Yes, I have had experience with this filler. It is not my first choice for a filler and it is not what we use.
The product they are using is called Gluvit. It is not made, nor specifically marketed as a filler. It is a three step process that takes anywhere from 3-7 days to fill a canoe and once the third coat goes on it is ready for paint in about 2 weeks. The draw backs as I see them are:
-It is not cheap. In fact it is quiet expensive 5-6 times that of oil base.
-It is toxic and labor intensive. The fumes are rather intense but they disappear much quicker than those of oil base fillers.
-The learning curve for a smooth streak free finish is high, but in reality the learning curve of oil base filler, in which one knows all the ins and outs, is high too. In fact achieving a knowledge about oil base filler, its application, and predictability is perhaps even higher.
- It also somewhat labor intensive from the time you first start to apply it until that first coat of paint goes on. Not only is the application and sanding more physical than oil base, there is twice the amount of labor involved in terms of man hours.
-It requires about 4-5 times the amount of sanding compared to that of oil base filler.
-During application and curing, it does not like to encounter sub freezing temperatures. Once fully cured, about 2 weeks, and when that first coat of paint has gone on it doesn’t matter what the temperatures are.
-It’s somewhat finicky about how it gets mixed. If it is not done well, and you apply it to the canvas, forget it. There is nothing you can do short of tearing the canvas off and starting all over again.
- It is more difficult to patch when torn because of how the canvas reacts to being torn. Under/over patches are doable but not nearly as easy with a canvas that has been filled with oil base filler. It is nearly impossible to sewn the canvas back together if the tear is big enough. It has also been my observation that when the canvas tears due to hitting a rock the tear will be longer on canvas filled with gluvit and will be shorter with oil base..
So what in the world could the benefit of this goop as a filler possibly be? Predictability and stability. There is absolutely zero guessing game as to how it will fair. It is eons more stable than oil base filler. It is rugged, the paint never blisters, never peels, and never cracks. You can fill your canoe up like a bath tub and let it sit for months and you will never experience paint blistering or lifting. This cannot be said for other fillers especially ones that contain lots of linseed oil. Heck wet grass can cause blisters to form on oil base filler.
Good points WoodNCanvas. I know of builders that use West System as their filler and they report good results. I do not have experience with west system as a filler so my comments are not based toward this product.
I was still curious to know more so I asked: I thought epoxy/canvas would eventually cause cracking ('spider web') of paint.....and less elasticity....that's why 'traditional' filler used by most wood canvas builders I'm aware of is linseed oil based
Yes, some might think this is too hard of a filler, that it doesn’t have enough flex. There is no doubt about it that it makes the canvas/filler system a more ridged covering or shell but it retains enough flex.
If you think about it the epoxy is stronger than the canvas so the flexing of the canvas is not going to break or crack the epoxy filler. The epoxy retains enough pliability to allow the hull to flex. Because nothing is bonded or adhered together nothing cracks or breaks.
I have never seen Gluvit prematurely crack under normal conditions or but have seen it do so under extreme conditions.
It (including the canvas) starts to become brittle in about 15-20 years. What happens is the canvas will start to pull apart in random places like someone slit the canvas with a knife. This usually only happens in one or two places and is isolated to 1-3 inch long slits.
The epoxy canvas shell does not like it when high amounts of moisture are trapped between the canvas and the hull. Normal conditions seem to be fine but because the epoxy acts as such a bomber barrier against liquid water and water vapor, when it is exposed to prolonged periods (an accumulation of years) of moisture being trapped inside, the canvas will start to crumble.
Oil base fillers seem to do a better job when moisture is trapped because of their ability to let water pass through them. But, this ability can also be a serious disadvantage………
Paul,
No, the epoxy does not soak all the way through the canvas to the hull. The weave absorbs it just like oil base filler. In fact the weave of the canvas may absorb slightly more oil base filler than the epoxy because of the difference in viscosity of the two.