Some time ago, The Shed made what seemed to be a canny investment in a coracle building course, resulting in a sort of upturned garden frame made out of willow and a problem – how to cover it in a way that would work as a boat for a couple of years.
The Shed spent some time on the options and went for what seemed like the rock-and-roll solution – glass fibre.
Our only actual practical experience on the subject amounted to ruining a couple of perfectly good cars in an attempt to hide the fact a wing was dropping off, but we had seen it done better and were willing to have a go.
Like screw sizes, fibreglass specs are a language invented by warehouse personnel to tell you it’s not that easy mate. And they are inclined to deploy it in spades when you confess that you want to cover a wicker boat. An image of Britt Ekland being cast adrift from a Cornish cove, with a black candle burning at the bows, hovers above the conversation, you feel. But we did eventually get some sympathetic help from David Pinson oft Arrowcraft Composite Engineering,
a serious small-boat builder who actually offers his own fibreglass coracle for about £300 – a bargain, The Shed can assure you.
The Shed’s coracle frame is, what, four foot long and a yard wide, maybe two foot deep, and officially valued at about a fiver in Shed assets, although it actually cost us about £300 to get this far.
We agreed with David that we needed a loose base fabric to drape over ribs and down into the, er, sideways bits. We suggest maybe five yards of metre-wide and David took the trouble to package this up with a couple of litres of resin and a curry-jar of hardener for about fifty quid, including postage.
It is not hard to put off a fibreglassing job in an English summer and The Shed adjourned it a number of times until this Indian Summer, 2015, finally issued the challenge.
We worked out we needed two per cent hardener – roughly two grams to 100 of resin – to get 20 minutes working time. Should be plenty? We mixed 500 grams at a time, to 10 grams of hardener, on a hot day. Sometimes we spread it in time, others it was turning to a lumpy gel before we finished. Unless you’ve got acetone, which would be more American Garage than Shed, for god’s sake, you are dumping a brush every 20 minutes too.
We ran out of materials with one skin almost on, but still see-through in most places; some patching and double-skinning done; but a lot of mistakes to fix. Fibreglass is designed to go down in tight layers. We have air bubbles all over the place, especially where we have tried to stick the cloth over the gunwales. It was a ridiculous mistake to try to paint it in tight, starting with dry cloth. Might have stood a chance if we had soaked the cloth, in a big bath, and then bashed it into place? But that would have meant togging up big-time and all we had was nine dozen cotton gloves, a fiver from Tavi market.
In the end, we have sharp edges flapping loose and fabric which is not stuck down but has half-set irrecoverably. Only thing to do is cut it back a bit and try to find a way of getting a lash over the gunnels all round, from the outer skin to the inner, smooth enough to get more fibreglass over the top, eventually.
Gaffer tape? Don’t think so. Papier mache? Take a fortnight. More fibreglass? Good money after bad until we’ve sorted the problem – anyway, not enough working time for this stage of the job, although a smaller ration of hardener might help. Expanding filler? Pricey and messy.
The Shed ends up googling for animal glue, recalling something Kevin McCloud boiled up one day and then stuck a crane to the side of his caravan with, or something like that. How about soaking muslin or scrim in that stuff?
Nearest thing we can find on the internet is hide glue, still used by furniture makers, but mainly for fine finish purposes. You can buy it but via Amazon it’s four or five quid for enough to mix up a pint and you’d need a lot more than that. Kevin would start with an old cow, of course. But even buying it in powder form, you have to brew it up and keep it hot in a double boiler in order to work with it; then you’ve got the knacked containers and brushes expense all over again.
There is nowadays a liquid hide glue, which sounds like a Shed dream of heaven – comes ready to squirt out and use. The Shed has voted to invest in a fiver’s worth to try but you’d need a gallon of it to do the job we have in mind. Meanwhile, a working party has been appointed to try PVA glue and some kind of bandaging material
If you cannot wait to know more, you are on the right blog.