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Delamination of a bowsprit along a glueline maybe caused by either a glue/epoxy staved joint or one of the "blanks" may have warped and stressed the glueline beyond the tensile/shear strength of the glue/epoxy.
When we purchased IDUNA, the bowsprit was delaminating along the gluelines after almost twenty years of service. We decided to build a new sprit instead of repairing the old sprit.
The decision to build a new sprit was based on the observation the gluelines were failing over several areas along the sprit, hence there was no way to ensure the sprit would not fail along an old glueline after repairs were made. We also felt it was easier to build a new sprit than to make extensive repairs. Material retail cost for three blanks of vertical grain Douglas fir and two quarts of Aerodux 500 glue was $275. I supplied the labor.
There are several approaches to repairing a sprit where the glue/epoxy has failed. Outlined below are two repair approaches:
1. Remove the wood in the area of the failed glueline, scarf in a new section of wood and shape it to the lines of the sprit,
2. Skill saw a slot into the sprit along the failed glueline and epoxy a slat of wood into the slot.
The first approach ensures the glueline is good over the replaced section of the sprit, whereas in the second approach, there is no means of knowing if all of the failed glueline was repaired.
Fair Winds,
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The bow-sprit on my new BCC has developed a crack along the glue line. The crack is
about 4 ft long and runs fore and aft. It is about 1/8’ at its widest point. It clearly
follows the glue line and is left of center by abour 25%. Sumio has offered to send me
a new sprit immediately.( worlds best warranty service) but I do not want to put him
to such expense unless it is necessary.
Has anyone had a similar problem ? If so how did you repair it?
I was hoping to hear that pouring on crazy glue and ignoring the
problem was the best solution. Damn !!!
On Friday, July 4, 2003, at 05:08 AM, Rod Bruckdorfer wrote:
Delamination of a bowsprit along a glueline maybe caused by either a
glue/epoxy staved joint or one of the “blanks” may have warped and
stressed the glueline beyond the tensile/shear strength of the
glue/epoxy.When we purchased IDUNA, the bowsprit was delaminating along the
gluelines after almost twenty years of service. We decided to build a
new sprit instead of repairing the old sprit.The decision to build a new sprit was based on the observation the
gluelines were failing over several areas along the sprit, hence there
was no way to ensure the sprit would not fail along an old glueline
after repairs were made. We also felt it was easier to build a new
sprit than to make extensive repairs. Material retail cost for three
blanks of vertical grain Douglas fir and two quarts of Aerodux 500
glue was $275. I supplied the labor.There are several approaches to repairing a sprit where the glue/epoxy
has failed. Outlined below are two repair approaches:
Remove the wood in the area of the failed glueline, scarf in a
new section of wood and shape it to the lines of the sprit,Skill saw a slot into the sprit along the failed glueline and epoxy
a slat of wood into the slot.The first approach ensures the glueline is good over the replaced
section of the sprit, whereas in the second approach, there is no
means of knowing if all of the failed glueline was repaired.Fair Winds,
<image.tiff>
----- Original Message -----
From: Jim Hiller
To: bcc@yahoogroups.com
Sent: Friday, July 04, 2003 9:26 AM
Subject: [bcc] Bow-sprit problemThe bow-sprit on my new BCC has developed a crack along the glue line.
The crack is
about 4 ft long and runs fore and aft. It is about 1/8’ at its widest
point. It clearly
follows the glue line and is left of center by abour 25%. Sumio has
offered to send me
a new sprit immediately.( worlds best warranty service) but I do not
want to put him
to such expense unless it is necessary.
Has anyone had a similar problem ? If so how did you repair it?
<image.tiff>
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— Jim Hiller <jhiller@ameritech.net > wrote: > I
was hoping to hear that pouring on crazy glue and
ignoring the
problem was the best solution. Damn !!!
On Friday, July 4, 2003, at 05:08 AM, Rod
Bruckdorfer wrote:Delamination of a bowsprit along a glueline maybe
caused by either a
glue/epoxy staved joint or one of the “blanks” may
have warped and
stressed the glueline beyond the tensile/shear
strength of the
glue/epoxy.
Jim: Hi!
We replaced the bowsprit on Zygote almost one year
ago, because of rot and delamination. I don’t have
Rod’s woodworking skills or tools and I was not in my
home port when I needed to do the repair. So a new
sprit, made of teak, cost me about US$1,000.
I agree with Rod’s prescription: you either build a
new bowsprit or splice a piece of new timber into your
sprit. From personal experience, reglueing a
delaminated glue line seldom results in a long-lived
join.
Just as important as the prescription is determining
the aetiology of the condition. Douglas fir glued with
resorcinol, epoxy, or a foaming glue such as Gorilla
Glue, does not delaminate spontaneously.
Weathering factors, such as rain and temperature
changes (eg the mechanical stress of daily expansion
and contraction from tropical insolation) are usually
to blame.
In our case, the linear polyurethane coating we had
had applied to the bowsprit failed, most likely
because of inadequate preparation when the LPU was
applied. That allowed rain water into the wood,
leading to rot and mechanical stress as the timber was
repeatedly dried and wet, heated and cooled.
So our total remedy included applying multiple coats
of clear varnish (so any water ingress can be detected
immediately). We also bought a cover for the bowsprit,
made of Sunbrella by Bob & Dolly Baltierra (Power
Steering and Marine Specialities, 639 Terminal Way,
Unit #19, Costa Mesa, California, Tel: 1 949 548 6978,
Fax 1 949 548 0639).
We now keep the bowsprit covered as much as possible.
Many glues, including epoxy, have a ‘deflection’
temperature that is easily reached when exposed to
tropical sunshine.
Cheers
Bil
BCC28 #116
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I built my first sprit of straight grain Douglas fir (resorcinol) and
painted it with marine enamel. It lasted 20 years until it was
distroyed when caught under a concrete dock during a hurricane. As I
was in a hurry, I bought some western red-cedar and glued it up with
epoxy and again used standard primer and enamel and it still looks
good after five years.
I don’t know what Sumio used for yours but I would certainly take his
woodworkers advice on the best way ‘he’ would like to see it
repaired/replaced. For my money, I’d rout out a 1/2 inch deep and
wide groove a foot past any delamination crack and epoxy in a
matching wood type stip.
I will note that my BCC has spent all of its life in a tropic,sub-
tropic environment and have had no problems. Also, I personally don’t
like using linear polyurathane paints on wood because of its ‘non-
breathing’ qualities.
Stan of Waxwing hull #22