Re: MDO Plywood
--- Inbolger@egroups.com, Vince and Mary Ann Chew
Vince,
Did you epoxy/glass the outside of the hull? Did the MDO soak up a lot of epoxy, more than the raw plywood?
Roger
<vachew@f...> wrote:
Vince,
Did you epoxy/glass the outside of the hull? Did the MDO soak up a lot of epoxy, more than the raw plywood?
Roger
<vachew@f...> wrote:
> I am using 1/2" MDO to build Dakota. I have 50 sheets in the hull so far
> and every seam was tape butt spliced first. See the pics in the Dakota
> folder at the "Files" link.
>
> Epoxy sticks extremely well to MDO. I am using Raka Epoxy which is low
> viscosity to begin with, and I store it in an old fridge with a light
> bulb keeping it above 70 degrees F. It saturates the paper and well
> into the wood.
>
> However, when taping a butt splice, you dish out the wood equal to the
> thickness of the layers of tape you will use. So you are glueing to wood
> not paper. Pre-coat the wood with epoxy. Don't forget to butter the ends
> with thickened epoxy as well. For my splices, I used three layers of 9
> oz. bias tape. I split my 6" tapes with a roller cutter. I cut three
> 48" lengths then ripped two into 2" and 4" strips and one into 3" and
> 3". This is enough for both sides of one joint. I dished the the end of
> each sheet exactly 1/2 the width of the widest tape. Since my widest
> tape was 4", I dished the plywood back 2" on the end of each sheet. I
> have tried several methods for dishing the wood including a power plane
> and a router. What I like best is a 4" angle grinder with a coarse #36
> flap disk.
>
> I work an a table of sawhorses and planks 40' long. I tape both sides at
> once. Instead of using weights, I made up pairs of clamping boards --
> each from two layers of 1/2" MDO cut 9" X 52" with the outer ply grain
> running lengthwise. When I glued the boards together, I rested the ends
> on sawhorses and set enough weight in the middle so they set up with
> about a 1-1/2" bow. In use, I clamp the ends together against the
> curvature. This spreads the pressure evenly across the splice in both
> the top and bottom. Of course, I have to place the plastic, peel-ply and
> the saturated tapes on the lower clamping board and then position it
> under the splice. On top I place the tapes in the splice, then the
> peel-ply, plastic and set the second board on top. I lay my tapes with
> the narrowest innermost, but I am not sure it makes any difference. I
> clamp the ends and let it set.
>
> For the bottom of my boat with three layers, I used one-sided MDO for
> economy since any voids on the backside would be automatically filled
> with thickened epoxy when I laminated the layers together. For the
> topside panels I got two-sided MDO since both sides will show. I paid
> about $38 and $42 respectively.
>
> Vince Chew
Vince,
I like your method better than mine for a couple of reasons, first by
"dishing out" you expose more of each ply layer to epoxy and second
by using mulitple layers of tape with the narrow strip in first all
three layers of tape contact wood. Well done!
One question,
What is a roller cutter?
Rick
--- Inbolger@egroups.com, Vince and Mary Ann Chew <vachew@f...>
wrote:
9
of
I like your method better than mine for a couple of reasons, first by
"dishing out" you expose more of each ply layer to epoxy and second
by using mulitple layers of tape with the narrow strip in first all
three layers of tape contact wood. Well done!
One question,
What is a roller cutter?
Rick
--- Inbolger@egroups.com, Vince and Mary Ann Chew <vachew@f...>
wrote:
>the
> However, when taping a butt splice, you dish out the wood equal to
> thickness of the layers of tape you will use. So you are glueing towood
> not paper. Pre-coat the wood with epoxy. Don't forget to butter theends
> with thickened epoxy as well. For my splices, I used three layersof
9
> oz. bias tape. I split my 6" tapes with a roller cutter. I cutthree
> 48" lengths then ripped two into 2" and 4" strips and one into 3"and
> 3". This is enough for both sides of one joint. I dished the theend
of
> each sheet exactly 1/2 the width of the widest tape. Since my widestI
> tape was 4", I dished the plywood back 2" on the end of each sheet.
> have tried several methods for dishing the wood including a powerplane
> and a router. What I like best is a 4" angle grinder with a coarse#36
> flap disk.
>
> > about $38 and $42 respectively.
