cast resin

[dozuki]

I am attempting to cast my own resin and i just put a piece onthe lathe and I don't think it's right. First it cuts like butter but it leaves little pitts all over the piece and the part that is cot of comes off in, well its like a powder. It looks like it is comming apart in little tiny pieces instead of ribbons. When I used a biece from a catalog it cut in ribbons. What did I do wrong. any suggestions.

 

[elody21]

Hi Paul,
A lot has been said about this lately. I have never had much problems with what you discribe, but here are a few things that might be the problem.

1.When turning PR you MUST, MUST ,MUST be gentle. You need a very sharp tool and a very light touch.
2.It sounds like you might need to lighten up on the catalyst Try using one or two drops less per ounce.
3. There seem to be different strengths of resin out there which might cause some to be more brittle than others,
4.Odd thought, but PR seems to turn better if it is not cold. Maybe try leaving it on the warm porch for awhile ?
5. I have found that colors like white or adding a little more pearl dust makes the blank a little softer.
Good luck with everything!

 

[JimGo]

Paul,
Alice has more experience than most of us here with homemade PR (YoYoSpin, PenWorks, and a few others may still have her beat, but she's certainly gaining ground!), so I'll certainly defer to her opinion. One thing I'll add is that I turn most of my wood with a skew, but for my homebrew PR, I have switched to a round scraper at Anthony (Penwork's) suggestion, and that made a BIG difference. I think its because less of the cutting surface touches the blank, which means I'm less likely to get a nasty catch and send pieces flying, but I've had MUCH better luck with the scraper than the skew. I haven't tried a commercial plastic blank yet, so I can't compare my PR to anything other than one piece that Anthony was kind enough to send me, which turned pretty much just like my homebrew stuff.

Good luck!

 

[Old Griz]

Jim, you mention problems with a skew on PR and acrylics... is the skew ground to a curved face or straight. I have found that the curve ground skew, like Alan Lacer does it, makes all the difference in the world..

 

[alamocdc]

Paul, the only thing I'll attempt to add to what Alice said is that my PR has a tendency to have what looks like small potholes in it if I try to cut too aggressively.

 

[JimGo]

Tom,
My skew is straight, and it makes sense to me that a cuved skew would make a big difference, for the same reason I mentioned with respect to the scraper; less surface area to "catch" the blank. Thanks for the idea! I'll have to try regrinding mine to be more rounded (not quite sure how I'll do that... )

 

[dozuki]

Thanks for the suggestions. I am going to try to mix a new batch using a little less catalyst. I am also going to give the scraper a go and see how that affects the piece. I just wis it didn't smell so bad

 

[scturner]

dozuki,

I may be wrong but I think those tiny pits you're refering to might be tiny powder or pigments that didn't quite make the mix just right. I've seen that happen in my cast as well but haven't been all that noticeable. I would suggest making sure you mix everything up very well (2- 3 minute) stir time before pouring into the mold. Just make sure everythings mixed really well and see if that fixes it.

BTW, I found a cool little tool at a Sally beauty supply store (East coast) the other day that is just great for mixing powders and PR in the mixing cup. It's a very tiny mixing wisk (really small). It's probably used for mixing hair dyes at beauty sallons but works great for PR making as well[].

 

[Old Griz]

Originally posted by JimGo
<br />Tom,
My skew is straight, and it makes sense to me that a cuved skew would make a big difference, for the same reason I mentioned with respect to the scraper; less surface area to "catch" the blank. Thanks for the idea! I'll have to try regrinding mine to be more rounded (not quite sure how I'll do that... )

Jim, if you go to www.alanlacer.com you should find your answers..

 

[JimGo]

David, should we be concerned that you even visited Sally in the first place?

 

[scturner]

Ok, Ok, after rereading that I just realized how that sounded. No Jim, I want to make it perfectly clear that I don't usually visit Sally on a regular basis[]. Actually, I was looking around for a squeeze bottle and a small dropper for PR mixing, you know just trying something different.

But got to tell ya, I laughed out loud when I read your post. That made my day!!! Thanks I needed that.[]

 

[JimGo]

Sorry, couldn't resist.

Tom, thanks. I'm gonna break down and get (at least) one of Alan's videos one of these days.

