big time PR problems

[schellfarms]

I finally worked up my nerve to cast some PR blanks. Some of the ones I've seen look so nice, I just couldn't resist. I seem to be having major technical difficulties. I purhased the supplies (luster powder, catalyst, clear casting resin) from douglass & sturgess as recommended in 2 threads I found (mr. Pickens' and mr.Turchetta's). Here's what I did.....

I decided to use the ice cube trays that are long and thin--about the size of each 1/2 of a slim line blank as my mold. I measured using a syringe with graduations on it and found that each hole in the tray takes about 3/4 ounce of liquid to fill. I wanted to try it out with 2, so I measured 1 1/2 ounces of PR and added 7 drops per ounce (in this case, 11 drops). I mixed well and added pearl white luster powder--several popsickle sticks full. I also added a small scoop of Jacard's interference blue powder (mica based, just like the luster pigment) and about 2 drops of the liquid luster powder. I wanted my pen blue, so I added about 3 1/2 or so cc's of dyn-a-flow cerulean blue pigment (liquid) to the mix. By this time, I'm jazzed, because the color is really nice an looks almost metallic. I coated my ice cube trays with a very thin shot of cooking spray to make them release easier and poured in the mix. I let it sit 24 hours and came home from work to find something the consistency of Karo syrup. Not at all what I expected. I figured the catalyst might have been a bit short, so as an experiment, I added an additional 5 drops to one of the wells and mixed with a skewer. After sitting overnight, it is still wet, but firmer--almost rubbery. I added some catalyst to the other well this morning--what do I have to lose?? I believe the dyn-a-flow is ok, as epoxy resin casts fine with it and cures nicely. I also used a few drops of food coloring to tint some luster powder in a tiny amount of PR in one of my "experimental" casts, so I don't believe that the water based dye is the problem, as that cured fine.

Sorry this post is so long, but I wanted to include everything I did so someone might see what I'm doing wrong. Is it likely that this will ever harden, or should I scrap it and start over???

 

[Draken]

I'd hazard a guess that you put too much other stuff in to color it. Try cutting back on the pearl white powder, and use either the dyn-a-flow or the liquid colorant. Also, since the PR shrinks slightly as it hardens, you shouldn't need to use the cooking spray to release the casting, but that may be dependent on the material the mold is made from. Try one without the spray and see if that isn't what kept the PR from hardening.

Also, what is the temperature of the area you cast the PR? The hardening process generates heat, and if it is too cold, the reaction won't occur or will be very slow.

Hope this helps,
Draken

 

[ed4copies]

Sara,

What is the ambient temp and humidity? We find that 75 degrees is kind of a minimum for good results. And high humidity is a problem-altho not as important as temp. If you don't get a good answer, I will turn this over to Dawn (My PR guru) and we'll see if we can be of further assistance. (You don't say in your profile where you are from-just USA-could be Az-hot or Ak-cold).[][][]

 

[JimGo]

I agree with Draken and Ed. Lower temperatures will significantly lengthen the curing time. The only thing I disagree with is James's guess as to which component is slowing the curing. I'd guess that you have too much of the dye-na-flow. 3 1/2 CC's is a lot to add. Next time, don't add the catalyst 'till after you have the color set up the way you want, and add only enough color and luster powder to get you the look you want. That will help ensure that you don't have the same problems again. BTW, the cooking spray may also be contributing to the problem; I'm not sure.

As for how to handle what you have there, add several drops of Acetone to the top of the ice cube trays, and let that sit for a while. Repeat two or three more times. The Acetone will act as an additional catalyst. Just be careful; I'm not sure how "gooey" the inside will be! The outside should be hard enough to allow you to get the PR out of the trays though.

 

[its_virgil]

It will eventually harden. Just set it aside and forget about it for a week or so. Remember what our mothers told us...."A watched pot never boils". Ambient temperature is definitely a factor as is the age of the PR. According to one mfg I contacted, the shelf life is 6 mos from the time is was made, not from when we open the cans. But, I've had some open for longer and it was fine. I think it is best to use colorant that the suppliers sell, but I've had good luck with India ink and powdered tempra paint and not so good luck with acrylic pigment. The acrylic cured but took several days. Next week is my turn to hose the Tuesday nite chat and my topic will be "resin casting" so pass the word. I'll post a notice here Sunday or Monday.
Do a good turn daily!
Don

 

[PenWorks]

Sarah, you got a bunch of good advice, I found.......
round molds tke longer to cure, as there is not much surface air to dry it.
The more powder & dyes mixes will take longer as well.
My flat molds harden very quick here in AZ , just plain hot and dry.
Still, my round molds take a day or two.

 

[schellfarms]

I'm in the boonies of North Mississippi, so the temp is definitely adequate--maybe even too hot as I cast in my barn (too stinky for indoors). The humidity is starting to creep up, however. Thanks for all the input, and please do ask at your group meeting. I really am excited about the liquid dyes, as I can see them at the art store and tell what they are, but the artstuf.com site doesn't show a color of the luster powders[]. They seem to be a great company, though, and willing to talk to you about their products.


