What is the maximum thickness for a single layer of epoxy?

The maximum thickness of an epoxy resin layer varies by the type of resin.

Primaloc Bar & Table Top Epoxy

Primaloc Bar & Table Top Epoxy should be applied in 1/8 inch layers. This is the thickness that the epoxy resin self-levels at, and it's the ideal thickness to prevent air bubbles from becoming trapped.

You can apply additional layers of table top epoxy to achieve greater finish depth. Simply wait 4 hours (no more than 10 hours) after applying the previous layer and removing any air bubbles, then apply a fresh batch on top of the partially cured finish. If done right, this new batch will blend seamlessly with the previous one, becoming a thicker overall coating.

If more than 10 hours have passed since the previous layer, you'll need to sand that layer with sandpaper between 220 and 320 grit.

Please note that after a depth of 1 1/2" the epoxy can start to lose some of its clarity. This is due to the subtle bending of light as it passes through thick materials.

Primaloc Deep Pour Epoxy

Primaloc Deep Pour Epoxy can be applied in layers up to 2 inches thick. This aspect makes it ideal for projects like river tables and filling large resin molds.

If needed, you can apply additional layers after the first. This is safe up to 6 inches thick, beyond which you may start experiencing issues. To accomplish this, simply wait 12 hours after you've applied a batch to allow it to partially cure, then apply the next one. For layers beyond the first, limit the thickness to 1 inch. This will avoid various issues such as excessive air bubbles.

Note: The reason why Deep Pour Epoxy requires a longer wait between layers is because it has a lower viscosity rating and needs more time to adequately solidify and present as a suitable bonding surface.