cardboard over, although you will need to wipe the overspray off it's wet side and allow to dry before applying the next spray. Overlapping intensifies colours. Occasional black adds drama. He filled in any gaps with yellow by freehand spray.

② Geometric
A right angle template cut from the edge of some cardboard together with some close nozzle technique created a sharp edged colour which was repeated by moving his template each time the same distance away from the previous spray marks. He then repeated from a different starting point with blue. The weave like pattern was produced by cutting the right angle shape into the cardboard. Because he used purple for this section, the resulting colour that overlapped the previous blue showed up as grey (as predicted from the Colour Wheel)

③ French Curves
Stewart had a Curvature Tool which could be bent into parabolic curves. This effect was created by spraying on the same side of the curve and moving it in random directions allowing the overlaps to create stronger colours.

④ Crackle Stencil
When spraying a long distance away through one of these stencils, the result will be a soft coloured effect and spraying closer will result in crisper edges providing the stencil is prevented from flapping about in the rush of air. Stewart used a Spray Mount (see below with Stencil) to keep stencils tight to the work area and is obligingly removable, particularly when working with this Crackle Stencil. After a going over with black, he sprayed the work area by freehand with his orange and his yellow airbrushes so that it laid a base of one colour gently melding into the other, which faded all the previous black crackle. When dried enough, he could re-stick the Crackle Stencil down and applied some more black spray varying from close to distant spraying. This resulted with sharp black running into fuzzy black giving a sense of depth.

⑤ Pattern Templates
Stewart had templates of solid teardrop shapes and size-matching teardrop holes. The largest example above was first sprayed with yellow/green through the teardrop hole and then with the solid teardrop masking the first spraying, he applied some black spray.  With stains being so transparent, the paler colour always needs some protection to be effective. Yellow/green stain would never have covered over the black yet it is quite impressive when done as above.

⑥ Still Life Stencils
These stencils tend to have spray through areas near the edges so holding them down with masking tape may not be an option. Consequently, using the Spray Mount as before, Stewart stuck this Sunflower Stencil in position so he could use one colour for the petals and a darker colour for the seed head. In his haste to proceed before all the stain had dried, you might notice there is a black blob on the left hand flower at 8 o'clock position where his still wet glove was removing the stencil, which just shows how easily it can happen.

(click for close up view)

   Masking
With a bare Beech platter mounted on the lathe at rest, Stewart wiped on a base colour with a cloth. The audience were asked for suggestions and being awkward, they requested a spiral decoration which was accomplished with the lathe turning slowly and a close pass of the airbrush moving smoothly from outside to centre with a dark blue.
The principle of this 'Layered Colour' effect is that the yellow base and blue spiral will mysteriously appear on the upper surface while the shapes on subsequent layers below will have different colours and shadows giving a 3D impression.

We had voted for a triangular theme.
Having suffered disappointing performance with standard masking tape, Stewart prefers B&Q's Painters Tape (slightly cheaper than Frog Tape). He had various widths to choose from and used his widest to form an oversized triangle first and labelled the ends with a ①.
He then distant sprayed a shadow on both sides of this ribbon.
Next, he made the remaining exposed yellow base colour a little darker with a distant spray of orange.
Another 2 triangles were masked over the top and their ends were all labelled with a ②.
He repeated the process of shadowing and distant spraying of orange on the reduced exposed areas which created an even darker orange background or he could use red spray.
Once all had dried, the tape was carefully removed in reverse order with the help of the numbered ends.

(click for close up view)

A different Masking technique is the Coloured Ribbon effect, which has every strand of ribbon with its own colour/pattern.
One tape at a time was applied across the work area and the edges of just that masking tape alone were shadow airbrushed in with black before the next tape was applied and the procedure repeated.
The sample had been with just 3 tapes to show us the principle.

The colouring trick was to remove the last tape applied (which had been from 12 o'clock to 4 o'clock) and freehand spray between the shadow edges with yellow gradient into orange colours. Any slight overspray into the shadow won't cover over the blackness so should remain unnoticed.
The next last tape (which had been from 1 o'clock to 5 o'clock) was now removed and revealed that the yellow/orange gradient appeared to pass below. This was carefully freehand sprayed between its shadow edges with parallel red & blue/green stripes.
The one remaining tape was then removed and Stewart sprayed on a soft blue/violet between its shadow edges.
Click on the photo for a closer look.
Other options listed above under Airbrushing could have been deployed before removing any of the tapes or even incorporated within the shadow outline.

