Resin Question

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cwasil

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I just got my polyester resin and colors in yesterday and I've got a few questions. I cast a 4oz & a 9oz yesterday and I'm wondering if the rest of you guys had the same consistency I did. I got my blanks prepped today and they seemed kind of brittle. When I drilled (9/32")the blank, at the bottom, a little larger chunk than any acrylic I've ever worked on popped out...it was still O.K. but it almost looked like a chuck of glass. The barrel trimming was fine, it shaved like any other acrylic I've dealt with. The actual turning was insane though. I started by taking a small 1/4" gouge after it and the best description I can give is that I was sandblasted. No big chunks, just small, sand sized pieces that kind of stuck to my arms. When I had hogged off enough material I switched to the skew and it shaved real nice. The biggest problem I found was at the end. Melting. After I turned it close to size I normally go 120, 220, 400 & MM to 12000 and, finally, HUT plastic polish. I was making a designer pen and at the nib end, where the thinnest material is, the 220 actually melted the plastic. The questions I have are this:

1. Is the consistency I had in my blanks close to yours?
2. Have you ever had a melting problem?

Overall, to anybody out there on the fence on this one...just do it. If I can do it, anyone can. I forgot my camera at work so I can't show you what I did but one is a lavender that looks alot like Anthony's color in his casting instructions. My only word of advice so far is to maybe trim an 1/8" off the edges of the resin block before cutting it into blanks. The "crap" kind of a accumulates near the edges so it might be best to just get rid of it instead of it accidently becoming part of your pen surface.
 
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YoYoSpin

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1. yes
2. no

Drill the backside of your blanks very slowly, and clear debit often. Never use a gouge on plastics...a negative rake scraper is best. But your clean up with the skew, at a 90 degree angle to the piece is spot on...and the best technique I've found for getting a clean finish cut on PR.
 

its_virgil

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For what its worth, I agree with Ed...I only use skews on plastics and my won PR...sorryh to say I am scraper challenged. But the skew is my tool of choice from start to finish on most materials.
Do a good turn daily~
Don
Originally posted by YoYoSpin
<br />1. yes
2. no

Drill the backside of your blanks very slowly, and clear debit often. Never use a gouge on plastics...a negative rake scraper is best. But your clean up with the skew, at a 90 degree angle to the piece is spot on...and the best technique I've found for getting a clean finish cut on PR.
 

PenWorks

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I am a scraper when it comes to resin, just a light touch with the skew when I'm done. If it is real brittle, I would guess just a little heavey on the hardener. Mine tend to be softer, more on the lines of the Tru Stone material.
 

Deere41h

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I too have had some home casting blanks that have been very brittle. I found that if you use a gouge on them it best be very sharp and you can't be aggressive with it. My two favorite tools for resin are a spindle master and a skew. Both work very well as long as I'm not too aggressive with them. Oh yes....they must me sharp! I have not tried a scraper but I will now.
 

Lornek8

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I've had expereinces like everyone else. Gouges tend to create major chip-out, skews are okay if used lightly. The best finish I get is from a square scraper, deburred, used as a skew scraper (tilted app 60-75 degrees). I have to play with the angle a little to get the best cut, but can go directly to the buffer and get a glass-like finish. The scraper peels ribbons of resin off, even on really brittle casts. Its not quick but gives a great finish.
Lorne
 

cwasil

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Thanks for all the input. I'll definitely try the scraper when I do the next blank. I guess I got so used to using the gouge as a roughing tool it wasn't really in my mindset to try anything new. As for my single instance of melting the PR, I'll lighten up a bit on the pressure of my sanding and call this more of a fluke than anything since nobody else has said they've had a problem. Thanks again and I'll show my results on Tuesday when I get another chance to turn.
 

cwasil

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O.K., last night I turned another PR pen with input given here. I must say even with a scraper, I still managed to get sandblasted. It wasn't quite as aggresive as a gouge but not a whole lot of difference. I still had to rough it out way oversize, skew it down to just a little oversize (.040-.050), sand it down to 12000MM (probably overkill) and then Hut's plastic polish. Not bad process given the end result and I'm sure I'll get better as I go along.

