My Official build thread. 27 1/2’ GA

[Brian.Dixon]

After shoveling snow for half a day I did manage to finish the last scarf on the starboard bottom panel blank.  I got the port blank off the jig without help.  That’s a lot of wood right there! 
Re: second layer bottom panel blanks.  Would it work the same to trace the the shape onto the second layer blank, then use a spacer block to lay out the cut line.  Just like it is suggested for bulkheads in manuals?  Did that make sense?   Less flipping me thinks!

You'll want to be sliding that second layer around and looking at it to make sure it fits, no?  Haven't heard of anyone not flipping the sheet over, but who knows?  Maybe you're on to something? 

Brian

[Todd j]

Sounds like it’s not fully recommended.  Just looking for a easier way.

[Brian.Dixon]

Sounds like it’s not fully recommended.  Just looking for a easier way.

I suspect the chance of making an error is greater, but that doesn't mean it won't work or that I'm correct.  Poke around with the idea out in the shop and try it... there is always room for improvement

Brian

[Todd j]

While the subject of stringers is still hot I have a question.  Should I preglass stingers if I will be adding to the top of them after the flip?  How far should I go?

[Brian.Dixon]

While the subject of stringers is still hot I have a question.  Should I preglass stingers if I will be adding to the top of them after the flip?  How far should I go?

Preglass all stringers before installation .... easier that way.  I do wrap the glass over the tops, and then between that and the fillets/glass tape to the hull, they're entirely encapsulated in glass.  That's a good thing below decks....

If adding to the tops of the stringers later on, then glass over the top of the added wood and let it overlap the original glass by a couple of inches.  Make sure ends of the added wood are buried in glass tape/epoxy to encapsulate the new wood completely..

Brian

[Todd j]

Groovy 
thanks

[Brian.Dixon]

Groovy 
thanks

Yeah ... sorry for the quick and dirty post.  Was in a hurry but wanted to respond.  You can do it in whatever order you want, the goal being all glass/epoxy under the deck.  If you glass the LVL first, then add wood and glass that later, the glass/epoxy between the LVL and deck-raising wood provides another 'rot stop'.  That would only matter if you one day decided to lag bolt into the stringers to mount something on the deck.  Any leakage and rot from an imperfect seal would stop at the glass on top of the original LVL.  But that's an extreme case.  You can decide what to do.  Personally, if I wanted to lag into the main stringers, I'd probably drill and oversize hole, fill with epoxy, and put a hex-head bolt into it head first (threaded end sticking up) and call it good.  Lots of ways to skin a cat!

Brian

[Todd j]

 No worries.  Your response was timely and had all the info in it I needed to satisfy my curiosities.  I do like the upside down bolt trick. 

[Brian.Dixon]

No worries.  Your response was timely and had all the info in it I needed to satisfy my curiosities.  I do like the upside down bolt trick.

Yeah .. with the head of the bolt buried in epoxy, there's no way it can come out OR cause water intrusion into the wood.  Similar for transom motor mount bolt holes ... oversize drill first, back-fill with epoxy and seal well, then drill correct size for the bolt through the middle of the epoxy 'plug'.  Use washers or aluminum plating bigger than the original oversize hole so that loads are distributed to the plywood, not just the epoxy plug.  My preference is a 1/4" aluminum plate, inside and out, holes drilled in the right place for bolts.

Brian

[Todd j]

I got my bottom panels cut out along with the second layer of bottom panels.  I just let the side of the first layer overhang the saw horses enough I could trace from the underside.  No flipping!   I glued up some more shelf blanks.  I need another sheet of 3/4” to finish those pieces.   I want to have everything cut and ready before I  butterfly the bottom.  I think it will look like mad progress that way

[Brian.Dixon]

Looking good!  Pretty soon, you'll go from big flat pieces of wood to something that is looking like YOUR BIG BOAT 


Brian

[Todd j]

I had a void in one of my shelf blank laminations.  I tried to fill it with unthickened epoxy.  It started to drip out the other side.  I taped some plastic to it to hold it back long enough for it to cure.  I will later be able to dribble some in and fill the void. I used what was left for another project.  Anyway,  I added some cabosil and used it where I needed it.  Had a bit left over.  Came.  Back in a hour and the solo cup was melted and the epoxy mix was cured hard as a rock.  Why didn’t the unthickened epoxy cure at the same rate?  It takes forever when you are “waiting “ for it.

[Brian.Dixon]

I had a void in one of my shelf blank laminations.  I tried to fill it with unthickened epoxy.  It started to drip out the other side.  I taped some plastic to it to hold it back long enough for it to cure.  I will later be able to dribble some in and fill the void. I used what was left for another project.  Anyway,  I added some cabosil and used it where I needed it.  Had a bit left over.  Came.  Back in a hour and the solo cup was melted and the epoxy mix was cured hard as a rock.  Why didn’t the unthickened epoxy cure at the same rate?  It takes forever when you are “waiting “ for it.

One thing that affects the cure rate greatly is the temperature of the epoxy.  Now, what that means when talking about epoxy in a cup versus epoxy on your project, is that the project (boat) will both draw heat out of the epoxy while it cures, and generally the epoxy on the project will have greater surface area which allows heat to dissipate into the room.  When the epoxy is in a cup, there is minimum surface area and the epoxy's heat that comes from the curing reaction is going to be more trapped in the epoxy ... so the epoxy gets warmer, cures faster, warms itself even faster, cures even faster etc...

If I want a little longer pot life out of a batch of thickened epoxy, I'll spread it out thin on wax paper, or sometimes, around the sides of the cup to increase surface area.

Be careful with epoxy getting hot .... I've seen epoxy in a cup get hot enough to smoke ... I'm certain that breathing uncured epoxy smoke (hot fumes) is not going to be very good for your lungs.  Your goal in using epoxy is to never expose yourself to it in a way that could cause you to develop a sensitivity to it ... once you develop a sensitivity to it, then that's it .... sensitive for life.  Use good gloves, sleeve guards, and keep the epoxy cool.

Brian

[davidnolan]

ive had a number of batches go off...   the solution is mix small batches and have everything ready.   I'm using 21 in epoxy now and there isn't time to mess around.... if there is any holdup I do exactly what brian says... dump out and or dumpe in shallow pans or multiple pans... and if its thickened I spread it on a piece of plastic like a big plastic box lid.......

I one time gave about 12 oz a 20 sec shot of microwave heat.... I started ewalkign downstairs and dy the time I got down the basement into the shop it was hot in my hands and congealing.....  I threw it into the boat thinking I could salvage the resin and big globs and what looked like snot runs hardened up making quite a mess.....     

[Todd j]

Thanks guys.  Good to know