Liquid Diamonds Changing Mix Ratio

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MRDucks2

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From the previous items we posted under our Novice Trials of Liquid Diamonds, Chuck (dalecamino) and I did not like the long time required for LD blanks to actually cure hard enough to turn and polish.

We had learned that Aldax Enterprises a Liquid Diamonds vendor in New South Wales states on their website,
“This product can be mixed at a ratio of 65% hardener. This will create a super clear bubble free finish. Mixing by weight (100:65 resin/hardener). Your pieces will cure faster, harder, and have less bubbles than the 2-1 mixture. This mixing procedure is not recommended on large pieces above 2”.

So, with Chucks approval (since he brought the Liquid Diamonds to my shop) I decided to run a test and see how changing the mix ratio between parts A and B affected the cure of the blanks.

I picked 4 ratios, the original 2:1, 1.8:1, 1.7:1 and 1.54:1 to see what the result was.
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One of each ratio was mixed and poured into each of the 4 voids of a 4 blank mold.

They were placed in a pot under 60psig and left for 22 hours (no reason for 22, that just happened to be when I got back to the shop. At that point they were removed from the pot and the mold. (Mold had been sprayed with Stoner Thermoset Epoxy Mold Release)
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They all looked good and were pliable, which we know is normal for Liquid Diamonds out of the pot. I checked each with my 2.5 pound weight to see how much they would sag under the weight right out of the pot:
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The standard 2:1 ratio
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A ratio of 1.8:1
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Ratio of 1.7:1
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The ratio of 1.54:1

There was some difference between the 2.0:1 and 1.8:1 but you can see the greater difference at 1.7:1. With my crude methods, there didn’t seem to be a lot of difference between the 1.7:1 and the 1.54:1.

I think the biggest difference shows up a day later.
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From fiddling around with the blanks, bending, squeezing, pinching, marking, it appears that for this test the 1.7:1 ratio produces in 24 hours out of the pot a blank that has very, very similar properties of the blank from the earlier test at 6 days out of the pot.

Here is that blank under the weight at 6 days for comparison:
IMG_0593.JPG
Obviously results may vary based on your temperatures, humidity, etc. I think the key is that if you do like/want to use Liquid Diamonds and don’t want to wait “4 or 5 days” before it is completely cured, you can modify the ratio to increase the hardener and thereby decrease the cure time.

Doesn’t take much and see what works best for you.

- Happy Turning!


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Dalecamino

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Awesome Mike! You have much more ambition than I do. Well done. I am waiting for the original cast blanks to pass the nail test, and the mood hits me, before I turn anymore of them. :biggrin:
 

Curly

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I'd be interested in your impressions of how the higher ratio resin/hardener blanks turn and finish compared to the normal recommended mix. Harder? More/less/same brittleness? How it polishes et cetera. Thanks.
 

MRDucks2

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I'd be interested in your impressions of how the higher ratio resin/hardener blanks turn and finish compared to the normal recommended mix. Harder? More/less/same brittleness? How it polishes et cetera. Thanks.


Thanks, Curly. That is a natural next step and will be coming up later in the week.


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edstreet

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No longer confused....
Interesting results. However you do not need to change the ratio to improve cure times. It’s certainly viable to do that with the standard ratio mix.
 

EBorraga

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Liquid diamonds is a THERMO SET epoxy. Meaning “temperature set/cure”

Mike understands that heat will make it cure quicker. His experiment was a basic one that only required a mold and Liquid Diamonds. Not every one has access to be able to heat the molds or resin. We can get all crazy with the chemical composition but again, this was a basic test that everyone can do at home. I think it has shed a little light on a newer epoxy resin that hasn't been tested as thoroughly as alumilite or Pr.
 

MRDucks2

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So far so good, Ed. You are stating facts about the material. I am not the one who raised the potential for the question, you were.

If you have a process for improving the cure time without modifying the mix ratio that would benefit the membership, please state it. We would all be interested.

The method I investigated is pretty straight forward and easy for most of us to accomplish, and based off of the work of others.

If you have a method of modifying the thermal properties during the cure that can be easily executed with a toaster oven and oven thermometer (or even a $30 infrared thermometer) by all means share. It would be of tremendous benefit.

If you want to discuss the theory of how it could work, I am not your man nor do I believe this is the venue.

There are many folks who have been researching how to achieve the best cure of thermoset epoxies either by catalyst, pressure or external temperature (heat/radiation) or a combination for the past 70 years.

For most of us common folk, controlling the catalyst could be the easiest and safest approach if executed carefully in small casts.

Not trying to provide the only answer, just passing on something that works.


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edstreet

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What is happening in your experiment is variation of thermal reactions inside the mixture. There is a limit to what that process can achieve. However any type of heat source can be used to heat the resin before it is mixed to achieve a greatly reduced cure time. Be it hot water, toaster oven and the like.

Liquid diamonds is a BPA resin and there is nothing new about the mixture.
 
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