Poly resin instructions: Is a pressure pot necessary?

[putnamm]

Hi, folks. I am ready to at least begin thinking about casting my own blanks. So I consulted the IAP library. I was ready Jay Pickens' "Instructions for Mixing Polyester Resin for Pen Blanks." It seems a very straightforward process. However, I am aware that many blank casters use a pressure pot to ensure the blanks come out with no air bubbles. I have to admit, this is by far the most intimidating part of the procedure for me! I was at first excited by the idea that some resin blanks don't need to be pressurized, perhaps due to their unique chemistry, etc. Then I thought that maybe Mr. Pickens just left that part out...

Can someone explain? Is there a way to cast resin blanks and not have to use a pressure pot? If so, I would greatly prefer that.

Thanks.

-Mark

 

[jimmyz]

Try letting the resin site in a hot (160 degree) water bath for 20 minutes or so. Than add the catalyst, slowly stir, and pour. Should greatly minimize or eliminate the bubbles.

 

[thewishman]

You can cast without pressure. My first attempt was with a steampunk (metal foils that had been textured and painted) with a tube. The mold was still-wet Play Doh. That pen is one of my favorite carries.

Pre-warming the resin helps, as does stirring carefully. Experiment, and be sure to write down how each batch was made - you never know when you'll create something that you want to replicate.

 

[BSea]

You can cast without a pressure pot especially if you are doing color castings. Bubbles are very rare, and usually very small. But as your resin gets older, it can thicken. Be sure and warm the resin if that happens. If you are clear casting, I'd think warming is a requirement. I've cast thousands of PR colored blanks (all without pressure). When I started, I didn't warm my resin. Now I try and warm it to around 85 degrees before casting.

 

[SDTurner]

Quick question, if you warm up the PR and then add mica powder/dye would the warm resin allow the mica powder to settle at the bottom or that's not really much of a problem? Since PR will be much thinner when warmed up in a hot water bath. Is it advisable to add mica powder, mix well and then put the PR in the hot water bath or should mica be added after PR gets out of water bath and once mixed add MEKP?

 

[LouCee]

Pre-warming the resin helps, as does stirring carefully. Experiment, and be sure to write down how each batch was made - you never know when you'll create something that you want to replicate.

When I first tried casting I kept track of everything I thought might help in the future, whether or not I warmed the resin, amount of resin, how many drops of catalyst, the type of colorant used and how much, the temperature and humidity in my garage, and maybe even other things I'm forgetting. Unfortunately there is one very important thing I didn't keep track of, my notes! To this day I haven't found them and that was 7 or 8 years ago. I was using 3" x 3" post-its and sticking them on top of each other, who knows where I stuck the pile of them. Lesson learned: use a large notebook. Not impossible to lose, but so far I haven't.

 

[putnamm]

You can cast without pressure. My first attempt was with a steampunk (metal foils that had been textured and painted) with a tube. The mold was still-wet Play Doh. That pen is one of my favorite carries.

Pre-warming the resin helps, as does stirring carefully. Experiment, and be sure to write down how each batch was made - you never know when you'll create something that you want to replicate.

What method do you use to pre-warm the resin? How do you heat it? Does it need a special container?

 

[BSea]

Quick question, if you warm up the PR and then add mica powder/dye would the warm resin allow the mica powder to settle at the bottom or that's not really much of a problem? Since PR will be much thinner when warmed up in a hot water bath. Is it advisable to add mica powder, mix well and then put the PR in the hot water bath or should mica be added after PR gets out of water bath and once mixed add MEKP?

It is a problem, but it doesn't really matter if you warm the resin or not. The warmer the resin, the thinner it gets, but the faster it sets. To be honest, it's more of an issue to get the timing right of when to pour. The closer you are to the PR setting, the less sinking you'll get. And there is no real formula to help. You learn over time which colors set faster. Some Mica powders weigh more than others. But since you're not using much, it's almost impossible to weigh the mica for each batch. And if you use dye for a color and Mica for another, the dye color will rise to the top. So for a 2 color pour, I try to pour about 2/3 of the dye color with about 1/3 of the Mica for the bottom color, and reverse that for the upper part of the mold. This isn't a real problem with pen blanks that are vertical, but it is a problem with flat molds, and game call & bottle stoppers that are vertical.

You can cast without pressure. My first attempt was with a steampunk (metal foils that had been textured and painted) with a tube. The mold was still-wet Play Doh. That pen is one of my favorite carries.

Pre-warming the resin helps, as does stirring carefully. Experiment, and be sure to write down how each batch was made - you never know when you'll create something that you want to replicate.

What method do you use to pre-warm the resin? How do you heat it? Does it need a special container?

I put the PR can in water about 100 to 105 degrees for about 30 minutes before I use it. It gets to around 85 this way for me. I used to take the temp of the water & resin, but I don't anymore. But this has given me consistant results. I also try to keep my garage around 80 to 85.

 

[Cwalker935]

I use a large mouth mason jar and plastic disposal cups that will fit down into the jar. I heat the water in a microwave or simply run hot water from your tap into the jar. After heating, I then set the plastic cup with the resin down into the jar and wait five to 10 minutes or so before adding the catalyst. Be careful if you are using a microwave only heat for 30 seconds or less depending on your wattage.

 

[SDB777]

You can cast without a pressure pot especially if you are doing color castings. Bubbles are very rare, and usually very small. But as your resin gets older, it can thicken. Be sure and warm the resin if that happens. If you are clear casting, I'd think warming is a requirement. I've cast thousands of PR colored blanks (all without pressure). When I started, I didn't warm my resin. Now I try and warm it to around 85 degrees before casting.

See.....I thought you were just getting the casting area warmed up for you(like Lyn does:biggrin


BTW, bubbles in blanks cost more:wink: So why pay more?




