Sign in to follow this  
Rimino

Varnish Temperature

Recommended Posts

I think it has been established that it is not your varnish.  I think the problem is with your varnishing technique. 

I use American Painter wash brushes from Michaels.  They look to be taklon  bristles which are a golden orange color and are fairly stiff.  The thing you are not doing is "tipping off."  Once the varnish has been brushed out to make an even coat, you go over the varnish with a gentle brush to remove the surface bubbles--this is the last step.  Look up tipping off.

For maximum transparency, do not add particulates to the varnish.  Color pigments go directly on top of the sealed wood.

On brush cleaning, I use two bottles of oil varnish solvent to dip the brush into.  Bottle 1 followed by bottle 2.  And then into a commercial brush cleaner that is mostly acetone.  Then wash in water using liquid dishwater detergent.  

Do not use steel wool--it leaves little pieces of steel in the varnish, and if it ever is exposed to water, your will have another problem of rust.   You need to find an environment that is dust free.

Of course we add solvents to our varnish to reduce its viscosity so it will brush easily.  Turpentine is a good solvent for these cooked oil varnishes.  You can always put thin coats on.

The big problem is if you ever  get "fisheye."  But you do not have that.

regards

Mike D

Share this post


Link to post
Share on other sites
22 hours ago, Joey Naeger said:

Possibly an unpopular opinion, but gasoline is a superb brush cleaner for oil varnish and it's much cheaper than your other typical solvents.

Gasoline has a lot of other crap in it, as you will find in any carburetor that has sat for awhile. I would choose white naptha over gasoline as it's more highly refined with less additives.

I personally use laquer thinner.

Share this post


Link to post
Share on other sites
On 4/5/2020 at 2:07 PM, Mike_Danielson said:

I use American Painter wash brushes from Michaels.  They look to be taklon  bristles which are a golden orange color and are fairly stiff.

I saw these there, they look super refined.  What about the old fashioned type of painter’s brush, very soft ultra refined silky sometimes jet black hair in an agitated flame shape?

4844188C-6773-46D6-8348-9FDC1B0163F6.jpeg

Share this post


Link to post
Share on other sites
14 minutes ago, Rimino said:

I saw these there, they look super refined.  What about the old fashioned type of painter’s brush, very soft ultra refined silky sometimes jet black hair in an agitated flame shape?

4844188C-6773-46D6-8348-9FDC1B0163F6.jpeg

I wouldn't consider that to be ideal for varnishing entire instruments. I mostly use stiff and wide brushes, often even cutting down the original length to render them stiffer.

Share this post


Link to post
Share on other sites
On 4/5/2020 at 12:30 PM, Rimino said:

 

 

Thanks, I looked at someone else’s varnish in the jar, applied it and it had bubbles also, extremely tiny when you look at it, so I realize my varnish itself might be fine.  I used my varnish again and therefore thought to apply in multiple layers and use steel wool on each layer as much as possible without taking the layer off and my varnish is starting to look better besides the fact I used artist’s Grumbacher turpentine and varnish makers linseed oil instead of Lowe’s turps and GNC flax oil that I washed although which didn’t alone solve the problem.  Once I learned the working method of how to make varnish it took me making a thorough mess and working with an impatient tireless questionable end in sight. I never knew it would be the same applying an already decent varnish which struck me with defeat after that. Does everyone else apply multiple coats of the color or a clear layer using steel wool and maybe pumice or sandpaper between each coat?

Steel wool has oil in it which may be the issue

Share this post


Link to post
Share on other sites
On 4/5/2020 at 2:29 PM, Joey Naeger said:

Possibly an unpopular opinion, but gasoline is a superb brush cleaner for oil varnish and it's much cheaper than your other typical solvents.

Gasoline is explosive. Seriously,  never use it for cleaning. 

 

Share this post


Link to post
Share on other sites
On 3/18/2019 at 2:13 PM, Michael_Molnar said:

I used to follow Tad Spurgeon's washing method. What a mess. So I switched to Varnish Maker's Linseed oil sold by Woodfinishing Enterprises. It is clean and works like the proverbial charm. 

I squirt a few grams of lime water paste into the hot oil and hot rosin to reduce acidity that attacks most pigments. I posted photos somewhere doing this.

I do not use mastic, but someday I just might do it. So far I have seen no need for it, but I like to experiment. Remember that it burns above 100 C. 

As for the pill, I just shoot for 2 or 3 inches. It's usually one thread. 

The only time I have seen bubbles pop up while brushing was due to cold turpentine thinner. Slightly warmed varnish helps to eliminate volatiles..  I think dirty brushes can be another source. I clean my brushes thoroughly first with turpentine, then wash religiously with Ivory (pure) soap. Smell the brushes for remnants of varnish. The brushes must also be completely dried before using. Another test for clean brushes is to flick the bristles in bright sunlight to see whether any dust flies away.  I store the brushes in a large closed jar. As my high school chemistry teacher taught: Cleanliness is next to godliness. 

