If you are of the balsa rail wrap/bender school like CMP and I or if you’ve dallied with the “real” 1/64"-1/32" fancy pants veneer you’ll know what a pain its is to:
- Pull the epoxied blue tape from the skin 12+ hours later
and
- Deal with sand thru’s or rail cracks that expose the bright white foam underneath.
What I’m experimenting with now is the following:
Sealing the EPS foam with spackle to smooth it then a light spray seal of Styrofoam primer.
On top of this I’m using the new H2O Krylon paint in the closest color to the surface wood I’m using in the skin and mixing in “champagne” pigment (for balsa) or another color again matching the wood color in the epoxy for the glass underneath the wood.
Finally I’m spray sealing the masking taped underside of the lam with a wood sealer allowing me to remove all the exterior blue tape prioir to vacuuming. Kind of the lazy guy’s version of JJP’s balsa strip superglue technique. The spray seals the wood from underneath reducing absorbtion of the resin through the skin on the real thin stuff which really blackens some dark wood like purple heart or koa…
The sealing of the foam and the wood allows me to use less resin concentrating it in the infusion of the glass which is what we’re all looking for.Why waste it soaking onto the styro or the moisture sucking balsa. Sealing the outside and inside of the wood also reduces the gassing effect during the hotcoat phase (cheater coats and using RR make a difference too).
The coloration of the foam and underlying resin lessens the impact of any sand thru’s and the requisite patching us rail wrappers are faced with vacuum bagging.
Actually spraying the foam brown or red or purple helps actentuate how screwed up your shaping really is allowing you to fix the bumps prior to bagging on the skin.
I’m also following CMP’s lead and building out my concaves using staggered thicknesses of balsa and then blending it in through sanding. Much easier to sand and fine tune balsa wood than it is with 1lb styro. CMP eliminated the shaping process altogether by cutting and strategically placing pieces of Dcell or thin foam under his lam to builld out some pretty wickedly complex curves kind of like a clay sculptor. The 1/16" balsa skin allows you so much more flexiblility.
For decks I’m building the center strip 8"-12" wide to act as both a springer and a deck patch using something hard and springy like bamboo or maple. If you cut the piece right you can add more stiffness where you stand and less where you don’t. If you build a top and bottom elongated christmas tree crown ornament shaped springer joining the top and bottom hardwoods at the nose and tail you should get a similar solid rail effect without the solid rails. Some guys are putting this stuff under their skin instead of building it in the skin itself.
Since I’m currently using pre-molded EPS blanks this skin technique makes sense but on my next lowes insulation bamboo sheet stringer experiment I’m gonna try inlaying some of these 2’-3’ pre-bent bamboo u-shaped trellaces with the open ends of the hoops joined to form a giant figure eight inset into the deck foam about 1/2" deep intersecting right where I stand. This will be my weirdest deviation aside from the 1 3/4" thick bert board we’re playing with… Using a lexan starfin on the guy now as the greenough paddle didn’t work… Might also try to convert it into a classic three fin bonzer if we can’t fin a single fin to suither design…
Just thought I pass some this on
you can take it for what it’s worth.
The solid wood rail guys have it easy once they get past getting the rails on.
Vacuum bagging a 1/8" or 1/16" deck balsa around a pin tail or double bump and getting a clean seam is an art form…
