I am about to order a gallon of resin , and i have an un-opened bottle of sanding agent and catalyst from last year , do they go bad? Can I still use them or am i better off ordering new stuff?
Surfacing agent goes bad easily (and quickly) because styrene evaporates so easily: look at what it looks like. If it’s still liquid, without wax particles floating in it, it should be good. If you find a bar of wax inside the bottle, it obviously isn’t any more…
Catalyst kept in a closed bottle should be OK, but I suggest you do a test before using it for a full glassing batch.
Though surfacing agent can be salvaged with a little styrene , mix well in a warm place and then strain it through a painter’s sieve/funnel to gwet out the bits that didn’t re-dissolve.
Catalyst- well, Methyl Ethyl Ketone Peroxide ( MEKP ) isn’t the most stable of molecules, ya know? It can break down due to heat, light or a combination of both. Best to store it in a place thast’s dark and at a stable temperature. As Balsa sez, do a test and if in doubt, pitch it and get more.
'cos a lamination that won’t go off isn’t any fun, ya know?
hope that’s of use
doc…
I ran out of sufacing agent and ended up throwing some surf wax into a jar of styrene. It disolved when warmed in a hot water bath. I am sure pure paraffin would be better, but it seemed to turn out allright.
So if you look into the surfacing agent and you can see bits of wax or sumin floating around but its only small, does it mean that its gone?
And should be renewed and not used at all ??
My experience, granted that it’s limited, is that if you give it a hot water bath the stuff should re-dissolve, though again it’d be a good idea to filter it before use.
hope that’s of use
doc…
Cheers.
I JUST used it yesterday and it has bits floatring around. I didnt think it was anything :S
Will try redissolve it though. The hot coat did have heaps of little bubleseverywhere though 
O well i’ll just sand em out.
Thanks for the info
Yes, MEKP polyester resin catalyst does age. If your catalyst is older than a year or has been exposed to prolonged high temperatures, you should properly dispose of it (it is an environmental hazard- take to local HAZ waste disposal unit- in west LA go to Hyperion water treatment plant, call first to get times that you can drop off) and get new stuff. Remember to minimize inhaling of MEKP by ensuring ventilation of vapors (no contact buzz allowed with this stuff)
BTW, there is not a specific/standardized formula for MEKP. It varies depending on manufacturer and application, so try to stay with the one associated with your resin manufacturer or use the one that has delivered results for you in the past. Should test in small batch (properly measure) if you have any doubts, it will save you time later on despite waiting for the kick, if its bad, it will not kick (harden).
Quote:
While all ketone peroxide products will lose active ingredients with aging, the MEKP/AAP blends
age much faster than the individual components, especially when exposed to warmer (80°F and
up) temperatures during transportation and storage.
Excessively aged mixtures have the potential to cause serious process and end product quality
problems. Norac attempts to provide consistently performing products for up to twelve months
from date of manufacture (when stored properly).
from: <a href="http://www.compositesresearch.org/research/">http://www.compositesresearch.org/research/</a> paper: MULTI-COMPONENT PEROXIDES FOR IMPROVED CURE by: Ken Weber, Frank Long, Dennis Fink</blockquote></div>Jah
ps- I prefer RR epoxy and wear organic vapors mask when using MEKP.
I got a picture of my wax for the hot coat before i delt to it:
Before i did the bottom hot coat. I took the can of it and put the base of it in hot water. In about a minute the bits floating around dissapeared (melted) and it was back to normal. I just used it then aswell. What does it mean if there are heaps of little bubles in your hot coat?? To much wax compund ?? lol
Cheers
thanks a lot guys , i just went ahead and ordered some extra cat. and surface wax as some insurance. The guy that i am restoring a board for wants me to paint the board before it is hotcoated because it is so badly yellowed , i know i have to use acrylic paint , but i dont know what kind , or where to get it , and what to thin it with. I have an air compressor and spray gun so i need to get the paint nice and thin. My biggest fear is getting a nice coat of paint on there and when i hotcoat , it will get destroyed . thanks in advance!
Quote:
What does it mean if there are heaps of little bubles in your hot coat?? To much wax compund ?? lol
Cheers
It may be that you stirred the mix too fast, got air in it, and then the resin kicked before all bubbles had had time to burst out to the surface…
Or it may be that the lamination behind the hot coat was not perfectly “closed” and bubbles came from it…
Or it may just be that things decided to go wrong, with no obvious reason… Happens all the time with me…
I got used to just squirting lots of catalyst in small amounts of resin when I was doing fins. I have bubbles in my fins which I first thought were air.
Guy at the fiberglass store said he had seen pieces of hard fiberglass cut open and smell the released catalyst which had been in little bubbles.
A catalyst by definition doesn’t get used up in a reaction. So if you use way too much catalyst the bubbles could be the visible catalyst.
Heck,
Even stryrene goes bad.
Was talking to Brad Basham just-a-while-ago about a quart of stryrene going hard on me(hard like a superball).When I asked him about ,“if stryene goes bad question” he looked at me w/ that curious ,“no one has asked me that before” look ,and said,"Yes, I have a can here I have to return to fiberglass supplies that was the consistancy of honey.He then proceeded to show me the going sour can of styrene.
It all has a shelf life…best I can tell you is to keep it cool,airtight,and in a dark place…oh yeah over time it seems that all these mentioned products do better in plastic bottles rather than metal cans…I/YOU would think that that would be the opposite…but in my experence…plastic bottles win hands down(this doesnot include evaporation,that’s another thread).
Aaha yea now that i think about it i think i am sturring it to much aye. I think im a little scared that if i dont hurry some then i will miss my opportunities and the resin will kick before im finished. Will try and calm down a bit lol.
Cheers Balsa