[PSUBS-MAILIST] R300 FRP work

[Sean T. Stevenson via Personal_Submersibles]

Cliff - I have once again been studying your photos of the R300 build,
and I was hoping you might be able to elaborate a bit on the process you
used to construct the FRP fairing.  There are a couple of details that I
am still fuzzy on...

>From what I understand of the photos, you design the hydrodynamic
fairing and then create virtual slices of the completed design, which
you fabricate out of expanded polystyrene.  I presume the slice
thickness just depends on the available thickness of polystyrene board
and/or how much work you want to do in shaping?  I notice that you have
these sections joined with wire ties in the photos... am I correct in
assuming that this was a temporary measure, and that you moved to
adhesives etc. prior to the body filler?

Once you've carved the EPS down to shape, you cover in a layer of body
filler which you can further refine and sand to a smooth finish, which
you then painted.  Is the paint necessary?  Or can you just apply a mold
release at that point?

After that, it would appear that you added flanges to define the mold
split lines.  Were these centered on the split line, or did you move
them slightly before laying up each half?  Furthermore, was it necessary
to split left and right, or do you think you could have done the mold as
only two parts?

Do you just use a mold release on the plug and then start fiberglassing,
or do you apply a gelcoat first?

Did you lay up the whole mold at once and then cut at the flange, or did
you do a section at a time?

Once the female mold was finished, I presume you did some further
finishing / smoothing to the inside surface?

Then a mold release / gel coat / glass to create the shell?

Once the shell was done and trimmed, how did you join the pieces
together and smooth the seam before casting your syntactic in?

Thanks in advance.

Sean