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Micro bubbles in epoxy
Posted by: Ryan Edamatsu (---)
Date: January 29, 2024 05:24PM

I used some Flex Coat high build and found some micro bubbles in the cured finish. They are not noticeable until you put a flashlight on it. Is this normal? When mixing, there were also bubbles. Using heat takes them away, but the micro bubbles in the mix remained even when using heat.

I prewarmed the bottles and used a heater in the room. I mixed the 2 parts on the bottom of an aluminum can that was cleaned with alcohol beforehand. Then poured it out on a foil. I applied it with a brush.

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Re: Micro bubbles in epoxy
Posted by: Michael Danek (---.alma.mi.frontiernet.net)
Date: January 29, 2024 05:41PM

Don't take a flashlight when fishing.

Seriously , You've done about all one can do. I would leave off the alcohol clean, and I blow softly on the surface of the pool of epoxy through a straw. My pool is in aluminum trays that I reuse with nothing more than a blow off to remove any dust that might have accumulated. I don't find any bubbles. But I don't look with a flashlight, either.

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Re: Micro bubbles in epoxy
Posted by: Herb Ladenheim (185.243.57.---)
Date: January 29, 2024 05:50PM

Get yourself a drum mixer.
Better than mixing by hand.
There is a technique to using it. You can't just go on auto pilot.
If you get one - come back here or email me and I will explain.


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Re: Micro bubbles in epoxy
Posted by: Daryl Ferguson (47.214.193.---)
Date: January 29, 2024 06:00PM

I recommend you watch Flex Coat’s video on mixing and applying their product and follow that to the letter. I did and I have never experienced any issues. That said, I quit using Flex Coat in favor of Gen4. There’s nothing wrong with Flex Coat and if that’s all I could get, I would happily use it. But, Gen4 is better.

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Re: Micro bubbles in epoxy
Posted by: David Baylor (---.res6.spectrum.com)
Date: January 29, 2024 06:15PM

First I would ask what you're mixing your epoxy with? When I first started out I used the same popsicle type sticks that I bought for mixing my Rod Bond epoxy. Now granted I wasn't experienced in mixing finish, but the popsicle stick made it hard not to introduce air into the mixture. I switched over to more or less lolly pop sticks that Mud Hole offers, and I introduced less air into the finish. That coupled with better mixing techniques has it down to where very little air gets into the finish from mixing. Another thing I do, is I always let the finish sit in the mixing cup for a minute or so before I pour it out into a small aluminum dish. The type that Mud Hole and Get Bit offer. After I pour it in a let it sit a while longer. And if I need to, I will gently blow on it. But don't get real close to it when you blow on it. I say this because I introduced a blush into finish while trying to get small bubbles out of the finish I was putting on a carbon fiber grip. I would think if it could happen on that, it could happen if you were blowing on finish on a wrap.

Then I would ask if you are actually trying to brush the finish on, or if you're simply using the brush to transfer finish to the wrap, and then pushing the finish with the brush. I know when I first started I wanted to get the thinnest finish I could, so I would take a little bit of finish and actually use the brush to try and force it onto the thread. Man did I mess up some wraps. lol Now I just use the brush to transfer finish to the wrap and use minimal pressure to push the finish over the wrap. I'm also no longer super careful about how much finish I put on. I actually glob a pretty good amount on. Once I get all my wraps coated I stop the rod with the guides facing up, and let it sit until it starts to sag to the bottom. When it does that I use a brush to wick the sag off. Then I turn the rod 180 degrees, and let it sit until it starts sagging again. And repeat the process of wicking the sag off. Usually by the 4 half rotation, I'm not seeing any, or very minimal sagging. At that point I just put the rod in a separate dryer I have, or just switch the belt on my power wrapper over to the drying motor.

At least for me, my finish problems went away when I stopped trying to be too precise with how much finish I was initially applying. And from playing with it trying to get it just right. One thing you'll learn with each rod you build, finish is a lot more forgiving than you might think.

Edited 2 time(s). Last edit at 01/29/2024 06:24PM by David Baylor.

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Re: Micro bubbles in epoxy
Posted by: david taylor (---)
Date: January 29, 2024 07:23PM

I buy the mixing cups, stir sticks and aluminum cups from MudHole. Mix gently in the cup for a good deal of time and let it sit one or two minutes at least. Pour gently into the shallow aluminum cup/pan and breathe your warm air onto it, or let it sit a moment and give it quick hit with a heat gun. With FlexCoat or Gen 4 I have not had bubble issues with this method. The mixing cups and stir sticks are made of plastic that is free of silicone, which is important. After I epoxy a few wraps I go back and hit them with a quick flame or heat gun.

