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Copper Epoxy Filler - Test Results

Penetrating Epoxies - Similar Test Results

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Paul Oman, MS, MBA - Progressive Epoxy Polymers, Inc.

Member: NACE (National Assoc. of Corrosion Engineers), SSPC (Soc. of Protective Coatings)

"Professionals helping Professionals"

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I must have a greedy streak in me because when I learned the prices being charged for solvent thinned epoxy I wanted a piece of the ‘penetrating epoxy' market. After a few tests and evaluations, I gave up and posted what I learned at www.epoxyproducts.com/penetrating4u.html.

I also got excited when I learned some people pay up to almost $300 for a gallon of copper filled epoxy. Wow! ($295 gallon at http://www.copperpoxy.com - this link to Copperpoxy seems to be down as of 4/03). Another opportunity. Once again, lots of tests and experiments. As with the penetrating epoxies, my sense of right and wrong, has gotten the better of me. I simply cannot simply add some copper to our epoxy and charge anyone a few hundred dollars for that small effort. Instead, I'll sell the copper at a fair price and let you add it to your epoxy yourself. This could literally save you hundreds of dollars while letting me sleep good at night. Copper flake/powder, purchased at 25 or 50 pounds at a time is not cheap, but only a few pounds per gallon are needed.

So how much copper do you use? What size copper? Which epoxy to use? I performed a series of experiments to find out.

The epoxy: The thinner the epoxy the better. The 41 micron copper flake we use acts like a thickener. A key issue becomes adding the copper but not getting the mixture so thick that it leaves brush or roller marks, or even becomes a paste. Obviously, the thinner the epoxy is to start with, the more copper you can add before it becomes too thick. The thicker epoxies also lack the uniform ‘new copper penny' look. With the thicker epoxies, the copper color is more like light and dark copper dots.

We are recommending our Low V epoxy for mixing with the copper.

(Low V in our marine catalog) (Low V in our industrial catalog)

We also recommend adding about a quart of Fumed Silica to the epoxy and copper. When added in bulk, fumed silica is an epoxy thickener, but when added in small amounts it provides some internal 'gel' properties to the epoxies, reducing drips and sags that are made worse by the heavy copper pigment. Note that is 'step' is very optional. If looking for a very very smooth finish don't add the fumed silica as it will provide just the smallest amount of 'filler bumps' to the mixture.

(fumed silica in our marine catalog) (fumed silica in our industrial catalog)

How much to use? The copper powder is only a bit heavier than the epoxy. Epoxies weight about 9 or 10 pounds per gallon. A gallon of the copper powder is probably 12-14 pounds. Add between 3 - 6 pounds of copper per gallon of our 810 epoxy. Three pounds will give you a nice, coppery colored finish without brush marks. At 4 to 6 pounds of copper you will certainly leave behind brush or roller marks, but you can sand these out.

If using a medium, or standard thickness marine epoxy, you can probably reduce the amount of copper by 20 or 30%.

We offer a special priced Epoxy/Copper package. Find out more about this in our catalog section on fillers, (mix-ins) under Copper. (copper in our marine catalog) (copper in our industrial catalog)

R.O. emailed Progressive Epoxy Polymers (12/20/09)
Hi,
I have been researching different options for a spring bottom painting and have come across a product advertised in XXXXXXXX Magazine. It is a two part, water born epoxy with spherical copper power for loading the paint prior to application. It is Copper Coat Anti-Fouling Paint, has EPA approval for use as a bottom paint and, according to their website ( www.xxxxxxxxxxxxxx.com) has 2 kg of copper powder per liter of paint. This translates to about 16 pounds per gallon. Have you seen this product and how difficult would it be to load one of your paints with this level of copper?
Thanks in advance. -- R.O.


Hi R.O.

Two things up front: we don't sell copper - epoxy bottom paint. We sell lots of different epoxies and we also sell a very fine copper powder (and other metal powders and epoxy thickeners/fillers). So all we can do is sell you the copper powder for you to blend, mix etc. with whatever you want. I just finished adding it to a water based acrylic to paint the roof of a birdhouse.

Secondly, I checked the website you listed (lots more on that later) - their product is not water based, but rather 'ordinary' 2 part epoxy. Not sure where you got the idea it is waterbased. From my experience, 98% of water based epoxies are only for use on floors.

The product/site you list is misleading. It is a simple basic epoxy with copper added (no problem with that) but then the marketing/sales folks got a hold of it. Lots of missing information and misleading statements. The goal isn't informed customers but rather to separate the customer from his money....

You cannot put 16 pounds of copper into a gallon of epoxy (note: copper powder - copper and air - weight about 1 pound per pint) - at about 6 - 8 pounds per gallon you start making copper putty. You cannot make a copper based coating with that much copper and they don't either. Here comes some of the misleading stuff: their sites claims 2 kg per liter of RESIN. Epoxies are 2 part products, resin and curing agent. Rather oddly on their site they don't tell you the ratio of resin to curing agent but a picture suggests it might be 1 to 1 - thus thinning the resin by half ( or worse).

Their MSDS is dated 2002 (considered out of date and invalid if over 5 years old) shows that the chemicals in the resin account for 54%-65% of the resin weight - so the other 35%-45% is the copper. That is about 3-4 pounds of copper per gallon of resin (not the blend of resin and curing agent you actually work with).

Normally a gallon of mixed epoxy has a coverage rate of about 100-200 sf per gallon. The less coverage the thicker the coating, but drips and sags become a real issue - often better to apply 2 thin coats. Anyway, I calculated their coverage rate and found it to be about 80 sf per gallon. So, it is a pretty thick product - we don't know how thick or thin the epoxy was to start with before the copper was added, but still at 80 sf per gallon, it suggests enough copper was added to make it quite thick.

They also do not mention price, so I have no idea what they want for the product but giving general retail pricing, they probably have a gallon of epoxy at about $70-$90 per gallon and perhaps $40 worth of copper. So, about $110 per gallon would be an expected price that still leaves the vendor making lots of profit.

So, bottom line --- I'm sure it is a functional mix of copper and epoxy worked out by someone who knows what is going on. However, their web site is not being very honest and open with you. It is your call if you want to do try their product.

paul oman

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Copper and our Low V epoxy used to create a copper roof on this birdhouse

A third-party reseach article on and about copper boat bottoms. Very informative and interesting, thanks to one of our customers for passing along the link - http://www.copper.org/innovations/2003/Nov2003/Cu_hull_sheathing_gg.htm

ANOTHER IDEA: ADDING THE COPPER POWDER TO AN INEXPENSIVE MARINE BOTTOM PAINT.....

Web site of someone using this copper with epoxy on a boat bottom (2/03)- CLICK HERE

Already know what you want?

Goto our 1-line product/price summary page MARINE or INDUSTRIAL

Knowledge is Power - We like informed consumers!

Learn the basics of epoxy at our educational EPOXY 101 page - Click Here.

Finally, email us back with your questions or comments before you buy - EMAIL HERE

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