| |  Re: Mixed too much epoxy
[Re: Cheshirecatman]
#165234
01/17/09 08:14 PM 01/17/09 08:14 PM |
Joined: Apr 2002
Posts: 805
Gainesville, FL 32607 USA dacarls 
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Gainesville, FL 32607 USA | I put several pumps worth of mixed epoxy in my wife's freezer compartment under a tight polyethylene cover. It was excellent for 3 days til used up later for fill etc.. No problems- except with the wife.....
Chemical reactions slow by 50% for each 10 degree C drop in temperature.
signed Dave Carlson PhD Physical-Organic Chemist.
Dacarls:
A-class USA 196, USA 21, H18, H16
"Nothing that's any good works by itself. You got to make the damn thing work"- Thomas Edison
| | | Re: Mixed too much epoxy
[Re: Rolf_Nilsen]
#165260
01/18/09 08:22 AM 01/18/09 08:22 AM |
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uk TEAMVMG
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uk | Rolf, thats quite a good technique for doing epoxy work overhead to stops mess and drips. Put it on cold and then warm it up once its in place to wet it out.
Paul
teamvmg.weebly.com
| | | Re: Mixed too much epoxy
[Re: Rolf_Nilsen]
#165261
01/18/09 09:05 AM 01/18/09 09:05 AM |
Joined: Apr 2008
Posts: 921
Alachua, FL Mugrace72
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Alachua, FL | So when it it heats up again, the chemical process starts up again? No problem?
Taking it a bit further, if I work in a cold room laminating parts and heat the part later, the process will still kick in at 100% (or as well as if I worked at a constant 20degC)? I have used this technique with catalyzed products many times. Usually with paints such as Imron, Awlgrip, DP40, and misc. epoxies. I found that by putting the unused portions in the refer I could keep them for a week or two and then use them with good results. However, I am not sure the chemical properties are as good as with a normal cure. I never saw problems but nothing I did was structural in nature. I wonder if structural expoxies might be compromised somewhat by doing this.
Jack Woehrle
Hobie Wave #100, Tiger Shark III
HCA-NA 5022-1
USSailing 654799E
Alachua FL/Put-In-Bay
| | | Re: Mixed too much epoxy
[Re: Mugrace72]
#165266
01/18/09 12:06 PM 01/18/09 12:06 PM |
Joined: Apr 2002
Posts: 805
Gainesville, FL 32607 USA dacarls
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Gainesville, FL 32607 USA | Re: Epoxy for CF cloth, glass repair or polyester gel coat repair. When West System or any epoxy is mixed- it does not care how fast it polymerizes. As long as this chemical reaction has correct amounts of each reagent, it should go to completion. Just at different speeds depending on temperature.
Thus if you heat it, for each 10 degrees C ABOVE room temperature its reaction speed will also double. So, I mix well and then immediately separate off the likely excess in a quite shallow dish so it does not cook off.
Keep cool in the fridge, then freeze asap covered, thus DRY: use a Zip-lok polyethylene bag. Newspaper-sleeve thin polyethylene tubes are very useful for a cup of epoxy because they WON'T TIP OVER.
Be sure to emphasize ahead of time to your female crew/wife that this is non-stinky epoxy. It is NOT catalyzed polyester resin and WILL NOT STINK UP HER FRIDGE. Now- does she really trust you?
Note- If you over-mix warm epoxy, mix in fumed silica gel or colored dye, then hold a compact storage cup- it may self destruct in 10 minutes. Quick and cool is best.
Dacarls:
A-class USA 196, USA 21, H18, H16
"Nothing that's any good works by itself. You got to make the damn thing work"- Thomas Edison
| | | Re: Mixed too much epoxy
[Re: Rolf_Nilsen]
#165276
01/18/09 03:11 PM 01/18/09 03:11 PM |
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uk TEAMVMG
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uk | Prepreg carbon comes with the epoxy already added and is kept in referigeration until use. this is how some high tech big boats are done so it must be structuraly sound.
Paul
teamvmg.weebly.com
| | | Re: Mixed too much epoxy
[Re: dacarls]
#165306
01/18/09 10:13 PM 01/18/09 10:13 PM |
Joined: Jun 2001
Posts: 12,310
South Carolina Jake
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South Carolina | Re: Epoxy for CF cloth, glass repair or polyester gel coat repair. When West System or any epoxy is mixed- it does not care how fast it polymerizes. As long as this chemical reaction has correct amounts of each reagent, it should go to completion. Just at different speeds depending on temperature.
Thus if you heat it, for each 10 degrees C ABOVE room temperature its reaction speed will also double. So, I mix well and then immediately separate off the likely excess in a quite shallow dish so it does not cook off.
Keep cool in the fridge, then freeze asap covered, thus DRY: use a Zip-lok polyethylene bag. Newspaper-sleeve thin polyethylene tubes are very useful for a cup of epoxy because they WON'T TIP OVER.
Be sure to emphasize ahead of time to your female crew/wife that this is non-stinky epoxy. It is NOT catalyzed polyester resin and WILL NOT STINK UP HER FRIDGE. Now- does she really trust you?
