Separating two piece molds

[jimcline]

Hey guys, me again. Man am I catching the devil trying to make molds. I just finished a two piece Senko mold out of DWP. Everything was fine til I tried to seperate the two halves. The top half broke in 3 pieces. My question is how long should I wait before seperating them? I gave it about 5-6 hours and it seemed hard. Is this enough time?. The bottom turned out fine. I think I might have poured the top too thin. It was about an inch thick and th bottom was about a 1/2 inch thicker. Any help appreciated. JIM

[GB GONE]

Jim,

Did you coat the lower portion of the mold with anything? If not, there is your problem. A thin layer of vaseline is what I use.

I usually de-mold within 30 minutes to 1 hour.

1 inch think is plenty for DWP.

Jim

[jimcline]

Jim,

Did you coat the lower portion of the mold with anything? If not, there is your problem. A thin layer of vaseline is what I use.

I usually de-mold within 30 minutes to 1 hour.

1 inch think is plenty for DWP.

Jim

Jim, I did coat the bottom with vaseline. I used popsicle sticks for the guide pins. 3 on each side and that may be the problem. I think the torque it takes to seperate that many guides may have been too much. I'll try again. JIM

[HJS]

I see ghostbaits already responded. I composed the following offline, but it bares repeating.

==========================================

Jim - There ought to be an 11th Commandment, "Thou shalt not go foolin' with your DWP mold for 24 hours after pouring"... and thats only if you dry it in a very warm place, almost hot. If you are drying at just ambient room temperature than wait a day or two before separating. Others will correct me if I'm wrong, but both PoP and DWP continue to get harder and harder until all the water evaporates, and that may take days at room temps. During the winter, I dry mine under the woodstove on a wire cookie rack. Temperature there runs around 120F to 140F, and its VERY dry there.

My only concession to waiting 1 or more days before "foolin'" with my molds is that I carefully remove the mold box from around the mold. I might do this 6-8 hours after pouring. My mold box is assemble with 4 screws and is easy to remove without stressing the DWP. This will exposed more surface area, the bottom and sides, to speed up drying.

Of course I'm sure you read on TU that after the bottom half of the mold is completely dry that you should apply a very thin layer of Vaseline to the top surface of your bottom mold, just a sheen, before pouring the top half. That helps greatly when separating them a day or two later. (I see you did this)

Mold thickness - Just measured a few of my molds. My molds for making the 4" paddletails are only 1" thick, thats 1/2" per side. The mold for my biggest lures, 9"ers and as big around as your thumb, is 3/4" per side. I'm probably cutting it close and perhaps another 1/4" thickness would not be overkill. For Senkos, which I've never poured, I'd say your molds wouldn't need to be any thicker than 3/4" per side. But thats only if you let them dry completely before working with them.

Definitely ditch the popsicle sticks, too much friction to overcome when separating. You need tappered alignments so they separate easily. Many TUers use a few small marbles. I drill a couple of very shallow depressions in the bottom half using a countersink drill. Then when the top half is poured the DWP flows into these holes, or around marbles, and makes perfect alignment devises.

[jimcline]

I see ghostbaits already responded. I composed the following offline, but it bares repeating.

==========================================

Jim - There ought to be an 11th Commandment, "Thou shalt not go foolin' with your DWP mold for 24 hours after pouring"... and thats only if you dry it in a very warm place, almost hot. If you are drying at just ambient room temperature than wait a day or two before separating. Others will correct me if I'm wrong, but both PoP and DWP continue to get harder and harder until all the water evaporates, and that may take days at room temps. During the winter, I dry mine under the woodstove on a wire cookie rack. Temperature there runs around 120F to 140F, and its VERY dry there.

My only concession to waiting 1 or more days before "foolin'" with my molds is that I carefully remove the mold box from around the mold. I might do this 6-8 hours after pouring. My mold box is assemble with 4 screws and is easy to remove without stressing the DWP. This will exposed more surface area, the bottom and sides, to speed up drying.

Of course I'm sure you read on TU that after the bottom half of the mold is completely dry that you should apply a very thin layer of Vaseline to the top surface of your bottom mold, just a sheen, before pouring the top half. That helps greatly when separating them a day or two later. (I see you did this)

Mold thickness - Just measured a few of my molds. My molds for making the 4" paddletails are only 1" thick, thats 1/2" per side. The mold for my biggest lures, 9"ers and as big around as your thumb, is 3/4" per side. I'm probably cutting it close and perhaps another 1/4" thickness would not be overkill. For Senkos, which I've never poured, I'd say your molds wouldn't need to be any thicker than 3/4" per side. But thats only if you let them dry completely before working with them.

Definitely ditch the popsicle sticks, too much friction to overcome when separating. You need tappered alignments so they separate easily. Many TUers use a few small marbles. I drill a couple of very shallow depressions in the bottom half using a countersink drill. Then when the top half is poured the DWP flows into these holes, or around marbles, and makes perfect alignment devises.

HJS, this was extremely helpful! thank you, JIM

[jimcline]

I see ghostbaits already responded. I composed the following offline, but it bares repeating.

==========================================

Jim - There ought to be an 11th Commandment, "Thou shalt not go foolin' with your DWP mold for 24 hours after pouring"... and thats only if you dry it in a very warm place, almost hot. If you are drying at just ambient room temperature than wait a day or two before separating. Others will correct me if I'm wrong, but both PoP and DWP continue to get harder and harder until all the water evaporates, and that may take days at room temps. During the winter, I dry mine under the woodstove on a wire cookie rack. Temperature there runs around 120F to 140F, and its VERY dry there.

My only concession to waiting 1 or more days before "foolin'" with my molds is that I carefully remove the mold box from around the mold. I might do this 6-8 hours after pouring. My mold box is assemble with 4 screws and is easy to remove without stressing the DWP. This will exposed more surface area, the bottom and sides, to speed up drying.

Of course I'm sure you read on TU that after the bottom half of the mold is completely dry that you should apply a very thin layer of Vaseline to the top surface of your bottom mold, just a sheen, before pouring the top half. That helps greatly when separating them a day or two later. (I see you did this)

Mold thickness - Just measured a few of my molds. My molds for making the 4" paddletails are only 1" thick, thats 1/2" per side. The mold for my biggest lures, 9"ers and as big around as your thumb, is 3/4" per side. I'm probably cutting it close and perhaps another 1/4" thickness would not be overkill. For Senkos, which I've never poured, I'd say your molds wouldn't need to be any thicker than 3/4" per side. But thats only if you let them dry completely before working with them.

Definitely ditch the popsicle sticks, too much friction to overcome when separating. You need tappered alignments so they separate easily. Many TUers use a few small marbles. I drill a couple of very shallow depressions in the bottom half using a countersink drill. Then when the top half is poured the DWP flows into these holes, or around marbles, and makes perfect alignment devises.

HJS, it seems I remember a post by Longhorn or someone about baking their plaster molds in an oven. Have you ever tried this? I would think it would speed up drying time dramatically, JIM

[Long Lake Lures]

Hi guys,

I have been using DWP for the last year or so to make one and two piece molds. I use regular silicone in a spray can as a release agent between the halves and split the mold using a hammer and putty knife after about two hours. After removing the model, I place the mold into a 250 degree toaster oven for a couple hours. A couple coats of elmers glue (learned on this website- thanks guys!) and I am ready to pour.

I find that long narrow molds have to be thicker than 1/2 " or else they tend to break.

I am also shocked at the price increase of DWP at Menards. Up to about 7.50/4 lbs now. If you have a cheaper source, I'd love to know about it.

Hope this helps.

Dave