Epoxy and Hand Lay up Questions?

[tunnels]

and dont forget the leave the pump running to it has all has gone off and your sure it has gone off

After reading your post you really sound like you are only guessing as to the gel time of when your resin Might have gone hard !!
NEVER GUESS !!
you should know instinctively right to the last minute what your gel is !
if you don't know then do a simple test sample before you start !!
guess work is trouble always and when you look at you catalyst dispenser and find its still full the thought of "DID I CATALYSE THAT MIX" ? or didn't I ! races through your head !!
ALL THESE THIS IS FROM HAVING BAD WORK HABITS !

[tunnels]

Yip using vacuum is really interesting and its amazing what it can do for you !
Its also amazing the number of professional people that use it every day but have very limited knowledge of how it actually works !
but there are exceptions and some really knowledgeable guys but they keep things to themselves and don't like sharing anything !
I love your comment about the socks filled with sand used as weights !!am going to remember that forever !

[tunnels]

when you did the test did you lay glass over the core?
Try a new test with a small piece. first set it with cabosill and epoxy mix to some thing. after that sets then lay the cloth over top and pour the resin on top of the cloth and use a spreader to work it over the cloth. make it like a small section of the core with the cloth over the sides.
Add resin as needed to make sure it is all soaked in as it starts to set a little. It is all in the procedure you use. You have to work it as it sets.
Then cut that up and see what you have.
Make sure you contour the edges of the core so the cloth lays nice. If it looks kind of crappie just use a sponge and water with a little dish soap in it to smooth it out as it kicks.
The surface tension of the cloth should hold the resin in the cuts.
Let me know what happens.

wow what comic book did all this info come from ??

[One Oldman]

I am using US Composites 3:1 epoxy. I don't really have any complaints but ambient temperature difference of only 10 degrees or so, or direct sunlight have a fairly profound effect on viscosity and set time. I have used about 12 gls so far and probably had less than 1 pint catch me naked. It does however behave considerably different than polyester. My putty will typically start to thin some after about 10 min in the cup or on a hawk. Depending on conditions sometimes more thickener will need to be added.
Have fun

[tunnels]

I am using US Composites 3:1 epoxy. I don't really have any complaints but ambient temperature difference of only 10 degrees or so, or direct sunlight have a fairly profound effect on viscosity and set time. I have used about 12 gls so far and probably had less than 1 pint catch me naked. It does however behave considerably different than polyester. My putty will typically start to thin some after about 10 min in the cup or on a hawk. Depending on conditions sometimes more thickener will need to be added.
Have fun

Ok lets take a step backwards !!
You need to be observant here ! , do you know why its becomes more runny after 10 minutes ??
what has happened and why ??what has caused it to become runny ??
Try using a bigger shallow container with lots more room for you mix and see what happens !
I would like to know what you find different and why!!
Epoxy is system all on its own and yes is nothing like polyester or Vinylester!. Personally I do not like using epoxy ! Its smelly , sticky and messy crap and at the end of the day has little to no advantages from using vinylester !!

[dwilfong]

Ok lets take a step backwards !!
You need to be observant here ! , do you know why its becomes more runny after 10 minutes ??
what has happened and why ??what has caused it to become runny ??
Try using a bigger shallow container with lots more room for you mix and see what happens !
I would like to know what you find different and why!!
Epoxy is system all on its own and yes is nothing like polyester or Vinylester!. Personally I do not like using epoxy ! Its smelly , sticky and messy crap and at the end of the day has little to no advantages from using vinylester !!

I think you need to wake up and smell the ester..........LOL

[tunnels]

I think you need to wake up and smell the ester..........LOL

The only time I have used epoxy is for wooden boats for glues and glass out side skins that's all !
As for as sticking cores and laminating with its only because of poor work skills and bad workman ship that people us it !!Its not all its cracked up to be ! Its certainly not the holy grail, there's no magic about it !, just over priced and highly over rated , I have replaced parts on boats with decent glass (definitely not woven roving ) and just ordinary general purpose polyester resin that has lasted by years !!, Epoxy high tech state of the art bull **** bits that fell apart in a very short time (some times only a couple of hours ) and came back with outboard motors hanging on with bits of rope !

[One Oldman]

I get basically the same results whether in a cup or spread out on a hawk. I personally think epoxy is a superior product to polyester due to water resistance and bonding strength but both have their pluses and minuses and like most things it becomes a trade off. As far as why it becomes thinner, I think that as it starts to generate its own heat it starts to thin like if you raised the temperature of the resin and hardener before mixing.

[tunnels]

I get basically the same results whether in a cup or spread out on a hawk. I personally think epoxy is a superior product to polyester due to water resistance and bonding strength but both have their pluses and minuses and like most things it becomes a trade off. As far as why it becomes thinner, I think that as it starts to generate its own heat it starts to thin like if you raised the temperature of the resin and hardener before mixing.

Yes so if you use a bigger shallower container then the heat dissipates better and you mix is able to stay at a better more workable consistency !
NOTE ALL RESINS do the same thing AND THE HEAT GENERATED ALSO MAKES IT HARDEN QUICKER !
That is why prepreg materials are special epoxies keep in a freezers sometimes for months at a very low temperature till they are ready to be taken out cut to shape ,laid and rolled with a hard roller !. But then need to be heated for a specified period of time to reach there full potential hardness !
Heat curing is a good thing and can also be done with polyester and vinylester resins and must be strictly controlled BUT NO WHERE near the high temperatures required for prepreg resins . Companies that produce high quality luxury boats leave there almost fully completed boats sitting in the molds for one or two weeks in a 24/7 warmed environment before they are taken out of the mold
This is a subject I will not talk about here on this forum !
There are ways of performing warmth curing during the manufacturing process and achieving very low resin to glass ratios at the same time and does not require a external heat source to make it work!. The resin savings can be and are significant for the amount of glass laid !
so read this http://www.fibreglast.com/product/ab...earning_Center

[W2F a V-King]

when you did the test did you lay glass over the core?
Try a new test with a small piece. first set it with cabosill and epoxy mix to some thing. after that sets then lay the cloth over top and pour the resin on top of the cloth and use a spreader to work it over the cloth. make it like a small section of the core with the cloth over the sides.
Add resin as needed to make sure it is all soaked in as it starts to set a little. It is all in the procedure you use. You have to work it as it sets.
Then cut that up and see what you have.
Make sure you contour the edges of the core so the cloth lays nice. If it looks kind of crappie just use a sponge and water with a little dish soap in it to smooth it out as it kicks.
The surface tension of the cloth should hold the resin in the cuts.
Let me know what happens.

Yes, I laid glass over the core. Just 1 layer of 1.5 CSM. And a single layer of really thin cloth under the scrim back side. I didn't bed it on anything but a thin piece of foam so I could pull it off and look at the penetration of resin on both sides. I wanted to see if the scrim backing dissolved or not. I don't believe it did, but it did clear out like it was fully saturated. I used these materials because I had them laying around. Haven't bought the actual glass yet. Have my list ready for US Composites. Didn't want to make that purchase until I was satisfied with my epoxy test.

This stuff is much better than polyester, IMO. Almost ZERO odor . I have never used Vinyl-Ester, so I don't know how it compares to that. I need a low to no odor resin.
Easy to work with, not messy at all. EASY clean up with ordinary rubbing alcohol. The only down side is the longer set time, but for me working slow by myself, it's a plus. I can roll the boat out into the sun when done with each section and speed up the set time. No heat generated in this either. I was expecting some heat, like mixing poly....NONE.

I will try your Idea, as I did not contour the edge of the core on the test panel, and I can see where that might help keep the kerfs filled up, will also try a panel with some thickened resin as well to see how that pans out.

So when you laid your core, did you spread the kerfs and wet them before bedding?

Or bed the core in place, then after it set, come back and wet, cover with cloth and wet again and work it in with a spreader?

Thank You!

