PR casting-I'm confused. Help please!

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shawnmhill

shawnmhill

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I received my first order of clear casting resin along with 5 colors and pearl essence from Douglas & Sturgess. Now I have read articles in the library and I may be retarded but I'm still confused. Here are those items:

1. I am using "resin saver" mold for Sierra. Do I need to coat them with something beforehand?

2. I want to mix say 3 colors, one being pearl. I know I need to make 3 separate cups but when do I mix together? Mix them after three or four minutes all together then pour in molds OR pour carefully one at a time in mold and let colors mix that way?

Like I said "This is my first try"! I'm sure to screw it up but I'm gonna try. I've got a great idea for my PITH pen that includes 3 colors plus I scroll saw a lot of fret work, hint hint. I just need to practice.

Btw, I'm not using a pressure pot! I saw the one that Curtis (MesquiteMan) blew up! No thank you!

Thanks guys and gals for all your help every time I ask! Maybe one day I will have the knowledge to contribute.

Shawn
 
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Cool. I will fwd any PMs I might receive. Looks as though several people have checked out my post. I'm sure everyone is busy. These questions may take a while to answer.
 
1) You shouldn't have to coat the molds
2) There is no good answer for this one other than 1 test = 1000 opinions. You will get different results depending on the temperature, amount of pigment, type of pigment and amount of catalyst (all affect how fast the resin starts to gel). Best thing to do is take good notes and only vary one thing at a time.
3) No need for pressure pot with pigmented casts.
 
shawnmhill said:
I received my first order of clear casting resin along with 5 colors and pearl essence from Douglas & Sturgess. Now I have read articles in the library and I may be retarded but I'm still confused. Here are those items:

1. I am using "resin saver" mold for Sierra. Do I need to coat them with something beforehand?

2. I want to mix say 3 colors, one being pearl. I know I need to make 3 separate cups but when do I mix together? Mix them after three or four minutes all together then pour in molds OR pour carefully one at a time in mold and let colors mix that way?

Like I said "This is my first try"! I'm sure to screw it up but I'm gonna try. I've got a great idea for my PITH pen that includes 3 colors plus I scroll saw a lot of fret work, hint hint. I just need to practice.

Btw, I'm not using a pressure pot! I saw the one that Curtis (MesquiteMan) blew up! No thank you!

Thanks guys and gals for all your help every time I ask! Maybe one day I will have the knowledge to contribute.

Shawn
Click to expand...

Shawn,
I don't have a resin saver mold but I don't think you have to coat with anything since it is silicone based. I make my own silicone molds and cast in both PR and Alumilite and don't use any mold coating and everything comes out just fine.

Everyone has their own way of casting. You will get so many different answers on how to do the 3 color pour. However this is how I do it:
1. I put the appropriate amount of PR in each cup
2. Color it to the level that I desire
3. Weigh it to determine the MEKP that is required
4. Add the MEKP to all the cups
5. Wait until the first cup gets ready to gel (This is the hard part)
6. Pour the first color into the mold
7. Immediately pour the other colors into the mold and with a toothpick or other small device swirl very slightly

If you mix the colors before they start to gel, you will just get mixture. IE: Yellow and Blue makes Green type of thing.

You are going to make mistakes but that is where you learn. People can tell you their method until the cows come home and until you figure out what works for you....it won't work...

Good Luck!

BTW, Harbor Freight pressure pots get a bad rap!! Many people on here use them. You just don't hear about the successes as much as the failures...
 
When it comes to pouring your colors. since you're doing more than one cast using a resin saver, try both ways...mixing together then pouring, and pour each separate and note which is which and make your judgement afterwards. When I pour my blanks I wait for each color to thicken (think maple syrup) and pour each cup at the same time and swirl with something. even if you think you're making a mistake keep a note of what you think you did wrong bc some of my best casts have been screwups! hope this helps and feel free to pm me with any questions.
 
I'm not a PR expert by any means. I can tell you from experience that the most important element is pouring at the right time. If you just mix your colors and pour them in the mold..it will look great. But then the different colored resins can start to settle out..I think it has a lot to do with weight. The resin itself weighs the same throughout, but you add things into the resin...in cup one perhaps you added a teaspoon of red paint and a thimble full of pearlex. In cup two you added 3/4 of a teaspoon of blue paint and 2 thimbles of pearlex. Most likely the resin in cup 2 is heavier than cup number one because the powder pigments add a lot of weight into the resin and so the blue will end up settling to the bottom of the mold before the resin gels enough to hold it suspended in place. So you end up with a blank mostly red on top and mostly blue on the bottom. If you get the timing just right..catch the two cups just as they are starting to flash off, pour them quickly now, and the colors won't be able to seperate by any weight issues because the resin will set up before there is time for colors to settle. Also, pouring as a product is starting to flash, this is when the product will be thicker, and now you can swirl colors together without the colors themselves blending into each other...ie you you blue and red..inbetween could end up purplish if poured to early. It takes practice and experience.
 
Shawn, if this is your first pour. Try to keep it simple and don't over do it. Don't try too many things at one time. Once you get the hang of it, the rest will fall into place and make more sense.
 
