JOhanPiers

Aging molds

4 posts in this topic

I am using Silastic and 2-komp polyurethane for making molds amd baits

When I have used the molds for a number of baits the mold starts to age, (actually the PUR reacts with the silicon) and the bait sticks to the mold. I have seen that this will be even more rapid when usin molding-epoxi than PUR.

Is there anyway to pretreat the mold before pouring my PUR into it so that the aging process will slow down?

Tech. sheat on the silicon I am using:

http://www.reptech.co.uk/data_sheets/Silastic%20P-1%20Product%20Information.pdf

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Johan,

If I'm reading the spec sheet correctly and your distributer has "Dow Corning 200 Fluid, 50 cSt." it looks like you can bump the shore hardness up from 25 to 61.

I think your molds are wearing out due to the low shore hardness. The lower the shore hardness the lower the shelf life. They are more porous and deteriorate quickly.

As an alternative you could try anything from the moldmax series and add ure-fil 3. Ure-fil 3 is a ceramic based powder that can be used to raise shore hardness in smooth-on rtv's. I've not tried it yet but it sounds like it would have the silt-like action of silastic j which has a shore hardness of 56.

I'm not sure what ya mean by PUR or molding-epoxy. All epoxies kill rtv quickly.

Shawn

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PUR = PolyURethane

The epoxi I mention is a moldingepoxi, some people use if for the bait type I am doing. It adhere better to the lead than PUR, but is harder and by so more proone to crack when thrown into a stone.

I?ll look into if there are som additive that I can use to prolong the life of my molds.

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PUR = PolyURethane

The epoxi I mention is a moldingepoxi' date=' some people use if for the bait type I am doing. It adhere better to the lead than PUR, but is harder and by so more proone to crack when thrown into a stone.

I?ll look into if there are som additive that I can use to prolong the life of my molds.[/quote']

Instead of an additive, why not a protectorant? Try using some paste wax as a MR. I know they sat RTV won't need a MR, but the wax will act as a barrier between the RTV and the PUR. It's worth a shot.

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