I do have one last problem though. Air bubbles or clumps of unmixed powder. I tend to think that it's the powder since I made a pink block using liquid dye and I see none of the specks. It doesn't look bad or anything but I'd rather not have them. If when I turn down the pink pen and find no inclusions (lack of a better term) I'll start buying the dyes but to use up my stock of D&S powder do you have any tricks in mixing? Maybe I used too much kind of like when your a kid making koolaid with 8 cups of sugar. For a 9oz mold I use 4 popsicle stick scoops of dyed powder and 2 pearlwhite. For a 4oz I'm using 2 scoops of the dye and 1 of the pearlwhite. I first mix in the catalyst and then I mix in the powder. The whole process takes about 2 minutes for a 4oz and maybe around 3-3 1/2 for the 9 oz. I feel I mix it pretty good but something isn't quite right. If you have any input please let me know. Thanks

The flash really showed the inclusions but, honestly, you have to be about 6 inches away from the pen to see it in normal light.

200567141350_DSC00001.jpg
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20056714168_DSC00002.jpg
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JimGo

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Hmmmmm...haven't had that problem yet. How are you forming your blanks, and how many drops of catalyst are you using per ounce?
 

alamocdc

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Sorry, but I can't help you with the powder dye question as I use something totally different from the rest. All in all, I think you made a fine looking blank, Chad. [^] Keep practicing and you'll get the result you want.
 

cwasil

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Jim,

I believe on this batch I used 7 drops per oz which was in the directions. I've since dropped it down to 6 drops per oz based on the fact that the PR was very brittle and that it is now very hot in Wisconsin (mid 80's). I found no difference in the gelling(sp) time and I'll soon find out if it turns any different.

I'm forming the blocks from the molds purchased on misterart.com.
 

JimGo

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Chad,
The reson I asked about the catalyst is that I had a simiar problem two weekends ago. However, it arose under different circumstances. I use cylindrical icecube trays from WalMart to make my resins. I was making a bunch of different colors, and when I got down to the last one, I forgot to put the catalyst into the resin before I poured it into the mold. Thankfully, my molds are approximately 1oz each, so I went back and put the catalyst in and then tried to stir everything up. Well, the stirring didn't work too well, and most of the catalyst stayed at the top. The bottoms of these particular blanks were a soft, grainy, gooey mess, and the middles had MASSIVE holes in them! I don't know what happened; I don't think there were big air bubbles in there, but yet somehow there were big holes in each. The other stuff I cast that day was just fine. It was low to mid 80's, if I recall correctly (which, BTW, I don't consider very hot, but that's just me!).

So, the moral of my nice, short story is, make sure you've stirred the catalyst well before you pour everything into your mold. My process is:
1) pour PR into disposable highball-type cup
2) mix in coloring agent for at least 30 seconds, and usually more like 60-90, to make sure it is as evenly distributed as possible
3) let it sit for 30-60 seconds, to let some of the air come out, and to give me time to go dig out the catalyst (I never remember to grab it when I'm collecting everything else!)
4) Count out the drops of catalyst, allowing them all to pool at the top of the PR
5) Mix everything for at least 45-60 seconds
6) pour into mold(s)

Hope this helps! Good luck!
 

elody21

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Isn't is possible that there are different grades of PR., maybe some setting harder than others? There seem to be several different prices even on the same site. I get mine at Mr Fiberglass, the cheapest I can find at $25.99 a gallon and $9.00 shipping. I have never had a probem with brittleness even when I goof and add too much catalyst. This is very confusing. Weather should not change the final results only the time it takes to get there.
 

JimGo

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I agree Alice, there may be different grades. Chad, where did you purchase your PR? My most recent purchase was a gallon from Douglas & Sturges (Artstuf.com); before that, I used a quart from Michael's.
 

ed4copies

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Chad,

Your pen looks great to me. Having attempted to photograph purple pens, I also HAVE to congratulate you on the color. If the photo is accurate, you have shown a color I have attempted to shoot a number of times-without adequate success!! Nice job!
 

cwasil

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Plymouth, Wisconsin.
This is my first shot at PR and I got it at artstuff.com

My steps were:

1.)Pour PR in a highball cup (note:do not use cheap cups. There is a reaction created when the catalyst hits the PR which caused the cups I used to actually slowly melt. I tried to do a carmine red 9oz block yesterday but only 7 made it after dripping out the bottom of the cup. The floor looks like I committed a murder.)
2.)Add catalyst 6 drops per oz
3.)Mix until the haziness clears, about 30-45 seconds
4.)Add all powder
5.)Mix for around 1-1 1/2 minutes
6.)Pour into mold

Now that I read your technique, Jim, I like it better to mix the powder in first and then the catalyst. Since the PR isn't going to set without the catalyst I could add the powder and mix until my hearts content to make sure the powder is all disolved in the PR. I could then let it sit to try and let the air bubbles out and, finally, mix the catalyst in. Your way makes more sense than the instructions.

Ed,

To get this color in a 4oz mold I used 2 scoops of D&S ultraviolet marine and 1 scoop of pearlwhite pigment
 
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