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will humidity affect epoxy curing time
Posted by:
Keith Smith
(---.adtran.com)
Date: August 24, 2014 09:45AM
i am doing my rod work in our basement, and have tried several brand epoxies, all seem to remain tacky for a couple of days...i have attempted to ensure proper ratio's on my mixing, and always mix at least 4-5 min...
Also, what do most of you use to ensure proper ratio's??? i am adding hardner first then adding my resin in a mixing cup matching the amounts as close as i can visually on the marks, and one last question, do any of you utilize any kind of lamps to improve curing time and finish???? Re: will humidity affect epoxy curing time
Posted by:
Phil Erickson
(---.dsl.pltn13.sbcglobal.net)
Date: August 24, 2014 11:36AM
If you are just eyeballing marks on the cup, it may be your problem. I use the small syringes available from any of the suppliers on the left. Re: will humidity affect epoxy curing time
Posted by:
bill boettcher
(---.dyn.optonline.net)
Date: August 24, 2014 11:39AM Re: will humidity affect epoxy curing time
Posted by:
Bruce Johnstone
(159.118.74.---)
Date: August 24, 2014 11:43AM
I find that on occasion my epoxy will remain tacky for a day or two after application. It seems to be just a surface tackiness. At other times it cures in about 12 hours and no tack. It might be humidity. I used to mix in the cup measuring by sight as you do, now I use syringes. It doesn't seem to make any difference. I just mix with a plastic stick for stirring until the mix clears up. Probably about 2 minutes. I have taken one rod fishing with the tack no problems and by the end of the day no tack. I just accept that some times it happens and let it go. I just plan on a day or two for the tackiness to go away and if it isn't tacky so be it. I always leave the extra in the cup and have played with it when its tacky and it seems to have cured just fine. it's just the surface that retains the tackiness. Edited 1 time(s). Last edit at 08/24/2014 11:46AM by Bruce Johnstone. Re: will humidity affect epoxy curing time
Posted by:
Russell Brunt
(---.mia.bellsouth.net)
Date: August 24, 2014 12:17PM
Humidity isn't a problem in general. However it is closely linked to what could be a problem, namely dewpoint temperature.
Good practice requires application and curing take place at least six degrees (F) above dew point. This is generally easy to do if you start work early as it often warms during the day. On the other hand, if you start late on a very humid day (85% RH and above), a drop in air temperature of just a few degrees could get you into trouble. A lot of this is very dependent on the epoxy formula. You would need to contact the maker of said formula for application instructions. Often they will have a minimum temperature range too. Typically you double cure time for every 18 degree drop in temperature. Many formulas give 50 degrees as lower limit however there are some that extend this to sub-freezing range. All of the above is "general" epoxy info and not rod wrap types. Russ in Hollywood, FL. Re: will humidity affect epoxy curing time
Posted by:
Keith Smith
(---.adtran.com)
Date: August 24, 2014 12:46PM
lots of good info, and i may be compounding my issues, i have been using the syringes then adding them to a mixing cup, but i always watch the lines on the cup also, Russell, what you mention may have something to do with this, i generally do my rods in the afternoons and we have (useally) very high RH levels, the drop in temps may be affecting this, and Bruce i have pretty much seen the same, the surface seems to remain tacky up till about 3 days, but i'm not really questioning the integrity of the epoxy mix, as it is, i have checked what i have mixed up (the left-over epoxy) in my foil cups and it appear to be incredibly durable, just tacky to the touch for several days, i have noted it with several brands of epoxy, i do most of my building in the winter, and during the winter our "air "is a lot dryer, plus i heat the basement with NG, they just seem to do better in the winter with the dryer air...
thanks for the input and replies, Keith Re: will humidity affect epoxy curing time
Posted by:
roger wilson
(---.hsd1.mn.comcast.net)
Date: August 24, 2014 03:39PM
If you are having any trouble with epoxy cure, just raise the temperature of the rod being cured. i.e. put the rod in a drying oven, or just raise the temperature of the room. If after the epoxy has set enough not to run, place it somewhere where it is 90 - 100 degrees and the epoxy will cure pretty quickly.
Although humidity does not affect the cure directly, temperature certainly does. So, if in doubt, raise the temperature of the rod as it is curing by what ever means you wish. Be safe Re: will humidity affect epoxy curing time
Posted by:
Tom Kirkman
(Moderator)
Date: August 24, 2014 06:16PM
Humidity will not change the set or cure time, but temperature definitely will.
............. Re: will humidity affect epoxy curing time
Posted by:
Wes Motsinger
(---.triad.res.rr.com)
Date: August 24, 2014 10:40PM
Make sure to mix atleast 4ml of both so that if your off a little it won't be so bad. Re: will humidity affect epoxy curing time
Posted by:
roger wilson
(---.hsd1.mn.comcast.net)
Date: August 25, 2014 01:00PM
The advice from Wes is not bad.
But, all that is necessary for any quantity of glue that you mix is to have identical portions of part A and part B. If mixing small portions, be sure to frequently scrape off your mixing stick and the side of the mixing cup so that you don't leave unmixed portions of finish on the stick or on the sides of the cup. Be safe Re: will humidity affect epoxy curing time
Posted by:
Jimmy Crain Jr
(---.ph.ph.cox.net)
Date: August 26, 2014 01:10AM
I used to eye ball it. Learned my leason now I only use syringes now I can mix 1cc + 1cc batches. I dont't waist epoxie and I am always close enough to dry on time. Re: will humidity affect epoxy curing time
Posted by:
Ken Preston
(---.opera-mini.net)
Date: August 26, 2014 06:35AM
Keith -
Seems no one answered your question about lights to speed cure - simple answer is "yes" . It's the extra heat generated. If you do a search on "Drying Boxes" you should find additional information.... and I'm sure someone has posted photos as well. Re: will humidity affect epoxy curing time
Posted by:
roger wilson
(---.hsd1.mn.comcast.net)
Date: August 26, 2014 04:15PM
Ken,
Although you said it, light does not speed the cure. But, as you said, increasing the temperature does speed the cure. Re: will humidity affect epoxy curing time
Posted by:
Steve Chontos
(---.delta.com)
Date: August 30, 2014 10:14AM
Keith, I'm a little late weighing in but early on in my rodbuilding career I had a lot of problems with my epoxy not drying. I had been using syringes the whole time but my problem was that I did not mix it long enough before using. It was recommended to me to mix the epoxy for at least 2 minutes, and I mix longer for larger quantities. I have not had any problems since using this advice.
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