Be patient and expect setbacks. It's a learning process.

The lime is still a mystery for me. I think it is the catalyst for alcaline cross-esterification, replacing lipids with abietic acid. Am I wrong?

Share this post


Link to post
Share on other sites
7 minutes ago, uguntde said:

The lime is still a mystery for me. I think it is the catalyst for alcaline cross-esterification, replacing lipids with abietic acid. Am I wrong?

I don't know, but my experience with rosin-based varnishes, without neutralization of the acidity, has been that they deteriorate rather rapidly.

Share this post


Link to post
Share on other sites
2 hours ago, David Burgess said:

I don't know, but my experience with rosin-based varnishes, without neutralization of the acidity, has been that they deteriorate rather rapidly.

You got me interested in your observation. Any ideas about how fast this happens and what happens to the appearance of a high acidic varnish? I know it can degrade organic pigments and even some mineral pigments. I always lime the hell out of mine.

Share this post


Link to post
Share on other sites
3 hours ago, David Burgess said:

I don't know, but my experience with rosin-based varnishes, without neutralization of the acidity, has been that they deteriorate rather rapidly.

What was your source for rosin? There are many ways it is produced and also from many differing trees.

Share this post


Link to post
Share on other sites
10 hours ago, Michael_Molnar said:

You got me interested in your observation. Any ideas about how fast this happens and what happens to the appearance of a high acidic varnish? I know it can degrade organic pigments and even some mineral pigments. I always lime the hell out of mine.

Without using anything to neutralize the rosin, the rosin and linseed oil varnish became darker and very brittle within about 2 years.

The rosin itself is acidic enough that when I originally cooked it using copper implements, the rosin took on a green tinge, and there were also some copper-colored flakes in the resin.

9 hours ago, DonLeister said:

What was your source for rosin?

Kremer.

Share this post


Link to post
Share on other sites

Determining the acidity of the rosin is not so simple and requires a minimum of chemical laboratory equipment, precise measuring instruments and a specific indicator (Phenolphthalein), unfortunately it is not possible to measure it with litmus paper....

Share this post


Link to post
Share on other sites
2 hours ago, Michael_Molnar said:

I don’t measure. As I said, I just nuke it. 

Does that create the possibility of ending up with a varnish which is excessively alkaline? Or does anything which isn't used up in the neutralization process fall out somehow?

Share this post


Link to post
Share on other sites
24 minutes ago, David Burgess said:

Does that create the possibility of ending up with a varnish which is excessively alkaline? Or does anything which isn't used up in the neutralization process fall out somehow?

The excess lime precipitates and collects on cool surfaces. It’s a bit of a craps shoot. I have never seen anything suggesting too much lime. I imagine that some acidity is needed.

@joerobson is the expert here, not me.

 

Share this post


Link to post
Share on other sites
5 hours ago, Davide Sora said:

Determining the acidity of the rosin is not so simple and requires a minimum of chemical laboratory equipment, precise measuring instruments and a specific indicator (Phenolphthalein), unfortunately it is not possible to measure it with litmus paper....

Right. That’s a big reason why I don’t measure.

Share this post


Link to post
Share on other sites
4 hours ago, Michael_Molnar said:

The excess lime precipitates and collects on cool surfaces. It’s a bit of a craps shoot. I have never seen anything suggesting too much lime. I imagine that some acidity is needed.

Why would some acidity be needed? And how would an overabundance of lime contribute to that?

Share this post


Link to post
Share on other sites
1 hour ago, David Burgess said:

Why would some acidity be needed? And how would an overabundance of lime contribute to that?

No. Lime kills acidity. I understand the acidity helps “wet” pigments. 

Share this post


Link to post
Share on other sites
1 hour ago, Michael_Molnar said:

No. Lime kills acidity. I understand the acidity helps “wet” pigments. 

Acidity can help to "wet" some things, like during soldering or brazing. But I still don't understand how this applies to varnishing. Never had a problem wetting pigments. Is this a solution in search of a problem?

Share this post


Link to post
Share on other sites
12 hours ago, David Burgess said:

Acidity can help to "wet" some things, like during soldering or brazing. But I still don't understand how this applies to varnishing. Never had a problem wetting pigments. Is this a solution in search of a problem?

Maybe. 

Share this post


Link to post
Share on other sites
23 hours ago, Davide Sora said:

Determining the acidity of the rosin is not so simple and requires a minimum of chemical laboratory equipment, precise measuring instruments and a specific indicator (Phenolphthalein), unfortunately it is not possible to measure it with litmus paper....

Thank you Davide. Hope you are doing well. I was planning of visiting you in Cremona in July. Not sure if my trip is happening. Probably not...

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
Sign in to follow this  

  • Recently Browsing   0 members

    No registered users viewing this page.