Casting resins cherry, emerald

Discuss casting techniques
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Archerm
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Re: Casting resins cherry, emerald

Postby Archerm » Wed Jan 10, 2018 4:28 pm

i have learned one thing you cant over cure a piece. :mrgreen: :mrgreen:
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sochin
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Re: Casting resins cherry, emerald

Postby sochin » Sat Feb 10, 2018 1:27 am

First post here. 4 years on the Asiga and now about 5 months on the Solus. Solus eats the Asiga and thanks to Mark and Rik for getting me up and running so quick when my Pico died. The Solus was always going to be my next printer as I told you Mark. I have had pretty much flawless prints since I got it.

Stick to what works for you for curing but to give you another opinion.......I do not UV cure either Cherry or Emerald at all. Never.

I have used heat cure only for years as it works better and is quicker for me. My resin of preference is B9 Cherry over the Emerald. I turn to the Emerald for pieces in the 15 gram plus range generally.

I believe that the heat releases more from deeper into the B9 resins than UV curing does. The smell from oven curing is a lot stronger than UV IMO and those smells/fumes/gases...pretty technical here I know..... are things that if you only UV cure I believe get released inside your flask during burnout.

I have no proof but I think UV curing, especially if it is not done for long enough can trap some things inside the B9 resin prints. It is also my belief that long term UV curing gets its positive result from the heat created not the UV light. The oven gets you the heat quicker.

Pseudo science but I did record results of a lot of very regulated casts to get to this somewhat anecdotal opinion. Removing UV curing from my process had no effect on results and UV curing alone never got me the fail proof results that heat curing has.

Stick to what works but this is what I do and it works for me. Some might find it of interest. I cast using Satin Cast or Omega+.

1 hour furnace at 150-200 c
remove from the oven and remove supports
3min microwave cycle in paraffin oil
10 min stand in the oil
3min microwave cycle in paraffin oil
10 min stand in the oil
remove from oil let cool
spray away excess oil with compressed air
30 min furnace at 150-200 c
remove from the furnace and stand till cool
tree and invest with slurry (demineralised water only) at 20 deg C - 260gr investment per 100mm water
stand flask for at least 6 hours after investment.

I used to do three microwave cycles but find doing only two gives the same results. This is the paraffin oil I use and improved my results when I introduced it. I use my oil about 5 times and then change to a fresh batch. I monitored this during testing and at about 7 uses of the oil I started to get surface deterioration.

My belief is that the microwave cooks the oil into the surface to some degree....and once the oil is over used it is cooking some of the stuff you want to take out of the resin that was released into the oil during previous usage back into the surface. Once again anecdotal but a theory.

Diggers Paraffin Oil is a colourless hydrocarbon commonly used as a fuel, lubricant and surface sealer. Put simply, Paraffin Oil is candle wax in a liquid form. It is used extensively in ‘oil lamps’ and as a base for creating scented oils to be burned individually or vaporised in any standard oil burner.

Lubricant for precision apparatus and plastic modifier
Fuel – heating, lighting and cooking
Water tank surface sealer
Excellent lubrication oil for hinges and moving parts in sewing machines
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M-Williams
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Re: Casting resins cherry, emerald

Postby M-Williams » Sat Feb 10, 2018 2:45 pm

Thank you for pointing out the importance of curing, whichever way it is used as long as it serves the purpose of "curing" resin.
We too use cherry almost all the time, and it is our resin of choice. just shake well before use.
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rkundla
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Re: Casting resins cherry, emerald

Postby rkundla » Sat Feb 10, 2018 3:37 pm

Heat does help continue the reaction internally as long as their are still radicals available (generated by the UV curing) to crosslink. However, as soon as the radicals are all used up, the polymerization of the resin will stop permanently. The hold period at 300°F in the SatinCast type burnout chart no only helps dry out the flask, but it does contribute to additional resin curing.

I think your heated oil cure is helping create a water-impermeable barrier that protects the liquid slurry investment from leaching uncured resin from the model during the setup period. That is why there is a lot of talk about using dips, coatings, spray paint, etc. on the prints to improve surface quality since uncured resin will definitely cause the surface to degrade.
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sochin
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Re: Casting resins cherry, emerald

Postby sochin » Sun Feb 11, 2018 12:34 am

rkundla wrote:The hold period at 300°F in the SatinCast type burnout chart no only helps dry out the flask, but it does contribute to additional resin curing.



Apologies in advance for switching between degrees F & C. My furnace has both on the front and I cure in C and cast in F.

I think there are quite few others that only heat cure B9 resins. I started doing it after I saw that was what TAJS was doing with B9 and getting results with heavy items so I refined it to what works best for me.

