mark poulson

Without seeing the actual bubbles, I'd say the problem you have is shrinkage of the plastic. I'd guess that the plastic is hottest, and therefore shrinks the most, when you pour the tail first, and that might be causing your bubbles. Typically, the srinkage in a open mold shows up as a dishing of the back. Even Roboworms' top pours, which are computer controlled, have dished faces. Pull one out and check it. The tail is tall and thin, and that may exaggerate the shrinkage from the hot plastic. Since it's an open mold, you might start pouring from the head to the tail, and only fill the whole mold partially to begin with. The plastic will still be hot enough to melt into itself if you go over it again right away, but that might cut down on the amount of shrinkage in the tail. Hope this helps.

I typically pour 4oz of plastic at a time, with an ounce of softner, and an ounce of salt, plus some flake. I add the salt and flake after the plastic is up to 360+-, and stir them in with a thin blade screwdriver, which has a soft rubber handle that doesn't get hot. If I stir very slowly, I get no bubbles, but I have to reheat the plastic before I pour, and I still have to stir it again to keep the flake and salt in suspension. On fatter bodies, like Ikas, it' not a problem, since the bubbles typically rise up through the hot plastic into the sprue hole. But on thinner worms, sometimes they get trapped. Is there a "secret" to stirring plastic without creating bubbles, aside from buying a mixing pot with a built-in stirrer?

Hahaha. They all seem crude to me, but they do the job.

If it's an open pour mold, do you start at the tail?

Found it.

Thanks for the links Dave. My POP molds are all made with pine borders and plywood backs, so I don't worry about damaging the POP with an adapter. I'll probably make a temporary reservoir from duct tape, and fill it as I inject, so there will be enough hot plastic to draw back down into the smaller sprue holes as the plastic cools and shrinks. That way, if it works, I can make a "permanent" adapter, and, if it doesn't, I'm not out a lot of work for nothing. I actually already use duct tape around the outside of my two part POP flick shake mold, and I don't have those problems with those worms. You'd think, since I already solved the problem by accident once, I'd remember how to do it the next time. Doh!!!! CRS bigtime!

Dave, What insert idea are you talking about? I can't find it with the search feature. Since the bubbles/hollow occurs at the top of the worms, I'm assuming the mixing air bubbles that normally make their way up and out when I pour are trapped by the narrow sprue, so the plastic cools on the sides of the POP mold at the top, and the trapped air makes that end hollow. I thought enlarging the sprue hole, or making it taller, so there would be a reservoir of hot plastic at the top that could be sucked back down into the top of the worm, would solve the problem.

Dieter, I was remembering the link from Finland.

For the amount I pour, it holds up fine. I am carefull not to cross thread the assembly when I am reassembling it after I clean it out. I spray PAM into the cylinder before I insert the plunger, and lower the entire tip assembly end into the hot plastic for a second or two before I pull back slowly on the plunger to fill the cylinder. I can inject two+ ounces before it gets too cool, and the plastic starts to thicken. I cut the original needle tip down to about 3/8" long, and drill the sprue holes in my POP molds to 1/4" diameter, which is a pretty snug fit, but leaves room for the plastic to overflow when the cavities are full. I've had good luck injecting flick shake and thin senkos, but I get a hollow tip at the sprue end with 5" full size senkos. I think I will either enlarge the sprue hole, so there's enough plastic to backfill the hollow end, or hand pour the larger worms. The specs on the injector say it's nickle plated brass, so it gets hot really quickly. I wear gloves when I use it.

Another member here, Diemai, has posted a link to a European site with crank making info. Do a search for Diemai, and you'll find it.

I prefer hand pouring, but I bought a Cajun injector for doing thin worms, like the flick shake and thin senkos, which are almost impossible to hand pour. I actually was going to try to adapt an open faced lizard mold to inject, but found it's much easier to hand pour it sloppy, and then press a piece of smooth plywood down on the open mold to make the overflow thin, and then trim it with an exacto knife once it's cooled. It only works because I pour for myself, not for sale, but it is simple and quick.

Amen!

It's about time. Clear lures with hilites catch fish!

I think curing time is critical with any top coat. I use a water based "interior" urethane by Target Coatings, and the instructions say to wait 2 hours between coats. I dip my lures in a salsa dipping jar. I've played around with it, and found that I can cut the recoat time to an hour, if I hit the lure with a hair dryer on low after a half hour, and once again 15 minutes later. The heat setting also seems to make the coating stronger, since I've never had a failure, while others who use the same brand have reported problems. As far as I can figure out, the heat setting is the only thing I do differently. I typically do two coats on cranks, and three on swimbaits, or cranks I've made from PVC.

Do you heat your plastics in that cup in a microwave?

Thanks Smallie. That's exactly what I'm looking for. Del nailed it! I'll have to get some of his night crawler, and give it a try.

My pig stye...errr... work area is in my gallery, on page 4, I think. I haven't figured out how to post pictures here in the forum yet, so the gallery is the best I can do.

I've bought a couple of lures from him, and they work. I bought the square bill shallow, adjustable weight crank, and the MegaBass shallow runner knockoff, the one that has bulging eyes. I also bought his DT16 knockoff, and it is good, too.

That bait looks great!

Rookie, That's funny, because I heard it was your misplaced ballast that was killing the action. Of your lure, I mean.

+1

I've never poured a hard plastic or resin bait, so any issues with offgassing are better left to others. But I have had top coat failures with D2T, and I use Createx, so I can comment on that. Other than water intrusion from cracks in the epoxy due to impacts (operator error), all my problems can be traced to solvent or moisture trapped under the top coat. My failures were from not heat setting each coat of paint, starting with the rattle can primer, enough to insure that either all the solvent was driven off, in the case of rattle can paints, or that the molecular cross linking had taken place and all the water was driven off, in the case of water based paints.

Dave, I love your machine. Great idea, and great execution.

My buddy named my four piece swimbaits the QT, for quatro trout.