Tuesday, 14 February 2012

Epoxy update #2

Having used the about 0.5KG of Reactive Resins Syntac EPAFD Epoxy for coating the gunwales on the Goat I am very pleased with the results.   I have tried both the "Fast" and "Rapid" hardeners and they give predictable cure times, easy over-coating and cures to an almost clear finish.  The resin has a low viscosity even at low temperatures that make it easy to coat and probably help it soak into the wood surface.

I am particularly pleased with a complete lack of amine blush that both West or PEC suffer from in perfect conditions yet the Syntac achieves no blush residue in the less than ideal conditions I have been working in.

Below are some pics of the gunwale that has had 3 coats applied, wet on tack.  All it needs is a little flatting down before a varnish is applied for UV protection.

Monday, 6 February 2012

An update on Epoxy

I have spoken on here before about moving from West epoxy to PEC for this project because I became fed up with the amount of amine blush and the cost of West.   Having used PEC quite a bit (3-4KG) for bonding, filleting and coating I am looking again at an alternative.  The PEC epoxy is easy to mix and use but is more viscous than would be ideal, heating the epoxy helps but when working in an unheated workshop on an unheated hull the epoxy soon thickens up.  The biggest issue with PEC (and I have spoken to them about this) is the cure time, it just seems to take ages.  I have tried using it for coating in a heated environment and that works fine but it still takes a much longer than the standard epoxy from West.   When using PEC in the workshop it literally takes days to reach a full cure.  Now if I was after an epoxy with a long working time and I was building during the summer or a in a heated workshop then PEC would be absolutely fine but for me as a home-user in a unheated garage in winter it just doesn’t quite stack up.  Unfortunately PEC don’t make a fast or rapid version of their product but on the positive side their product did not produce amine blush, there was a small amount of blushing but significantly less than West.

So next up on the epoxy test will be Syntac EPAFD from reactive resins, having spoken to them I am going to try their “Rapid” and “Fast” hardeners.   I am hopeful that the Rapid hardener will allow wet-on-tack coating of the Goat at cold temperatures (5-10 Celsius) this will hopefully allow up to three coats in a working day.   I’ll report back on how I get on but so far I have been impressed with the knowledgeable staff and willingness to help.

Saturday, 4 February 2012

More on gunwales, inwales and knees (and other stuff!)

With the inner and outer gunwale in place the knees at the stern and breasthook at the bow have been fitted.  The bresthook is a complicated shape with lots of angles to measure and transpose onto the Doug-fir but it turned out pretty well and I’m pleased I set aside some time for this when I wouldn’t be rushed. 

The long process of planing the gunwales down to size so they match the sheerline of the hull sides followed and I have the blisters to prove it was done by hand.  In some respects I could have used an electric planner (if I owned one) but sometimes the traditional way of doing things is ultimately more satisfying and as long as the plane blades were kept sharp they cut through the Oak, Doug-fir and cedar sandwich that makes up the gunwale.  Once complete I have run the router with a radius cutter around the top of the inner and outer gunwale and then around the inside of all the gunwale gaps (for want of a better name) and this has finished it off nicely.   The only sharp edges left are the bottom edge of the inner and outer gunwale that will both be rounded by hand as the curvature of the hull does will not allow the router to be used.

I really like the pictures below, there is an honesty about this boat as it’s construction is visible to all that want to look.   Yes, it’s never going to be a traditional wooden boat with all the skills required to build it but it is not pretending to be that at all and is lighter, faster and ultimately more usable as a result. 

Having bought some really nice quality stainless steel rowlocks on ebay these have been temporary fitted in position.   When fitting the inner gunwale spacers I had used two slightly longer ones where the rowlocks would be fitted.   The rowlocks have also been raised slightly on an oak pad each side so that the oars are well clear of the gunwale when rowing.  The rowlocks came with a stainless plate and this has been recessed into the top of the oak pad although it’s not my best bit of carpentry, I guess that’s why I’m a “wood butcher”.  The pic below is before the oak pad was recessed.

Finally the top of the middle seat has been roughly cut to size and once glued into position I will use the router and flush trim bit to tidy up the edges.   It is too cold to do any epoxying in the garage at the moment so the seat top has not been fitted, however it has come into the warm of the house and been epoxy coated to save time later.