Uh-Oh - another convert

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soligen

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Well, I haven't even turned anything but wood yet, but since I found a 40% coupon for one item at Hobby Lobby that expires today, I decided to try a cast.

Got a little blue pigment and some mother of pearl powder and cast my first blank about an hour ago into a 3/4 PVC pipe. Mixed a little too much so I have a second blank about 1 3/4 long that I can use for CBs or segments.

What sucks now is waiting until tomarrow.

I do have a couple questions. Will CA glue work on PR? And for the possibility that I over shoot my target diameter (or segment with wood), can a CA finish be applied to PR?
 
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Dennis:
CA works fine on PR to glue in tubes, etc. If you have micro mesh (to 12000) and some plastic polish, I bet you will find that the PR needs no finish as you can make it really glossy with just the plastic polish. But you can successfully put a CA finish over PR.

To me the hardest thing about casting is trying to make sure that you get the fewest air bubbles possible. There are really good cast tutitorials on this site and Don Ward (its_virgil) has a very good tut on his website: http://www.redriverpens.com

I hope this helps.
 
When I cast the PR, i noted that it smelled like bondo and fiberglass resin. I have some fiberglass resin from an un-related project about 8 months old, so I figured I had little to loose by trying it, as I figure it will be bad by the time another use for it comes up.

So, I cast a blank with fiberglass resin as an experiment. Here is what I noted.

1) The resin is not clear - it is brownish, so bright ot light colors are likely not an option.
2) I put in 1/2 the hardener the package called for, and the resin still heated up alot. In a PCV pipe is was definately not comfortable to hold, but didn't burn me. If I choose to do this again, I would try 1/4 the hardener.
3) It hardened way faster than PR. About 3 hours after casting I trued it up on the lathe, drilled it, and glued in a painted tube.

4) Next morning I turned the blank (single tube polaris) - about 20 hours after casting. I had a big chip out in the center. I tried to fill it with CA, but wasn't having luck. By the time I turned the blank down enough to remove the defect, the shape was too wierd, so this blank will not be a pen, but I decided to sand it up and buf - just for the experience.

5) The blank seems soft. I can mar it with a fingernail, but 5 minutes later you can't see it. The mar must compress it, and it recovers over time. It didn't polish to the full gloss I would normally want. I'm guessing due to the softness.

Maybe it will get harder over time, maybe not. I'll try to remember to report back in a week. If it doesnt, I wont be using this resing again. If it hardens and polishes well at a later date, I'll cast some dark colors to use up what I have.

Contrasting to PR curing, I de-molded the PR after about 6 hours and the blank was able to be bent slightly, but at 12 hours seemed rigid. Probably should have waiting until the next day, but I get ansy when trying new things.
 
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The catalyst for the fiberglass resin is rated at 1/8" or so. You need a LOT less for a 3/4" thick cast.

Post curing will work for fiberglass resin as well. Stick it in a toaster oven at 150* for a couple hours. It will help with the softness.
 
Dennis , the fiberglass resin is almost the same stuff as the PR we use but the chemistry is a little different . It is a general purpose resin and is primarily used for thin layers of fiberglass cloth and as Don said the hardener is used a little differently (I find about 5 drops , or 3 drops if you preheat your resin , per ounce of resin works well) and is the same hardener used for Silmar41 and other casting polyester resins . The main differences are , as you found out , it is a different color , in the thickness of a pen blank it stays soft for a longer period of time and it is more brittle then silmar41 , it also turns a little differently because it has fillers added and when you add the colored pigments it is being overloaded (too much filler not enough resin) . It turns into as powder instead of the ribbons we get with the Silmar41 . If you use it and don't post cure it , it will take a couple of days to turn hard enough to turn but it will get hard .
 
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The PR is showing the same behavior with fingernail marks. I guess I'll wait longer.

I dont have a toaster oven, and the wife wont appreciate me doing this in the big oven. Maybe I'll toss em in the car tomarrow for an hour or 2.

I was getting ribbons (very light and fluffy) with the fiberglass resin - maybe becasue it was still a little soft.
 
The ribbons might be because there is less filler in the resin you are using , not all companies use the same formulas . Yes a few hours in a hot car will work , but you are gonna stink up your car so I wouldn't sit in the car with them . Also put them on some waxed paper or you stain or damage your interior . While they are hot they will still be soft but they will harden when they cool back down .
 
Some baking in the car, and some time and things have hardened up nicely. I re-sanded/buffed my test turning and it buffed up well. In the past I buffed with white diamond only. I picked up some blue buffing compound which is supposed to be finer than white diamond. Tried the blue for the first time on this test fiberglass resin turning. Seems a bit glossier to me, but average customers likely would never know the difference. I think the extra buffing is probably worth it for some pens - especially dark blanks.

Haven't turned one of the fully hardened blanks yet. Maybe this weekend I'll do one with my crappy old tools, then again next week when I get the wood chuck.

I may need to do a bit of CA finish on these, as I have a few small pits from (I presume) bubbles.
 
Hello may I ask a question? If you use a 3/4 piece of PVC for the mold how do you get the finished blank out of the pipe?
Thanks!
JIM
 
Jim , when PR cures it shrinks so it will pull away from the sides of the mold . A good smack on the table and it should fall right out . If the mold is old , after a few casts it will start to stick to the mold and will take more work to get out . If you cut one side of the pipe you can pry it apart and pop the blank out then tape the pipe shut for the next cast .
 
corian king said:
Hello may I ask a question? If you use a 3/4 piece of PVC for the mold how do you get the finished blank out of the pipe?
Thanks!
JIM
Click to expand...

Jim,
I tried for some time to cast in PVC. My results were not like the rest. My casts stuck from day one. I think it may have been affected because I was using Silmar 40 instead of 41.

Are you thinking of starting to cast? If you are, PM me and we will talk again. You can get all your supplies at a local shop in Norfolk to save shipping costs.
 
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