Brittle homebrew-ideas?

[ed4copies]

Finally playing with Polyresin-did a gallon worth this weekend. Now, I am turning them. Boy, are they brittle!! So, my question is, did we use too much (7 drops per oz) of the activator? Or, being in Wisconsin, does it take longer for this to "cure"-it seems to be getting easier to turn each day (original batch made last Saturday-temperature about 60 degrees).

Any thoughts from those of you who have made PR would be appreciated.

Yes, I will post pics (my other half, the artist, made the colors and some of Sunday & Monday's productions will be VERY unique). But I am hoping I can be more comfortable that they will not shatter before I use better pen bodies.

Again, thanks to one and all for any experience-driven direction.

 

[Efletche]

I would like to see the pics myself because I have an interest in doing the resins too. I am also curious if the Polyresin would be good to use for stabilizing blanks?

 

[Old Griz]

I doubt the polyresin would be good for stabilizing because of the quick set up time.. that stuff starts to set up in minutes... so you would probably never get it to penetrate before it starts to gel..

 

[Efletche]

What if you soaked the blank fro a few hours in the resin BEFORE you add the hardener?

 

[Old Griz]

The set up of the resin is a chemical reaction.. the hardener and resin need to be mixed together.. there is no way to mix a couple of drops of hardener to the resin if it is embedded in a blank..
You only use a couple of drops of hardener to a larger amount of resin.. it is not an equal mix..
It just won't work for stabilizing...

 

[ed4copies]

Griz,

I agree, your logic is sound. Logic has never stopped me from trying, will answer that question (corncob test) AFTER we solve the brittle issue.[]

That experiment is one of about 5 reasons we wanted to try this ourselves. If you just want REALLY NICE BLANKS, stay with EPR (Yoyospin)-colors are beautiful, turns great, cost is reasonable!!!

 

[alamocdc]

Ed, I'm not sure what to tell you, but mine wasn't brittle and our weather has been about the same as yours. I made mine (one small test batch) on Monday and cut it up and turned it last night. I used the same activator to resin ratio as you, too. I wanted to make sure I gave it enough time to cure since I changed the coloring material. For a while I afraid it was going to be too rubbery. Sorry I couldn't be more help.

 

[ed4copies]

Thanks, Billy. Any info is better than No info-hoping some of the real experienced pourers will pick up on this tonite. We'll see!

 

[Ben]

Originally posted by ed4copies
<br />Griz,

I agree, your logic is sound. Logic has never stopped me from trying, will answer that question (corncob test) AFTER we solve the brittle issue.[]

That experiment is one of about 5 reasons we wanted to try this ourselves. If you just want REALLY NICE BLANKS, stay with EPR (Yoyospin)-colors are beautiful, turns great, cost is reasonable!!!

I too must agree!!! EPR is absolutly amazing!!! Here is a link to the first 3 that I completed.
http://www.penturners.org/forum/topic.asp?TOPIC_ID=6683
The only reason I don't have more of them done is because I'm waiting for my pen kits and a new mandrel in the mail[xx(]...
I too have pondered the thought of how to stabilize using poly resin...
I had the absolute pleasure of finally turning one of BB's stabilized blanks and it ACTED SMELLED and CUT JUST LIKE PLASTIC!!! It was at this time that I thought about the PR as well.
My idea was to place the blank into let's say a Mason jar or similar receptacle. Then in another jar mix the resin and hardener, and as soon as you add the drops of hardner, pour the mixture into the empty jar with the wood blank... At this point I think you'd have to act pretty quickly. NOW, place your jar with the wood and the resin into a 2 Qt. Foodsaver vacuum seal canister, and SUCK SUCK SUCK the AIR OUT!!! The Foodsaver will actually pull 24" of vacuum @ sea level!
I'm not sure , but I think the resin needs oxygen to be able to harden, so by sucking all of the air out of the jar , this MAY prolong the hardening until you actually pull out the saturated blank out of your jar??? I'm not sure... Who knows, you may end up with a jar full of hard resin with a blank stuck inside it after all is said and done, but I definately am going to give it a try. I have had some pretty good success with the Foodsaver vacuum chamber using sanding sealer. The sealer definately penetrates the entire wood blank. I maded the mistake and didn't let one dry enough, and when I drilled it out, the shavings from the middle of the wood were still wet!
I'm glad that there is someone else out there that isn't afraid to try this crazy stuff too. I was hoping that I wasn't the only one...
Post your results here!!! If I have any luck (or lack of luck) I will definately post my results too! Take care, and drive safely


