Thread: Sikabond PVA clamp time

Timbatech recommends clamp times of 90 mins @ 20 degrees or 60 mins @ 30 degrees for their PVA on low density timbers. Given that all PVA glues are essentially the same that should be about right, but I would go with 2-3 hours just to be safe.

If the timber is bent and you're relying on the clamps to close significant gaps in the joins (more than 2-3mm) I would suggest leaving it overnight as the joins will be under a fair bit of tension and may pop open if the glue isn't well set.

The reason the cure time is so wide, is because many things can affect the cure time of PVA, e.g. humidity, temperature, type of substrate being glued.

Originally Posted by China

The reason the cure time is so wide, is because many things can affect the cure time of PVA, e.g. humidity, temperature, type of substrate being glued.

& moisture content of the material to be bonded.

Clamp time is generally minimum of 30 minutes, but that is only one part of the equation. Most manufacturers recommend that the joint not be disturbed i.e. no handling for 12 hours. Most wood workers work on 45 min to 1 hr min clamp time. How and when you clamp up multiple laminates has a significant impact on the quality of the end product.

I like to hold material in clamps for far longer if there is a chance of either side of the glue joint to "move" - warp, twist, cup etc. I generally ease off the clamps but still maintain reasonable clamping force until the moisture content has stabilized across all members in the joint/s. Less chance for movement then.

Thanks guys. Much appreciated.

Originally Posted by China

The reason the cure time is so wide, is because many things can affect the cure time of PVA, e.g. humidity, temperature, type of substrate being glued.

this.

and its probably sold all over the world so its easier to give a longer generic time then what actually happens.