CRAFTSMANSHIP Boatbuilder’s Notes
EXPERT ADVICE SHAVE HOOKS Scrapers you could shave with BY MIKE BURN
Most normally associate the tri-square ‘scraper’ as merely a tool for scraping off paint, pretty ineffectually, but if this humble job is to be done effectively we need to do better than that. The first essence is a razor-sharp edge, indeed adequate to shave with. With such an edge the paint, warmed, is removed in one stroke with the paint-absorbed layer of wood removed at the same time while warm. This gives a virgin surface that can be re-covered immediately as the grain is open ready for a fresh application – because it has been cut not squashed. Sanding merely fills the grain with dust which inhibits paint absorption unless strenuous efforts are made to vacuum it out. This first essential for sharpness is a blade of tool-steel quality. Harris is the only maker I know that makes such. Avoid the fancy expensive carbide-tipped scrapers as carbide cannot be made sharp enough for this wood-cutting job. Also, they cannot be ground into the fancy forms that facilitate effective paint removal on complex ahapes.
BENCH GRINDER
The second essential is a properly maintained ‘off-hand’ bench grinder – with a diamond dresser constantly to hand. It is not possible to sharpen a tool with a blunt or clogged wheel.
90 CLASSIC BOAT APRIL 2012
Most decent bench grinders come with a matrix-style diamond dresser these days – utterly essential. Like a new sharp file, there is nothing like the happy hiss of a grinding wheel doing its steel-crafting job well – if it’s noisy or rough it’s clogged. The edge I can achieve even had boatbuilder John Krejsa (YN, CB284) coming to me to sharpen and set his plane blades – on a grinder! When making Sheila’s new exotic rubbing strake for me, John was using one of my forned shave hooks as a shaver/planer to achieve the concavity to match the minute curve of the hull – a moment’s work with a fine sharp shave hook. The test of a truly sharp edge is that, when a finger is drawn gently across it in the cutting direction it grabs you – if it doesn’t it isn’t sharp.
TWO-HANDLED
The third essential is handling – it must be a two-handed job or the blade merely skips over the surface; trying to heat-gun with one hand while removing with the other is a failed strategy. Hold the blade to steer and provide the pressure needed to cut through everything in one pass, while using the handle to ‘draw’. This is far faster – one heat then one pass.
Mike Burn owns the Albert Strange- designed yawl Sheila (CB118)
The pictures show the many fancy shapes I have knocked up to do specific jobs. Make a tool quickly to do the job, then it be easily done well first time – basic engineer’s strategy. Sheila’s exotic toe-rail, heavily concave inside while round on top, was easily cleaned with one hook ground up to the exact inside profile and the top profile. They can also be used as push-shavers – like a chisel – to keep detail sharp and clean.
Above: Shape shifters – an array of Mike’s shave hooks. Below: Bench grinder by De Walt
IMPOSSIBLE CORNERS These fine sharp tools can be used in all sorts of carving jobs too – the one with the very fine ends has been a gem for recreating edges and getting into impossible corners to regenerate neat detail – it cuts like a fine chisel. The two big scrapers are Harris’s contribution to heavy paint removal – their blades are made of the same quality tool steel and, being four- sided, they can be rotated for a real fest of paint shiftin’ – there is nothing remotely as good available. My engineer’s heart bleeds for those I watch struggling with rubbish tools, taking hours to do a job. So, no more crude scrapers cobbled out of soft steel botched up with a file, nor fortunes spent on carbide fancies – above is shave hook heaven. At £1.99 each, the Harris Tri- Squares are cheap magic. Do not accept any compromise.
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