Hi there ,
Firstly let me thank you in advance for your hard earned knowledge and tips…
So, a few years ago, say two or three?, I bought a 55g drum of silmar 249 laminating resin as I was really going for it and was going to glass tons of boards!!.. Well… that didn’t happen. I did glass some for sure but I would be out of my shop for months at a time then go back and glass etc, etc.
Long story short, I’m ready to glass more boards and I think my resin has got a little bit thicker, although it might be the cold?!
I have about half the drum left. Its stored inside in a relatively cool room. Actually its pretty cold in there right now as its winter up here!
My questions are -
Is there a definite life span of resin?, if so what is it?
would the cold affect it and make it thicker?
if its because the Styrene has evaporated can I add some to my resin each time I mix a batch to lam/hotcoat etc ?
Will the thicker resin have weakened? , basically is it still ok to use or will the board be compromised etc?
I know that’s a ton of questions to answer but any help with this one would be greatly appreciated, especially from anyone that has worked in a glass shop. Thank you so much for your time, Cheers.
Thanks AquaGlassing for your speedy response! Wow, 6 months… I’ve prob glassed 15 or so boards with old resin then, Oh well, no one has complained yet!!
Is there anything negative that you know of that can happen to a board that has been glassed with older resin?? Anything I should be concerned with??
Should I even bother trying to add styrene or should I just get new resin? I would like to try and use this resin if I can, as I have it.
I will heat up my room today and get the room to 70 and see what the consistency of the resin is like and report back.
If it is still like molasses when the room is at 70, how much styrene should I add. Lets say per 32 ozs of res, so I can work out ratio?
Any help you could give me regarding these questions is most appreciated, and thanks for your time, Cheers.
I’m not a pro glasser, but I work in industrial coatings and this is a common issue we deal with. Have you ever worked with a zahn cup?
No one can tell you how much styrene to add. It has to be determined by taking a viscosity reading of your current resin and comparing it to a reading of some fresh resin. The simplest way to do this is with a zahn cup. This will not give you a true viscosity in centipoise. Rather it gives a simple measurement (in seconds) that you can use to determine what to do. I’m sure The internet is full of zahn vids, so I’ll spare you the details.
I don’t think I’ve ever had a container of resin that was still useable after two years. If yours is still in a liquid state, even though on the thick side, I can only assume the container was sealed really tight.
As others said, warm it up first and see how it flows. If you still have half the drum left that’s a lot of resin to throw away and worth enough $ to try to salvage. Maybe do a test batch and see how it behaves? After you warm it up, of course.
Well, I just learned something new. I’d never heard of a zahn cup before. I did the Google thing and learned about it. Seems like a very simple item to detrmine viscosity. Low tech, and effective.
I’ve had resin purchased ‘fresh’ off the shelf and found it to be lumpy and crystalized. I strained it through cheesecloth and once the chunks were removed what was left seemed OK. That said, I think I’d much prefer using resin that was actually fresh. I’ve since given up on purchasing even 5 gallon cans… if I don’t use it up pretty quick, it’s too sketchy.