Sign in to follow this  
actonern

inducing craquelure on fresh varnish

Recommended Posts

Some threads ago a poster mentioned using dilute hide glue wash on top of oil varnish to induce craquelure in new instruments.

For those that have done this, how long does it take for the craquelure to show itself?

Best regards,

Ernie

Share this post


Link to post
Share on other sites

Try doing a search for Nussbaum, As I recall Matthew Noykos was the thread starter. I don't recall that specific technique being covered, but many good ideas were put forth.

Share this post


Link to post
Share on other sites

Hei Actonern if this can help you:

"We use it for achieving crackle on the varnish of a restored area if it calls for it. With an airbrush, I will spray a thin layer of shellac over the area and then immediately apply nussbaum over the top of it, sometimes using a hairdryer to speed up the drying. Afterward, I will wipe off the nussbaum with water and paper towel and the shellac underneath is crackled. How thick I apply the nussbaum will affect how fine the crackle becomes.

Also, I use it for antiquing a section, usually putting it under the edges or in the corners of a repair where dirt would naturally accumulate like a neck graft. "

I really do not understand what kind of solution does he use when he says "...then immediately apply nussbaum over the top of it" ...walnut hulls in water?walnut oil?

This seems a good craqueleure tecnique..

Share this post


Link to post
Share on other sites

Usually you put something that shrinks over the top of a coat that moves alot like oil varnish.For instance glue over oil varnish. The glue will dry and shrink much more than the oil varnish, when cracks appear you can apply a dark colour. I personally have never had luck with glue though. One of the best commercial craquelure varnishes is Lefranc and Borgeous craquelure kit ,which comes in two parts ,though you have to watch the varnish as it contains petroleum and isnt really suitable for violins but the effects can be good. Other commercial ones tend to be based on pva or something similar and are awful to use.

Im not sure what the Nussbaum does in the above post apart from colour the cracks.Ive never seen shellac crack very easily when applied over oil varnish as its quite elastic.

Other tings to try are sugar solution .

Share this post


Link to post
Share on other sites

I google searched nussbaum and can't find anything usefull. What exactly is it?

To get a crackle finish I think all you have do is violate the fat over lean rule. Put a lean fast drying layer over a fat slower drying layer

Share this post


Link to post
Share on other sites

That what you call "Nussbaumbeize" = "Nuttreestain" is made today with brown-coal and has nothing to do with Nut or Nuttree. The right description (in german)

is "Körnerbeize - Nussbaum" and available from Hammerl. I cannot find it on his website but he have it.

It works with semidried varnish both alcohol and oil based with the last coat. Softer and fresh varnish makes larger and deeper fields, dry varnish can be make very small one. Use the stain very thick, and dry it under a slight infrared light. After it is done you can wash the stain easy away.

post-1262-0-08799400-1306959704_thumb.jpg

Share this post


Link to post
Share on other sites

Generally, I think that less is more, regarding crackle and antiquing.

The L&B kit mentioned is perhaps better for oil painitings, I think it gives a large crackle pattern not really suited to the fine crackle you see mostly on old instruments.

:)

Share this post


Link to post
Share on other sites

is "Körnerbeize - Nussbaum" and available from Hammerl. I cannot find it on his website but he have it.

http://www.joha.eu/shop/en/stains-liquid/various/nussbeize-braun-pulver-wasserloeslich.html

It says nut stain, but it is nussbaum from walnut hulls.

Hei Actonern if this can help you:

"We use it for achieving crackle on the varnish of a restored area if it calls for it. With an airbrush, I will spray a thin layer of shellac over the area and then immediately apply nussbaum over the top of it, sometimes using a hairdryer to speed up the drying. Afterward, I will wipe off the nussbaum with water and paper towel and the shellac underneath is crackled. How thick I apply the nussbaum will affect how fine the crackle becomes.

Also, I use it for antiquing a section, usually putting it under the edges or in the corners of a repair where dirt would naturally accumulate like a neck graft. "

I really do not understand what kind of solution does he use when he says "...then immediately apply nussbaum over the top of it" ...walnut hulls in water?walnut oil?

This seems a good craqueleure tecnique..

