Continuing with where I stray from or modify Gordon Gravett's techniques, I'm not a fan of using Artex or similar to represent the bark for the following reasons:
- The coat of PVA glue applied to the armature to improve adhesion of the mixture is difficult to apply to bare wire and it takes quite a long time to thoroughly dry
- Even after coating the armature with PVA glue, I haven't found the mixture adheres at all well to the wire, especially if it's thin wire
- The mixture sets too quickly for me and although I've tried retarders I always feel rushed in case the mixture starts to set up
- The final result is brittle, even with copious amounts of PVA added to the mixture
So, instead I use Staedtler FIMO modelling clay (easily sourced from art supply shops or, as ever, Amazon) in two ways.
First, I wrap a thin layer of the clay (I use black) around the main trunk(s) and primary limbs of the armature, pressing and shaping it by hand:
and once happy with the overall shape I stipple the surface of the clay with a stiff brush to represent the bark texture:
[Note, these photographs were taken after I had added the fine wire to represent the secondary growth on the main trunk but that would be the next step - inserting fine wire directly into the clay.]
Once I'm happy, the clay-clad armature is put in an oven set at 110C for 30minutes to harden.
The next step involves mixing some fresh clay with Sculpey Clay Softener (again, easily sourced from art supply shops or Amazon):
to a create a brushable mixture:
This 'gloopy' mixture is then carefully brushed onto the secondary limbs and terminal branches (which I add to the armature immediately after applying and baking the coat of clay to the main trunk) and subsequently hardened in an oven set at 110C for 45minutes. This step may well need to be repeated in order to build up the correct thickness of the branches - this photograph was taken after the first application and as you can see additional layers are still needed towards the top of the tree:
Note, the Sculpey-softened clay doesn't set completely hard even after being baked several times - it sets to a firm, rubbery consistency and so it's not easily damaged unlike Artex.
Currently the trees which will be positioned in the landscape side-by-side are as shown here - I will post additional photographs once they're ready to paint: