Too dry epoxy hand lay up, will it delaminate?

[Norado]

I did a smaller area starting from sanded dry laminate where I weighed the resin in the pot and the glass before I started. I spread it out a little more generously than before and then weighed the remaining resin. That came out to 38% resin content (and was wetter than previous area). Poured over remaining resin to get to 50:50. That gave me a good idea as to what different contents look and feels like working with. The biax is stitched. It has been chilli in the shop with the boat being maybe 55°F, I've used a fan heater to heat the surrounding air taking care not to heat anything too dramatically. I've also mixed the epoxy in front of the fan getting the pot up to 70 before applying it.

[foufou]

I have found it useful to use peel ply ( a nylon fabric layer) over the last layer. This produces a smother finish and absorbs some of the excess resin without drying out the laminate. It also leaves a slightly rougher texture which would help another bond on top. It peels of easily after the epoxy is cured. And you can always use a shop vac for simple vacuum bagging. F

[UNCIVILIZED]

Hmmm, curious. Might the resin be one designed for infusion? As they're purpose designed to be thin, & flow much better. A viscosity number would also likely tell well enough, as should product name & specific formulation.

Also, when you're weighing things, are you using enough of each so that they're in significant enough quantities for the scale to accurately measure them? Since most instruments often don't do well near either end of their measuring range.

And does the resin as well as your test laminates seem to have good physical properties once cured?

The above said, if the laminates are really that lean, & bonding between layers is a concern, I suppose that you could thicken it slightly (cringe). Or wet out the glass, & then use slightly thickened resin in between these wetted out layers.
The irony being that your "problem" is much the reverse of the one that most people have.


Edit: What's your fabric weight? And just out of curiosity, from what maker? Also, not that it'll solve anything, but pics would be interesting. Especially of the uncured, wetted out fabric.

[TeddyDiver]

Actually with unidirectional and in some extent with Biaxial it's not too hard to get into lower resin ratios with hand layup. Anyways when the area stays relatively small to be squeezed enough.

[ingrid75]

If you have 'starved the lay-up' there is a very good chance that it will delaminate. No matter how much material you put over it. As a wise man once said, "if you don't experiment on scrap, you experiment on your project."

[Norado]

Epoxy is Sicomin SD1500 with SD2503 hardener. http://www.sicomin.com/datasheets/product-pdf39.pdf

Fabric is Biaxial 600 GSM.

I don't think I need to thicken anything I just need to use a little more and not work it that hard.

The gray areas you see in the photos are colloidal silica filler to even out the scored foam that lays underneath the first layer. The gray and green areas have been wetted out equally. It's really hard to judge something like this from looking at a photo, to me it looks like air bubbles all over but that is not the case when you can inspect it up close.

Here is 4 layers of 50:50
https://goo.gl/photos/ac5a7n63dCqshwsJ7

Here is two layers of drier
https://goo.gl/photos/YxVLx1wQcMrXmw8V6

[capngeo]

Originally Posted by Norado

I did a smaller area starting from sanded dry laminate where I weighed the resin in the pot and the glass before I started. I spread it out a little more generously than before and then weighed the remaining resin. That came out to 38% resin content (and was wetter than previous area). Poured over remaining resin to get to 50:50. That gave me a good idea as to what different contents look and feels like working with. The biax is stitched. It has been chilli in the shop with the boat being maybe 55°F, I've used a fan heater to heat the surrounding air taking care not to heat anything too dramatically. I've also mixed the epoxy in front of the fan getting the pot up to 70 before applying it.

Here in Florida, most of the year, we have to chill our epoxy so it doesn't kick off in the bucket!

[HappyMdRSailor]

Originally Posted by Norado

Paul, I've pretty much followed your method but kept squeezing out resin until there was little to no wave in front of the squeegy. The goo that came out was white. Glass still translucent with green core visible.

Thanks for the input everyone!

Perfect end result... Translucent is what you're going for! Try to not "work" the resin with the squeegee so hard or fast to minimize your white resin foam... You're creating air bubbles... Gentle and easy... like frosting a cake... But not too many passes either!

You're doing great...

Originally Posted by TeddyDiver

Actually with unidirectional and in some extent with Biaxial it's not too hard to get into lower resin ratios with hand layup. Anyways when the area stays relatively small to be squeezed enough.

Ain't that the truth!

Originally Posted by Norado

Epoxy is Sicomin SD1500 with SD2503 hardener. http://www.sicomin.com/datasheets/product-pdf39.pdf

Fabric is Biaxial 600 GSM.

I don't think I need to thicken anything I just need to use a little more and not work it that hard.

The gray areas you see in the photos are colloidal silica filler to even out the scored foam that lays underneath the first layer. The gray and green areas have been wetted out equally. It's really hard to judge something like this from looking at a photo, to me it looks like air bubbles all over but that is not the case when you can inspect it up close.

Here is 4 layers of 50:50
https://goo.gl/photos/ac5a7n63dCqshwsJ7

Here is two layers of drier
https://goo.gl/photos/YxVLx1wQcMrXmw8V6

Tough to tell in these pics, but the 2 layer dry looks about "as lean" as I would consider covering... Again, your confirmation was your yard guy... Unlikely he's a neophyte glassman...

Originally Posted by capngeo

Here in Florida, most of the year, we have to chill our epoxy so it doesn't kick off in the bucket!

I was considering reporting this post as inflammatory... Until I got to the banghead...

At least you don't have to have 3 different hardeners like here!

[Redpcx]

If it looks clear, and the next layer is clear, it is saturated. Flat surfaces normally do well, vertical is trickier.

[UNCIVILIZED]

I'm having trouble pulling up the data sheet on the resin. But if you're truly concerned you could always do an improvised peel test, courtesy of some water pump pliers

[Norado]

Thanks again everyone for all the input, I will grind back some fiberglass in the overlap areas and do an assessment. Might try too peel some off if I can grip it!