Ben

 

[Lornek8]

How did you cast the resin? In larger, thicker castings, you need to reduce the amount of catalyst used. The amount of heat generated can cause the resin to get brittle when it cures. If the resin is poured in flat molds up to about an inch or so thick, the amount of catalyst shouldn't be an issue. When I pour cylinders (app. 2.5" dia x 5" length, app. 7 ounces of resin), I need to go down to about 2 drops of catalyst per ounce of resin. If I go much higher, the resin will crack when it cures. Hope this helps.
Lorne

 

[Lornek8]

While I was writing my last post the message regarding using the food saver to suck the resin into the blank was posted and I thought I would add my 2 cents. I work a lot with resin to make saltwater trolling lures and in such, have tried a variety of different thing with resin. I have used a vacuum bleed pump to suck the air out of resin to remove the bubbles from the cast. I have found that if I go much over 15" Hg that the resin actually begins to bubble. I think that I may be beginning to boil the resin. So be careful, it is highly flammable. There are additives that can be used to thin the resin, I think its Styrene Monomer. Its probalby not available from craft stores and is even more flammable/explosive than resin. It does however thin the resin to app the consistancy of water or maybe skim milk. This should help get the resin in the blank. One other thing, I have found that the vacuum actually tends to increase the cure of the resin slightly.
I've just picked up a vacuum pump for a vacuum chuck and am thinking about attempting to stabilize blanks with resin again. If I do get to it i'll let you all know how it goes.
Lorne

 

[Lornek8]

Sorry, in my last post I mentioned that i've found the use of vacuum to increase the cure of resin. What I meant to say was that it speeds up the cure of resin. It gets harder, faster.
Lorne

 

[RussFairfield]

A few more thoughts on this that might save you some time.

There is a difference between a "coating" resin and a "casting" resin. Do not use a resin that is made for "coating".

"Casting" resins are slower to cure, and up to a 1 or 2-hour pot-life should be easy to find. The slower cure eliminates the heat and the bubbles.

Put a wide place in the vacuum line to keep any resin from getting pulled into the vacuum pump. You can use a second Mason jar in the vacuum line for this.

You don't have to leave the blanks in the vacuum jar until the whole thing is cured, but only until the resin has penetrated the wood. 15 to 30 minutes is sufficient time. Drilling out the center will help. .

DO NOT add new resin to replentish what is in the jar.

The polyester resins DO NOT require Oxygen to cure. The opposite is true, and they must be sealed from contact with air. The coating variety of resins contain a wax that rises to the surface and seals it from the air. When using the casting resins, you will have to wrap the blanks tightly in Saran Wrap or similar to seal them.

The ratio and mixing of the catalyst is critical. A gummy result can be the result from too much catalyst, not enough catalyst, not thoroughly mixed, or nothing that you did or didn't do.

You might also consider that:

Any good resin varnish will do the same thing. There is an article here somewhere on this site on using Polyurethane. I prefer a Waterlox type varnish because it is thinner as it comes from the can and the phenolic resins do a good job on the wood.

Elmer's White Glue or Titebond, diluted to a 50/50 mixture with water will do as good as anything else. Use whichever gived the best color. The Titebonds will give a yellow to amber cast to the wood, but they will be easier to sand than the Elmer's.

I use a very thin CA Glue because it is faster, easier to use, and less of a mess.

 

[JimGo]

Russ, thanks for the tips! Did I read your post correctly, that you stabilize with CA? Isn't that expensive?

 

[53Jim]

being in Wisconsin, does it take longer for this to "cure"

Ed,

I'm just south of Green Bay, and I mixed up a gallon of this stuff over the winter and it did seem to be a bit brittle, but what I did was use a disk sander to Kinda-Sorta round the corners before putting it on the lathe.
Another thing, like Griz says -Scary sharp tools- and very lite cuts. I always had some chipping right in the beginning, but after it's round it seemed to turn very smoothly.

Good luck

 

[ed4copies]

Thanks, Jim.

I have turned a lot of plastics, and recently turned EPR (yoyospin) homebrew, so I kind of knew what to expect. However, this batch is worse than micapearl. AND LOTS more difficult than Ed's (yoyospin).

I think we will adjust formula a little as soon as the next batch arrives.

Will report on results in a week or so.

Thanks to everybody!