I hope someone can offer some advice here with a problem I am having with a balsa hull and tissue paper covering.

I am attempting Vic Smeed's Tiddler tug at the Model Boats plan size of 20" or so, and I am using the suggested balsa hull construction, at least as far as the deck. I have what is a satisfactory hull complete albeit with a few areas filled with the green putty stuff. I then attempted to cover the hull using aircraft tissue paper but have run into problems. This is my first attempt with this method and clearly the practice pieces I tried were not representative of what happened when I moved on to the hull.

I sealed the balsa with several coats of 50-50 thinned non-shrinking cellulose dope, rubbed down between coats. I then applied an over-size sheet of tissue paper to the main side chine from the deck down, with an overlap of 1/4" to the next chine, snipped along the edges to fold over the curves. This was applied with more thinned dope. I did the same for the bottom sheet, overlapping to the middle chine again. The problem has been when I added the middle chine and added, in effect, an overlap to the overlaps. Specifically, the overlaps tended not to stick and I ended up with a lot of very uneven, bubbling and/or loose edges. Sanding did not really help and, rather than slap filler everywhere and cover it all up, I have spent some time removing the tissue paper (with thinners AND paint stripper – it was stuck down well in places).

What went wrong? I have seen somewhere the idea that one uses thinned sanding sealer rather than dope, and that the tissue is smoothed immediately with rolled kitchen towel to flatten the covering and to remove excess sanding sealer. I had thought also that if I followed the same procedure as above for the first two chines, I should then add an under-size piece of tissue paper to the last chine so that it only lays on the overlaps, rather than creating further layers over the hard chine edges.

Any thoughts or suggestions gratefully received.
Nick

Hi All,

Many thanks for the replies, comments and suggestions — Eze-Kote and lightweight glassfibre cloth seems to be the people's favourite. The only tiresome element there might be the right angle under the rubbing strip. I cut the tissue paper to fit that line rather then risking an ugly fillet of paper and gunge, and I guess the glassfibre could be cut in the same way before layering on.

But using wallpaper paste instead of dope sounds an interesting idea. I guess I need to experiment with some test pieces.

As to simply going from a sealer to undercoat, my limited experience has suggested that that approach works fine if using solid balsa, ie, bread-and-butter construction, but when using a sheeted hull like the Tiddler it is not long before the finish develops hairline cracks, although not necessarily directly in line with the grain. This could of course be my layering on too much sanding sealer or not allowing enough drying time between coats or finishes.

Nice model, Ray. I am intending to go for a wartime outfit in grey and more grey, but I rather need to get the hull done first. At least a day's worth of cleaning, sanding and doping has about got me back to where I was a fortnight ago.

Thanks again,
Nick