Old Resin

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schaf

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Oct 13, 2006
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51
Location
Bribie Island, Australia.
Hi,
Some advice please if someone can help.

I have a tin of casting resin on the shelf for a long time and when I opened the tin the resin had gone hard. My question is would the small bottle of part B ( the hardener) still be ok to use or should it be thrown also.

regards
Terry
 
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I have heard the hardener will become less effective with time. Mine does not last long enough to find out. If the pr is hard from age, throw it all out. you will get more hardener with new pr and it you will know it is good.
 
I agree whit the captain.Throw away all of the old stuff. PR casting is hard enough with the fresh resin, don't complicate it by using old supplies.
 
My advice is use the PR as a doorstop, and go buy yourself some Alumilite. There are several topics on here that will start a debate going, one of which is whether to cast with PR or alumilite. Alumilite is initially more expensive, but is soooooo much easier to use, cures faster, is not deadly toxic like PR, isn't as brittle (my wife just dropped a PR pen I cast from about 2 feet onto our wood floor and the thing shattered like fine china), and is overall much more reliable. I could go on and on and I'm probably sparking a huge fire, but I'm just speaking from my own experience here. You'll end up spending less in the long run b/c you won't be throwing out resin and screwing up castings and so forth.
 
GouletPens said:
...Alumilite is initially more expensive...You'll end up spending less in the long run b/c you won't be throwing out resin and screwing up castings and so forth.
Click to expand...

2 Gal of Alumilite: $160.00 http://www.alumilite.com/ProdDetail.cfm?Category=Casting Resins&Name=Alumilite Clear

2 Gal of Silmar 41 Clear Polyester Casting Resin: $69.00 http://www.uscomposites.com/polyesters.html

- I can do things with PR that I am unable to do with Alumilite (e.g. labels)
- Alumilite has a 5 minute open working time (some like that, I don't)
- You have to measure Alumilite by weight. I use 3 drops/oz. in the summer and 4 drops/oz. in the winter on MEKP. How much easier can you get?

My suggestion is to do what I did: Buy some fresh PR and some fresh Alumilite and work with both of them. Then decide if the cost and fast open time is what you are looking for.
 
Blind Squirrel hit the nail on the head. Ive used both with success and problems in each, but Im a pr man myself. The only thing I cant do with pr that I want to is cast dried flowers. The heat in the pr makes them turn white. Other than that, I cast everything ...candybar lables, snakeskin, shredded money, worthless wood, and more. The only drawback to pr is the odor. Alumilite is odorless in the room. Pr will stink up the entire house for a couple days. I pour outside, place in pressure tank, and then bring it in. As far as being too brittle, its all in how you mix it. Make it too hot and it will be too brittle. Good luck. John
 
One other problem I have with alumilite is the finish. It just does not give that "POP" shine you get with PR.

As was said, the only problem with PR is that is smells. I have an exhaust fan over my mixing area. That solved that problem.
 
I use alumilite because my shop is under the kitchen and I don't want the fumes around with my 5 kids and other daycare kids in the house. That being said, I can cast labels with alumilite and I've had better success at the shiny finish with putting a thin CA finish (2 coats thin) on the alumilite. I started doing this with WW blanks due to the wood at the surface and found it works well on the alumilite. NOt trying to fuel anything, just my $.02.
 
Plexiglas is NOT a good finish over Alumilite. It starts off looking good and shiny, but over time the surface becomes pebbled. Sounds weird - but that's how it worked for me with the money blanks.
 
schaf said:
Hi,
Some advice please if someone can help.

I have a tin of casting resin on the shelf for a long time and when I opened the tin the resin had gone hard. My question is would the small bottle of part B ( the hardener) still be ok to use or should it be thrown also.

regards
Terry
Click to expand...

The resin has self-accelerated. The catalyst has most likely deteriorated if it is MEKp, as it is a peroxide and as such likes to oxidise out. Safely dispose of them both. Or save the hardened Polyester block and cut it up for use as spacers or jigs.

If you want to use a Polyester resin, Silmar 41 or 40, and various Swing resins are good polyester resins to choose from. They are availble from US Composites or Composites One and other suppliers I can't think of off the top of my head.

With ANY resins care should be taken for ventilation of fumes. Alsways read and keep on file a copy of the associated MSDS's
 
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