By Dan Roberts - Salisbury, NC - USA
... From a Plywood Hull
From Practical Sailor at this LINK comes a quote:
"There is no reason to remove fiberglass
that is adhering to a plywood hull
or deck. If the glass has separated in
small areas, grind the loose glass away
down to the plywood, then reglass the
exposed section. The only practical
way to remove fiberglass is by sanding
or grinding with a disk sander, a tedious
and messy job. You must take care
when grinding not to remove the surface
layer of veneer from the plywood,
so this is a job which requires a
certain amount of care."
I have found a better way to remove fiberglass from a plywood hull.
I bought a rare boat. Designed by Howard I. Chapelle back in the '30's, it is a 30' double ended sharpie cruiser (built in 1971) whose lines can be seen in Chapelle's book, "Boatbuilding". I doubt if many of this design have ever been built, so I figured if it was worth buying it was worth restoring to a high degree and I was determined to remove the polyester/fiberglass outer covering both to better enable an assessment of what needed doing and to upgrade it to epoxy saturation later in the process.
Searching the internet for various methods of paint stripping, I stumbled across the Speedheater infrared paint stripper made in Sweden and sold on the web by several dealers for nearly $500.00.
A high price? Maybe, but it has the advantage of being easy, relatively clean and faster than you may think.
The instructions say to hold it in place for 20 - 30 seconds then scrape off the paint...and it works like a charm.
But it will also loosen/soften the polyester resin holding the layers of glass cloth to the hull and after cutting around the 12" x 5" heat affected zone with a razor knife, a corner can be lifted, grabbed with a pair of pliers and simply peeled off in one piece. All this in about 45 seconds or so.
It is quiet, easy work that would probably be mind numbing were it not for the Jimmy Buffet music filling my shop.
The result leaves some cured polyester resin on the hull which is easily sanded off with a palm sander. I test sanded a small area.
But I have a new solution to speed that up too...Microplane, known for their cheese graters and wood forming tools has come out with stainless steel sanding discs they claim work 9 times faster and will last as long as 30 - 40 regular sanding discs. I'll let you know how they perform.
They are available from all the usual woodworking suppliers, come in coarse, medium & fine grits. and they cost around $10.00 /pair.