Recently started having issues with curing the thread epoxy. After learning the hard way that you actually do need to be precise with the measurements of 2-part thread epoxy, I didn't have any issues for a long time.

Now I found out the hard way that the first coat needs to be totally cured before applying the finish coat. Had three rods in a row with sticky epoxy that just wouldn't cure 100%. Even after a week sitting idly, the epoxy had a slight sticky surface.

Finally put them in my Equinox hatchback in the sun for about 6 hours. Next day, issue cured, literally.

If it was tacky for a week - you still have mixing/proportion issues.

You can put subsequent applications of epoxy on well before the prior application has fully cured. Epoxy cures by a chemical reaction, not evaporation.

.............

Mark Brassett Wrote:
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> Now I found out the hard way that the first coat
> needs to be totally cured before applying the
> finish coat.

While the epoxy is partially cured (tacky), a new coat of epoxy will chemically bond to the original.
Now...this may not super critical when dealing with thread wrap...but its standard process.

My theory is that the second coat on a nearly, but not fully cured first coat inhibits the exothermic reaction of first coat thus not allowing the gasses and heat energy to dissipate in order to complete the process. Exothermic reactions are technically an evaporation.

Billy, I became a believer in accurate epoxy measurements about a year ago so I don't think it could be that problem.

I create these posts to encourage comments and criticism. So let'em rip.

I would really like to hear from some of the chemists that create Flex Coat and ProKote for a greater understanding.

Mark

Best practices are always the foundation of success when measuring, mixing and applying Flex Coat finish. We have detailed all of these steps in the instructions that come with all of our finishes and epoxy glues. We have several videos that detail all of these steps on our youtube channel as well. Not to mention the wealth of knowledge shared and re-shared on this great site. With all of that said...

Always measure accurately, no less that 3cc of each part. I measure a minimum of 5cc of each part for a 10cc mix because I personally don't like to tip toe on the edge of a cliff and I like easy round numbered math. If you live in cold weather then heat the bottles prior to measuring to about 90 degrees F, no hotter. This will aid in measuring and mixing. It is still hot here in Texas so I don't heat my finish this time of year. Mix the finish with a round non-porous stirrer. The mixture will appear marbled, then cloudy, then marbled again and then clear, mix it until it is crystal clear. Scrape the walls and bottom of the mixing cup making sure that every part is thoroughly mixed. Then once mixed clear, pour it out on a paper plate covered with aluminum foil. This will slow the reaction, giving a longer working time, it will aid in popping any bubbles and it will give you a working surface to use under your rod to catch any drips. Once finished, let the rod rotate for 2 -3 hours at which point the epoxy should still be tacky but won't run off the rod. You can check on the status of the epoxy cure by hanging on to the residual finish on the aluminum foil. Don't get fingerprints on you rod checking the finish. After 8 to 10 hours the finish should be tack free in 72 degree F room temp. Full cure in 24 hours.

You can re-coat as soon as 8 hours safely, I say that because if the first coat is still tacky, it can literally take the brush our of your hand, trust me I have lived it. Besides, if there is a problem with the cure of the first coat, you won't know it until 8 to 10 hours when it should be tack free. Don't build a house on a shaky foundation. The chemical bond between coats is still possible in the 8 to 10 hour window. Remember, "Best Practices." We like 2 coats of finish here at Flex Coat. The first is a saturating coat only, again, detailed in our videos on Youtube. The second is what you see is what you get. Don't over work the finish. We finish at 200 rpm.

Flex Coat has been in business for 45 years and counting. Our finish is proven by that time. Best Practices. This is how we do it.

Flex Coat Company
Professional Rod Building Supplies
www.flexcoat.com

Thanks, John. Have you ever had the issue I described while testing your product? I applied the second coat on all three of those rods between 4 and 5 hours of applying the first coat. 72 degrees F indoors.

John Cates Wrote:
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>We finish at 200 rpm.