[dwilfong]

I set all my core pieces first with the epoxy cabosil mix. Then I came back and contoured all the edges and made a thicker putty mix to fill in all the edges to make smooth transitions for the glass. After all this setup then I cut my DB 1700 and laid that on top. Then I use a spreader to spread the epoxy around. You can mix a large batch of epoxy and pour it all over and use the spreader to move it around that way it has plenty of time to saturate into everything and extend your kit time because it's not sitting in the pot

[tunnels]

Yes, I laid glass over the core. Just 1 layer of 1.5 CSM. And a single layer of really thin cloth under the scrim back side. I didn't bed it on anything but a thin piece of foam so I could pull it off and look at the penetration of resin on both sides. I wanted to see if the scrim backing dissolved or not. I don't believe it did, but it did clear out like it was fully saturated. I used these materials because I had them laying around. Haven't bought the actual glass yet. Have my list ready for US Composites. Didn't want to make that purchase until I was satisfied with my epoxy test.

This stuff is much better than polyester, IMO. Almost ZERO odor . I have never used Vinyl-Ester, so I don't know how it compares to that. I need a low to no odor resin.
Easy to work with, not messy at all. EASY clean up with ordinary rubbing alcohol. The only down side is the longer set time, but for me working slow by myself, it's a plus. I can roll the boat out into the sun when done with each section and speed up the set time. No heat generated in this either. I was expecting some heat, like mixing poly....NONE.

I will try your Idea, as I did not contour the edge of the core on the test panel, and I can see where that might help keep the kerfs filled up, will also try a panel with some thickened resin as well to see how that pans out.

So when you laid your core, did you spread the kerfs and wet them before bedding?

Or bed the core in place, then after it set, come back and wet, cover with cloth and wet again and work it in with a spreader?

Thank You!

The scrim on the backs of any core balsa or foams is made of fiberglass !!! the only thing that dissolves is the adhesive that holds the scrim in place onto the core !!.
Problem !! , what was you reasoning to used a very thin fine cloth over top of the 1.5 csm and under the core?? this makes no sense to me at all !!
ok lets look at this a little closer , the idea of having csm where it is , is for what reason ??
Are you using it to just hold resin in place till the core is pressed down on top ???
So in reality and fact by having the thin cloth over the top of the csm it is acting like as a filter screen and only allowing resin to pass through and no glass fibers from the csm that are needed to be able to move and flow with the resin and get into all those voids and gaps as you press the core down squashing the resin up into those gaps !So in reality all you have done is compressed the csm and squeeze the resin out !! That's not a good idea at all !!.
REMEMBER THIS BY putting any fine glass cloth anywhere with in any laminate is dangerous !!, IT becomes a perfect shear release line just like using peel ply where in the case of a hard impact the laminate will simply shear very easily along the fine cloth line and come apart like pages of a news paper in the wind !this can and will happen no mater what resin you are using !!

When laying all and any core no mater what it is it needs to be cut to size , shaped, and beveled and rounded parts sanded and placed back in position perfectly before you start the job ! Filling and bogging edges is really bad practice !!

[XstreamVking]

With the slow setting epoxy you will need to add some filler to the resin to prevent run out. Also will be lighter/stronger and use less resin with the putty in the scores of the core than resin alone. I would completely prep the core, set the core with putty, let cure, fill and smooth the scores and edges with putty and then coat the surface with resin and glass over with bi ply right away. No run out to worry with and not gonna get any stronger or easier.

[W2F a V-King]

Made another test panel today with contoured edges to allow the glass to lay down smooth. Will cut it in half tomorrow.

Dave - That soapy water and sponge trick is cool.....allows you to lay anything down nice and smooth as long as it's tacky.

Xstream...I'm liking that route. Easy, lite and strong...

Thank you. Will try to get some pics when I actually start laying this stuff in the hull.

[dwilfong]

Made another test panel today with contoured edges to allow the glass to lay down smooth. Will cut it in half tomorrow.

Dave - That soapy water and sponge trick is cool.....allows you to lay anything down nice and smooth as long as it's tacky.

Xstream...I'm liking that route. Easy, lite and strong...

Thank you. Will try to get some pics when I actually start laying this stuff in the hull.

Yes epoxy is much different than esters in how it kicks. Gives you lots time to play with it. It is a proportional kick not just a lock up like esters.
You can use your finger to smooth out the filler putty also to make good transitions to the core.
There is a epoxy that thins with water also. It is used to pickle water saturated wood in bilges.
Epoxy dose so much more than any old school ester will ever do.
Time for some to wake up to the 21st century and stop smelling the ester.................................................LOL LOL LOL
I found all this out reading comic books you know.