Thursday, February 18, 2016

Pilothouse Console

Pilothouse Console


I ordered more meranti BS1088 plywood, fiberglass and epoxy. While waiting for the orders to arrive, I designed the pilothouse console.

              Side view                       Rear view                             Front view
Pilothouse console


 Design details...
Elevation

Layout on plywood panel



Detail dimensions for windshield
Materials have arrived. Time to start cutting and glassing.

I saved the plywood pieces cut out to make the openings for the side windows and windshield. The glass supplier used the plywood pieces as templates for cutting the 1/4-inch laminated safety glass windows and windshield.

Pilot house side panels cut and glassed



Exterior window frames cut from select pine and epoxied to the
exterior of the pilot house



Interior window frames cut from ½ ACX and glassed


Interior window frames painted. These will be installed using
screws to allow future window maintenance.

Backer added to top of pilot house side panels





Edge stiffener added to pilot house side panels



Pilothouse console clamped for gluing


Pilothouse console clamped for gluing

Backer added to top of pilot house front

Backer added to top of pilot house rear




Curved roof beams, 3/4 plywood. cut, routed, sanded and glassed




Roof beams installed

3/8 plywood roof panel, inside glassed then the weave is filled
and it is sanded for future varnish



Kerfs cut in outside of the roof panel. 4" OC, ¼" deep




Roof panel bent over roof beams and epoxied in-place



Masking roof outside before filling kerfs




Kerfs filled with thickened epoxy and masking removed



Glass the roof panel




After cutting the roof panel to final dimensions,
the filled kerfs can be examined




Route, sand and glass the roof edges



Fill the weave on the roof panel exterior




Flip the pilot house and fillet the roof beams to the roof panel




Two coats of varnish on the inside of the roof


Cut, route, sand and epoxy the pilot house nailers



Install nailers along bottom edge of top half of pilot house
and start varnishing the exterior



After three coats of varnish on the exterior, flip it over


Scouring pad on RO sander for lightly
scuffing varnish between coats

Final of the four coats of varnish on the roof

Pilothouse console in final position.
Pilothouse varnish complete (2 coats on interior surfaces,
3 coats on exterior vertical surfaces,
4 coats on exterior horizontal surfaces)

Bottom half of pilothouse console will be glued to the deck.
Top half of p
ilothouse console will be screwed to bottom
half to allow future removal if needed.

Interior

The top half of the pilothouse console is fastened to the bottom half with brass wood screws, from the inside, into the nailer. The horizontal strip of pine beneath the window is the nailer - more meat for the screws to grip.

Pine strip nailer on outside of top half

Column splice piece on inside


Column splice and top half
fastened to bottom half with brass screws
from inside

Column splice and top half
fastened to bottom half with brass screws
from inside
Interior of pilothouse console glassed to deck with
17oz. 4-inch biax

Exterior of pilothouse console glassed to deck




Vent tube, for venting the bulkhead chamber beneath the deck,
installed on the inside wall of the pilothouse, with a cap.



It is a sunny windy day so I thought I would drag her outside and do some sanding in the wind.

She hasn't seen the light of day in a long time.


It is going to be a tight fit...


Oh shit! Gonna have to raise the house 1 inch.





Monday, February 15, 2016

Does Size Matter?

How Big Should Fillets Be?

I think, in general, stitch and glue boat builders oversize the fillets. The epoxy is orders-of-magnitude stronger than the wood and especially stronger than plywood. The weak link in a plywood/epoxy joint is the bond between the plies of the plywood.

I had a few extra sections of a plywood/epoxy joint that were headed for the trash. But, since I love destructive testing, I put them to good use.

This is a very small epoxy fillet in 9mm BS1088 Hydrotek meranti. The legs of the fillet are maybe ¼-inch. This is way too small for a boat hull but plenty big for a cabinet.




The outside has 6oz. fiberglass tape set in epoxy.


I thought I could break them with my hands. I couldn't. I had to whoop 'em with a hammer.
 

Notice that the fillet is intact.


As expected, the mode of failure is disbonding of the plywood plies.





Larger fillet = More plywood area = Stronger joint 

But, this comes at the expense of large amounts of epoxy. And epoxy ain't free!!! 

Fiberglass set in epoxy will also spread the load over greater plywood area. Pound for pound, a small fillet covered with heavy fiberglass set in epoxy is probably a more efficient use of epoxy than a gigantic fillet.

Small fillet with heavy fiberglass = More plywood area = Stronger joint