How To Make 2 Piece Pop Mold - Newbie

[Semi22lr]

New to mold making and looking for some links to articles or posts on step by step process to make a 2-piece worm mold. In particular I want to make a mold to duplicate a Zoom Super Fluke. Just doing some research at this point. Have searched this site and not found any detailed instructions but I may have missed it. Any help is greatly appreciated.

Thank you very much,

Mark

[mark poulson]

I've mad a couple of POP molds that work.

First, I made a box, with a 3/4"X2" pine frame, and 1/4" plywood top and bottom. For my latest Ika mold, the box was 3"X12" inside, 4 1/2"X13 1/2" overall, and 2" deep.

After I made the box, I cut it in half lengthwise on the table saw, so I had 2 4 1/2"X13 1/2"X 1 1/4" halves. I put the halfs back together, and drilled a through hole at each end for 16D nails, which I use to align the halves.

I put a row of drywall screws through the pine into the cavity, to act as keys to lock in the POP, and cut strips of fiberglass drywall tape to lay into the cavities to reinforce the POP.

Then I mixed up the POP, filled one half of the mold, and layed in 12 fat Ika bodies so they were embedded half way, spaced so they were tight to one side, and had about 1/2" between each Ika body.

I used a putty knife to try and smooth the POP around the Ika bodies, and a fine artist's brush with water to wash the POP off the Ika body parts that were exposed.

The POP set in about 1/2 hour, and then I put it, with the Ika bodies still embedded, into my oven, set at 170, and let it dry for another half an hour.

Then I sprayed the POP with spray Pam, trying to keep as much as possible off the exposed Ika bodies. The Pam dried quickly, in another half hour, since the first mold half was still warm from the oven.

Then I filled the second half of the mold with POP, leaving it a little less than full to allow for the Ika bodies. I brushed some POP onto the exposed Ika bodies, to be sure all the details were covered, and then set the first mold half down onto the second half, the one with the wet POP in it, and used the 16D nails to align them.

I clamped the two halves together, turned the mold over so the wet POP was on top, and tapped the mold with a screw driver's rubber handle to help any air bubbles move away from the Ika bodies. The POP had squeezed out of the sides a little when I clamped the halves together, but I wanted to get as many air bubbles away from the Ika bodies as possible.

In another half hour, the second POP mold half was set, so I separated the two halfs with a screwdriver, and put the second half into the oven at 170 degrees for half an hour.

While I was waiting for the second half to dry, I used a drywall knife to cut air vent grooves from the Ika body cavities in the first mold half to the pine mold sides. They wound up being about about 1/8" wide.

Once the second half was dry, I removed the Ika bodies from the first mold half, and brushed carpenter's yellow glue, cut 50% with water, over both the mold halves. I used a soft brush, because the details of the molds were still soft at this point. It's important that you clean the mold halves before you glue them, because the glue will make whatever's in them almost impossible to remove.

Once I'd covered everything with the diluted glue, I tipped the molds up to drain out any extra glue, and used compressed air, gently, to blow any excess glue out of the mold cavities.

I let the glue dry overnight, and the next day I used a dremel to grind out spru holes for the Ika bodies, and to extend the vent holes through the pine.

Then I put the halves together, aligned with the 16D nails, and clamped them again.

I heated my plastic, and, VOILA!, I was pouring.

Take your time building the mold box, and getting the plastic masters clean after you've embedded them in the POP.

Lay out all you materials and equipment ahead of time, and walk through the POP process dry first, because, once you add the water to it, you only have a short working time with the POP before it gets too hard. Use cold water. Hot water will set it off too fast. And use clean water. Dirty water will also accelerate the POP.

Good luck.

[Semi22lr]

Mark,

Excellent detail. Greatly appreciated. Do you have any photos of the mold you can share?

Mark

Edited June 15, 2010 by bassyaker

[mark poulson]

I would if I could. I'm still trying to figure out how to attach photos. Maybe when my youngest comes home she'll help me. She's 15, so she knows everything about computers, and everything else for that matter.

[mark poulson]

Here are some pictures of the two molds I've made so far. They both work well.

One is for plastic tails for my QT swimbaits. The other is for fat Ika bodies.

The are both made from either POP or 20 Smooth Set drywall mud. Both work well.

I didn't have any more hinges when I made the Ika mold, so I use 16D finish nails, cut off, for locaters.

I actually like that system better. I won't bother with hinges in the future.

Edited June 18, 2010 by mark poulson

[Semi22lr]

Mark,

Great photos to go with your detail description of the process. I really appreciate it and plan to give it a try soon.

Thank s.

Here are some pictures of the two molds I've made so far. They both work well.

One is for plastic tails for my QT swimbaits. The other is for fat Ika bodies.

The are both made from either POP or 20 Smooth Set drywall mud. Both work well.

I didn't have any more hinges when I made the Ika mold, so I use 16D finish nails, cut off, for locaters.

I actually like that system better. I won't bother with hinges in the future.

[Tree_Fish]

Here are some pictures of the two molds I've made so far. They both work well.

One is for plastic tails for my QT swimbaits. The other is for fat Ika bodies.

The are both made from either POP or 20 Smooth Set drywall mud. Both work well.

I didn't have any more hinges when I made the Ika mold, so I use 16D finish nails, cut off, for locaters.

I actually like that system better. I won't bother with hinges in the future.

Hey Mark those molds are awesome! I hope to implement your mold boxes into my mold making process and I have a question for you. When you put the mold half into the oven to cure I'm assuming you are putting the mold box in with it since you have screws put in from the side to stabilize the PoP, my question is do you put anything under it or do you just set the box directly on the rack? Do you seal the wood used to make the box so it doesnt absorb the water from the Pop? Or does the oven dry them both out?

[Pitbull Baits]

Looks like in the first picture there is some wood on the bottoms or backs of the molds..