Sunday, July 14, 2013

When not to work...

The other afternoon I has some time to work on Tiki. After deciding to mill a channel in a stringer I set up the dado blades on my trusty old, cheap, Craftsmen table saw. Looking at the picture you can see there are zero "safety" gadgets on this saw. I put safety in quotes since in my experience many of these gadgets just get in the way and make power tools more dangerous. But and its a BIG BUT, these power tools must be treated with respect! Think things through, total concentration. These tools are like a Black Mamba ready to strike. Ready to take a finger off or kill. So here I was about to pass these stringers through.  The problem was, my mind wasn't ready. I was in a funk which had my mind wandering off on stupid tangents. I was an accident waiting to happen. Thankfully I recognized the situation and I just stopped, put everything down and walked away.

I wish I could say I had this type of awareness all the time:) As I've gotten older I do find myself thinking through the "What ifs" of situations much more often. In part this means I always wear a face shield when working with power tools that throw material and wear a respirator when power sanding fiberglass or working with fillers like West System 406 Colloidal Silica.

Wednesday, July 10, 2013

Experimenting with Xynole -- 374 hours

I got the idea of using Xynole from David at BoatSmith, he is a professional Wharram builder down in Jupiter Florida. He had told me once in a conversation that he used Xynole on the hull exterior instead of FG as called for in the plans. Also on the RAKA site they call Xynole the poor man's Kevlar.  It's supposed to have much higher impact and abrasion resistance than fiberglass.
So in with my last epoxy order I bought a couple yards of 68ich wide 4oz  Xynole. It was $8.75/ydr compared to $6.50/ydr for 60inch wide 4oz plain weave fiberglass cloth.

My test spot was in the stern buoyancy compartment below the stiffener, a small triangular area. I wanted to observe the wet-out up close and make sure the wet-out was thorough. So first I cut a pattern using craft paper then cut the Xynole and did the wet-out on my plastic covered work bench.  I found out it really soaks up the epoxy. It seemed to use 2 or 3 times the amount of epoxy than my 12oz FG biaxial tape. Next the transfer from bench to hull was tricky since the cloth stretches and flops around easily due to the open weave.
Stern buoyancy compartment, Xynole experiment. 
I think it's obvious this is not the material to use for a clear coat:) Above the stiffener the plywood has just 2 coats of epoxy and sanded. Oh well, this is why I did my experiment in the bottom of the buoyancy compartment, a place only viewed by serious contortions. But should there ever be a puncture event in this area, the Xynole will deflect and absorb the hit and hopefully keep water from entry. I'm debating if I should use the Xynole on the interior of the bow buoyancy compartment, this is the area most likely to encounter some mysterious object in the middle of the ocean in the middle of the night.

I should note that I've planned not to paint the buoyancy compartments and other lower areas of the hull. I don't ever want creeping wood rot hiding behind paint. If there is a problem, I'd rather see it earlier than later.

Monday, July 8, 2013

Keel Fillets and glassing DONE!!! -- 373 hours

From Stem to 

Not really too much picture worthy with this work, just pouring epoxy to a uniform level in the 7 distinct keel compartments from stem to stern. The front four were actually much easier to get done since I was able to lift the rear of the hull to get the three front compartment keel areas close to level. This made it easy to pour a less thick mixture and let it self level. The rear three compartments took longer since lifting the front wasn't as straight forward as lifting the back. The skeg is only a few cm off the floor so really to get the rear near level the whole hull forward of the skeg needs to be lifted. This seemed too hard, so instead I used thicker mixtures and made small dams about 15cm apart. Then I'd pour a thinner mixture in between, creating steps that then were filled with thicker mixtures. This worked pretty well between bulkheads 4/6 and 6/7.  But from bulkhead 7 to the stern post the buoyancy compartment swings upward quickly so mostly very thickened epoxy is needed to stick to the near vertical gaps.

I feel like I've had a pretty good run this past month but it's time to throttle back on Tiki work and  put more time in to other household projects e.g. crack repairs.  After a minor earthquake last October we had several hairline cracks on the SW dome face. We didn't realize it until this spring when we got back from our southern vacation. So I've started cleaning and caulking, but many hours ahead since we also decided to change house colors.

Tuesday, July 2, 2013

Don't let this happen.... -- 353 hours

It takes a lot of epoxy to fill the keel and attach stringers/stiffeners so don't do like I did and wait until you start the last gallon bottle of epoxy resin to order your next batch from your favorite supplier:(

The issue is that I have several, what I call, "wet edges" of epoxy kicking and I'm very low on epoxy and about to run out.

With epoxy I use the term "wet edge" (which is from painting) for the time period after pouring during which when new epoxy is poured and it will still chemically bond with the first pour. The type of hardener, the ambient temperature, and volume of epoxy all combine to set the wet edge time frame.

The temperature in my basement is about 72degF and dropping slightly. This past week has been cool and wet here in Maine, for instance today we had a high temp of about 61degF. And I'm using RAKA 606 slow hardener so the wet edge period is about 24 hrs. Around this time the bond becomes less and less chemical and more mechanical until after about a week when it has completely kicked. The point being I what to keep that chemical bond going as it is much stronger than the mechanical bond.  Also after this wet period is when amine blush can develop, although luckily I have virtually no issues with blush at this site.

Lower hull stringers between bulkhead 3 and 4.
A little tip to help spread the hull when installing stringers/stiffeners. First dry fit the port and starboard pieces. I use two screws on each piece to hold the stringer. Then using two pieces of wood with notches over lap them and use safety wire to hold them together. Then using a screw clamp its easy to carefully adjust the spread to get the desired "fair" curve of the hull.