Re: [bolger] type of abrasion? Polyester fabric and checking
> The one time I used Xynole, it sucked up soooI agree that more wood instead of Xynole and epoxy will make
> much epoxy, I have no doubt that I could have
> doubled the thickness of the bottom plywood
> for more strength at less cost.
a stronger bottom. It will also make a heavier bottom
which in some cases is better for the boat's performance,
especially in a sailboat that can use some extra weight
down low.
But if the goal is abrasion resistance so that maintenance
can be minimized, Xynole is a better choice because it will
resist being worn through more than wood or wood and
fiberglass, and in this case the boat won't need to be
hauled and repaired as quickly or as frequently in order to
prevent water from getting into the wood after a bit of
rubbing on a rough beach or some rocks or whatever.
The thing is, many people these days are spoiled. They want
all the fun that comes with owning a boat, but they don't
want to be bothered with the 'hassle' of maintenance and
repairs. For these people Xynole may make more sense than
more plywood because it keeps the bottom waterproof better.
Sincerely,
Ken Grome
Bagacay Boatworks
www.bagacayboatworks.com
> XynoleI am not sure that PCB endorses Xynole sheathing. Does anybody know
if PCB has written his opinion of Xynole anywhere?
I think that where PCB wants a tough bottom, PCB specifies more wood.
(Clam skiff, Topaz etc. with multiple layers of plywood, and the
addition of a plywood shoe.) Or in extreme, he puts on steel plating,
like with AS-39 which withstood an real world test lately.
The one time I used Xynole, it sucked up sooo much epoxy, I have no
doubt that I could have doubled the thickness of the bottom plywood
for more strength at less cost.
I can see that I am going to have to do some mining in my old copies of
Boatbuilder and dig out the article. The abrasion test used a disk
sander applied with constant pressure and measured how long it took to
go through the material being tested. It was done by a fellow builder
and it seemed to me to be a fair test. I liked it because it addressed
something that I had never seen tested before, and it was done in the
spirit of inquiry and the results were shared. The results convinced me,
and I have used Xynole on all bottoms that I have fiberglassed since.
Somebody directed me towards the site that had using the 20 mil plastic
as a smoothing agent
http://www.duckworksmagazine.com/03/r/articles/glass/bottom.htm
and
http://www.pbase.com/dr_dichro/electric_boat
If I were to build another skiff with Xynole bottom I would like to try
this stuff for the filling coat, might save a lot of effort.
And a final thought, if I were building a boat that would be anchored
out so that antifouling was needed I would have a Xynole sheathed bottom
and I would try copper and the thinest low viscosity epoxy from
Progressive Epoxies and thin some more it so it could carry the max
amount of copper and apply it as the finish coat using the plastic over
technique. Using the plastic would allow you to use more copper then
just rolling it on as it doesn't level well when the copper/epoxy ratio
is high.
HJ
Roger Padvorac wrote:
Boatbuilder and dig out the article. The abrasion test used a disk
sander applied with constant pressure and measured how long it took to
go through the material being tested. It was done by a fellow builder
and it seemed to me to be a fair test. I liked it because it addressed
something that I had never seen tested before, and it was done in the
spirit of inquiry and the results were shared. The results convinced me,
and I have used Xynole on all bottoms that I have fiberglassed since.
Somebody directed me towards the site that had using the 20 mil plastic
as a smoothing agent
http://www.duckworksmagazine.com/03/r/articles/glass/bottom.htm
and
http://www.pbase.com/dr_dichro/electric_boat
If I were to build another skiff with Xynole bottom I would like to try
this stuff for the filling coat, might save a lot of effort.
And a final thought, if I were building a boat that would be anchored
out so that antifouling was needed I would have a Xynole sheathed bottom
and I would try copper and the thinest low viscosity epoxy from
Progressive Epoxies and thin some more it so it could carry the max
amount of copper and apply it as the finish coat using the plastic over
technique. Using the plastic would allow you to use more copper then
just rolling it on as it doesn't level well when the copper/epoxy ratio
is high.
HJ
Roger Padvorac wrote:
> Does anybody know what type of abrasion was used in the test on abrasion resistant coverings for boat bottoms? While barnacle covered cobbles and coral sand are both abrasive, they are quite different, and might abrade different materials on boat bottoms at different rates.
