Delamination with epoxy
 

On my wood Tolman Skiff, I have found a couple of places where two
layers of wood epoxied together are delaminationg. Nothing serious
but if left unfixed would lead to problems. Basically, the directions
said to paint all surfaces with thin epoxy and then before it cured to
spread the thicker and then to join the pieces. So, how am I getting
delamination?
I live in Florida so it is subject to extreme humidity and heat.

Delamination with epoxy
 

Delamination with epoxy
 

In article ,
says...
On Thu, 18 Sep 2008 06:01:39 -0700 (PDT),
wrote:

On my wood Tolman Skiff, I have found a couple of places where two
layers of wood epoxied together are delaminationg. Nothing serious
but if left unfixed would lead to problems. Basically, the directions
said to paint all surfaces with thin epoxy and then before it cured to
spread the thicker and then to join the pieces. So, how am I getting
delamination?
I live in Florida so it is subject to extreme humidity and heat.

epoxy is neither impervious to water, or UV stable. It should not be
thinned, either, as that makes all it's weaknesses even weaker.

I thought Republicans were at least smart enough to read the manual...


What do you mean by "delamination"? Are you referring to glued joints
failing?

I think the first questions would be "did you use epoxy or polyester?"
and "how did you thin epoxy".

I ask as many people do use the term "epoxy" as a description of any two
part system; and the only proper method of thinning epoxy is by use of
rather exotic chemicals that you can't buy at your local paint dealer.
Using acetone, gasoline, alcohol, etc., may make the resin more liquid
for a short period but results in a weaker joint.

--
Cheers,

Bruce in Bangkok
(pbaige125atgmaildotcom)

Delamination with epoxy
 

Delamination with epoxy
 

On Sep 19, 7:07 am, Brian Nystrom wrote:
wrote:
On my wood Tolman Skiff, I have found a couple of places where two
layers of wood epoxied together are delaminationg. Nothing serious
but if left unfixed would lead to problems. Basically, the directions
said to paint all surfaces with thin epoxy and then before it cured to
spread the thicker and then to join the pieces. So, how am I getting
delamination?
I live in Florida so it is subject to extreme humidity and heat.

I think you may have misinterpreted the directions. For laminating, you
need to coat both surfaces with epoxy and allow it to soak into the
wood. You may need to apply more to areas that are particularly
absorbent. Once the surface is sealed, you need to thicken a batch of
epoxy with silica, wood flour, microballoons, etc. and spread that over
the surfaces to be laminated. Clamp the surfaces lightly and allow it to
cure. The purpose of the thickener and light clamping is to prevent the
epoxy from being squeezed out of the joint.

This is West System epoxy and when I mean thinned I mean I simply have
not added thickener like microballoons or microfiber. I did not add
thinner. The epoxy straight from the pumps is mixed and painteed on
the bare wood and allowed to soak in, Then microfiber is then added
to thicken it and strengthen the joint, smeared on evenly and the two
parts are then joined with screws to hold them together. small
amounts of delamination has occurred at two joints that were not
covered with glass

Delamination with epoxy
 

Delamination with epoxy
 

Delamination with epoxy
 

On Fri, 19 Sep 2008 07:30:15 -0700 (PDT),
wrote:

On Sep 19, 7:07 am, Brian Nystrom wrote:
wrote:
On my wood Tolman Skiff, I have found a couple of places where two
layers of wood epoxied together are delaminationg. Nothing serious
some snipped

This is West System epoxy and when I mean thinned I mean I simply have
not added thickener like microballoons or microfiber. I did not add
thinner. The epoxy straight from the pumps is mixed and painteed on
the bare wood and allowed to soak in, Then microfiber is then added
to thicken it and strengthen the joint, smeared on evenly and the two
parts are then joined with screws to hold them together. small
amounts of delamination has occurred at two joints that were not
covered with glass

I'm not sniping just gathering information.

Are you saying that the actual glued joint has failed or partially
failed? I'm a bit confused by the word "delaminated".

If the epoxy glue failed but the joint has screws holding it together
how do you know it has failed? Is there movement in the joint now that
wasn't there originally?

I ask as I build stitch and glue dinghys that have no fasteners.
Several are ten years old and exhibit no problems so far and I have
always considered epoxy to be pretty much a life time glue. However,
if someone else is having problems I certainly want to know as I don't
want to sell a dinghy and have it fall in pieces. (don't want my own
to either :-)


Bruce-in-Bangkok
(correct Address is bpaige125atgmaildotcom)

Delamination with epoxy
 

Bruce in Bangkok writes:

I ask as I build stitch and glue dinghys that have no fasteners.
Several are ten years old and exhibit no problems so far and I have
always considered epoxy to be pretty much a life time glue. However,
if someone else is having problems I certainly want to know as I don't
want to sell a dinghy and have it fall in pieces. (don't want my own
to either :-)

And my boat has seen 22 sailing season so far. No fasteners, just epoxy.
Problems I have had so far have been due to either UV-degradation or
errors in my workmanship.

http://hem.bredband.net/b262106/

--
Martin Schöön "Problems worthy of attack
show their worth by hitting back."
Piet Hein

Delamination with epoxy
 

cavelamb himself wrote:
wrote:

On my wood Tolman Skiff, I have found a couple of places where two
layers of wood epoxied together are delaminationg. Nothing serious
but if left unfixed would lead to problems. Basically, the directions
said to paint all surfaces with thin epoxy and then before it cured to
spread the thicker and then to join the pieces. So, how am I getting
delamination?
I live in Florida so it is subject to extreme humidity and heat.
-------

sounds like the screws used to clamp together the wood was a bit too
tight and squeezed out too much of the epoxy. Result, an epoxy starved
joint. Epoxies don't 'soak in' so a pure surface bond only....

Also note that wood expands and contracts with moisture, epoxy and other
materials with temp. so the two can be 'working' against each other....

paul oman
progressive epoxy polymers inc
www.epoxyproducts.com/marine.html

Delamination with epoxy
 

On Sep 22, 7:08 pm, Paul Oman wrote:
cavelamb himself wrote:
wrote:

On my wood Tolman Skiff, I have found a couple of places where two
layers of wood epoxied together are delaminationg. Nothing serious
but if left unfixed would lead to problems. Basically, the directions
said to paint all surfaces with thin epoxy and then before it cured to
spread the thicker and then to join the pieces. So, how am I getting
delamination?
I live in Florida so it is subject to extreme humidity and heat.
-------

sounds like the screws used to clamp together the wood was a bit too
tight and squeezed out too much of the epoxy. Result, an epoxy starved
joint. Epoxies don't 'soak in' so a pure surface bond only....

Also note that wood expands and contracts with moisture, epoxy and other
materials with temp. so the two can be 'working' against each other....

paul oman
progressive epoxy polymers incwww.epoxyproducts.com/marine.html


The boat is two years old and has had good use.
The delamination is very localized. It shows by the edge of the ply
separating slightly from the underlying wood and showing a crack
sufficient to push in a hacksaw blade a half inch and in one place
over 1 inch. These cracks are from 4" to 8" long. They are in 3
places, one 4" long, one 6" long and one 8" long.
I used slow cure hardener because I was working in the summer heat and
the fast cure would cure before I could use it.