A method of forming a three-dimensional object is provided herein, which may be carried out by: (a) providing a carrier and a fill level, the carrier and the fill level having a build region therebetween; (b) filling the build region with a polymerizable liquid, the polymerizable liquid comprising a mixture of (i) a light polymerizable liquid first component, and (ii) a second solidifiable component that is different from the first component; the polymerizable liquid further comprising a Lewis acid or an oxidizable tin salt in an amount effective to accelerate the formation of the three-dimensional intermediate during the irradiating; and (c) irradiating the build region with light to form a solid polymer scaffold from the first component and also advancing the carrier away from the build surface to form a three-dimensional intermediate.