>
> Vince Chew
I am using 1/2" MDO to build Dakota. I have 50 sheets in the hull so far
and every seam was tape butt spliced first. See the pics in the Dakota
folder at the "Files" link.
Epoxy sticks extremely well to MDO. I am using Raka Epoxy which is low
viscosity to begin with, and I store it in an old fridge with a light
bulb keeping it above 70 degrees F. It saturates the paper and well
into the wood.
However, when taping a butt splice, you dish out the wood equal to the
thickness of the layers of tape you will use. So you are glueing to wood
not paper. Pre-coat the wood with epoxy. Don't forget to butter the ends
with thickened epoxy as well. For my splices, I used three layers of 9
oz. bias tape. I split my 6" tapes with a roller cutter. I cut three
48" lengths then ripped two into 2" and 4" strips and one into 3" and
3". This is enough for both sides of one joint. I dished the the end of
each sheet exactly 1/2 the width of the widest tape. Since my widest
tape was 4", I dished the plywood back 2" on the end of each sheet. I
have tried several methods for dishing the wood including a power plane
and a router. What I like best is a 4" angle grinder with a coarse #36
flap disk.
I work an a table of sawhorses and planks 40' long. I tape both sides at
once. Instead of using weights, I made up pairs of clamping boards --
each from two layers of 1/2" MDO cut 9" X 52" with the outer ply grain
running lengthwise. When I glued the boards together, I rested the ends
on sawhorses and set enough weight in the middle so they set up with
about a 1-1/2" bow. In use, I clamp the ends together against the
curvature. This spreads the pressure evenly across the splice in both
the top and bottom. Of course, I have to place the plastic, peel-ply and
the saturated tapes on the lower clamping board and then position it
under the splice. On top I place the tapes in the splice, then the
peel-ply, plastic and set the second board on top. I lay my tapes with
the narrowest innermost, but I am not sure it makes any difference. I
clamp the ends and let it set.
For the bottom of my boat with three layers, I used one-sided MDO for
economy since any voids on the backside would be automatically filled
with thickened epoxy when I laminated the layers together. For the
topside panels I got two-sided MDO since both sides will show. I paid
about $38 and $42 respectively.
Vince Chew
and every seam was tape butt spliced first. See the pics in the Dakota
folder at the "Files" link.
Epoxy sticks extremely well to MDO. I am using Raka Epoxy which is low
viscosity to begin with, and I store it in an old fridge with a light
bulb keeping it above 70 degrees F. It saturates the paper and well
into the wood.
However, when taping a butt splice, you dish out the wood equal to the
thickness of the layers of tape you will use. So you are glueing to wood
not paper. Pre-coat the wood with epoxy. Don't forget to butter the ends
with thickened epoxy as well. For my splices, I used three layers of 9
oz. bias tape. I split my 6" tapes with a roller cutter. I cut three
48" lengths then ripped two into 2" and 4" strips and one into 3" and
3". This is enough for both sides of one joint. I dished the the end of
each sheet exactly 1/2 the width of the widest tape. Since my widest
tape was 4", I dished the plywood back 2" on the end of each sheet. I
have tried several methods for dishing the wood including a power plane
and a router. What I like best is a 4" angle grinder with a coarse #36
flap disk.
I work an a table of sawhorses and planks 40' long. I tape both sides at
once. Instead of using weights, I made up pairs of clamping boards --
each from two layers of 1/2" MDO cut 9" X 52" with the outer ply grain
running lengthwise. When I glued the boards together, I rested the ends
on sawhorses and set enough weight in the middle so they set up with
about a 1-1/2" bow. In use, I clamp the ends together against the
curvature. This spreads the pressure evenly across the splice in both
the top and bottom. Of course, I have to place the plastic, peel-ply and
the saturated tapes on the lower clamping board and then position it
under the splice. On top I place the tapes in the splice, then the
peel-ply, plastic and set the second board on top. I lay my tapes with
the narrowest innermost, but I am not sure it makes any difference. I
clamp the ends and let it set.
For the bottom of my boat with three layers, I used one-sided MDO for
economy since any voids on the backside would be automatically filled
with thickened epoxy when I laminated the layers together. For the
topside panels I got two-sided MDO since both sides will show. I paid
about $38 and $42 respectively.
Vince Chew