Announcements
New Discussions
Suggestions light wind big chop?
by fa1321. 05/08/21 07:26 AM
Downhaul under spinnaker
by CapriSun. 04/22/21 09:01 AM
Previous Thread
Next Thread
Print Thread
Rate Thread
Hop To
Page 1 of 2 1 2
Mixed too much epoxy #165225
01/17/09 05:58 PM
01/17/09 05:58 PM
Joined: Oct 2002
Posts: 1,226
Atlanta
bvining Offline OP
veteran
bvining  Offline OP
veteran

Joined: Oct 2002
Posts: 1,226
Atlanta
I mixed up about 6 oz too much MAS epoxy and resin, and being the frugal guy that I am I didnt want to throw it out, so I put it outside (10deg)to keep it from hardening. Will it still be usable, or will it freeze and be un-usable?

Any chemists out there that can help?

-- Have You Seen This? --
Re: Mixed too much epoxy [Re: bvining] #165227
01/17/09 06:12 PM
01/17/09 06:12 PM
Joined: Nov 2003
Posts: 749
Santa Cruz, CA
SurfCityRacing Offline
old hand
SurfCityRacing  Offline
old hand

Joined: Nov 2003
Posts: 749
Santa Cruz, CA
Between lams we have a refrigerator in the shop that we put the unused portion in. It just slows down the inevitable. The chemical process has started. And down to 10deg, I don't know. My frige is at like 55deg +or-.

We mostly use that technique for gelcoat. It allows the boat that we're working on to cure a bit between coats so we don't get sags.

Re: Mixed too much epoxy [Re: bvining] #165229
01/17/09 06:38 PM
01/17/09 06:38 PM
Joined: Feb 2007
Posts: 266
UK
Cheshirecatman Offline
enthusiast
Cheshirecatman  Offline
enthusiast

Joined: Feb 2007
Posts: 266
UK
Suggest you don't let it freeze. Some pre-pregs store at 40f (4.4C) for up to 6 months but are very susceptible to moisture which effects bonding properties. However, bulk epoxy ?????

Cheshirecatman

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 Offline
old hand
dacarls  Offline
old hand

Joined: Apr 2002
Posts: 805
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: dacarls] #165258
01/18/09 07:48 AM
01/18/09 07:48 AM
Joined: May 2003
Posts: 4,451
West coast of Norway
Rolf_Nilsen Offline
Carpal Tunnel
Rolf_Nilsen  Offline
Carpal Tunnel

Joined: May 2003
Posts: 4,451
West coast of Norway
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)?

Re: Mixed too much epoxy [Re: Rolf_Nilsen] #165260
01/18/09 08:22 AM
01/18/09 08:22 AM
Joined: Nov 2005
Posts: 1,203
uk
TEAMVMG Offline
veteran
TEAMVMG  Offline
veteran

Joined: Nov 2005
Posts: 1,203
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 Offline
old hand
Mugrace72  Offline
old hand

Joined: Apr 2008
Posts: 921
Alachua, FL
Originally Posted by Rolf_Nilsen
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 Offline
old hand
dacarls  Offline
old hand

Joined: Apr 2002
Posts: 805
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
Joined: Nov 2005
Posts: 1,203
uk
TEAMVMG Offline
veteran
TEAMVMG  Offline
veteran

Joined: Nov 2005
Posts: 1,203
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: TEAMVMG] #165278
01/18/09 03:33 PM
01/18/09 03:33 PM
Joined: Sep 2004
Posts: 2,584
+31NL
Tony_F18 Offline
Carpal Tunnel
Tony_F18  Offline
Carpal Tunnel

Joined: Sep 2004
Posts: 2,584
+31NL
Originally Posted by TEAMVMG
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.

Have you been watching the Vendee lately? eek

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 Offline
Carpal Tunnel
Jake  Offline
Carpal Tunnel

Joined: Jun 2001
Posts: 12,310
South Carolina
Originally Posted by dacarls
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: Jake] #165317
01/19/09 07:14 AM
01/19/09 07:14 AM
Joined: Oct 2002
Posts: 1,226
Atlanta
bvining Offline OP
veteran
bvining  Offline OP
veteran

Joined: Oct 2002
Posts: 1,226
Atlanta
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.


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 Offline
Carpal Tunnel
Jake  Offline
Carpal Tunnel

Joined: Jun 2001
Posts: 12,310
South Carolina
Originally Posted by bvining
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
Posts: 3,224
Roanoke Island ,N.C.
Team_Cat_Fever Offline
Carpal Tunnel
Team_Cat_Fever  Offline
Carpal Tunnel

Joined: Sep 2002
Posts: 3,224
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: Jake] #165413
01/20/09 09:28 AM
01/20/09 09:28 AM
Joined: Feb 2006
Posts: 3,348
F
fin. Offline
Carpal Tunnel
fin.  Offline
Carpal Tunnel
F

Joined: Feb 2006
Posts: 3,348
"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. wink

Re: Mixed too much epoxy [Re: fin.] #165423
01/20/09 10:25 AM
01/20/09 10:25 AM
Joined: Jun 2001
Posts: 12,310
South Carolina
Jake Offline
Carpal Tunnel
Jake  Offline
Carpal Tunnel

Joined: Jun 2001
Posts: 12,310
South Carolina
Originally Posted by Tikipete
"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. wink


Uhh...yeah - that too! blush


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 Offline
Carpal Tunnel
Team_Cat_Fever  Offline
Carpal Tunnel

Joined: Sep 2002
Posts: 3,224
Roanoke Island ,N.C.
Originally Posted by Jake
Originally Posted by Tikipete
"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. wink


Uhh...yeah - that too! blush


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 Offline
old hand
dacarls  Offline
old hand

Joined: Apr 2002
Posts: 805
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 Offline
Carpal Tunnel
Team_Cat_Fever  Offline
Carpal Tunnel

Joined: Sep 2002
Posts: 3,224
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
Re: Mixed too much epoxy [Re: Team_Cat_Fever] #165506
01/21/09 06:10 AM
01/21/09 06:10 AM
Joined: Feb 2006
Posts: 3,348
F
fin. Offline
Carpal Tunnel
fin.  Offline
Carpal Tunnel
F

Joined: Feb 2006
Posts: 3,348
Since I'll be starting a project for myself soon, I'm thinking of working out of a wide shallow pan rather than a cup.

Whachya'll think?

Page 1 of 2 1 2

Moderated by  Damon Linkous 

Search

Who's Online Now
0 registered members (), 36 guests, and 251 spiders.
Key: Admin, Global Mod, Mod
Newest Members
BowWave, Joachim, GilliganF80, heretic, Carlos_Ledo
8104 Registered Users
Top Posters(30 Days)
fa1321 1
Forum Statistics
Forums26
Topics22,387
Posts267,025
Members8,104
Most Online1,650
Sep 10th, 2019
--Advertisement--
Powered by UBB.threads™ PHP Forum Software 7.7.1