As indicated above, it you don't mind paying for it, an epoxy mixer does an excellent job. I just don't build enough rods to warrant the purchase.

I also prefer to put on 2 or 3 thinned coats of epoxy rather than globbing on a thick coat.

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Re: Micro bubbles in epoxy
Posted by: Tom Kirkman (Moderator)
Date: January 29, 2024 08:13PM

Heat can cause micro-bubbles. In effect the finish boils and micro-bubbles are the result.


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Re: Micro bubbles in epoxy
Posted by: Spencer Phipps (---)
Date: January 29, 2024 08:29PM

I saturate my brush, insuring I have removed the air in the bristles with finish before I start than I can't pull any bubbles out of the brush while applying finish.

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Re: Micro bubbles in epoxy
Posted by: Ryan Edamatsu (---)
Date: January 29, 2024 10:56PM

I used the paintbrush handle to stir the epoxy. It is round. I may try letting the mix sit for a moment before application. But I'm thinking the epoxy could start to set up sooner, before I finish.

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Re: Micro bubbles in epoxy
Posted by: Chris Catignani (---)
Date: January 29, 2024 11:16PM

Some food for thought...

Air is occupying space in the thread...whether its NCP or not.
Once you apply finish, as the finish saturates the thread...the air starts to release.
The thicker the finish, the further the air needs to travel to escape.
Also...the more viscous the finish...the harder it is for the air to escape.

IMO...its always a good safe bet to apply a thin coat first.

Also...and Tom alluded to this above about heat.

(Not saying you did this but)
If you mix 3cc resin and 3cc harnder of FlexCoat High Build, and have it sitting in a mixing cup,
it will cause a small exothermic reaction causing the finish to set up faster than it should.
And this gets back to what I mentioned initially about a viscous (thicker) mix.

Edited 1 time(s). Last edit at 01/29/2024 11:25PM by Chris Catignani.

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Re: Micro bubbles in epoxy
Posted by: Neil Toland (---.source.akaquill.net)
Date: January 30, 2024 04:50PM

Michael Danek Wrote:
> Don't take a flashlight when fishing.

Love that

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Re: Micro bubbles in epoxy
Posted by: Kerry Hansen (---.wavecable.com)
Date: January 30, 2024 06:05PM

Here is what I do. it may not be the "BEST" per some, but you may pick up something to improve your Method.

Mixing cup: I use a stainless tapered one like condiments in a restaurant are served. Easy to scrape with my spatula. Easy to clean with a dry paper towel for reuse, mine are 30-40 years old. I have a double ended stainless spatula with narrow tip on one end and a wider one about 1/4-3/8" on the other end, that have a flat tips to cleanly scrape bottom of mixing container better than a round tip can do.

An old secret I learned from my Mother in the 1950's is when she baked something, if she had something like Honey and a oil in the recipe, She measure the oil first, then she measured the Honey. this way, the Honey did not cling to the surface of the measuring cup, rather it just poured out cleanly. So I put the thinner Hardener into the mixing cup before I put the thicker Resin thus helping with a more complete homogenous mix.

I mix until I cannot see any wispy-ness in the mixture indicating it is completely mixed.

I pour the finish out on a tray that is covered in Aluminum foil.

Brushes: I use inexpensive art brushes that are flat with square ends that are made from soft stiff nylon bristles sorta resembling a spatula like Ralph said to use and are easily cleaned so the same one can be used for years. I like longer bristles when I have a choice. I have a selection of different widths to match wrap sizes.

I lay the brush, bristles only, on the finish which wicks up into the bristles displacing all the air bubbles in the brush.

I work fast because the slower you are, the more viscous the finish becomes which impedes bubbles rising up to the surface to burst. 

I have enough time in my builds to use two coats. The first is extremely thin, just enough to SEAL everything from air escaping then later a second coat for appearances.

While applying the first coat, I do like the RodMaker video and add a very small dab of finish on the tunnels. 

I have a variable speed dryer that I can turn up the speed quite fast so i can do a quick 1 second wave with my alcohol burner under each wrap to burst any bubble that is hanging on but certainly not boiling the finish. Just a micro swipe.

I use a dryer to turn the rod with new finish, separate from my rod lath so I can start work on another.

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Re: Micro bubbles in epoxy
Posted by: david taylor (---)
Date: January 30, 2024 06:49PM

Yes, heat if not applied properly can cause micro-bubbles or other issues. With my alc burner or more commonly used heat gun I have the system down pretty well.

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Re: Micro bubbles in epoxy
Posted by: Ryan Edamatsu (---)
Date: February 16, 2024 08:40PM

I have found that if I do very thin coats, I can get a finish with no bubbles. But the problem is that they have to be very thin enough that it takes many coats to get an ideal finish buildup without any bubbles. This way is time consuming and requires more epoxy usage and waste. I know some people prefer to do one coat and have no issues.