 

[dozuki]

I thought i would give you an update. i tried another batch with only 5 drops and it seemed to turnbetter, a lot fewer potholes. unfortunatly there were a few bubles and the bubles developed into cracks while turning. So that won't even be a pen. I'll keep at it even though it really depresses me seeing how far I have to go to get anywhere near some of you PR casters. If i can figure out how to i'll post some pics.

 

[elody21]

Originally posted by dozuki
<br />I thought i would give you an update. i tried another batch with only 5 drops and it seemed to turnbetter, a lot fewer potholes. unfortunatly there were a few bubles and the bubles developed into cracks while turning. So that won't even be a pen. I'll keep at it even though it really depresses me seeing how far I have to go to get anywhere near some of you PR casters. If i can figure out how to i'll post some pics.

It does get discouraging at first. I am sure we all have had more failures then we want to admit. I have been working on one design for 4 months! Each time there is something new that it wrong. I think you are probably past the majority of difficulties.
I was turning PR resin this morning as just as an example of how light a touch you need, think of your pen blank as a raw egg, and be THAT gentle. I happen to use a large, sharp, roughing gouge, but I use it basically as a scraper like the others have said. barely touching the blank. Don't give up!

 

[dozuki]

since you mentioned it I also use a roughing gouge. I can make it work a lot better than my skew. Skews are evil don't you know.

 

[cwasil]

I'm probably in the same boat as you are as I've now turned down about 25 to 30 homebrew PR pens and all I can say is get used to the skew. I think you can use a scraper or a roughing gouge to get down to around 1/4" oversized but after that I think you'll need a skew to straighten everything out. I'm not sure what everyone else gets when they rough it down but I get little tiny chips that tear away...with an occasional big one. I use a scraper or gouge (whatever is sharpest at the time) to rough it down because it's fast (and I love to be sandblasted) and then I use the skew to take off the remaining material to get to the finished OD. If the skew is sharp I'll get long ribbons of material and a nice enough finish to start with around 220 grit sandpaper.

As for the potholes, I believe what those are is unmixed powder dye. I get a few of those on my lavender and blue blanks, not sure why as I mix the PR, pearlwhite & powder dye for a long time and these still show up. All I can say is switch to the liquid and this won't occur anymore. I use a liquid pink also and none of the "potholes" occurs.

No matter what I try, PR is relatively brittle. I've dropped the catalyst all the way down to 3 drops per oz and I still get sandblasted. It's a little better but not enough for me to stick around the shop for hours waiting for my batches to set up, swirling the dyes frequently. Not sure what Yo Yo or anyone else does to solve this but, as it stands, I just learn to live with it. I tested some of my first finished pens by dropping them on the sidewalk, then tossing them, whacking them on the counter and such and even though it seems brittle while turning none of the three ever shattered much less obtained a crack so I feel pretty confident in the product. Kind of touchy to turn but worth it.

Hope this helps.

Chad

 

[LarsNCSU]

I've recently had one of my pens crack when it was dropped. I had problems when making that batch so I tested a piece from another batch and it shattered. Is this just a catalyst issue? Is there anything that can be added to the PR to make it lees prone to these issues? I'm currently getting my PR from Artstuf.

 

[PenWorks]

You can try casting with a little less hardener, should be a touch softer and less brittle. Bottom line, it is a plastic of sorts, most will crack when dropped on a hard surface. I dropped my 650.00 Delta and it cracked [V] So it happens to most resins.

Remember, your pen is a Fine Writing Instrument, not a basketball []

Lucite & Ebonite are less prone to cracking and chipping, I have dropped my little lucite shop penceil a bunch without any ill effects.

BTW, Welcome to IAP []

 

[LarsNCSU]

Thank you for the insight and the welcome to the group. I've been inspired by your postings and examples on the subject. After a few trials, I've had some good batches. Then, I gave one of my blanks to a friend who turned his own cigar pen. Then he accidentally dropped it onto concrete, leaving a crack.

I actually had the opportunity to visit Douglas and Sturgess (Artstuf) in San Francisco before I made my first purchase. They had mentioned that epoxy resin would be much stronger than PR. I've been contemplating trying the epoxy for this reason. But, until my friend dropped his pen, I'd been extremely happy with PR.

Based on what you said, I believe I'll go ahead with PR, instead of experimenting with epoxy.

Thanks,

 

[btboone]

I'm about finished experimenting with PR too. I've done enough to see that acrylic that I buy is a whole lot better looking than the PR I cast.