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Don Noon

Beady eyes... extreme version of fisheye

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3 hours ago, joerobson said:

If the beading happens with differing top coats, it is likely a mechanical bond failure.  Try abrading the under surface to give it some tooth.

The beading happens with the same top coat over differing initial (dry) coats.  But not now, with the change of solvents.

2 hours ago, lpr5184 said:

Why so secretive about a solvent? I think it would be valuable to know the name of this solvent.

Someone sent me the info about this solvent in a PM, so I don't know if it would be right to advertise it.  And I think it's pretty obscure so that nobody would be accidentally using it.

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But Don,

Can't you just do something "normal", What's wrong with balsam turp.

I mean it's a challenge already to get the "perfect" varnish with three known ingredients.  Rosin (resin), linseed oil, turp.

By known I mean using exactly the same ingredients, I have been improving my varnish since 2013. It gets better and better. Because I get the feel for them.

No offence, this is just how I see things do the same over and over and over again until the result is excellence

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One more question... does the beading happen when other (good- proven) varnish is applied over the dry "bad" varnish?

I would like to know what is the stuff that makes this happen as there may be other chemically similar thinners that can do it...

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7 hours ago, Peter K-G said:

Can't you just do something "normal"

No.  Never tried.:)   Doing normal things would tend to get normal results, and that's not as interesting.

6 hours ago, HoGo said:

One more question... does the beading happen when other (good- proven) varnish is applied over the dry "bad" varnish?

An interesting question, but I can't test that now, as the bad varnish no longer exists, and previous samples are used up.  No real need to know at this point, other than an academic exercise.

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Let's think the unthinkable--the mystery solvent is contaminated with something, maybe silicone.

If this happens again, use a coat of shellac to restore bite.   This is my secret, but I am going to reveal it to all.  I never could keep a secret.

Mike D

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9 hours ago, Don Noon said:

No.  Never tried.:)   Doing normal things would tend to get normal results, and that's not as interesting.

 

so .. Abby Normal,

What is your line of testing this mysterious varnish pointed towards?!?

I'm in for the study of anything that WORKS so don't misconstrue my question.

on we go,

Joe

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37 minutes ago, joerobson said:

What is your line of testing this mysterious varnish pointed towards?!?

I'm in for the study of anything that WORKS so don't misconstrue my question.

It was a slow-evaporating solvent (not as slow as Lavender), and seemed really great at dissolving things and mixed with everything.  So, initially, it looked like fabulous stuff. Unfortunately, it didn't work in the wetting department.

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I find that glass is a good test material..  You could see if a completely inert surface gives trouble.  (I get cut-offs of glass for free from my hardware.)

At least you could see if the problem was with surface tensions in that second coat.   (unrelated to the surface to which it is applied.)

 

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without knowing the exact recipe and what it basically is it's hard to be able to trouble shoot the issue....however if I were to take a stab at it it would this;

the first acted "normal" and performed as expected, meaning you apply it, it soaks in, drys and leaves a sealed wood product. However the second coat, instead of flowing out, skinning over, and drying with a fairly uniform film is beading up as shown.

To me this is the solid base unbinding with the solvent as the solvent simultaneously evaporates away, as this is occurring the surface tension of the fluid on the surface is lost, this showing as beading. It does not show on the first coat because the raw wood absorbs the solvent before the reaction can start to show itself, Once sealed however the first film coat prevents the solvent from being rapidly absorbed into the raw wood, thus allowing the material to start the reaction sitting on top of the first coat.

To me this would indicate that solvent was incorporated cold into the solution and or fugitive solvent that appears to mix ok when the solution is liquid,yet when the drying process starts the solvent separates from the solids, or flashes off, leaving primarily solids "goo" that without the solvent looses its surface tension and beads as shown...

 

edit, a glass test while great for most initial finish tests will not catch everything. A single application in this case may show as drying ok on glass, as unlike the wood that absorbs the solvent and allows for even skinning and drying , the glass in this case may be deceptive in that because in is not absorbent, the the glass may allow the solvent to appear to be ok by retarding the evaporation rate enough to give on the impression that the finish is ok because when pooled on the glass the pooling allows for the solvent to "stay alive" and or not separate from the solids. More than one coat on glass may reveal something

back in the late 90's I dealt with a very massive {national} expensive finish nightmare where a well known product had a formulation change, that formulation change casued the product to do basically what this is doing, or it worked fine if you only applied 1 coat to a  thinnly sealed floor or raw wood floor, once multiple coats started to get built up however the entire thing would fisheye

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14 hours ago, jezzupe said:

without knowing the exact recipe and what it basically is it's hard to be able to trouble shoot the issue....however if I were to take a stab at it it would this;

the first acted "normal" and performed as expected, meaning you apply it, it soaks in, drys and leaves a sealed wood product. However the second coat, instead of flowing out, skinning over, and drying with a fairly uniform film is beading up as shown.

To me this is the solid base unbinding with the solvent as the solvent simultaneously evaporates away, as this is occurring the surface tension of the fluid on the surface is lost, this showing as beading. It does not show on the first coat because the raw wood absorbs the solvent before the reaction can start to show itself, Once sealed however the first film coat prevents the solvent from being rapidly absorbed into the raw wood, thus allowing the material to start the reaction sitting on top of the first coat.

To me this would indicate that solvent was incorporated cold into the solution and or fugitive solvent that appears to mix ok when the solution is liquid,yet when the drying process starts the solvent separates from the solids, or flashes off, leaving primarily solids "goo" that without the solvent looses its surface tension and beads as shown...

5

This sounds right. If there is a very small amount of cold solvent, I have had no problems. There is a threshold where the beading steps in due to flashing off. Normally, I add solvent to a hot varnish solution which evaporates the volatiles. I have to remember to follow my successful recipes. 

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