Note- If you over-mix warm epoxy, mix in fumed silica gel or colored dye, then hold a compact storage cup- it may self destruct in 10 minutes. Quick and cool is best. Dave, I've had a little different experience with mixing epoxy when it was cold in that it wouldn't cure. Once mixed and the reaction started, I've never had a problem with low temperatures. I have, on a couple of occasions, mixed West System (fast hardner) when the resin and hardner were below 40 degrees and I had real problems with it curing. I make sure it's warm now before I start to mix.
Jake Kohl
| | | Re: Mixed too much epoxy
[Re: bvining]
#165384
01/19/09 07:48 PM 01/19/09 07:48 PM |
Joined: Jun 2001
Posts: 12,310
South Carolina Jake
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South Carolina | I went back to my 6oz of mixed epoxy/resin in a plastic container in about 30 mins at about 20deg and it had hardened and melted the plastic cup. It hardened faster than the part that I was making in the warm shop. So, I guess the mass of liquid had already started the chemical reaction and had enough internal heat that it wouldnt slow down.
Interesting.
I bet if you use the slow hardener, the exothermic heat generated wouldn't be extreme enough to overcome the ambient temperature.
Jake Kohl
| | | Re: Mixed too much epoxy
[Re: Jake]
#165390
01/19/09 09:45 PM 01/19/09 09:45 PM |
Joined: Sep 2002
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Roanoke Island ,N.C. Team_Cat_Fever
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Roanoke Island ,N.C. | In other words the pero-fluvial cryobenarium would not exceed the polar molecular matriculum dicrundi.There by not having a gelatinous mound of defecation in the sub 32 degree insulated box.
(If youda used the slow hardenerer your sh!t wouldn't of kicked in da freezer)
Tawd
"I said, now, I said ,pay attention boy!"
The cure for anything is salt water - sweat, tears, or the sea
Isak Dinesen
If a man is to be obsessed by something.... I suppose a boat is as good as anything... perhaps a bit better than most.
E. B. White
| | | Re: Mixed too much epoxy
[Re: fin.]
#165423
01/20/09 10:25 AM 01/20/09 10:25 AM |
Joined: Jun 2001
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South Carolina Jake
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South Carolina | "So, I mix well and then immediately separate off the likely excess in a quite shallow dish so it does not cook off." D. Carlson. Fellas, I'd reread the good Doctor on this one.  Uhh...yeah - that too! 
Jake Kohl
| | | Re: Mixed too much epoxy
[Re: Jake]
#165466
01/20/09 05:49 PM 01/20/09 05:49 PM |
Joined: Sep 2002
Posts: 3,224
Roanoke Island ,N.C. Team_Cat_Fever
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Carpal Tunnel
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Roanoke Island ,N.C. | "So, I mix well and then immediately separate off the likely excess in a quite shallow dish so it does not cook off." D. Carlson. Fellas, I'd reread the good Doctor on this one. Uhh...yeah - that too! Well.. With the cost of west System ,I would never mix more than I needed, therefore taking off the excess is not an option. Once I know I have excess(usually scraped off of the project), it's too late. I've tried saving it by cooling it and it has never worked for me . Slowed it down, but still gelled within 20 minutes. I would think if there was a way to save extra, some of the boatshops I worked for would have used the technique. Todd
"I said, now, I said ,pay attention boy!"
The cure for anything is salt water - sweat, tears, or the sea
Isak Dinesen
If a man is to be obsessed by something.... I suppose a boat is as good as anything... perhaps a bit better than most.
E. B. White
| | | Re: Mixed too much epoxy
[Re: Team_Cat_Fever]
#165494
01/20/09 11:04 PM 01/20/09 11:04 PM |
Joined: Apr 2002
Posts: 805
Gainesville, FL 32607 USA dacarls
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Gainesville, FL 32607 USA | Whut it is, is them thar boy molecules want to get all jiggy with the girl molecules REAL BAD, and never let go. If'n they's too cold, not much happens, even if they is an equal number of them all mixed up close together. But if y'all lets thesehere boys and girls get too hot, its like the clothes all get flung off and they start to seriously party down. Cooling them off don't help much then- its too dang late, Bubba. Hope this helps.... The ol' Doc.
Dacarls:
A-class USA 196, USA 21, H18, H16
"Nothing that's any good works by itself. You got to make the damn thing work"- Thomas Edison
| | | Re: Mixed too much epoxy
[Re: dacarls]
#165496
01/20/09 11:20 PM 01/20/09 11:20 PM |
Joined: Sep 2002
Posts: 3,224
Roanoke Island ,N.C. Team_Cat_Fever
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Carpal Tunnel
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Roanoke Island ,N.C. | So it's all about proper parenting.
"I said, now, I said ,pay attention boy!"
The cure for anything is salt water - sweat, tears, or the sea
Isak Dinesen
If a man is to be obsessed by something.... I suppose a boat is as good as anything... perhaps a bit better than most.
E. B. White
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