>
> For those with only sandy beaches, I got this from the dictionary:
> Cobble: a naturally rounded stone larger than a pebble and smaller than a boulder often arbitrarily limited by geologists to a size ranging from 64 to 256 millimeters (2.5-10") in diameter
>
> You get cobble beaches a lot where glaciers deposited glacial till from mountains made up of hard rock, and the beaches are still steep enough that the sand and pebbles are still being washed into deeper water.
>
> In any case, most of the time my boat (that I'm planning on building) will be on beaches with barnacle covered cobbles near Seattle, and the polyester fabric worked better on beaches like this for HJ - thanks HJ for mentioning the type of beach that your boat is typically exposed to.
>
> May your day be filled with clarity, grace, strength, progress, and warm laughter,
> Roger
>
> ----- Original Message -----
> From: "Harry James" <welshman@...>
> To: <bolger@yahoogroups.com>
> Sent: Saturday, September 06, 2008 8:55 PM
> Subject: Re: [bolger] Re: Polyester fabric and checking
>
>
>
>> In the Boatbuilding test and I think you have quoted it Ken one layer of
>> Xynole was four times as abrasion resistant as one layer of 6 oz glass.
>> When the test was adjusted for thickness of coating the Xynole was 2
>> times as abrasion resistant. As a practical matter, Xnole or Dynel is
>> much easier to work around corners of chines and such. If I bother with
>> glass at all I will always put Xynole or Dynel on the bottom. Glass on
>> the sides is just to stabilize the wood surface, glass on the bottom is
>> for abrasion resistance, why not do 4x effectiveness?
>> ...
>>
>> HJ
>>
>
>
> [Non-text portions of this message have been removed]
>
>
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Does anybody know what type of abrasion was used in the test on abrasion resistant coverings for boat bottoms? While barnacle covered cobbles and coral sand are both abrasive, they are quite different, and might abrade different materials on boat bottoms at different rates.
For those with only sandy beaches, I got this from the dictionary:
Cobble: a naturally rounded stone larger than a pebble and smaller than a boulder often arbitrarily limited by geologists to a size ranging from 64 to 256 millimeters (2.5-10") in diameter
You get cobble beaches a lot where glaciers deposited glacial till from mountains made up of hard rock, and the beaches are still steep enough that the sand and pebbles are still being washed into deeper water.
In any case, most of the time my boat (that I'm planning on building) will be on beaches with barnacle covered cobbles near Seattle, and the polyester fabric worked better on beaches like this for HJ - thanks HJ for mentioning the type of beach that your boat is typically exposed to.
May your day be filled with clarity, grace, strength, progress, and warm laughter,
Roger
For those with only sandy beaches, I got this from the dictionary:
Cobble: a naturally rounded stone larger than a pebble and smaller than a boulder often arbitrarily limited by geologists to a size ranging from 64 to 256 millimeters (2.5-10") in diameter
You get cobble beaches a lot where glaciers deposited glacial till from mountains made up of hard rock, and the beaches are still steep enough that the sand and pebbles are still being washed into deeper water.
In any case, most of the time my boat (that I'm planning on building) will be on beaches with barnacle covered cobbles near Seattle, and the polyester fabric worked better on beaches like this for HJ - thanks HJ for mentioning the type of beach that your boat is typically exposed to.
May your day be filled with clarity, grace, strength, progress, and warm laughter,
Roger
----- Original Message -----
From: "Harry James" <welshman@...>
To: <bolger@yahoogroups.com>
Sent: Saturday, September 06, 2008 8:55 PM
Subject: Re: [bolger] Re: Polyester fabric and checking
> In the Boatbuilding test and I think you have quoted it Ken one layer of
> Xynole was four times as abrasion resistant as one layer of 6 oz glass.
> When the test was adjusted for thickness of coating the Xynole was 2
> times as abrasion resistant. As a practical matter, Xnole or Dynel is
> much easier to work around corners of chines and such. If I bother with
> glass at all I will always put Xynole or Dynel on the bottom. Glass on
> the sides is just to stabilize the wood surface, glass on the bottom is
> for abrasion resistance, why not do 4x effectiveness?
> ...
>
> HJ
[Non-text portions of this message have been removed]