I have not seen a chart but the process we use for B9 resins is the first 2 hours are a ramp from 0 degrees F to 800 deg F which sounds kind of similar. After 2 hours we flip sprue up and from there over the next 3 hours take it up to the investment limit, hold for another hour then drop back to cast over the next hour.

On the other hand for the Kevvox LC 200 resin we used to preheat the furnace to 300F and burn it out in 3 hours total. That stuff goes up in a ball of flames. Each resin is different and I could never get the Kevvox LC200 to be reliable with heavy items no matter the burnout cycle I tried.

Marc yes I love the B9 Cherry. Maybe I have a soft spot for it because it was the first resin after years of hit and miss with others that I actually got to work. I prefer to handle it better over other resins, very easy to inspect prints for flaws and I believe it gives great definition. The fact that it is dirt cheap is just an added bonus. I used to pay $800 a litre for Asiga resins that would not cast. My resin bill for the first year I owned an Asiga was about $3000. How things have changed.

Compared to the Asiga in general the Solus seems to cure the B9 resins more fully during printing without over exposure which has lead to a better cast I feel.

This is the surface of one of the first rings if not the first I cast off the Solus that I emailed to Mark. B9 Emerald, Satin Cast and about 15 grams in a Palladium 925 Silver alloy. Devest and rinse under water and a little pickle. Amazing absence of grow lines and the printer speed is about double that of the Asiga.

Back to work. Casting today.
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rkundla
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Re: Casting resins cherry, emerald

Postby rkundla » Sun Feb 11, 2018 12:55 am

sochin wrote:This is the surface of one of the first rings if not the first I cast off the Solus that I emailed to Mark. B9 Emerald, Satin Cast and about 15 grams in a Palladium 925 Silver alloy. Devest and rinse under water and a little pickle. Amazing absence of grow lines and the printer speed is about double that of the Asiga.


Smooth as a baby's bottom! Looks good. How does that Palladium/Sterling alloy work for you by the way?
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sochin
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Re: Casting resins cherry, emerald

Postby sochin » Sun Feb 11, 2018 11:33 pm

rkundla wrote:How does that Palladium/Sterling alloy work for you by the way?



Very nice. Casts normally, remelts well. Customers love it. I have some swimmers that destroy sterling silver with pool chemicals. No problems with the Palladium alloy.

Soldering is a little tricky....fuse works if you are game and the design allows it. Solder joins don`t go black which is nice.
smokepl
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Re: Casting resins cherry, emerald

Postby smokepl » Tue Apr 24, 2018 3:06 pm

Hi
I was wondering when you microwave the emerald (3 times per 2.50 or 3 minutes) is your water boiling or not? when I do 2.30 minutes, last 10 seconds my water is boiling. Is it better to boil the water or not? also does it have to cool by itself? or can I mix cold water slowly to speed up the process. Dry curing versus curing in water will make different? what kind of process or reaction occurs between these two? Thank you for all replays. Very appreciate any help.
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Jewelermdt
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Re: Casting resins cherry, emerald

Postby Jewelermdt » Wed Apr 25, 2018 1:00 am

I believe it's that point that the water boils that does the best curing. This is also why you Don't want to add cool water. Let it cook for those 10 to 15 min between cycles. On another forum a member suggest to boil in pan of water for 10 min and let cool down. That's all he does.
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sochin
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Re: Casting resins cherry, emerald

Postby sochin » Wed Apr 25, 2018 5:21 am

smokepl wrote:Hi
I was wondering when you microwave the emerald (3 times per 2.50 or 3 minutes) is your water boiling or not? when I do 2.30 minutes, last 10 seconds my water is boiling. Is it better to boil the water or not? also does it have to cool by itself? or can I mix cold water slowly to speed up the process. Dry curing versus curing in water will make different? what kind of process or reaction occurs between these two? Thank you for all replays. Very appreciate any help.



Microwaves vary in strength and the volume of the material being heated will also vary the time/temperature again I am guessing.

As jewelermdt wrote it is the soaking in the heat that helps cure the resin. That said water boils at about 100c and cools quite rapidly.

That is why I prefer to use paraffin oil, it gets a lot hotter (way before boiling) and holds the heat for longer. With paraffin oil you need to keep the temperature under it`s flash point which is about 150c IIRC but do your own homework if you decide to try it. It will not boil till 300c but you run the risk of fire after 150.

I use a food thermometer so I know what temperatures I am exposing the resin to and in particular how hot the parrafin oil is getting for safety. You only need to do this initially until you get the times sorted for your microwave`s strength. I also use it to check my slurry temperature and vulcaniser.

cheers,
Sochin

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