I've gotten nussbaum from the link I provided above and I have also made it. We had some nussbaum in the shop and it had been here forever, way before I ever starting working there. Recently it ran out, so I went on a little nussbaum research quest. The stuff I bought works well, and is pretty much the same as the stuff from before. I also decided to try making my own and it's very easy. I just boiled walnut hulls in water for a couple of hours. I put the hulls in a nylon to keep the hulls out of the water, but you could probably just as easily strain it afterward. After I boiled it, I just let the resulting water stain dry for awhile. If I let it continue to dry completely I would probably end up with crystals like the stuff I bought from hammerl, but I left it thickened in a small jar. I use that to apply for coloring under edges and necks and stuff, but I will use the crystals (reconstituted with a little water) when I use it for crackleure (this mostly has to do with the consistency. The thickened stuff in the jar works too, but I have to thin it if I decide to use an airbrush). We have found that we can control how fine the crackleure is by how thick the nussbaum is applied. We tried it with an aribrush and found you can have a lot of control. In the quote above I said "immediately apply nussbaum over the top of it". "Immediate" sounds a bit frantic. I probably should have said apply the nussbaum while the shellac is still soft. You don't want it to be downright wet.

In the US, I believe the stuff is sold as Van Dyke crystals, but everyone I have talked to always refers to it as simply nussbaum.

Jeffrey Holmes has talked about using gum arabic and it sounds pretty interesting. I have been waiting for an opportunity to try it. Now that I'm thinking about it again, I may try it now. I'm in the middle of some other varnish experiments on scraps so it would be easy enough to throw another thing to test on the list. I can report back later, but if he sees this, it would probably be better coming from the man himself if he feels inclined to comment.

I have never tried hide glue for crackleure, so I can't really comment on that.

Share this post


Link to post
Share on other sites

I've used gum arabic to create crazing on varnish. But you have to use pure gum arabic not the prepared stuff you buy in a bottle. The bottled stuff has glycerin in it to prevent crazing ;-)

Simply apply thin dilute gum on the surface of the varnish and hit it with a warm hair dryer. The type of crackle you get depends on how dilute the gum is and how fast it dries. If you don't like how it looks, wipe it off with water and try again, it is only the gum that's cracking not the varnish beneath. After you have the sought for effect another coat of varnish is painted over the gum to seal and set it in place.

Oded

Share this post


Link to post
Share on other sites

Generally, I think that less is more, regarding crackle and antiquing.

The L&B kit mentioned is perhaps better for oil painitings, I think it gives a large crackle pattern not really suited to the fine crackle you see mostly on old instruments.

:)

Ben No you can alter the size from very small to very large ,depending on how long you leave the aging varnish(which is the first part of the kit) to dry.I believe the aging varnish is just mastic and damar in a petroleum solvent. The cracking varnish which you apply on top by brushing at 90 degrees to the first part is water soluble and seems to me to be possibly gum arabic solution. This you can wash off and re-aply if it looks wrong.Using a hair dryer tends to make the cracks larger.You also have to apply it in low humidity (a dry warm day is fine), which also might point to gum arabic or some sort of sugar solution which are hydroscopic.

After you have coloured in the cracks and the colour has dried you can carefully wash off the water soluble cracking varnish.

Share this post


Link to post
Share on other sites

http://www.joha.eu/shop/en/stains-liquid/various/nussbeize-braun-pulver-wasserloeslich.html

Jeffrey Holmes has talked about using gum arabic and it sounds pretty interesting. I have been waiting for an opportunity to try it. Now that I'm thinking about it again, I may try it now. I'm in the middle of some other varnish experiments on scraps so it would be easy enough to throw another thing to test on the list. I can report back later, but if he sees this, it would probably be better coming from the man himself if he feels inclined to comment.

I've used gum arabic to create crazing on varnish. But you have to use pure gum arabic not the prepared stuff you buy in a bottle. The bottled stuff has glycerin in it to prevent crazing ;-)

Simply apply thin dilute gum on the surface of the varnish and hit it with a warm hair dryer. The type of crackle you get depends on how dilute the gum is and how fast it dries. If you don't like how it looks, wipe it off with water and try again, it is only the gum that's cracking not the varnish beneath. After you have the sought for effect another coat of varnish is painted over the gum to seal and set it in place.

Oded

Thanks Matthew. I use gum arabic in a very similar way to how you describe using nussbaum. Since this subject came up last, as I threatened, I've experimented with it's application via airbrush... which I must say seems to work quite well when you're trying to get an even application on complex curved surfaces. Clean the brush/gun right away, though, or you end up with a sticky mess.

Oded; Not sure which bottled gum arabic you're suggesting doesn't work. The Windsor Newton stuff from my oil paint kit works quite well. I checked the label. No mention of glycerin, unless they are using it as "preservative" (which I suppose is possible), but the English 'cello I just touched up and crackled with it didn't seem to mind, whatever was there. :)

I'm using it (and glue as well as other techniques) to "match" what is already present on an older instrument as closely as I can, though... not to antique a new one... so control is a big issue for me.

