Thread: Can Interlux Brightside be mixed with epoxy

Modern epoxy fillings are indeed a wonderful thing.
Cheap cask wine & tasteless crackers sans cheese are not.
Thinking seriously about giving up the crackers.

Happily, removal of uncured goo is not my experience. Merely the logical extension of
the fact that one can use a variety of solvents to remove epoxy from one's person. All
of them must do something bad to its structure or you you wouldn't be able to remove
more than what you can scrape off.

Prost!

Originally Posted by andrew allan

And, for what it's worth I have fiberglass kayak, but having just built a wooden boat, I figured, I could ask such questions on this forum.

AA

Howdy AA ... and you are very welcome as the information is applicable to almost any boat.

MIK

If you really want to use epoxy and still have it yellow then you can add powdered pigment - kind of like adding graphite only it's yellow!

I'm not sure about yellow in particular but many pigments are metal oxides and such oxides are often very hard materials. Adding these could well give a harder coating than adding graphite would achieve. This is pure speculation on my part but I think it sounds good.

Having said all that though it sounds like the original suggestion of a sacrificial rubbing strip of timber could be the best.

Andrew, without getting into a drawn out chemical and physical dissertation, which I've done before, but am just not in the mood for tonight, the chemical and mechanical combinations of elements in single and multiple part polyurethane paints and epoxies are dramatically different.

Chemically, the polyurethanes are a pre (single part) or post (two or more part) catalyzed chemical reactions, typically with solvent vehicle(s) to help penetration and keep particulates in suspension, until cure begins (gel stage). In a nut shell they remain the same, but are altered slightly by the solvent(s). As a rule these are 2 dimensional in nature on a molecular level.

Epoxy is a thermost plastic. A polymer created from two chemicals that mate, change each other and become a new substance on a molecular level. This type of reaction is 3 dimensional in nature.

Unlike paint which out gasses it's vehicle (leaches out it's solvents), epoxy (at least the stuff we use in the marine environment) generally doesn't have any solvents at all, relying solely on the chemical interaction of the resin and "activator" to make a new compound, that's 100% solids.

On a chemical level, they (paints and epoxies) have some similarities, particularly in regard to the unmodified prepolymer subunits and some base chemicals, but they interact quite differently with each other, making them incompatible in a cured matrix.

You can harden paints and epoxies for that matter, but generally when you make alterations to the resins, you have to accept some compromises on other physical qualities. For example there are a few different "modifiers" you could use in resin to make it's modulus of elasticity rise dramatically, but the usual trade off is the epoxy becomes more brittle or the paint has too much surface tension (this is how you get "wrinkle" paint BTW). To address the brittleness, the easy thing would be to add reinforcement (fibers), which is exactly what is done in boat building, but this too has a trade off, which is it will no longer be clear, but progressively more cloudy, depending on reinforcement type and content by volume. With paint you might need an emulsifier, but then you'd probably have film thickness issues.


Those of us that actually do fool around with our goo (that sounds kind of fun don't it), do so for one of two reasons. Because we have a good understanding of the chemical and physical changes we're working with or because we don't know any better and haven't had substantial enough of mistakes, to teach us how easily (read costly) it is to screw up a batch of epoxy.

On a personal note, as Michael and a few others know, I'm a straight up kind of epoxy guy, though have been known to enjoy it on toast occasional (usually with a beer for breakfast).

Hi there,
Well after reading this thread, (and like a child with a chemistry set) I thought I'd mix some white brightside paint with some epoxy to see what it would actually do. My thought was that given I had previously found the epoxy thinners were completely useless for cleaning a paintbrush with brightside on it, that they would be so incompatible they wouldn't even mix. Anyway, put a small amount of the paint in with a small mix of resin and hardener and the paint floated on top. So I mixed it a little and it still floated on top. Then I mixed as fast as I could and eventually had it mixed into the epoxy. I then left it for a few minutes, and there it was floating back to the top again though the epoxy now had some colour to it (see picky). I found the only way to keep them mixed (or having the paint adequately in suspension within the epoxy) was to let the epoxy thicken up a but over half an hour or so and then repeatedly mix it. Even then, white flecks of paint were coming to the surface as it set.

Now, see what a water based paint will do . . . and this time keep the paint to goo ratio below 20% by volume.

Twas not much paint at all. Just the scappings off the side of the stiring stick. My prediction on the water based paint is that the water in the paint will react adversly with the epoxy (much like left over glue left out in the rain before it has set).

Don't predict, test. It's the only way, unles you want to absorb a bunch of chemical information you'll never use again.

In a sense it is a pointless experiment because it would be crazy to put something like that on a boat and expect it to a good job - even if it did mix and cure.

The two products are meant to do different jobs.

However I was somewhat interested in a schoolboy kind of way to see what would happen!!!!

Best wishes
MIK

Okay, then you try it too. The next batch of goo you mix, save the last tablespoon full and place a few drops of acrylic house paint in it, mix well and smear it on something. You can perform a peel strength test later, assuming it doesn't just fish eye like crazy and prevent the cure. I'll give you a hint, it will not prevent the cure, if the paint is below 20% by volume.