I need some advice regarding invisible wraps and how to eliminate bubbles.

I'm doing a North Fork MB 808 blank with K series titanium framed spin guides. Gossamer white silk thread. Standard Threadmaster finish thinned with DNA at a ratio of 1 part mixed finish to 1 part DNA. No heat in my drying box, rotation only.

I did several test wraps with a mid sized guide to get the technique down. After doing the rod, the largest 3 guides exhibited a significant amount of bubbles in the tunnel. I had checked the rod twice after finishing during rotation out to about an hour after finishing and the bubbles weren't there. When I went to do the 2nd coat in the morning, there were a lot of bubbles in the tunnels. And some large bubbles. The fly guides were just just fine.

I stripped the wraps and rewrapped the guides and finished again. This time I checked every 15 minutes during rotation and at about 45 minutes some very fine (under 0.5 mm) bubbles showed up in the tunnel again. About a half a dozen on each side of the largest guide. This was an improvement over the initial attempt, but still unacceptable as far as I'm concerned.

Any advice on how to eliminate these bubbles would be appreciated. I'm a little stuck on what to try next.

Thanks in advance for any assistance.

..........

Better to have and not need than to need and not have.



Edited 1 time(s). Last edit at 06/12/2015 06:35PM by Matt Davis.

Obviously air is getting trapped in the tunnels and working its way out, although it's taking it a while to do so. I think I'd try filling the tunnels first, by placing a drop of epoxy at each opening and then allow it to wick in, or even try blowing it in there a bit. With no epoxy on top of the wrap, the air should escape more easily right off the bat.

For most of us, the standard procedure is to coat the wraps first and then come back and fill the the tunnels. This might be the reverse of what you need to do.

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[www.rodbuildingforum.com]

Thanks Tom

I'll add my technique...

With a tunnel facing up, I apply finish at the tip of the foot and let the finish wick in from the tip of the foot to the open end of the tunnel. Applying slightly more finish as the air leaves the open end of the tunnel. When the tunnel fills, I flip the rod and do the other tunnel.

I have a titanium toothpick (very fine) that I can slide into the tunnel to work any air out.

Finally, I finish the rest of the wrap.

I don't put the rod in the dryer until all the air bubbles are out of the tunnel. It isn't until later on that the bubbles appear.


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

We like to fill the open end of the tunnel first.
i use one of the plastic handled finish brushes with the plastic end sharpened in a pencil sharpener.
That gives me something substantial to grip.
Then taking just a drop of finish we dab it first on one side of the tunnel, then turn it 180 and put a drop on the other side.
Less on small guides, a little more on larger ones.
After all the guides have been treated this way, we then start rotating under power to add finish to the rest of the wraps.
When thinning, I keep it to just a few drops of thinner, taking a brush, dipping it into thinner, and flaking it off into the mixed finish.
Let it sit a couple of minutes, you can see the bubbles leaving the slightly thinned surface.

Best wishes,
Ron Schneider
Schneider's Rod Shop
Mountain Home, Arkansas
[www.schneidersrods.com]
mtnron40@yahoo.com
870-424-3381

There's another possibility.

You are using an extremely large amount of alcohol. When this evaporates, what is replacing it? Air? Just a thought...



Edited 2 time(s). Last edit at 06/12/2015 12:08PM by John E Powell.

Matt,

I would back way off on the solvent as well. It doesn't take much to help it penetrate the Gossamer silk. 1:1 is too much, and produced a very spongy finish for me. You only need a few drops, and use acetone if you have some, if not, then the DNA will work.

On the latest attempt, did the bubbles appear before or after it was in the dryer? If after was the heat on or off?

Joe

The only way I've found to keep bubbles out of my clear wraps is to briefly hit the wraps with a heat gun while rod is in the drying rack.
I mix 1:1:1 (hardner, resin, thinner), fill tunnels first as described above, cover rest of wraps, wipe most of expoxy away from wraps, then hit with heat. The heat seems to allow the finish to thoroughly penetrate the wraps, and eliminates any bubbles that are under or along guide foot.
Curous to hear if you've noticed the threadmaster yellow after thinning? It's an issue I've had with that finish + acetone or DNA.

Every time something like this comes up, and it comes up often, I wonder why someone would chemically alter epoxy in a way that was not intended by the chemists who created the formula. And for everyone that posts there are probably many more who don't post and experience the same kinds of problems.

There is no need whatsoever to add DNA, Acetone, Xylene, or any of the other chemicals I've seen posted. Proper application technique followed by the application of heat will give predictable desirable results every time.

John,

This is the only application where I thin epoxy. The thread does not go as clear without the solvent as it does with the solvent.

Joe

Joe,

I understand, I was commenting on the problems people experience, not the successes they achieve.

Since you brought up the successes, I wonder if you happen to have a photo comparing the end results of a straight epoxy vs thinned with a couple drops of Acetone? If you do have something like this, I'd enjoy seeing the difference for an invisible wrap.



Edited 1 time(s). Last edit at 06/12/2015 01:30PM by John E Powell.

John,

I don't have pictures handy. If I can find my spool of Gossamer, I'll make some wraps to show. My daughter likes to look through my thread box, and spools have a tendency to wander off. The silk happens to be one of those spools at the moment.

Joe

Is acetone going to melt the silk, I don't know, just curious

Thanks everyone for your input.



Joe V - The bubbles have always appeared after the rod was in the dryer. Upon going into the dryer, I had no bubbles at all. The tunnels filled well and bubbles just weren't there. I assumed it was because of heat so I didn't use heat at all on my latest attempt. The bubbles were fewer and smaller.


John P - I thinned because that is what others with experience doing these types of wraps recommended. I personally have never thinned my finish on any of the 500+ rods I've done, until now. When in Rome...

I think your problem is to much thinner. My guess is the bubbles aren't from air but distillates trying to escape and getting caught in the hardened epoxy. I don't think you would need thinner. Most won't agree with this but I put my epoxy and hardener In the fridge for a half hour before mixing then do a quick mix and apply. Since heat cures the mix I feel it gives me a few extra minutes of a more fluid mix. However you mix and apply try it without thinner

Phil

Phillip, putting in the fridge is probably one of your problems. It will work best if it is at room temperature 70 degrees or a little higher

The bubbels are forming inside the epoxie from both the dna or asatone . they will evaporate and create bubbels because after a sertain amount of time the gas cant escape the epoxie anymore, ie traped gas.

Curt

That's why acetone is the better solvent for this - it's more volatile and will evaporate more quickly, hopefully before the epoxy has gotten too thick to allow any more air to escape.

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Question? I've read in more than a few places that acetone will damage a graphite blank. If that is in fact true, wouldn't acetone be the last thing you'd want to thin your finish with?

I would not use acetone to wipe down or clean my rods but at only 1/3 part of what's being applied and applying to the wraps not the rod as a thin coat should not be a problem.