Having clamped a pair of mould-half panels together, I figured I could just cut them out with a jig saw….
The "Offending" Saw - as always it's the bad workman who blames his tools!
So off I set, slowly and carefully sawing along the line – 2 inches in I encounter the first problem – there is so much dust I can’t see the line… At this point I engage “smug-mode” and pick up the shop airline, and with the spare hand blow the dust clear as I saw…
… I reach the end and discover (horror) that the b*&^&^y saw has cut at an angle to the vertical – and (double horror) this mis-cut has resulted in the lower panel being significantly undersize (we are talking about a ~5mm undercut!) grrrrrr….
I check the saw and the blade is square to the foot, so I am mystified…
A number of posts to the Selway Fisher Builders Yahoo group follow… (this really is a great group of people) and a deal of suggestions emerge within a few hours. These range from observations that cutting 1.5inches of chipboard in one go is too ambitious, thru to real Zen-like encouragement to chill more, take up a pipe and cut them with a Japanese hand saw – excellent!
So, I take some of my scrap chipboard (I just made a nice new bit of this) and draw curved lines and practice my sawing (by hand and other approaches) – including sawing it an inch oversize and improving my planing and surforming technique.
In the end two key factors emerge 1 – you cannot saw two at a time (you were right Graham) and 2 – I was going too slow! By setting the variable speed JigSaw to “flat out” and keeping my feed rate slow the desired results emerge….
The first three mould-halves bolted together, showing the marking out (Nos 1,12 and 16)
I leave the workshop with three assembled and very “boat shaped” moulds – life is good again!