How long do your resin/epoxy fills last...?

[Doug Rasmussen]

I've always stuck with solid wood. But now have beautiful dark to black desert ironwood where I'd like to fill open cracks with black died resin.

I'm asking because my experience with epoxy on boats is not so good. Maybe 15 year or so and cracks, etc.

The desert iron wood is for small oval jewelry boxes for the granddaughters for Christmas. Time flies so I'd like this use to last far longer than 20 years. My wife has a couple boxes I made for her 40 years ago and still like new that were glued up with Weldwood plastic resin glue and flaws filled with a sawdust glue mixture.

Youtube is full of slab table makers bridging the slabs together with epoxy filler that I can't believe will last very many years. It seems to be a newish thing so does anyone know how long they'll last?

I've seen suggestions to use CA glue/sawdust mixture for a filler. Also read that CA has a relatively short life span, something like 10 years or so.

Possibly I could fill the gaps with solid wood, but not even sure what type glue or how long glue lasts on an oily wood like this.

 

[John K Jordan]

Over the years I've seen and felt a number of cracks and turned grooves filled with various things like metals and minerals in resin or epoxy, especially if the filler is thick and rigid. As wood naturally shrinks and expends with seasonal humidity changes many of them show separation or the boundaries can be felt as sharp edges. Worse if the wood is not quite dry when filled causing the filler to sit "proud" of the shrinking surface.

It might be different with a flexible filler that would bond strongly to the contact surface but move with the wood. Is a strong but flexible resin available?

 

[Richard Coers]

Over the years I've seen and felt a number of cracks and turned grooves filled with various things like metals and minerals in resin or epoxy, especially if the filler is thick and rigid. As wood naturally shrinks and expends with seasonal humidity changes many of them show separation or the boundaries can be felt as sharp edges. Worse if the wood is not quite dry when filled causing the filler to sit "proud" of the shrinking surface.

It might be different with a flexible filler that would bond strongly to the contact surface but move with the wood. Is a strong but flexible resin available?

Polyester resin is very brittle, urethane resin is not. I have no idea how flexible urethane resin really is. This is one of the first suggestions given on Google. https://specialtyresin.com/products...LN1me4Nh8xy0Ln_GFSmqLC-1YWvEYuO9YXzBM89jw0cuk

 

[john lucas]

I made several pieces using west system epoxy about 20 years ago. I still have one of them and its just like new.

 

[Steve Tiedman]

I would have the think that that harsh environment a boat lives in, relative to the fairly calm and stable environment most artistic turning live in, may be part of the answer.

If the turning can be allowed to be fully acclimated to its final environment before the epoxy and finishing processes, and if it's final environment is mainly conditioned throughout the year, and even kept from direct sunlight, and not parked in front of heating and cooling vents, and if the gaps being filled are relatively small, and (deep inhale...) a quality adhesive filler material is used, there is a very good chance, in my mind, that Doug probably won't have many, or any, issues.

Does epoxy putty stay more flexible than liquid epoxy? Can it by dyed?

Doug, could you experiment with the Weldwood and dye colors, or dark sawdust (or dark dyed wood that was turned to sawdust) on another piece of wood, just to see how it would turn out through the finishing process? Maybe even Titebond wood glue with dark sawdust, might that remain flexible in the gaps? (Maybe the different Titebond version have different flexibility characteristics.)

There are construction adhesives that remain somewhat flexible, but they probably would not be suitable for woodturning.

 

[Bill Blasic]

I too used west Systems epoxy many many years ago and nothing has happened to it as it is still black and in the piece. I believe it was colored with artist oil paint.

 

[Steve Tiedman]

I too used west Systems epoxy many many years ago and nothing has happened to it as it is still black and in the piece. I believe it was colored with artist oil paint.

Oil paint, no kidding? Huh, I would think the oils and solvents would mess with the epoxy.

 

[Kevin Jenness]

Marine epoxy is degraded by uv light so it needs a uv resistant coating if exposed to significant sunlight. Moderate sized fills in dry wood in a relatively stable indoor environment will last a long time- as JKJ said, seasonal wood movement may cause a resin fill to lose its flush position with surrounding wood. You might want to look to a maker of "river tables" who has been in business for more than ten years to see what they use. This guy seems to know what he is doing, although I didn't find any mention of a guarantee on his site.

West System G3 is made to provide a flexible bond for dissimilar materials but I don't know if it is suitable for filling large voids. Urethane resin is worth investigating. I keep marine epoxy on the shelf for bonding and filling and have excellent results with it for decades.

Epoxy is highly resistant to most chemicals, including mineral spirits, and is a good base for most finishes. I haven't come across anything in my shop that will break down a cured film except scrapers and abrasives.