John, by this do you mean you apply the epoxy at 200 rpm? I assume you after application you slow it back down to a standard dry rpm?

Thank you,

~Kevin

For the John. flexcoat guy. If measuring by weight, is it 50/50 or slightly off?

Tim Scott Wrote:
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> For the John. flexcoat guy. If measuring by
> weight, is it 50/50 or slightly off?

Measuring by weight will not be 50/50 and will vary from one epoxy to another. All the thread wrap epoxies are the market today are designed to be measured by volume. No need to make things difficult after the epoxy formulators have made it so simple.

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Mark Brassett Wrote:
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> My theory is that the second coat on a nearly, but
> not fully cured first coat inhibits the exothermic
> reaction of first coat thus not allowing the
> gasses and heat energy to dissipate in order to
> complete the process. Exothermic reactions are
> technically an evaporation.
>
> Billy, I became a believer in accurate epoxy
> measurements about a year ago so I don't think it
> could be that problem.

YOu can make posts for whatever reason you want, but you're 100% wrong abotu everything I quoted above. YOu can say what you want...your tacky finish says otherwise and tehre are ONLY 2 causes - improper measureing or improper mixing.

One thing I do to add another level of confidence that I'm not putting poorly mixed epoxy onto a rod is to take the epoxy from the middle, not the edges, of the "puddle." Since I always seem to mix too much, this is easy and makes sure that I don't pick some that might not have been mixed enough.

Mix it right, apply at a reasonable temperature, and the epoxy will harden. Some take longer than others, but it will harden through the chemical reaction of the two components when mixed. I have never had a "bad batch" either.

Mark Brassett Wrote:
-------------------------------------------------------
> My theory is that the second coat on a nearly, but
> not fully cured first coat inhibits the exothermic
> reaction of first coat thus not allowing the
> gasses and heat energy to dissipate in order to
> complete the process. Exothermic reactions are
> technically an evaporation.
>

Mark...No number of additional coats will inhibit heat conduction.
The heat is a side effect of a chemical reaction.
By the time you add the second coat, the cure process is practically over.

There is also no out-gassing with epoxy.

Mark

It sounds like you are under mixing your first coat, not measuring well or both. Always subscribe to best practices that are outlined in all our instructional material and videos and you should eliminate the issues you are having.

Flex Coat Company
Professional Rod Building Supplies
www.flexcoat.com

Kevin

Yes, we finish at 200 rpm and then let the rod cure on a speed of 6 to 40 rpm.

Flex Coat Company
Professional Rod Building Supplies
www.flexcoat.com

Tim

Tom nails it. Don't make things difficult, the finish is designed to be measured by volume. Best Practices. Don't fight it. Just follow the instructions.

Flex Coat Company
Professional Rod Building Supplies
www.flexcoat.com

Tim

...However, if you must, you can measure Flex Coat High Build 1 gram of part A to .838 gram of part B. I am not sure of the minimums of measuring by weight. Maybe look at 10 grams of Part A and 8.38 grams of Part B and see what kind of volume you have. Keep in mind we don't recommend anything less than a 6cc total mix. Its getting complicated already. I should say that we don't recommend this and that our epoxy is not designed to be measured this way. This is only if you want to add an extra layer of difficulty to your life.

If you would like to discuss this more, give me a call at 512-858-7742

Flex Coat Company
Professional Rod Building Supplies
www.flexcoat.com

Thank you Flex Coat!

A couple years into this hobby I started having some trouble with tacky epoxy. My measurements were right on, still tacky epoxy. The somebody here told me to make sure I was mixing the epoxy long enough, I wasn't. I started mixing for at least 2 minutes and I have never had a problem since.

After testing on an old blank section, I determined that was my problem also. Tom and Chris were right, the mixed epoxy does not gas off any molecules. I mixed a test batch using the recommended procedure by John Cates and placed it on an analytical scale to cure. The mixture weighed 2.05 grams after mixing. The next day it still weighed 2.05 grams.