Humbrol Tiger Moth

[Piecost]

I was concerned about the use of vacuum formed polystyrene on the finished model. So I made a trial nose to test the following;

1. How well the plastic attaches using canopy glue

2. How well (unchalked) yellow Asuka covers the different colours of the white plastic and balsa

3. How well chalked Asuka covers the different colours of the white plastic and balsa

4. Does pre-painting the plastic and/or then balsa before tissue covering help?

5. Does the tissue cover the double curvature of the plastic without wrinkles?

6. Does wallpaper paste work Ok. The stuff made from powder and water.

7. Is the plastic stiff enough to withstand the tissue shrinkage?

Conclusions, so far

1. The 0.25mm plastic is stiffer than the soft 1/16" sheet fuselage sides. On one side the plastic glued reasonably flush. The other the plastic was proud. I cut and reglued the plastic. Perhaps the moulding was too wide. A small overhang was Ok since the plastic could be sanded. If underflush then lightweight filler could be used. The canopy glue stuck Ok, but may notnsand well.

More will be answered as I progress...

Reproducing the vacuum formed parts has been a knightmare and has trippeled the build time of this project. I am not even happy with the neatness of the moulds.

The photo shows the nose with aluminium tape holding the rear part of the plastic onto the fuselage side and household DIY lightweight filler applied to the joint.

The inset squares on the balsa side are to simulate the inset strips on the empenage. To find out how prominant they appear under the tissue after sanding.

The nose has been given local areas of lightweight filler and a couple of coats of Sand'n'Seal. This fills then grain nicely.

[Piecost]

The test piece has been painted with 50% thinned Tamiya acrylic. The paint does not reduce the contrast between the plastic and balsa. It may even enhance it, due to their differing textures.

I have applied yellow chalk pastel onto some yellow Asuka tissue. I will cover half with chalked and half with unchalked and tissue and see how they compare.

[pb_guy]

It looks like it is the grain of the wood that shows through the lighter colour paint, which is acting more like a heavy stain than paint. Perhaps a layer of thin white or yellow tissue overlaying the wood, then sealed and painted might overcome this transparency. But that does add a bit of weight.
ian

[Piecost]

I have now added the yellow Asuka tissue, as Ian suggested. One side is chalked and one is not, as shown in the photos. It was attached with wallpaper paste and is yet to recieve a coat of Pledge acrylic floor polish to seal and waterproof.

Initial conclusions prior to the Pledge coat:

The first conclusion is that the chalk is very subtle. It is hardly worth doing. But I will persist since I have specifically bought chalk for it.

The paint on the white plastic prior to tissue covering significantly helped it match the balsa. Definately worth doing.

Painting the balsa yielded a slightly deeper colour. This can be seen at the nose, in the photos. I am not decided whether to paint the sheet balsa areas.

If I do; I have no idea if it is better to paint the balsa before applying the tissue or to simply paint the covered model as per normal practice. I am not seeking a perfectly opaque finish, but for the plastic, balsa and open framework areas to look uniform.

I will see if the coat of pledge makes the tissue more transparent and changes the conclusion.