Around about how much time do you let the resin sit with the hardener in it? I know maple syrup consistency, but I saw a video on youtube that they let it sit for 30 minutes. What do you use instead of a pressure pot to get rid of bubbles. I saw someone, somehow vibrated the table with something.
 
Tim, there is no good answer for that one. There are simply too may variables. Type and amount of resin, amount of catalyst, type and amount of dyes, temperature, humidity etc. Each will have an effect on the gel time.

And generally, if you are doing colored/dyed PR blanks (without inclusions) you will not need a pressure pot (etc).
 
Thank you ALL! I appreciate the advice! I'm headed out to the garage. Wish me luck! This stuff doesn't blow up if it's too hot...........will it? It's hotter than the Devil's butt here! Thanks again guys and sorry for the corney saying but it was the "cleanest" one I could think of.
 
Tanner said:
What do you use instead of a pressure pot to get rid of bubbles. I saw someone, somehow vibrated the table with something.
Click to expand...

A lot of people use an ultrasonic jewlry cleaner. The most popular one seems to he the large one from HF. I went to buy one but my HF store just remodeled and they couldn't find one (other than the one on display).

What I am doing for now is clamping a palm sander to an old TV tray table to set up some vibrations. Someone else posted that they set the PR on their running band saw.

Just make sure you have good ventillation. Dont cast in the house, and wear a respirator.

After the first time I cast, I was sick to my stomach at dinner. I didnt use a resprirator as my filters were shot, but I was outside with a slight breeze blowing. I think the illness was something else, but you never know. I have a new respirator now.
 
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Unless you eat the liquid resin, respiratory exposure will present itself mostly as pneumonitis, which is chemically induced pneumonia the degree of illness depends on the exposure. Be smart, be safe work with a resporator and or fume extraction system if you can't work outside.
 
If your pouring outside and it's real hot, you won't have to wait as long to mix. Resin cures with heat. Your timing will grow when it cools off.
 
I'm a little slow, so someone explain to me how the heck an ultrsonic jewelry cleaner gets bubbles out of a PR cast. I think the mold is too big to put inside. It won't balance on top. I'll need to search this.
 
Tanner said:
I'm a little slow, so someone explain to me how the heck an ultrsonic jewelry cleaner gets bubbles out of a PR cast. I think the mold is too big to put inside. It won't balance on top. I'll need to search this.
Click to expand...

You normally put the PR in the ultrasonic cleaner while it is still in the mixing cup. You still have to pour it into the mold after it is taken from the cleaner but without mixing and careful pouring, you will introduce minimal air.
 
Tanner said:
Around about how much time do you let the resin sit with the hardener in it? I know maple syrup consistency, but I saw a video on youtube that they let it sit for 30 minutes. What do you use instead of a pressure pot to get rid of bubbles. I saw someone, somehow vibrated the table with something.
Click to expand...

Tim:
The only time I use a pressure pot is with alumalite . Since I pour mostly PR, I use an ultrasound cleaner with heat to thin my virgin resin.

Here, this time of year, I start "mixing" the different colors of catalysed resins at about 10 minutes. A "toothpick test" tells me when to add different layers. If I dip a toothpick in the different colors and if drips quickly, it is too soon. It the resin doesn't drip at all, it is too late. Somewhere in between these two extremes is the ideal mixing point. Determining this point IS the hard part of casting.
 
Additionally, after I pour the mold, I sit it on my running scroll saw for about 10 minutes to vibrate out any remaining bubbles.

Then I put the resin-filled mold in my genuine Wal-mart $15 toaster oven set at 150 degrees for about 30 minutes (as long as the timer will go). After this post cure the blanks are usually firm.

Out of respect for the process, I wait one day to turn the blanks.
 
PTownSubbie said:
Shawn,
I don't have a resin saver mold but I don't think you have to coat with anything since it is silicone based. I make my own silicone molds and cast in both PR and Alumilite and don't use any mold coating and everything comes out just fine.

Everyone has their own way of casting. You will get so many different answers on how to do the 3 color pour. However this is how I do it:
1. I put the appropriate amount of PR in each cup
2. Color it to the level that I desire
3. Weigh it to determine the MEKP that is required
4. Add the MEKP to all the cups
5. Wait until the first cup gets ready to gel (This is the hard part)
6. Pour the first color into the mold
7. Immediately pour the other colors into the mold and with a toothpick or other small device swirl very slightly

If you mix the colors before they start to gel, you will just get mixture. IE: Yellow and Blue makes Green type of thing.
Click to expand...

Just a quick question, while you are waiting for all three cups to thicken up, are you vibrating them or using something to get the bubbles out??

Thanks.
 
timing

Working with PR and PearlEx today (about 80 degrees)

After heating and shaking and stirring in MEKP I let the blue set in the molds for about 10 minutes before I put the MEKP in the gold.

Just about when the blue was getting to jello consistency, thinking I had 3-4 more minutes, I went back to the gold and it was already like tofu.

I quickly cut the gold into chunks and dropped them in the molds. Then I poured the balance of the blue on top. The blanks really look super.

I poured everything outside but the smell still permeates the house and the wife is not happy. The blanks look super. I'll turn them tomorrow after taking pictures. Did I tell you that the blanks look super?

Lee
 
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