   Centrifugal Colouring
This type of colouring relies upon paints rather than stains.
Both 'Jo Sonja' & 'Chestnut' are renown for their water based Acrylic Iridescent Starter Sets (Chestnut set of 9 x 30ml about £37 as of May 2025) both of which are particularly eye-catching.

Stewart had prepared a platter treated with Ebonising Lacquer.

With the lathe turning slowly, he used a brush to load yellow iridescent colour in a ring close to the centre and gradually increased the lathe's speed until he could see that some of the paint was nearing the edge (typically 2000rpm) before he stopped the lathe. This resulted in very thin streaks over a wide area - or it should have! Looking at the photo to the right, it is certainly a bit one-sided; this is probably due to the Screw Chuck not holding the piece perfectly square and consequently out of balance.  Regardless, he re-loaded a brush full of blue just inside the ring of yellow, which was still wet and mixed to form a new set of green streaks overlapping. Although the result was asymmetric, he thought it rather pleasing; but that didn't deter him from wiping it all off and preparing for the next sample which was a combination of Dabbing & Centrifugal.

Having returned his work area to the Ebonising Lacquer and with the lathe at rest, Stewart took a large blob of Jo Sonja's Silver on a wad of paper and dabbed it around to the outer edge.
The Centrifugal paints for this project were some Jo Sonja and Windsor & Newton, which are both more expensive than Chestnut but they are so thick that one uses much less because they need thinning with 'Flow Medium' which is a thinning agent better than water because it won't alter the pigment colour and coverage nor reduce the acrylic's adhesive strength. He was seeking runny colours to create a burst of colour.  This was achieved by putting blobs of runny red and gold around the central ring with the lathe at rest and turned the lathe on, quickly increasing speed before stopping when he saw that most had started to streak away from the centre.

Now for a variation on Flat Dabbing.
Using paper rather than risking rag getting caught up in moving parts, you can take a painted decoration like the last sample and before it hardens and with lathe at a slow speed, simply wipe the paint streaks flat from centre to outer edge with yellow paint.
He then did the same with blue paint but starting further out.
It might require some more colour towards the edge, in which case just load the paper directly and start close to the thinned area.
As can be seen in this example to the right, the streaks are still visible beneath the rubbed paint as radial marks.

In general, the order of work for
  Staining is Bare Wood → Stain → Sealer → Lacquer

  Paint is Bare Wood → Sealer → Paint → Lacquer

The final finishing touches after the colouring had fully dried with :
  Staining - was to seal the stains with aerosol Acrylic Sanding Sealer (in order to avoid a cloth disturbing the surface) and then with up to 3 coats of Gloss Acrylic Lacquer. If the lacquer was applied directly to the stain, it will not adhere as strongly as it does to sealer.
  Paint - can be treated with Gloss Acrylic Lacquer directly but it will need to be cut back if applying more than 3 coats.

   Basic Colouring a Textured Surface
Stewart's texturing tool of choice was a Proxxon long-necked mini Angle Grinder.
Safety considerations are pretty well common sense :
  ♦ the OFF switch is easily knocked so check it is off before plugging in;
  ♦ hold it safely in your hand aiming away from everyone when plugging in;
  ♦ held in both hands with the lead out of the way when working on a spinning piece;
  ♦ the cutting edge should touch the wood at its 7 o'clock position so both the blade and the affected wood are moving away from the operator;
  ♦ let the cutters do the work without any force of weight affecting the engine rpm;
  ♦ don't let the tool's cooling holes become blocked or covered up
  ♦ do wear a face shield
  ♦ unplug as soon as you're finished.

Remounting the Dabbing demonstration piece, Stewart started at the centre and worked at a constant and smooth movement towards the outer edge but stopping just before it so as not to damage the rim.  If you changed your pace or angle, you will end up with a hollow.