I'm always hesitant to take a rod out of the dryer until the epoxy is set and no longer tacky. But I feel that is over kill, so is there a set amount of time you'll let a rod dry before taking it out of the dryer without worries of the epoxy running?

Steve

It can vary on several factors. I usually place my epoxy on a piece of foil after mixing and brush it on from there. I always tap on the remains left on the foil to see if it is tacky or set up after enough time has passed. I think it might be a case of better safe than sorry.



Edited 1 time(s). Last edit at 04/27/2021 11:26PM by Mark Hahn.

If your leftovers are set, so is your wraps.

I check my leftover epoxy for the thumbprint test. No thumbprint ,good to go!

Steve

Think about this, the drying time is the last operation in the assembly of the rod, all your hard work, care and soul is in that rod therefore you better not risk marring the blank.SO follow the excellent advise from the above responders and then go an extra hour or two.

Good luck and have fun


John

At normal room temperature, most epoxies will be set in 2 hours. For that reason, I'd go 3 hours to provide some margin for error.

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kMy normal process is to remove the rod from the dryer after 3 hours to make room for the next one. Normally, not an issue.

Steve,
All of the above replies are very good although Tom’s and Roger’s “3 hour = set enough” seems a bit iffy and premature to me; it's probably OK , but…… There are three factors involved with the pot life and cure rate of epoxy; the epoxy (catalyst) itself, the curing temperature, and the thickness of the epoxy applied. Different epoxies exhibit different curing times and I have found with our thread epoxies, the “light” ones require more time than the “high-build” versions. And then, different brands themselves require different cure times.
Epoxies are thermosetting plastics basically meaning when the resin is mixed with the catalyst (hardener), it produces heat to cure. Even in quite cold conditions, the mixed epoxy will eventually go-off (cure) but may require considerably more time than at typical room temperature of 70*F. Inversely, raising the curing temperature will reduce the amount of time required. Generally, most epoxies are formulated to cure at 70* - 80*. While raising the temperature will shorten the cure time, too much heat too soon can adversely affect the strength of the epoxy but is of more concern with structural epoxies and applications than our thread wraps. Most epoxies will produce their ultimate result if given 6-12 hours of set time at 70* - 80* followed by a post cure of 140*-150* for 4 - 8 hours, again not critical for our purposes.
The thicker (more mass) of the epoxy will shorten the pot life and cure time due to its thermosetting properties. This is one reason why “high-build” versions go-off quicker than “light” ones and also the reason many pour their mixed epoxy on aluminum foil or dishes to add to the pot life / working time.
I attempt to schedule by builds so that the epoxy is applied to the wraps late in the evening, put in the heated curing cabinet and rotated overnight. Is that much time required? = probably not. Have I ever had the epoxy sag on a wrap? = no.
I like John’s reply above the best.

Mark Talmo
FISHING IS NOT AN ESCAPE FROM LIFE BUT RATHER A DEEPER IMMERSION INTO IT!!! BUILDING YOUR OWN SIMPLY ENHANCES THE EXPERIENCE.

The thickness of the epoxy, other than a large contained mass producing more exothermic heat, which itself causes a faster set time, doesn't really have anything to do with overall set and cure time on our guide wraps. An epoxy thread coating on one guide of perhaps 1/32nd inch thickness will set and cure at the same rate as the same coating on another guide at 1/16th inch thick. The difference in terms of the coating thickness on guide wraps isn't enough to create any practical difference.

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I've noticed my drying times differ a lot. maybe due to humidity and heat and..... As others have mentioned previously, I also check my leftover finish to determine dryness. I keep my tin and check with a tooth pick or stir stick. It has never gone wrong.

Humidity will have no effect on set and cure time. Temperature does. For every 20F above or below about 70F, you will see a halving or doubling of the set and cure time.

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I would love to crank the temp up to 90F if possible to get my finished rods to cure faster but I can barely tolerate being in a room north of 70 degrees for very long. I'm an air conditioner lover and live in a single floor dwelling so there's no escaping to a cooler temp for me. If I built a bunch of rods year in year out I would have a dry box for sure but I only build a select few throughout the year so when I do build the waiting to cure part is often the most stressful time for me. I'm constantly fending off those annoying fruit flies trying to prevent them from landing on my wraps before they become tack free .

I also check the leftover finish to see what stage the cure is in & estimate how much time I have left.

I've been using the Generation IV epoxy from Andy Dear and like it a lot but it's cure time is noticeably longer than regular Threadmaster which has the fastest cure time that I have experienced .

I am loving TM Lite at 70F.

I gave up on the Threadmaster Lite because the only real difference I noticed between the regular Threadmaster and Lite is the Lite takes much longer to cure. Viscosity didn't seem all that different but that's just my experience with it.

There is a difference between an epoxy coating being set enough to not sag and its being set enough to not be damaged by contact, like a thumb print. Not all epoxies cure (not dry, cure) at the same rate. I know that while Pro Kote might not sag in 3 hours, it is far from hard enough to prevent damage from contact. Know your epoxy and the conditions under which it is curing and act accordingly.

I'm able to stop turning TM Lite after about 3 hrs. at 70F. If I push on the leftover finsih I can still make light prints.

I don't typically do a bunch of rods at one time, and I just have a single dryer set up. I usually let mine run 7 or 8 hours to be safe, or run all night if thats how it works out. The thumbprint test is good if I am going to immediately be handling the rod like delivering it to a customer, I've made that mistake before. My question was intended more towards the epoxy being dry enough so it won't sag once I remove it from the dryer and stand it straight up. Right now I got 10 rods from a new customer and I am trying to run them back to back when I have the time. I think to be safe I'll keep shooting for 5 hours.

Thank you for all the input, it's all good information. Sometimes I hesitate submitting the question fearing it repetitive or just dumb (as I did here), but this one turned out good.

Steve

I always test if it's time to remove the rod by using those bamboo shish kabob sticks to push the left over epoxy to one side of the plastic mixing cup and if I see that it levels out I keep the rod slowly spinning on the dryer until it cures more. Last thing I need is to take it off too early and notice sagging even if it's just a little bit .

It's probably worth mentioning that epoxies don't "dry," they cure as the result of a chemical process. So the set time and the cure time are two different things. Few epoxies are going to cure in a few hours, but they will certainly set in a couple or three hours (most anyway). By "set" I am talking about that point where they will no longer sag, drip, run, etc. Cure is when the epoxy has attained it's designed final hardness.

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