I also tried playing with epoxy resin, and boy does that stuff throw off some heat. I mixed about 1/2 oz total volume of the wal mart stuff that cures in 5 minutes, and for some reason, it foamed like a good lager beer!!! A new tube of the stuff didn't do it, though. BTW, can you turn epoxy like you can PR after it's cast?

 

[schellfarms]

IT WORKED!!!! It is still in the mold, but appears to be completely hardened.[]

 

[JimGo]

Sarah,
Was it merely a matter of patience, or did you do something else to get them to harden?

 

[schellfarms]

Well, they appeared to be firm, but when i pushed them from the mold, they were still gooey. It's been about 9 days now, and they are still rubbery, but I'm gonna hold out and see if they firm up. They seem a little better. I did make a few discoveries, though. If you use an enamel based paint (the little bottles of model car stuff) it goes into the PR like it was made for it!! I did try again with the water based acrylic, too--just used less this time. It is still tacky after 2 days, but we'll see. Maybe the enamel is the answer to my need to color this stuff[)]

 

[Draken]

When I used acrylic based colorant, the blanks never felt dry on the outside, but it was just a thin layer at the top, the bulk of the blank was cured. The problem I found out later was that the colorant looked like it was working just fine, but when I turned the blanks, discovered that the colorant separated out of the blanks during curing. When I got them down to pen sized, you could see areas of clear PR, and clumps of color, which looked quite ugly. Virtually all of the blanks I cast using that colorant ended up in the trash. I'm going to stick to the powdered pigments that artstuf.com sells specifically for PR so I don't waste it in the future. Hope you have better luck with the enamel colorants.

Hope this helps,
Draken

 

[its_virgil]

I tried universal colorants from the paint store and did not have good results with them. I am using the following things to color PR: pigments purchased from my resin supplier(both powder and thick liquid), India Ink, powdered tempera paint...these have all worked for me.

Every PR cast I've made, colored or clear, has been "wet" on the surface exposed to the air. It dries after a few hours or in a day or so.

Tomorrow nites chat will focus on resin casting. Look for an announcement later today or tomorrow.

Do a good turn daily!
Don

Originally posted by Draken
<br />When I used acrylic based colorant, the blanks never felt dry on the outside, but it was just a thin layer at the top, the bulk of the blank was cured. The problem I found out later was that the colorant looked like it was working just fine, but when I turned the blanks, discovered that the colorant separated out of the blanks during curing. When I got them down to pen sized, you could see areas of clear PR, and clumps of color, which looked quite ugly. Virtually all of the blanks I cast using that colorant ended up in the trash. I'm going to stick to the powdered pigments that artstuf.com sells specifically for PR so I don't waste it in the future. Hope you have better luck with the enamel colorants.

Hope this helps,
Draken

 

[schellfarms]

how do i access the chat? i'm new to this whole chat thing.

also who do you purchase the powder and thick liquid from?

sarah

 

[its_virgil]

I get pigment from either Douglass and Sturgess Art Supply, aka http://www.artstuf.com or http://www.mrfiberglass.com Douglas and sturgess have the best colors but mrfiberglass has the best price on PR.

Here is the chat info. If it doesn't work email me and Ill send the info to you. http://tinyurl.com/pnt7t

do a good turn daily!
Don

 

[huntersilver]

I second the Douglass and Sturgess Art Supply, they have great
prodcuts and pricing. Although, I am fortunate to stop by their store (well not that fotunate, parking really sucks in SF[] )

 

[PenWorks]

Originally posted by huntersilver
<br />I second the Douglass and Sturgess Art Supply, they have great
prodcuts and pricing. Although, I am fortunate to stop by their store (well not that fotunate, parking really sucks in SF[] )

I'll secound that. Everytime I do the SF Pen show, it seems every parking lot I go to, wants 15.00 bucks from me [:0] What a cash cow those parking lots are.

 

[its_virgil]

PR from Douglas and Sturgess is $41.35 per gallon and from mrfiberglass.com is $28.60 per gallon. I've heard some say that D&S has better resing, but I can't tell any difference...mrfiberglass's PR performs as well for me as D&S's resin does. And, $13 per gallon difference is substantial.
Do a good turn daily!
Don

Originally posted by huntersilver
<br />I second the Douglass and Sturgess Art Supply, they have great
prodcuts and pricing. Although, I am fortunate to stop by their store (well not that fotunate, parking really sucks in SF[] )

 

[mick]

I'll second Don's opinion of the Mr Fiberglass resin. I've used both the DS and the Mr Fiberglass as well as the Castin Craft brand that Hobby Lobby and Michael's sells. I can't tell a difference in any of it...........except the price [] I too use the D&S pigments........great stuff!!