Cutting ply

I cut gentle curves by hand with a pullsaw.... cuts faster and smoother than
a jigsaw.... but not round *tight* curves.

"Brian" <dont.even.DeleteThis@think.about.it> wrote in message
news:4266370f$1@clear.net.nz...
 > Does anyone have any tips on the best ways to cut marine ply (6, 9 and
 > 12mm)? In particular I want to cut curved 8' boards for a dinghy. So I
 > guessing that a band saw is a good bet but I don't have one. Are there any
 > other methods that can produce good results?
 >
 > Thanks<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Cutting ply 

On Wed, 20 Apr 2005 23:08:28 +1200, Brian <dont.even DeleteThis @think.about.it>
wrote:

 >Does anyone have any tips on the best ways to cut marine ply (6, 9 and
 >12mm)? In particular I want to cut curved 8' boards for a dinghy. So I
 >guessing that a band saw is a good bet but I don't have one. Are there
 >any other methods that can produce good results?
 >
 >Thanks

A power jig-saw does good work, if equipped with the right blade. A
fine metal blade might be better for thin sheets, which otherwise show
one ragged edge unless backed.

Brian Whatcott Altus, OK<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Cutting ply 

skil saw


"Brian" <dont.even.DeleteThis@think.about.it> wrote in message
news:4266370f$1@clear.net.nz...
 > Does anyone have any tips on the best ways to cut marine ply (6, 9 and
 > 12mm)? In particular I want to cut curved 8' boards for a dinghy. So I
 > guessing that a band saw is a good bet but I don't have one. Are there
 > any other methods that can produce good results?
 >
 > Thanks<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Cutting ply 

One extra hint. When cutting splintery wood like meranti. Lay a batten
along the finish cut line and score the top side with a crate knife before
starting the cut with an up cutting saw like a circular or jigsaw. It
prevents chipping of the face veneer so you will end up with a much cleaner
edge. Not needed with a reasonably fine toothed a band saw.

Saw outside the line and trim to it with a plane, router or belt sander.
For long slow curves I use a circular saw set just deeper than the sheet. I
do the gross trimming with a power plane and finish up with a low angle
block plane.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: <a style='text-decoration: underline;' href="http://www.rutuonline.com" target="_blank">http://www.rutuonline.com</a>
Shameless Commercial Division: <a style='text-decoration: underline;' href="http://www.spade-anchor-us.com" target="_blank">http://www.spade-anchor-us.com</a>

"Brian" <dont.even.RemoveThis@think.about.it> wrote in message
news:4266370f$1@clear.net.nz...
 > Does anyone have any tips on the best ways to cut marine ply (6, 9 and
 > 12mm)? In particular I want to cut curved 8' boards for a dinghy. So I
 > guessing that a band saw is a good bet but I don't have one. Are there any
 > other methods that can produce good results?
 >
 > Thanks<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Cutting ply 

Depends on what kind of saw you happen to have.

An electic circular saw can follow a curved line because the blade only
has to be set very shallow. Use a thin kerf blade with lots of teeth. I've
used a blade with 40 teeth. They make a special plywood blade with many
more teeth but I haven't found it to be any better. The only problem with
a circular saw is they tend to be heavy so the plywood should be well
supported and you have to go slow. I've found the thin blade of a jig saw
(sabre saw) can wander off the line pretty easy to you have to be careful.
You can also try sawing through masking tape to reduce tearing along the
edge. The jig saw and circular saw blades cut on the upstroke so the tape
has to be on the top side.

Brian (dont.even@think.about.it) writes:
 > Does anyone have any tips on the best ways to cut marine ply (6, 9 and
 > 12mm)? In particular I want to cut curved 8' boards for a dinghy. So I
 > guessing that a band saw is a good bet but I don't have one. Are there
 > any other methods that can produce good results?
 >
 > Thanks


--
------------------------------------------------------------------------------
William R Watt National Capital FreeNet Ottawa's free community network
homepage: <a style='text-decoration: underline;' href="http://www.ncf.ca/~ag384/top.htm" target="_blank">www.ncf.ca/~ag384/top.htm</a>
warning: non-FreeNet email must have "notspam" in subject or it's returned<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Cutting ply 

On the first stitch and glue dinghy I built, I did it slow and carefully
with a jigsaw, and a block plane to finish.

