The cosy library set featured in the previous post included a fully ‘working’ fireplace. Any ‘flames’ needed were to be added in post-production using CGI so I didn’t have to worry about those. But my brief was to make the physical prop work .. that is ‘light up’ .. to an extent, at least incorporating a suggestion of glowing embers. At the time of making it was not yet clear whether the ‘coals and logs’ part would be seen in different states i.e. from fully stocked to nearly spent, so my thinking was that this part needed to be made as a separate and interchangeable shell .. a translucent one .. independent from the source of light. In any case, I didn’t want to mess with integrated electrics since they’re almost always a bit cursed, in my experience. So I decided to make the fireplace setup open at the back so that it could be lit from behind as simply as possible. Below is the only photo I managed at the time of the fire lit up, a quick test in daylight before the surfaces were fully painted and accessorized ..
I designed the ‘coals and logs’ unit to sit within an ornamented grate which hid its edges and also masked spillage from the light source behind. This meant that it would be easy and quick to substitute different stages of the fire modelled on the same base-shape.
I chose to make the base shape in Kapa-line foam, probably because this was easiest .. but Super Sculpey doesn’t readily stick to much, especially foam, and to have any control over the modelling a firm base layer is essential. So I started by massaging small portions of Sculpey to become almost paste-like and working them into the surface. Once this was covered the resistant, wax-like qualities of Sculpey could be fully exploited .. I much prefer to model by pushing/impressing, kneading and displacing, hardly ever cutting or scooping out, and a whole variety of weird impression tools will often do much of the job for me. I had a bag of strange, impossibly hard and oversized ‘croutons’ I’d found in a Chinese supermarket and I didn’t have to do much with these to create an interesting textural starting point. When it came to the ‘logs’ or chunks of coal I used a custom impression tool I’d made for tree-bark .. Sculpey modelled and baked over an old scalpel handle .. using it in a partly random way, just to create some spontaneous interest.
But the whole looked dull, deliberate and lifeless, until I attacked the surface with brushes! The most successful was the black plastic one, like a large and sinister toothbrush, which accompanies wire brushes usually in packs of three .. I’d never found a good use for these plastic ones before, and none other since really! Once the Sculpey work was finished I made a standard mould from it comprising a silicone ‘skin’ part supported by a plaster jacket. This is common practice, even though it takes a little longer to complete than just pouring a block of silicone, because it cuts the amount of silicone rubber used to easily under a quarter.
I had two options for casting the hollow, translucent shell .. using either clear epoxy or polyester resin. But epoxy resin can only be made thixotropic (converted from a liquid to a spreadable gel or paste) by adding a filler powder such as fumed silica. Dependant on the amount of powder needed, the epoxy resin could lose much of its transparency, whereas clear polyester resin can be thickened using a specially thickened gelcoat additive which is almost as clear. I needed to mix the clear polyester, gelcoat and shared catalyst together first before tipping the mixture into the mould. I had to wait about 15mins before the mix firmed up enough to be ‘shaped’ into a relatively even shell, using a chopstick as a spatula, but the window closed fairly quickly after that.
I’ve said ‘clear polyester’ but in actual fact it was the ‘general purpose’ or GP polyester resin from Tiranti, not the ‘Clear Casting’. I’ve always used Tiranti polyesters (whether general purpose, ‘multi purpose’, ‘clear casting’, gelcoat or thixotropic paste) partly because I’ve never had any major problems with any of them. They’ve also lasted far longer than any others I’ve bought .. for example, I used the same can of GP polyester on-and-off for over five years! Tiranti’s GP cures a warm grey/beige which can be seen from the following photos, but this was fine for my purpose, and the cloudiness (compared to Clear Casting) was also something which I’d hoped would diffuse the light for a better effect.
I removed the cured polyester shell from the mould the next day, and designed/made the ‘stool grate’ (that’s the proper term) around it using Palight foamed PVC. The photo below shows this primed in Humbrol matt black enamel (not yet given its metallic gilding), set up against the fireback and the hole cut to let the light through. There were restrictions to the depth that the fireplace unit could be, and I could have solved this with much more blackening or shading around the stool grate .. a shame, but there was no time left. What did work nicely were the strips of vinyl wallpaper I used to suggest the fireback stonework, washed and sponged with acrylic.
To give the rich ember colour when lit, I had thought of coating the underside of the polyester shell with red/orange/yellow glass paints (i.e. Marabu GlasART or Pebeo Vitrail) which I know work very well. But it the end I felt it would be more adaptable if the colour came from the light source, or through gels fixed behind the cut hole. Since I’d spent some time on the modelling (especially on getting the texture interesting) the painting was fairly simple .. an overall skim in black first with a large ragged brush, followed by less of a skim in mid-grey and then even less in light grey. Again I used Humbrol enamel for this, just to be sure the paintwork stayed on the polyester surface if the piece was going to be handled.
I used a thicker Palight for the fire surround and mantel shelf below, and the small ‘designs’ were cut/carved using the thinnest .. 1mm. Palight of whichever thickness can be carved and sanded with surprising ease .. it’s a lot like carving a soft wood, but without having to cope with grain direction, and the exposed ‘grain’ hardly looks any different to the rest. Here in the UK it’s available in white up to 10mm thickness from Bay Plastics at http://www.plasticstockist.co.uk though from 2mm onwards it’s actually ‘Palfoam’, which is an even softer variant.
For creating a controllable ‘speckle’ with a slight sheen to it I base-coated first in a lighter tone then mixed darker acrylic with some acrylic retarder gel, to stipple it over. This allows a decent amount of working time in which to even out the effect and it makes the paint into more of a glaze. Most of the tube acrylic paint companies offer their own brand, though one will work with another, however the ‘gel’ type has become less common. Now it’s usually a thickish, glycerine-like liquid but it should work in the same way.
Thanks again to Astrid Baerndal for the only photo I have of the fireplace installation properly assembled, under natural light with no atmosphere unfortunately, in the hurry to ship the whole model off. The large fish were modelled in Super Sculpey over Styrofoam base-shapes; hollow-cast in polyurethane resin; basecoated in Humbrol matt black enamel, then ‘dusted’ with Treasure Silver Wax Gilt finish like much of the rest. More about the making of the fish can be found about a third of the way down my general article Modelling and shaping, one of the group Making realistic models which is first on the menu in the Methods section.