Sealing a new water putty mold

[Saugerman]

I have read everything I could find about making a water putty mold.I have read that it is a good idea to seal the mold also. Is the reason for sealing the mold ,to keep out any moisture while setting around in storage,or does it need to be done before it is ever used? I baked the mold at 225 degrees for 1 hour in my convection oven, but do I need to seal it before ever pouring any lead in it? I hope to find out how to get the most life out of it. The mold is of a bait simalar to the fish head spin. The first mold I made of a spinnerbait that I like, turned out fair ,but after pouring only a few times it crumbled in a few places. Will sealing it stop that?

[sagacious]

I have read everything I could find about making a water putty mold.I have read that it is a good idea to seal the mold also. Is the reason for sealing the mold ,to keep out any moisture while setting around in storage,or does it need to be done before it is ever used? I baked the mold at 225 degrees for 1 hour in my convection oven, but do I need to seal it before ever pouring any lead in it? I hope to find out how to get the most life out of it.

Saugarman,

Good job on reading-up on the available material. I would suggest that you do a search here for info on making molds from Bondo, as you'll end-up with a much more durable, and longer-lived mold. Unfortunately, there is not much that can be done to extend the life of an already-made water-putty mold, aside from being careful during it's use.

POP and WP molds do not require 'sealing' for use with lead. What you read about sealing is in the context of pouring plastic into molds made from those materials.

A long time back, I experimented with spraying the cavities of POP and WP molds with ultra high-temp engine or BBQ paint. That did help to reduce powdering and chipping/erosion, but the flaw in these molds is that they eventually develop deep cracks as the water is cooked-out of the gypsum base. Water is part of the chemical compound that solidifies these materials, and as it is slowly cooked-out the mold is irreparably damaged. You're much better off with Bondo, as this fundamental compositonal change is either essentially eliminated or substantially reduced, dependant on the cavity volume of the mold.

The mold is of a bait simalar to the fish head spin. The first mold I made of a spinnerbait that I like, turned out fair ,but after pouring only a few times it crumbled in a few places. Will sealing it stop that?

Sorry to say, but this mold may not fare much better. Wish I had better news-- but now ya know. In any event, all experience is good experience and should prove useful during your next mold-making project.

I have made some plaster molds that cast 100+ 9oz custom-designed jigheads, but this requires considerable skill in manufacture, pouring, and use. More often they show cracks or damage much earlier in use. Making useful POP and WP molds requires more skill and experience than when using Bondo. I have written extensively here on how to make long-lived POP molds (do a search if you wish), but many folks want instant results and don't have the necessary patience required to work with POP to make durable molds. POP and WP aren't very forgiving or durable anyway, but Bondo Autobody filler is. Speaking practically, it's not worth my time to use anything other than Bondo to pour a custom mold.

Read-up on Bondo and give that a go.

Hope this helps, good luck!

[Saugerman]

Thanks soo much for your reply Sagacious, I will try my next mold out of bondo,I have some that I purchased from Wa-mart some time ago. It is for car body repair.I have never used any before,but will give it a try.