Casting resins cherry, emerald

Discuss casting techniques
smokepl
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Re: Casting resins cherry, emerald

Postby smokepl » Wed Apr 25, 2018 5:21 pm

sochin wrote:
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


Thank you Sochin.
I read somewhere your post, that you are changing the paraffin oil every 5th time is that correct? Does paraffin oil create any fumes? which is harmful for breathing? Have you heat more than 150? or always below that?. What do you thin, this one should work? https://www.amazon.com/Gallon-Paraffin- ... +oil&psc=1 How long do you wait between microwaving, until save to touch? I will try paraffin oil for sure. I just have to buy extra microwave because I don`t think it is save to use the one I use for food. Thanks for helping.
smokepl
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Re: Casting resins cherry, emerald

Postby smokepl » Wed Apr 25, 2018 5:23 pm

Jewelermdt wrote: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.


Thank you for reply. I will give a try with paraffin oil as recommended by Sochin. Maybe baby oil would be better? what do you think?
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sochin
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Re: Casting resins cherry, emerald

Postby sochin » Wed Apr 25, 2018 11:02 pm

smokepl wrote:
Jewelermdt wrote: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.


Thank you for reply. I will give a try with paraffin oil as recommended by Sochin. Maybe baby oil would be better? what do you think?



Hi smokepl....I am not sure what is in baby oil and from a a look at wikipedia it could be any number of things......you can try whatever you like.

I use real paraffin oil because it is basically liquid wax and is used to seal the inside of water tanks so I believe what remains on the surface seals the resin a little and results in a better cast for me. Just get it from a hardware store and it will be cheaper than baby oil. I use it about 5 times and then throw it out. It gets contaminated with the resin and changes colour.

After the microwave you spray off the excess oil and let the rest dry on the surface. To speed this up I usually spray the excess off the prints with compressed air and then put them in the furnace at about 180-200c for 20-30 min to dry them.

cheers,
Sochin
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sochin
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Re: Casting resins cherry, emerald

Postby sochin » Wed Apr 25, 2018 11:44 pm

smokepl wrote:
sochin wrote:
smokepl wrote:Does paraffin oil create any fumes? which is harmful for breathing? Have you heat more than 150? or always below that?. What do you thin, this one should work? https://www.amazon.com/Gallon-Paraffin- ... +oil&psc=1 How long do you wait between microwaving, until save to touch? I will try paraffin oil for sure. I just have to buy extra microwave because I don`t think it is save to use the one I use for food. Thanks for helping.




Missed those questions........You need to read the Safety data sheet for whatever you use. Consider advice from forums but do your own due diligence before acting on it. There will be a link to the Safety data on the product .

I don`t heat a bowl of paraffin oil over 150c because I do not want any risk of fire and about 150 is the flash point for the paraffin oil I use. Initially you need to check the temp after each cycle as you may need to reduce the heating time so as to not go over the flash point temperature for your specific microwave, paraffin oil, container size and oil volume.

It is all about the temperature of the oil and length of time in the oil....you need to modify the microwave power on and stand times to maintain that about 150 for as much of the about 40 mins (or what ever you use) you have the resin in the oil. So it may not be as simple for you as 3 cycles of the same duration with the microwave. By the third cycle, or however many you use you may only need 1 minute of microwave to get the oil back to 150c.....and 3 minutes might take you well over.

I have my microwave on a trolley and heat the oil/resin in it outside my door in open air. I don`t know if the fumes are harmful or not but I take no risk. I believe fume hazard is covered in the Data sheet anyway. As it is used for burning indoors in lamps I believe it is safer than kerosene but it does have the resin in it.

I leave the prints in the resin for 10 minutes after the final microwave cycle. The oil is still too hot to touch after 10 minutes. I leave my oil bowl in the oven and remove the prints from the oil using wire or tweezers. I let the print stand and cool on tissues before touching as they are both hot and soft.

I would never use the same microwave for resin and food also.

That Amazon paraffin looks like the same stuff. There is a link to the one I use I think in my other post somewhere but you may not be able to get that brand.

cheers,
Sochin
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rkundla
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Re: Casting resins cherry, emerald

Postby rkundla » Thu Apr 26, 2018 12:59 pm

I'd be concerned about using such flammable liquids in an enclosed appliance without any means of automatically regulating the temperature of the liquid. One mistake is all it takes for it to go up in flames.

Another option that may reduce the risk could be a temperature controlled hotplate with thermostat to help regulate the heat. You can use pyrex beakers to hold the paraffin. Those types of hotplates cost more than a cheap microwave however.

