One Coat Pop Mold Sealer.

[t-billy]

First I tried some spray on concrete sealer. Worthless. After finding this forum and doing some reading I tried the Elmers/water mix. It worked well but took a few coats. Last weekend I picked up some Elmers pro bond professional strength wood glue. Interior/exterior. Lable says weather proof with strong initial tack. Seems accurate. I'm mixing it about 60% water 40% glue. It really bonds well with the pop. I flood the cavity and let it soak for 10-15 minutes. I suck the majority of the glue back out with a baster and save it,then blow the excess out of the cavity. Then pop it in the oven on 180 or so for a couple hours. I've been getting a nice glossy finish and a good seal with one coat. I should also mention that before sealing I bake my molds for a few hours at about 280 to dry them. Hope this helps.--------Best regards.

[longhorn]

Good Information...thanks

[t-billy]

You bet Longhorn. Thank you. Your posts on pop mold making have been a big help to me. Just a quick update. I went to my local home improvement store to buy a gallon of Elmers. They didn't have it. So I bought a small bottle of Titebond III Ultimate wood glue to try. No good. It dried to a dull rough finish. I guess all super wood glues are not created equal. I'll be sticking with the Elmers even if I have to buy it in small bottles.

[used rubbers]

Dang, I couldn't find the Elmers either so I bought the TiteBond and was going to do them tonight, did you use a 60/40 ratio, I have never tried finishing them this way, I have tried lacquers, spray ons, paints, and nothing has worked so I hope this does.

[t-billy]

Yeah I used about a 60/40 ratio. The two glues are not even close to the same. I found the Elmers at walmart. The elmers is very tacky even diluted. It also dries to a very smooth glossy finish. I tried a 50/50 mix first and it was too tacky. One coat dried too thick and lost a lot of definition in the mold. 60/40 or even a little thinner seems to work best for me. If you can find it I think you'll be happy with the results.

[Piscivorous Pike]

That is good to know. I have needed a good filler/sealer on some of my poorer molds. I have been using elmer's white but wanted a slicker finish and tried some diluted D2 epoxy. Results was only slightly better. Your post sounds like the elmers wood glue is the way to go and will give me even a better surface than the epoxy. It should stop the bubbling I have experienced from porous POP.

I begin tonight on a series of new molds that Longhorn has inspired me to work on! Like many others and yourself, he is a big help and I enjoy what all of you have to offer.

I would comment that I have read and experienced that POP once it reaches 150 degrees F, (likely after it dries out) when drying in the oven it will begin to deteriorate, reverse back to plaster. I have accidently over heated some of mine and found they do crumble. I would therefore watch that temperature, I now keep it at 170, lowest my oven will go.

Thank you for sharing the glue tip! I have storage container full of adhesives, I pretty sure I have some in there right now and Walmart is only a block away if I don't.

Has anybody added the water soluable glues, e.g. both types of Elmers, to the POP mix when making the original cast? I wonder if that would make it smoother, harder, more crack and heat resistance?

[used rubbers]

Great idea with the glue in the mold, I am going to try that as there is one lure I pour for a friend that seams to crack. It is so thick and stays warm so long it cracks the POP. I have tried a very thick mold but still no luck. I was going to try adding an aggregate such as fibers/stones but will try the glue first.

[bluegrasslover]

First I tried some spray on concrete sealer. Worthless. After finding this forum and doing some reading I tried the Elmers/water mix. It worked well but took a few coats. Last weekend I picked up some Elmers pro bond professional strength wood glue. Interior/exterior. Lable says weather proof with strong initial tack. Seems accurate. I'm mixing it about 60% water 40% glue. It really bonds well with the pop. I flood the cavity and let it soak for 10-15 minutes. I suck the majority of the glue back out with a baster and save it,then blow the excess out of the cavity. Then pop it in the oven on 180 or so for a couple hours. I've been getting a nice glossy finish and a good seal with one coat. I should also mention that before sealing I bake my molds for a few hours at about 280 to dry them. Hope this helps.--------Best regards.

I haven't tried the glue you're talking about but I did try blowing off the excess with my air compressor after flooding and it worked really good. Got the best, smoothest seal coat yet.

Greg

[Piscivorous Pike]

...Has anybody added the water soluable glues, e.g. both types of Elmers, to the POP mix when making the original cast? I wonder if that would make it smoother, harder, more crack and heat resistance?

I made a DWP mold and instead of plain water used a mix of water and the elmers wood glue in about a 50/50 to 60/40 mix.

After setting and drying the mold seems less porous and slightly smoother to the touch. I still must glaze and seal the cavity.

Only use and time will tell if it made a difference in wearability.

I made two other molds, one POP one DWP and sealed them with the wood glue. It did make a great slick finish in the cavity.

thank you for the tip, that is how I am going to make them from now on.

Edited January 29, 2010 by Piscivorous Pike

[mark poulson]

Has anyone here tried drywall mud, like Smoothset 40, for making molds? It dries semi-hard, shows fine details, and doesn't shrink.

And it gives you almost 30 minutes open working time to get you masters set, and your vent holes in place.

I made my first two piece mold this week with the Smoothset, and it came out alright. It had bubbles and voids beneath the masters, and around them, so I'm going to remake it, and hand butter the plastic masters before I set them in it this time.

I used spray pam to keep the second half from sticking to the first half, and it worked fine.

I plan to coat both halves with diluted carpenter's glue after they cure out, to make them stronger and smoother.

A word of caution about adding glue to either pop, or drywall mud.

Glue makes drywall mud shrink.

The taping mud that's used for embedding the tape, and coating the nails, has glue in it, and it shrinks.

That's why there's much less glue in topping compound, which is what's used for final coatings, to get a smooth finish.

I would do a test run of whatever material I plan to use, either pop or drywall mud, to see if adding glue when you mix it makes it shrink.

Edited January 29, 2010 by mark poulson

[bluegrasslover]

Has anyone here tried drywall mud, like Smoothset 40, for making molds? It dries semi-hard, shows fine details, and doesn't shrink.

And it gives you almost 30 minutes open working time to get you masters set, and your vent holes in place.

I tried it. I got really good detail with it but the mold was EXTREMELY fragile. It broke and so I don't think I'll use it again. If anyone knows how to toughen it up I might try it again, otherwise, I'm done with it.

Greg