Does Epoxy resin go bad?

[Chip]

I've some fiberglass repairs coming up. I've had some epoxy West System 105 with 205 & 206 hardeners that I've had in the shop since about 2007. Does that stuff go bad after ten-plus years? Would you use resin that old?

 

[Alan Gage]

I've some fiberglass repairs coming up. I've had some epoxy West System 105 with 205 & 206 hardeners that I've had in the shop since about 2007. Does that stuff go bad after ten-plus years? Would you use resin that old?

I've used resin/hardener that was around 5 years old and it worked ok. Can't remember what I used it for but I made sure it wasn't something really important, or that couldn't be re-done, in case it didn't work. I wouldn't want to build a canoe with it but for smaller projects it might be fine.

You could always do a test batch.

Alan

 

[dougd]

I can't say as I have an answer for you Chip, I go through resin pretty quickly so it doesn't sit around but I have often wondered about this. I know varnish and paint and the such will harden after a certain amount of time. Also, has it been stored in a warm place? I would at least open both containers and see if it's still liquid and not solid and if you have pumps I'd clean them out real good before using. Hoping others chime in. I'm curious!

dougd

 

[Boatman53]

I agree with Alan. Mix up a small batch and glue something together, or coat something similar to what you intend to do. I’ve used old epoxy but never that old.
you could also call or email West System and see what their input is.

Jim

 

[Guest]

I know Chip uses West System, and as usual West is forthcoming with information

West System Storage and Shelf Life

https://www.westsystem.com/the-105-s...ge-shelf-life/

The only issue I have had is West System hardener turning dark. One very old can, probably 205 Fast Hardener, was nearly black. I used it for non-critical, non-visible purposes and it stuck fine, but was noticeably darker than fresh resin.

 

[dogbrain]

Good link Mike. That tells everything anybody would want to know. Raka brand hardener will get more of an amber tone with age. I've also had Raka resin crystalize over time, but putting it in a warm water bath and shaking it up will dissolve the crystals.

Mark

 

[Canotrouge]

That is one questions I asked West System and Ecopoxy and both said the same thing, no shelf life expiration date.... Good for ever kind of thing!

 

[Chip]

I found a photo of a boat repair I was working on in 2005, and I know I had the resin for that project, if not before. So the resin is a minimum of 15 years old.

I used the resin last week to strengthen a soft spot in my Solstice's hull. It worked, though as folks stated above, the 205 hardener had become almost black. The resin itself was clear and without crystals. Here are photos of the epoxy, in the pot, and applied to the hull.




Thank you for the advice, which was spot on!

 

[Guest]

Well that came out Fugly-poo, with an accent on the poo. 15 year old 205 Fast hardener, not surprised.

Please tell me you plan to top coat that dirty diaper area with paint, maybe a width wise band from one coaming to the other.

 

[MagicPaddler]

I have used some epoxy paint that was over 50 years old. I painted a bench top just to use it up. It worked well. I have some Shell oil epoxy that is over 30 years old and it still works but needs to be heated to dissolve the crystals.

 

[Jim Dodd]

I have some RAKA resin (5 yrs) that crystallized. Warming the jug in hot water will bring most of it back to liquid state.

The Hardener turns yellow.
When mixed, it has a very short pot life. It's OK for small projects, I wouldn't use it for wetting out a hull !

I need to order some more.

Proper storage is the Key to keeping Epoxy ! Don't let it get Cold !

Jim

 

[ppine]

Working with epoxy is labor intensive. What if it is not so good after sitting around? I have thrown out some leftover epoxy and hardener that is 10 year old or older.

 

[Guest]

I have used old epoxy, even resin with blackened hardener, for non labor intensive uses where I didn’t care about aesthetics. I painted the flush cut top of a dead, dry stump, paint old (and new leftover) epoxy on sawhorse feet, especially the over tall sawhorses that are stored outside, the frame of movable steps made from old stair risers that likewise live outside, the inside of an ancient pinhole rusted wheelbarrow, etc.

I’m too cheap to throw out epoxy, and it’s probably better to use it up than have it end up in a landfill.