I'm going to give the water boil a try. I have one of those hot water pots so I'll create a basket for my prints to sit in so they aren't on the element at the bottom of the pot. ;-)
rsaldivar
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Re: Casting resins cherry, emerald

Postby rsaldivar » Thu Apr 26, 2018 8:02 pm

yes , hot plate is the way to go , you have to start with room temp. water and go to boiling , 200 f or so , while getting something in there to hold the resins down and keep them from rising to the top from the boil , then once it reaches boiling hold for 10 min. ,after that turn off or disconnect and allow water to come to 120 or 150 f , enough to where you can put your hands in the water and not burn yourself , the cooling down it very important because this is when cracks can happen ,so don't accelerate this part , plastic needs to aniel at its own pace , whole process should take 30 - 45 min. tops , this is meant to relieve the stress of the resin and keep it from reacting with the investment and also doing away with the contaminates that polymers leve after growing , but be mindful as to what resin your using , some have to be heat treated in different ways , the green and the soluscast aren't made of the same thing , my experiments show that the blue needs to be boiled after removal from the build plate without any iso or acetone , where as the green doesn't , so for the blue , you remove from build plate then into the beaker with water for boiling NO ISO OR ACETONE , iso after the boil for about 5 sec. only , where as the green will handle the iso before the boil , Iv ran several tests for the blue and if iso before the biol , CRACKS ALL OVER , then after its dry , straight to treeing up , no UV or if you want 5 min. uv but not necessary ,

try a test cast to see , no UV , but be aware , the blue will leave the beaker messy whereas the green won't as much by far , I recommend optima investment at 40/100 with 5 hours or overnight bench sit , 3 hours at 350 f , 1.5 hours at 700 f , 3 hours 1450 , down to cast temp. , wich for me is 800 f
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sochin
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Re: Casting resins cherry, emerald

Postby sochin » Thu Apr 26, 2018 8:54 pm

rkundla wrote:I'd be concerned about using such flammable liquids in an enclosed appliance without any means of automatically regulating the temperature of the liquid. One mistake is all it takes for it to go up in flames.


Hi Ron,
That is why it is essential to do trials using a thermometer, recording the data and setting up a proper regulated procedure for the specific setup one has.

As you know for both of these following points .......and written for others that may not.......flash point in both open and closed cup defining uses the introduction of a flame to the product to see at what temperature it will ignite. We are not talking about autoignition temperature at 150c for paraffin oil.

I agree however especially for those that cannot be bothered to measure things, don`t heat paraffin oil and stick to water.

cheers,
Sochin
smokepl
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Re: Casting resins cherry, emerald

Postby smokepl » Fri Apr 27, 2018 4:57 pm

I been looking all over around for paraffin oil with flash point around 150C and I was able to find only with 117 and 124C flash point. Anyway new microwave is on its way as well as paraffin oil(124C). I will be measuring temperature very closely until will get used to it. I will keep extinguisher near by just in case. Does anyone of you know paraffin oil with better flash point than the one I am getting? Thank you
smokepl
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Re: Casting resins cherry, emerald

Postby smokepl » Fri Apr 27, 2018 5:18 pm

rsaldivar wrote:yes , hot plate is the way to go , you have to start with room temp. water and go to boiling , 200 f or so , while getting something in there to hold the resins down and keep them from rising to the top from the boil , then once it reaches boiling hold for 10 min. ,after that turn off or disconnect and allow water to come to 120 or 150 f , enough to where you can put your hands in the water and not burn yourself , the cooling down it very important because this is when cracks can happen ,so don't accelerate this part , plastic needs to aniel at its own pace , whole process should take 30 - 45 min. tops , this is meant to relieve the stress of the resin and keep it from reacting with the investment and also doing away with the contaminates that polymers leve after growing , but be mindful as to what resin your using , some have to be heat treated in different ways , the green and the soluscast aren't made of the same thing , my experiments show that the blue needs to be boiled after removal from the build plate without any iso or acetone , where as the green doesn't , so for the blue , you remove from build plate then into the beaker with water for boiling NO ISO OR ACETONE , iso after the boil for about 5 sec. only , where as the green will handle the iso before the boil , Iv ran several tests for the blue and if iso before the biol , CRACKS ALL OVER , then after its dry , straight to treeing up , no UV or if you want 5 min. uv but not necessary ,

try a test cast to see , no UV , but be aware , the blue will leave the beaker messy whereas the green won't as much by far , I recommend optima investment at 40/100 with 5 hours or overnight bench sit , 3 hours at 350 f , 1.5 hours at 700 f , 3 hours 1450 , down to cast temp. , wich for me is 800 f



When I used to use SolusCast i was giving a very quick bath. 10-15 sec maximum then fast blown by electric computer duster and straight to dry curing. Anything longer than that was giving me a cracks. I am using denatured alcohol from home depot.
rsaldivar
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Re: Casting resins cherry, emerald

Postby rsaldivar » Fri Apr 27, 2018 9:25 pm

smokepl ,
try it exactly as I said , you can finish printing and get to treeing up in less than an hour , this is a new system , do as I said and see for yourself

ALSO , TO ALL YOU WHO ARE USING OIL OR LOOKING TO USE IT , PLEASE UNDERSTAND THAT THE IMPORTANT PART OF HEAT ANNEALING CURE TREATMENT IS NOT SO MUCH BASED ON THE AMOUNT OF HEAT OR HOW LONG ( FOR THIS PLASTIC 10 MIN. IS SUFFICIENT ) BUT THE SLOWER COOLING IS WHAT IS MOST IMPORTANT , WHICH IS WHY WATER IS SUFFICIENT , OIL WILL HOLD HEAT LONGER BUT THAT'S NOT THE GOAL , 10 MIN. BIOL IS THE GOAL AND GENTLE DECREASE OF TEMP. , remember you're not trying to cook the resin , your trying to relive the stress , water is sufficient

just make sure you do it diff. depending on the resin, green or blue , don't do them the same way

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