9 month old poly resin

[pescaloco]

hello all,

just wanted to get some feedback on older polyester resin, it is in a 55 gallon drum and has some crystalization, I have been much slower with my progress than planed, any way the project is a composite foam panel pilot house over male mold.
Would you have concerns over using this resin ?
is styrene or other compenets of the resin seperating a concern ?
I was told it is good for a year and any chunky stuff could be strained.
what is the verdict from the pro's, don't want to waste a bunch of money, but, of course the end results are important to me.

Thanks, mark

[diagram]

Call your supplier or the tech line from manufaturer. I say tech line because they often give the real "skinny" on products. You can probably find info on internet but, manufactorer will give specifics - or should be able to.

[tinhorn]

I've seen lots of lumpy old polyester resin used to make suitable parts. If you're using polyester, you're likely not dealing with exotic, high-performance applications. All the same, I'd make a test panel and post-cure the parts in the sun for a day.

[the1much]

its o.k.,,,you should mix it before each use since its so long between times,,,,and that crystallization is just what happens when its in the open air for a while. other then that i've seen a 5 gallon bucket last people for years, as long as its in a cool dry dark place,,,like the corner of my shop ;)

[fiberglass jack]

mix it well by placing a lenght of pipe into the drum with a airline attached let a little air go though to let it bubble up for a hour this way the resin should mix well then buy some 5 gallon plastic pails and pour the resin into them use a strainer to catch the chunks fill the pails to the top and before you seal them squeese the pails to remove any air and store in a cool place

[the1much]

mix it well by placing a lenght of pipe into the drum with a airline attached let a little air go though to let it bubble
show off :P

[ondarvr]

At 9 momths of age it may, or may not be OK, my guess is that it should be usable. Get the specs for that resin from the supplier and test it to see if it's still close, what normally happens with age, is the viscosity will drop and the gel time will lengthen. The crystals are normall in some types of resin when it's been stored, but it doesn't mean it's bad. If you try to spray it through a chopper or wetout gun the chunks will drive you crazy if you don't strain it first.

DO NOT put a pipe in the drum and bubble air through it, it will not mix the resin and will only evaporate needed styrene out of it and possibly add oil and water from the compressor.

You will need to determine if the resin is usable by making a small panel or part, don't risk a large expensive project with a resin of unkown quality

[pescaloco]

guys,

thanks for the replies, I was concerned about gel times an possible under cure due to older age.

this is a core rez resin product, susposed to be a gereral laminating polyester, the weird thing is it doesn't have the usuall tacky outer surface after cure that loads you sand paper up, it has a very clean dry cut (dust) from the sand paper, you guy seen laminating resing like that ??

thanks alot for the feedback
mark

[fiberglass jack]

th resin you have contains wax

[ondarvr]

GP resins are normally an 80/20 DCPD-ortho blend, DCPD's tend to cure much better on the surface, this is where the secondary bonding issue comes into play. After a few days they can become almost tack free without wax. I'm not saying it doesn't have wax in it, it may, you can take the code off the label on the drum and the supplier can tell you if wax has been added. DCPD's are a little more difficult to store for long periods of time also, those small crystals forming in the drum are common. If you mix the resin very well, then strain the chunks out it will last longer, once the small chunks start to form more resin will harden around them much faster.

[fiberglass jack]

to find out if there is wax in the resin get a glass jar and fill it half full with acetone then place a few table spoons of resin into it place the lid on and shake it for a min or 2 let stand for a little while the wax will rise to the top like a oil slick
if the resin is a little to thick you can add a little styrenne to thin it out the promoters in the resin like colbalt and dma wont evaporate so you should be fine using a air line to bubble the resin make sure you have a water and oil trap and filter and bubble softly this way the sytrine will say put

[ondarvr]

fj

The viscosity of resin is too high for the bubbling of air to do any mixing at all, an actual drum mixer is needed to blend all of the ingredients back together, the only affects bubbling will have are negatives.

At 9 months the heavier components will be at the bottom of the drum, styrene and a few other things will be at the top. It will be very important to mix it thoroughly before use.

[the1much]

fj

an actual drum mixer is needed to blend all of the ingredients back together,


does beatin on the top of the drum with 2 sticks count as a"drum mixer"? :P

[fiberglass jack]

I worked for a company for 3 years and the cheap ass that owned it would only buy expired resin ve gp iso what ever was the cheapest we even used casting resin to lay up truck bodys there would be chunks of floting in the resin sometimes we would have to cut the tops of the drums off to get to the resin all the resin went hard and was tested with a meter to test barcol and passed the test by the ministry of transportation we use to add 5 gallons of styrine to a 55 gallon drum and add 250ml of colbalt bubble away and the resin was good to go.

[the1much]

hmmmmmmm,,,now thinking bout it,,one of my aaaaaaaabosses, hadone of those aaaaaaccents from aaaaaaacanada,,and he was aaaaaaaacheapo!! ;)

[ondarvr]

It sounds like your old boss used all the correct methods, so bubbling must be great then.

[pescaloco]

thanks for the replies, I feel a lot better :) :)

I was able to do some lay up this week end and seems to have gone very well

good tip on the acetone and resing in a jar to check for seperation / wax

I will mix well strain and get into 5 gal buckets where there is no air space above to futher allow solidification of the resin.

Thanks as allways for sound advise, it is much appreciated

Mark