Scott (gonna thunder in a minute here...yuck) B

 

[BSea]

See.....I thought you were just getting the casting area warmed up for you(like Lyn does:biggrin


BTW, bubbles in blanks cost more:wink: So why pay more?




Scott (gonna thunder in a minute here...yuck) B

I do both. Resin doesn't stay warm without the garage being warm. I . . . . . I mean the studio.

 

[putnamm]

So are these resin products only available online? Is there not a store I can walk in to and buy them?

 

[BSea]

You can buy Casting Craft poly resin at Michaels & Hobby lobby. One place sells MEKP (CATALYST required to cure the resin) with the resin, the other doesn't. You can get it there, but it's not sold as a kit.

I will caution you that the resin has a shelf life, and from what I've heard, it's a gamble on the quality of the resin you get from these places because the turnover isn't good. You may get some that is totally useless. I'm not speaking from experience though. I've only bought online.

Another thing to bear in mind is that there is a learning curve with pouring blanks. A quart will get you started, but you could easily end up with only a few blanks that you consider worth showing from that quart.

 

[chartle]

So are these resin products only available online? Is there not a store I can walk in to and buy them?

You can buy Casting Craft poly resin at Michaels & Hobby lobby. One place sells MEKP (CATALYST required to cure the resin) with the resin, the other doesn't. You can get it there, but it's not sold as a kit.

One thing to look for if you go to one of these stores. Make sure its the kind of resin that uses the little bottle of MEKP and is not a two equal parts type resin.

The reason I say this is that the 2 part stuff comes from the aluminite company and some have assumed its the same aluminite that people here talk about. Its not the same stuff its just made by the same company.

Also Micheal's has kits of Pearl Ex 12 or 16 in a kit. Sign up for their ads and you should get 40 to 50% off one item coupons emailed to you.

 

[thewishman]

You can cast without pressure. My first attempt was with a steampunk (metal foils that had been textured and painted) with a tube. The mold was still-wet Play Doh. That pen is one of my favorite carries.

Pre-warming the resin helps, as does stirring carefully. Experiment, and be sure to write down how each batch was made - you never know when you'll create something that you want to replicate.

What method do you use to pre-warm the resin? How do you heat it? Does it need a special container?

I didn't heat the resin, just mixed and poured. It was one of those, "This resin has been sitting for months while I try to do everything perfectly, if I don't do something soon, the resin will turn to gunk and I will have wasted ANOTHER chunk of money on a ANOTHER project I never even start."

 

[RetiredGuy23]

Here in South Florida lack of heat is generally not a problem. All I have to do is shut down my a/c and pretty soon it's 85. Before I cast I move all of the casting supplies that I am going to use into my shed in the morning and turn off the a/c. I love Silmar 41. I have found a pressure pot unnecessary.

 

[JohnU]

Like above, casting can be done without pressure, but don't be discouraged over a pressure tank. They are easy to build and sooner or later your going to want to expand your casting to objects, which then leads to trying alumilite and other types of casting, where a tank is needed. I was overwhelmed when I started with no one close to show me. After reading the library article here on setting up a pressure tank and trying it, it wasn't hard to figure out. Your really just adding a shutoff valve and removing the inside metal rod.

As for the resin warming. Water works fine as long as you don't get water in the resin. I personally just line a small box with tin foil and place a clip light near it with my plastic cup of resin inside, like a home made easy bake oven. After stiring a couple time and turning the cup ( about 20 min on average) the Polyresin is thin and ready. What you don't want to do is leave it unattended or overheat it. I like to heat is slowly to keep control of the temp. If it's too hot, the catalyst will react quicker and you'll have a glob before you mix or pour it. Been there done that. Currently I go through about 5 gallons of Silmar 41 a month from US Composites. There are other places to get it. Just do a google search, to find one closest to you. Also, check any local boat or fiberglass repair shops in your area. The problem with buying it off the shelf is you don't know how long it's been there. I've never had a problem with the quality of the product I order from the company. Plus, it's their product, they will stand behind it.

Just remember, there are advantages to both alumilite and poly resin. They each have their necessary uses. You will enjoy them both some day. It all depends on what your casting, tints or dyes used, and the results your looking for. You'll get lots of opinions and ideas here but what will matter most is what works for you and your set up where you live and cast. Obviously what info in Illinois probably isn't necessary in Florida. Give it a try. You won't know until you doit, just make sure to be safe. Good luck and I look forward to seeing your casts!

 

[Edward Cypher]

Heating and PR buying

So are these resin products only available online? Is there not a store I can walk in to and buy them?

If you have a Plastic Care nearby they sell PR packaged for them from Similar 41. It is only about 50 bucks a gallon way cheaper than Michaels and Hobby Lobby even with the coupon. If you do not have one check out plastic shops in the area, they usually have something equivalent and also sell the cutting board material to make you molds out of cheap in there cut=off section.

You can buy Casting Craft poly resin at Michaels & Hobby lobby. One place sells MEKP (CATALYST required to cure the resin) with the resin, the other doesn't. You can get it there, but it's not sold as a kit.

I will caution you that the resin has a shelf life, and from what I've heard, it's a gamble on the quality of the resin you get from these places because the turnover isn't good. You may get some that is totally useless. I'm not speaking from experience though. I've only bought online.

Another thing to bear in mind is that there is a learning curve with pouring blanks. A quart will get you started, but you could easily end up with only a few blanks that you consider worth showing from that quart.

There is a huge learning curve as mentioned by BSea. I've poured about 5 gallons and am still on the low end of the learning curve. I do heat my resin but I used a HF sonic cleaner which also releases a lot of bubbles it was a great buy with the 25 percent off coupon which is here again for Easter.