Injecting half a mold

[fish_4_all]

What is the best way to block of the bottom half of a mold and inject only the top? Not a laminated , as in top half of the whole bait.  I want to only inject the top portion of the mold and not inject the lower eggs. Would it be best to leave the sprue in to the point where I want to start the injection? Would it be better to fill the parts with a couple of the pieces injected prior and leave the sprue completely open?

http://www.basstackle.com/Salmon_egg_sampler_mold_p/401-1-49.htm

I want to only inject the top 3 and not the bottom 2.

I know if I want to inject the lower ones only I will have to block the upper ones with pieces previously poured. I am just not sure if I should leave the sprue in to block the bottom part or do the same with previous pours.

[BareKnuckleJigs]

I would use some plastic that possibly You consider "junk" (I have a bunch of it that I only use to warm injectors and molds), inject the mold You only want to use part of, then cut a section of the runner (plastic) and put it back into the runner where You want the plastic to stop.  I've thought about doing this but have never tried it...so it's just a thought, not an experience, on my end.  I think the main "issue" to be watchful for, is any possibility of Injector Pressure pushing the Runner Plug...which is barely an issue, IMHO.

[ghostbaits]

I do this all the time with lots of molds when testing. Just keep the runner from the previous injection. Cut off where you want it to stop and put runner back in.

You won't have any issues.

Jim