Again, the bubbles are not easy to notice unless you put a flashlight against it, and they hilghlight in the light. I don't know if this means I'm doing something wrong, or if this is actually normal. I compared to some factory rods I have, and actually have the same results of finding bubbles when using a flashlight. I don't know what other builders epoxy finish job looks like and if there's bubbles like mine.

I'm still getting bubbles in the thread epoxy. Even after mixing and pouring it out onto a tray of aluminum foil, there is still bubbles that refuses to disappear no matter how much heat I use. When using no heat, or breathing on it for low heat, the results are still the same. I then tried to brush the epoxy on the threads and then using heat on it, I still have the bubbles that originally refuses to burst from the tray. Brushing on the epoxy on the threads or just touching the threads with the brush made no difference. Any advice is appreciated

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Re: Micro bubbles in epoxy
Posted by: Spencer Phipps (---)
Date: February 17, 2024 01:52PM

Watching the ladies at Lamiglas they mixed there finish just like they would if they were making a cake by hand, quick swipe of heat for a piezo igniting propane torch and they were done, the brush they used looked more like a disposable acid brush than what most use here.

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Re: Micro bubbles in epoxy
Posted by: David Sytsma (---.res.spectrum.com)
Date: February 18, 2024 09:50PM

When I was using Flex Coat I always used an epoxy mixer. You do end up with far fewer bubbles. My method was to measure using syringes and adding the components into the medicine cups with the graduations for dosing. These would go on to the mixer for 5 minutes, then get poured out on to a piece of aluminum foil that I formed walls on by molding it around a jar lid. The foil container went on a dessert sized paper plate. I used the Flex Coat disposable brushes or inexpensive artist brushes from Hobby Lobby. I'd reuse the artist brushes, but toss the disposable ones. I apply my finish at ~100 rpms, After I had the epoxy applied by having it wick off the brush, I'd put it on a dryer at 8 rpms and use a drinking straw to VERY GENTLY exhale on the wraps. Any bubbles would disappear.

I don't use the epoxy mixer with the Gen4 I use now, although I did try it a couple of times and it worked just fine. If you follow the directions (I now use Flex Coat mixing sticks or plastic coffee stirrers to mix) you will rarely have any bubbles

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Re: Micro bubbles in epoxy
Posted by: roger wilson (---)
Date: February 19, 2024 12:10AM

I have always used standard flex coat for thread finish. I use what I call a 1+ coat of finish.

I Never thin the finish with any sort of solvent. Adding a solvent, changes the properties of the finish to be softer.

Some folks say it is all right to have a solvent to thin the first finish. But, when I realize that the solvent softens the epoxy, it is akin to mixing goo in cement for a foundation for a house. Who would want a soft foundation on a house.

So, I simply use a plastic cup that I obtain from the grocery store in about a 1 or 2 oz size.

I never pour the mix out of the cup onto any thing.

I use a popcicle stick that I have clipped off square and then use a sander to completely flatten the ends of the stick, but put a soft corner on each side of the end of the stick to avoid cutting through the mixing cup.

I use a syringe to place equal parts of part A and part B in the cup in no particular order.

Then, I mix for 120 seconds or 2 minutes, as measured by the clock on the wall. I mix slowly, frequently wiping the sides of the cup and wiping off the stick on the top edge of the cup to insure that every particle of epoxy is well mixed.

Just as soon as the mix is finished I apply the finish at speeds of typically about 25-50 rpm, using my power wrapper.

I apply finish using a disposable brush, similar or the exact flex coat brush. I never clean brushes and get one mix of one coat of finish out of each brush. But, I only pay about 5 cents for each brush, so it is easy to use the brush just once before pitching it.

When applying finish the brush normally never really touches the blank. Just the finish touches the blank and the rotating blank pulls the finish off of the brush. After a generous applicaiton of finish has been applied, I will use gentle heat to thin the finish a bit and I use the brush to dab off any excess. I observe the finish very closely for the first 10 minutes, and if I find any thick spots, I dap off the excess. If I find any thin spots I apply a bit more finish in those areas. After letting the rod turn for about 10-15 minutes and finding no problems, I move the rod to the dryer for long term drying. I will do a final inspection on the rod after the 1+ coat of finish has dried and in about 90% of the cases, I will apply no more thread finish. For the few times that I note a guide with an issue, I will add finish on the single guide or the couple of guides that I find with a minor problem and will add a 2nd coat to those guides to correct the issue and then let it dry overnight.

When, in production mode, by only needing one coat of finish and one drying cycle, that means that 12 hours is cut from the production time of a rod before wrapping and shipping.

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