# Casting mold type



## wwillimon (May 6, 2021)

Does poly pro work for casting molds. I dont know very much about casting blanks but I am wanting to try some. How much pressure and length of time do you leave in pressure pot?  It may be more than I want to get into.


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## JohnU (May 6, 2021)

I’ve seen people on YouTube using poly propylene for molds.  Mostly for smaller stuff because it’s more flimsy.  Your mold types can differ depending on how large your cast will be.  I like HDPE because it’s more rigid and available in multiple thicknesses.  My mold selection comes down to what I’m casting... color, clear casts, embedded objects...etc. then there’s vertical or a block mold.  It really all comes down to your individual preferences and the results you get from each.  
Time in the tank will depend on your resin.  They can differ from 15 min up to 18 hours, and the type of resin will be determined by the type of blank you want to make.  The resins most of us use have their pros and cons depending on what type of blank your making.


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## Kenny Durrant (May 7, 2021)

I like the HDPE molds as well. They cost a little more but my first one looks like the day I bought it. They’ll last forever. I’m not familiar with what you’ve asked about but you asked a pretty broad question. Depending on what your casting might depend on the type of resin you’ll need. That in turn might dictate the style of mold and the material it’s made of. It’s my opinion that casting is a whole new hobby in itself. That being said there’s another learning curve involved.


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## Ted iin Michigan (May 7, 2021)

I've been using HDPE from the start and I like it a lot. I've done it 2 ways (see photo). The original was the 1/4" laminated to some baltic birch because that's what I had laying around. It worked well but I got a sheet of 3/4" HDPE on Amazon and making the mold was a LOT easier. I prefer the full 3/4" but both seem to work fine. Everything is just screwed together with #6 wood screws. Easy assy/disassy.


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## wwillimon (May 7, 2021)

Ted iin Michigan said:


> I've been using HDPE from the start and I like it a lot. I've done it 2 ways (see photo). The original was the 1/4" laminated to some baltic birch because that's what I had laying around. It worked well but I got a sheet of 3/4" HDPE on Amazon and making the mold was a LOT easier. I prefer the full 3/4" but both seem to work fine. Everything is just screwed together with #6 wood screws. Easy assy/disassy.
> View attachment 306074


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## wwillimon (May 7, 2021)

I am just wanting to try and make a few pen blanks and maybe make some personalize  blanks. Dont know squat about pouring resins. When I was a kid my Mom and Dad had a craft shop and we poured a lot clackers when it was a big deal. We used glass molds.


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## wwillimon (May 7, 2021)

wwillimon said:


> I am just wanting to try and make a few pen blanks and maybe make some personalize  blanks. Dont know squat about pouring resins. When I was a kid my Mom and Dad had a craft shop and we poured a lot clackers when it was a big deal. We used glass molds.


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## Lucky2 (May 7, 2021)

Hey Wesley, wouldn't screws be more appropriate to use, then the large clamps you're using? The clamps are a lot larger then screws, so, they would require a much larger pressure pot.

Len


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## Jans husband (May 7, 2021)

I don't have a pressure pot but on the few times I have cast resin blanks round a tube with labels, I have ended up with very small bubbles.

I saw on a video a few months ago that bubbles could be avoided by holding the filled mould on a vibrating machine (like the top of a switched on Grinding wheel) for a minute, because that vibrates the bubbles to the top of the resin where they pop.
Not tried it yet, but JohnU may be able to confirm one way or the other whether that would work.
Over to you John!!
Cheers,
Mike


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## Ted iin Michigan (May 7, 2021)

Wesley - Oh, man. I'm sorry. You asked a couple simple questions and we got off track. 
1 - About the poly pro - I have no experience here but I've seen it done. Thinking if you're just going to do a few you should give it a try (and report back here )
2 - About the pressure - It varies but for the most part the equipment you use will have a max pressure (normally under 100 psi). I use a converted Harbor Freight pot and I keep my pressure to around 60 psi. That works great for me. Different resins, etc might have different results. I use Alumilite Amazing Clear Cast.
3 - About the time in the pot - Again, it varies. This time it will vary a lot, depending mostly on the resin you use and the ambient temp. My standard rule of thumb is for 3/4" blanks, leave it in the pot overnight. And my shop is heated but I do let it cool off overnight. So average temp (winter) will be under 60F. Using this rule of thumb I haven't had any fails.
Hope this helps - again, sorry for getting "off topic".


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## wwillimon (May 7, 2021)

Lucky2 said:


> Hey Wesley, wouldn't screws be more appropriate to use, then the large clamps you're using? The clamps are a lot larger then screws, so, they would require a much larger pressure pot.
> 
> Len


The clamp is on there for the silicone seal that I had curing. It will be put together with screws when I get the ends fixed with the tube stops. It will be made out of HDPE. I may have over killed it(dont know).


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