Thread: Does epoxy stick to silicone?

Pretty sure it doesn't stick to silicone. I was looking at some silicone bowls yesterday that are advertised as suitable for mixing epoxy
Flexible Silicone Bowls - Lee Valley Tools

If that brush spreads nicely then it sure looks like a good option.

As far as a solution for the foam bits, I use disposable bristle brushes. They cost a bit more than the cheapest foam brushes but I find they work very well for epoxy. I trim the bristles down to about half their original length which works a lot better. Make it more of a brush rather than a smear.

My wife uses those same bowls when she goes backpacking. They work well for that.

For mixing epoxy, I use old yogurt containers or the translucent plastic ones you get soup in at the Chinese take-out restaurant. Hardened epoxy pops right out of both of those. You can usually get 7 or 8 uses before they crack. Sometimes more.

Originally Posted by paulie

And I got many reproachful looks from my children as I threw away so much epoxy-covered garbage. They took to calling me "Bigfoot" in reference to my gargantuan carbon footprint.

Kids...

Yeah, I didn't actually get the bowls. I also use old yogurt containers. I've sometimes picked up official plastic mixing tubs when I didn't have any yogurt containers but I've found that they actually don't work as well as the yogurt containers. The official ones seem slightly more heavily built, or at least less flexible, and as a result are much more difficult to re-use.

Epoxy won't stick or affect cured silicone. Nothing I know of sticks to silicone, in fact it's remarkable silicone sticks to anything. So the brush should be ok. Is there something wrong with using a normal paint brush and washing it out in cleaning vinegar before it cures?

Cheers
Michael

To be honest, I didn't know about vinegar until after my boat was done. No one ever told me! I found out around the time I was coating the spars.

But even so, cracking off a glob of hardened epoxy would be a lot easier than washing a brush. And my experience with bristle brushes is that they leave behind bristles, not much better than foam. But maybe it's because I bought cheap ones.

MY 2 CENTS WORTH.

I use micro fibre rollers for epoxy with a short nap 3mm, at around $1.00 each , they are cheap and disposable.

the rollers leave a good finish and do not fall apart,.

Jeff
vk4

Micro fibre? I never saw those on sale at any of the local boat supply stores. I'll have to look harder, or online.

Originally Posted by mic-d

Nothing I know of sticks to silicone, in fact it's remarkable silicone sticks to anything.

Maybe it is like Teflon. By itself, pure Teflon won't stick to almost anything, least of all metal pans. You have to use IMPURE Teflon as a glue layer between the metal and the pure Teflon on top.

Howdy,

There's a whole uncertain area of what constitutes a green approach.

Solvents used to clean up gear are perhaps the biggest health risks, the biggest contributors to greenhouse. But because they are "invisible" it is easy to ignore their effect.

For factories producing consumer items the big areas of improvement, often in response to legislation in the more Green conscious EEC has been the reduction of VOC (volatile organic compounds) and also to reduce waste.

Epoxy is ahead of the game at least on the construction end because the good epoxies are all "high solids" ... little or no added solvents. This is also what gives it the high waterproofness. Add to that the idea of using items for as long as possible and then disposing starts to make sense. I understand that is what the carbon conscious factories do too. The cleanup has too many negative effects.

With epoxy we can use vinegar for cleanup which avoids the volatile organic compounds. The fly in the ointment (epoxy) is any traces of vinegar left on the tools can prevent the epoxy from curing the next time they are used. So generally I would only recommend for tools with hard surfaces that can be rinsed, wiped and dried effectively.

Another factor is good quality disposable stuff. For example I know my friends who sell disposable rollers have had problems finding good quality ones at times. But good quality rollers would certainly do all three coats on the bulkheads or all the coats on a set of foils for the cost of one 3" (75mm) roller. Or maybe 2 to do the whole coating and glass taping of the outside of a goat.

But the problem is always finding a good supply.

Of course it is almost impossible to talk about this in a way that wouldn't seem like hedging to kids. That is the problem faced by all management as a greater requirement to be really green. It is great they keep the pressure on!

In general I think the use of epoxy is a sound environmental choice. It provides protection for the wooden structure (keeping the carbon that makes up the wooden structure out of the atmosphere) so that the structure continues in perfect condition for well over a decade, rather than the slowly increasing leaks and problems of alternative glues and coatings.

It also avoids lots of additional maintenance coats of paint and varnish ... depending on how much sun the structure gets ... So think of how much industrial processing to make paint, solvents to cleanup, rollers and brushes it saves through the years.

I know I use it a lot ... but this photo is Peter Hyndman's Goat after 12 or 13 years. There had been a lot of care to avoid sun contact, but the boat was in the open under covers for years and would collect enough water to turn lifejackets green with mould - just imagine the tropical heat mixed with water in the boat.



The varnish and two pot paint has not been touched once. A real example of how epoxy stabilises the wood fibre so there is no movement in the structure because of humidity, stress, freezing or water ingress or any combination.

I think we will all eventually see more realistic evaluations of green-ness rather than the sort of "making points" version that I am using above.

One that riles me is the "recycling" of plastics ... like shopping bags .. into pseudo wood. REAL recycling seems to me that it should approach the original usefulness of the original raw material. I think the loss of potential pharmaceuticals, as one example, because it is profitable to make disposable shopping bags is a tragedy. Allocation of resources under a market driven system assumes the resource is unlimited. Allocation always moves towards profitability rather than best potential use. So that's the reason for having governments and regulation.

But that is an answer we will gradually struggle towards solutions.

I hope that long lived wood epoxy structures end up on the right side of history! At least they are better than plastic shopping bags and probably fibreglass or aluminium boats.

Look forward to see how the silicon brush goes. If it provides a lot of use without solvent cleanup and without holding vinegar then it will be truly worthwhile.

Best wishes
MIK

Originally Posted by vk4

MY 2 CENTS WORTH.

I use micro fibre rollers for epoxy with a short nap 3mm, at around $1.00 each , they are cheap and disposable.

the rollers leave a good finish and do not fall apart,.

Jeff
vk4

Whoa! Do you have any brand names and/or pics?

Good one Jeff!

MIK

Originally Posted by mic-d

Nothing I know of sticks to silicone, in fact it's remarkable silicone sticks to anything.

Then why is it impossible to remove silicone from anything it is applied to? Silicone caulking is ridiculously impossible to completely remove from any surface it touches.

Originally Posted by BobWes

Then why is it impossible to remove silicone from anything it is applied to? Silicone caulking is ridiculously impossible to completely remove from any surface it touches.

I was being facetious Bob. I know silicone sticks when applied in the uncured state. Cured silicone is another matter if you've ever tried to paint over it or even silicone over old silicone residue. Presumably the brush is made from cured silicone

Cheers
Michael

Well, it sounds promising enough, and the brushes are cheap enough, that I'm going to buy a couple. I have some repairs to do on my Goat and I'm still hoping to find time to build a new boom before sailing season starts, so I'll have a chance to try one out. I'll report back on how well it works.