The second I used just a jigsaw.

The third I used a jigsaw and tried to go as fast as possible. Errors
greater than 1/4" were trimmed with the jigsaw. But otherwise it all
got hidden in the tape seam anyway.
 >> Stay informed about: Cutting ply 

Nice boat you are building! One day I would like to try something so
elegant.

The idea with the router is so obvious. I have used the same idea for
straight edges with ply in the past and got great results. I don't know
why I didn't think of using a batten and doing curves the same way. I
also like the jigsaw jig idea.

Thanks for this tips.

Meindert Sprang wrote:
 > "Brian" <dont.even DeleteThis @think.about.it> wrote in message
 > news:4266370f$1@clear.net.nz...
 >
  >>Does anyone have any tips on the best ways to cut marine ply (6, 9 and
  >>12mm)? In particular I want to cut curved 8' boards for a dinghy. So I
  >>guessing that a band saw is a good bet but I don't have one. Are there
  >>any other methods that can produce good results?
 >
 >
 > Pre-saw with an electrical jig saw, outside the lines. Nail a batten down on
 > the lines and use a router with trimming bit, rolling along the batten.
 > Makes a Perfect cut.
 >
 > You can also tack the batten down first and slide the jigsaw aloing it, with
 > a block screwed under the sole in such a position that the blade cuts about
 > 1/8 to 1/4" from the batten.
 > See my website at
 > <a style='text-decoration: underline;' href="http://www.customware.nl/boats/en/index.html," target="_blank">http://www.customware.nl/boats/en/index.html,</a> look in the diary at February
 > 19 for pictures.
 >
 >
 > Meindert
 >
 ><!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Cutting ply 

I had not heard of a pullsaw but have read up on them and they sound
worth looking into. The idea of a narrower cut due to narrower blade
makes a lot of sense.

I will keep my eyes open for one in the shops.

Thanks for the info.


James wrote:

 > I cut gentle curves by hand with a pullsaw.... cuts faster and smoother than
 > a jigsaw.... but not round *tight* curves.
 >
 > "Brian" <dont.even RemoveThis @think.about.it> wrote in message
 > news:4266370f$1@clear.net.nz...
 >
  >>Does anyone have any tips on the best ways to cut marine ply (6, 9 and
  >>12mm)? In particular I want to cut curved 8' boards for a dinghy. So I
  >>guessing that a band saw is a good bet but I don't have one. Are there any
  >>other methods that can produce good results?
  >>
  >>Thanks
 >
 >
 ><!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Cutting ply 

Today I have bought some fancy blades which I am told should do a better
job than the standard blades that came with the jigsaw.

They are bosch "clean for wood" - "clean cut" blades with 1.4mm pitch
teeth. I will post an opinion when I try them out.

Thanks for the reply

Brian Whatcott wrote:

 > On Wed, 20 Apr 2005 23:08:28 +1200, Brian <dont.even.TakeThisOut@think.about.it>
 > wrote:
 >
 >
  >>Does anyone have any tips on the best ways to cut marine ply (6, 9 and
  >>12mm)? In particular I want to cut curved 8' boards for a dinghy. So I
  >>guessing that a band saw is a good bet but I don't have one. Are there
  >>any other methods that can produce good results?
  >>
  >>Thanks
 >
 >
 > A power jig-saw does good work, if equipped with the right blade. A
 > fine metal blade might be better for thin sheets, which otherwise show
 > one ragged edge unless backed.
 >
 > Brian Whatcott Altus, OK<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Cutting ply 

You are right about the weight of the circular saw. I don't think the
beast I have would work very well. Using masking tape is an interesting
idea but it would of course require that the lines be drawn on the tape.

