Wood filler choice

[MJWB]

Morning all. Have a bit of wood filling to do, on deck but in an area which does get wet at times, rainwater, soogee'ing the deck and occassional salt water spray.
Any recommendations on best filler to use please? I'm assuming something epoxy.

 

[Poignard]

I hope it doesn't seem sarcastic to suggest it but the best filler for wood is wood, ie a 'graving piece'.

Fitting a graving piece

 

[MJWB]

I hope it doesn't seem sarcastic to suggest it but the best filler for wood is wood, ie a 'graving piece'.

Fitting a graving piece

Yep noted but I'm talking small cracks which just need sealing/closing before coating and before these become bigger. Not decorative, structural or even very visible, albeit I notice them as I'm looking. When I say on deck I don't mean repairs to a wooden deck. Just mean outside.

 

[Poignard]

Yep noted but I'm talking small cracks which just need sealing/closing before coating and before these become bigger. Not decorative, structural or even very visible, albeit I notice them as I'm looking. When I say on deck I don't mean repairs to a wooden deck. Just mean outside.

In that case, Brummer Green Label Waterproof Stopping is what I have used. Available in various colours.

Brummer Stopping Woodfiller for Interior & Exterior wood, Wood Fillers | Finney's Wood Finishes

 

[WoodyP]

Having spent a lot of the summer repairing sash windows and frames l have been using Timbabuild 2. Part epoxy filler.
Timbabuild Wood Repair – Epoxy Resin for Timber Restoration

 

[MJWB]

Having spent a lot of the summer repairing sash windows and frames l have been using Timbabuild 2. Part epoxy filler.
Timbabuild Wood Repair – Epoxy Resin for Timber Restoration

Many thanks

 

[BobnLesley]

Having spent a lot of the summer repairing sash windows and frames l have been using Timbabuild 2. Part epoxy filler.
Timbabuild Wood Repair – Epoxy Resin for Timber Restoration

I've used that too (a wooden house porch that hadn't been painted in twenty years) and I would use it again if I needed to do a similar job

 

[WoodyP]

I've used that too (a wooden house porch that hadn't been painted in twenty years) and I would use it again if I needed to do a similar job

They actually show it's use in boat restoration. I will let you know in 50 years if it works and was the answer to a maiden's prayer.

 

[thinwater]

Practically any epoxy will also work. Thicken it with colloidal silica or one of many other fillers. Handy trick if you only have a little bit to do. One less products. But yes, I use one of the commercial products if I have it on-hand. They are easier to work and tool.

 

[ducked]

Isnt epoxy too hard to accomodate the sort of movement you might expect from wood (type/species unspecified) on a boat deck?

 

[thinwater]

Isnt epoxy too hard to accomodate the sort of movement you might expect from wood (type/species unspecified) on a boat deck?

A fair point.

Many of the epoxy product mentioned above, like West Systems G-Flex, are softer epoxies with some flex. If the next coat is epoxy, harder is better. If varnish, softer sounds logical. But in reality good bonding is most important. I've done a lot of testing and they will all work as well as the surface finish.

 

[Jim@sea]

I am doing a repair on a wooden porch which has gone rotten, I use ordinary car body filler, one trick I use when filling wood I drill some holes into the wood at an angle so when the filler sets it is less likely to move. Also a trick I did when a was repairing a boat hull which had osmosis, one place on the long keel had bulged again after me just grinding it out, filling it and then painted with two pack paint, after it bulged out I ground it out again quite deeply, I screwed in a stainless steel flat top screw to about 1/4 " of the surface, also drilled holes at an angle, then filled it with body filler, the idea being that the body filler by going underneath the flat top screw head it would "grab" the screw and be less inclined to bulge again. That bulge never came back.

I did my first Grp hull repair in the early 1980's after I bought a 1974 Nauticat 33, the boat had been treated for osmosis on the waterline but in those days International Paints had not started selling Two Pack Paint, so the hull had been painted with ordinary boat paint and it had come back again, but as I had a body shop and could do a respray on a mini with one litre of 2 pack paint, I used Ford Ambassador Blue on the Nauticat Hull and the osmosis did not come back.

 

[ducked]

I am doing a repair on a wooden porch which has gone rotten, I use ordinary car body filler, one trick I use when filling wood I drill some holes into the wood at an angle so when the filler sets it is less likely to move. Also a trick I did when a was repairing a boat hull which had osmosis, one place on the long keel had bulged again after me just grinding it out, filling it and then painted with two pack paint, after it bulged out I ground it out again quite deeply, I screwed in a stainless steel flat top screw to about 1/4 " of the surface, also drilled holes at an angle, then filled it with body filler, the idea being that the body filler by going underneath the flat top screw head it would "grab" the screw and be less inclined to bulge again. That bulge never came back.

I did my first Grp hull repair in the early 1980's after I bought a 1974 Nauticat 33, the boat had been treated for osmosis on the waterline but in those days International Paints had not started selling Two Pack Paint, so the hull had been painted with ordinary boat paint and it had come back again, but as I had a body shop and could do a respray on a mini with one litre of 2 pack paint, I used Ford Ambassador Blue on the Nauticat Hull and the osmosis did not come back.

I've used polyester car body filler on a plywood dinghy, but allegedly it absorbs water due to the (talc?) filler, so wouldn't seem an optimal repair material on something continously submerged, like a boat hull.

Your observation that it bulged on your first repair attempt tends to confirm this, though I suppose it could have been due to residual solutes in the fibreglass

If you used the same materials the second time except for better mechanical keying of the filler, it still may not have been the keying that stopped it bulging. Possible variables include residual solutes in the fibreglass (which might have been less the second time around), variation in making up small batches of filler and thus excess free catalyst/monomer, and differences in paint cover integrity and thickness.