Regular PVC T pipe fittings make good stock material to properly orient and isolate antenna elements from the boom.
Shown are four T fittings: one for the LFA reflector, one for the Director and two for the full-wave loop.
Note a pipe is glued into the middle fitting to strengthen and thicken the portion holding the element. Each fitting will have a 5/8 inch hole drilled perpendicular to the T axis.
After using this technique for a while, I find they work pretty well for temporary situations like Field Day, but do not hold well enough for permanent installations.