I have been looking at circular saw blades but have not found anything
specially of ply. I will look for something thin with lots of teeth though.

Thanks

William R. Watt wrote:

 > Depends on what kind of saw you happen to have.
 >
 > An electic circular saw can follow a curved line because the blade only
 > has to be set very shallow. Use a thin kerf blade with lots of teeth. I've
 > used a blade with 40 teeth. They make a special plywood blade with many
 > more teeth but I haven't found it to be any better. The only problem with
 > a circular saw is they tend to be heavy so the plywood should be well
 > supported and you have to go slow. I've found the thin blade of a jig saw
 > (sabre saw) can wander off the line pretty easy to you have to be careful.
 > You can also try sawing through masking tape to reduce tearing along the
 > edge. The jig saw and circular saw blades cut on the upstroke so the tape
 > has to be on the top side.
 >
 > Brian (dont.even@think.about.it) writes:
 >
  >>Does anyone have any tips on the best ways to cut marine ply (6, 9 and
  >>12mm)? In particular I want to cut curved 8' boards for a dinghy. So I
  >>guessing that a band saw is a good bet but I don't have one. Are there
  >>any other methods that can produce good results?
  >>
  >>Thanks
 >
 >
 >
 > --
 > ------------------------------------------------------------------------------
 > William R Watt National Capital FreeNet Ottawa's free community network
 > homepage: <a style='text-decoration: underline;' href="http://www.ncf.ca/~ag384/top.htm" target="_blank">www.ncf.ca/~ag384/top.htm</a>
 > warning: non-FreeNet email must have "notspam" in subject or it's returned<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Cutting ply 

I do like the idea of trimming with a router because my experience using
jig saws is wavey.

Thanks


Glenn Ashmore wrote:

 > One extra hint. When cutting splintery wood like meranti. Lay a batten
 > along the finish cut line and score the top side with a crate knife before
 > starting the cut with an up cutting saw like a circular or jigsaw. It
 > prevents chipping of the face veneer so you will end up with a much cleaner
 > edge. Not needed with a reasonably fine toothed a band saw.
 >
 > Saw outside the line and trim to it with a plane, router or belt sander.
 > For long slow curves I use a circular saw set just deeper than the sheet. I
 > do the gross trimming with a power plane and finish up with a low angle
 > block plane.
 ><!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Cutting ply 

Very interesting idea. I was wondering how much could be covered by the
taped seam. Also the fact that some overlap is built-in to the design to
be trimmed later means that for at least half the cuts I don't need to
be too accurate.

Thanks

Evan Gatehouse wrote:

 > On the first stitch and glue dinghy I built, I did it slow and carefully
 > with a jigsaw, and a block plane to finish.
 >
 > The second I used just a jigsaw.
 >
 > The third I used a jigsaw and tried to go as fast as possible. Errors
 > greater than 1/4" were trimmed with the jigsaw. But otherwise it all
 > got hidden in the tape seam anyway.
 >
 ><!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Cutting ply 

"Brian" <dont.even.TakeThisOut@think.about.it> wrote in message
news:426777be@clear.net.nz...
 > Nice boat you are building! One day I would like to try something so
 > elegant.

Thanks. Well, it wasn't too difficult. After all, it was our first boat we
built.
I need to update the site, she's already sailing for two years...

 > The idea with the router is so obvious. I have used the same idea for
 > straight edges with ply in the past and got great results. I don't know
 > why I didn't think of using a batten and doing curves the same way. I
 > also like the jigsaw jig idea.

The jigsaw jig made the job very easy. Once setup, it's just a matter of
tacking the batten in the right shape, run the jigsaw, run the router and 10
minutes later you have perfectly cut strake which looks like it's been
laser-cur. But indeed, the obvious solutions often aren't so obvious..

 > Thanks for this tips.

My pleasure!

Meindert<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Cutting ply