Thread: Outdoor furniture joinery + gap filling

Epoxy should hold if you work it well into the grain.

If you're no good at cutting mortice and tenons (> 1mm) then you probably should use polyurethane, otherwise epoxy is good.

Polyurethane foams up and fills gaps, however the foam is not strong and does not contribute to joint strength.

It is a common myth that polyurethane glue is suitable for joints with large gaps.

Epoxy won't expand to fill a loose joint. But you can put enough in the joint to occupy the gap.

Gorilla glue sucks (at filling gaps)

When I talk about gap filling I mean tear out not joints

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I would just sand the tear out down I would have thought , unless it’s badly splintered up. Sometimes it’s easier to just select another piece of stock rather than spend time on making something looking good, usually it will open up again anyway, especially blackbutt.

Hi Q. Can you eliminate tearout by cutting your boards differently? When I lay decking I use a speed square, circular saw and cut with the underside of the board facing up. Tearout will only be present on the underside (because of the cutting action of the blade) and the seen face will have a nice clean cut.

Originally Posted by pippin88

Polyurethane foams up and fills gaps, however the foam is not strong and does not contribute to joint strength.

It is a common myth that polyurethane glue is suitable for joints with large gaps.

Epoxy won't expand to fill a loose joint. But you can put enough in the joint to occupy the gap.

Gorilla glue sucks (at filling gaps)

Definitely... But if it's lightly used outdoor funiture, which most is, polyurethane is more than enough to hold in a poorly made joint. The joint won't loosen for at least a decade or more. It's a balance between functional and over building.

OP: If you do go the epoxy route then use a saw dust filler or most will settle at the bottom of the joint and be useless.