Cuprinol in filler...


Sometime ago there was a discussion about using Cuprinol in filler. I'm probably remembering incorrectly, but I think that it was stated that Cuprinol had changed it's formula and was no longer compatible with oil based filler. Can anyone shed light on Cupinrol's use as an additive to oil based fillers?

Cuprinol is now water-based, so would be incompatible with oil-based fillers. I've used a DAP wood preservative as filler or canvas pre-treat, but a quick web search suggests that is also no longer available and its replacement is water based as well. One thing to watch for with any sort of preservative is the presence of water repellents. Many of these additives are incompatible with subsequent finishes. If the product claims to be paintable, then you may be able to use it to pre-treat the canvas before filling, but I think I'd want to test it thoroughly for compatibility before committing to doing it on a canoe.

Instead of these, I've gone to adding a mildicide paste to my filler - it comes in little packets from the hardware store, and is compatible with oil-based or water-based paints.

Mouth wash

This is a little different but I think it serves the same end result- keep the canvas from rotting. I take two quarts of 'Ceprocal" mouth wash and two quarts of water- put it in the sprayer and use it to wet down the canvas before stretching. I figure that if it can kill all them germs in my mouth, then it ought to kill them little canvas eating microbes. Seems to work- and I have no problems with filler or finish. Lee...:p
Hey, I like that idea. I've tried the mildicide packets in the filler, but not the mouthwash. I like it if it works. Does it give the canoe a "minty fresh" smell?
In Canada, at this point anyway, we can still get this stuff call Wood Preservative, which is Zinc Napthenate. It is much like the old cuprinol, is clear and you can apply straight to the canvas, or use it as part of the thinner component in your filler.
Maybe it is time to make a trip north of the border and stock up. Not sure how much longer we will be able to get it either.

Hi Jim, the mouthwash does have a 'sweet' smell- as my honeybees seem to fly around the wet canvas checking things out but they do not seem to want to land on it. I'm not sure how long the canvas will hold up as I have only been doing this for about seven years -so far so good- we will have to wait a little longer but I will keep all advised. Lee.^....:)

I work at a General Motors facility. We are on a program to dispose of all our oil based paints etc as toxic waste and can no longer purchase / use / store them.

This is a program started by the EPA. Seems oil based liquids are a thing of the past except for special applications. Maybe Cuprinol has changed it's formula in response to this?
What?.... Isn't anyone is going to ask the obvious question, Can the mildewcide packets be used for mouthwash? Or is that one just too obvious?