Share this post


Link to post
Share on other sites

This same idea is used for cracked paint. Using an airbrush sounds like a smart idea since the cracks (in my limited experience using this for antique painting) tend to follow brushstrokes... especially if the brushstrokes are heavy, and too much of the cracking/skin medium is applied.

Share this post


Link to post
Share on other sites

I was just playing around with some gum arabic that I mixed up to get some craquelure on a chinese I've had sitting around. I brushed it over the existing spirit varnish and it dried but wouldn't craze until I put a blow dryer to it. Then it crazed but started to have some places where it would lift off of the varnish.

I rubbed a dark oil based wash into the cracks, but most of it came off when I went to wash off the dried gum arabic.

Interestingly though, the varnish below the gum arabic was craqueled in a nice way. Not really enough to hold any color but easily seen when light reflects on it.

I can't say that I felt like I had complete control over the process though. The craquelure pattern was irregular sort of like the way mud flats crack, but pleasant looking.

Share this post


Link to post
Share on other sites

I was just playing around with some gum arabic that I mixed up to get some craquelure on a chinese I've had sitting around. I brushed it over the existing spirit varnish and it dried but wouldn't craze until I put a blow dryer to it. Then it crazed but started to have some places where it would lift off of the varnish.

I rubbed a dark oil based wash into the cracks, but most of it came off when I went to wash off the dried gum arabic.

Interestingly though, the varnish below the gum arabic was craqueled in a nice way. Not really enough to hold any color but easily seen when light reflects on it.

I can't say that I felt like I had complete control over the process though. The craquelure pattern was irregular sort of like the way mud flats crack, but pleasant looking.

Not sure I'd try the process on fully cured varnish... I have a feeling the heat may have aided the lifting of the varnish. A little too violent for me. :)

Anyway, controlling the stuff (any of the methods, really) takes some practice. I've found the coating thickness (and how evenly the coating is applied and how thick the mix is), then how quickly the coating is dried, has a great deal to do with the result. For example I've accomplished a fine, even crackle on test strips using the airbrush and my varnish drying cabinet. Spray on and light, controlled hair dryer passes (on low) brought up a nice medium pattern on a Betts. Brush application with a slightly thicker mix allows you to get directional crazing (like what you see at the c bouts on a Pressenda). Very light scoring before application can "guide" the pattern... etc. You do have to watch the stuff like a hawk, or you'll end up with a rude (severe) looking patch. Again, I'm not doing this to the entire instrument. I apply it only where I need to bring in (mimic) a pattern that exits elsewhere and only when I believe the stuff will get me what I want. Otherwise it's better to score in or stamp a pattern into soft-ish varnish.

Share this post


Link to post
Share on other sites

What ever method and bases you try, I highly suggest you do test panels mocked up with the same "system" you intend to use on a violin. There are many variations and levels of effect based on what fininshes one is using, how thick the coats are, the application method as well as the dry times before appling a shrink coat. Tis is a "no backsies" applicaton method, if you are not happy with the effect on the violin, stripping the varnish may be the only way to start over. You may be able to resolvent a layer and get back to a usable finish base, then again you may not. Having made samples, the predictability level will be increased.

Share this post


Link to post
Share on other sites

Can someone please explain what the nussbaum does?? Induce cracks ? How? Its not a glue/gum/resin so what is its purpose apart from the colour? As far as i know its a extract of walnut husks in water,likely high in tannin but thats it.

Share this post


Link to post
Share on other sites

Can someone please explain what the nussbaum does?? Induce cracks ? How? Its not a glue/gum/resin so what is its purpose apart from the colour? As far as i know its a extract of walnut husks in water,likely high in tannin but thats it.

You're right, it doesn't make much sense if it's only nussbaum. But what I remember when I was collecting walnuts to eat them is that the husks, when getting really dark were giving this brown colour but it was very viscous and very sticky. Like a varnish or some glue. That might be part of the explanation, having a semi viscus medium that will dry faster than the varnish and at the same fill some of the crack with dark colour?

Share this post


Link to post
Share on other sites

Not sure I'd try the process on fully cured varnish... I have a feeling the heat may have aided the lifting of the varnish. A little too violent for me. :)

It was only the gum arabic that lifted, the years old spirit varnish stayed put except for the craquelure.

And again, this was not a valuable instrument.

I noticed that Oded mentioned varnishing over the dried gum arabic, any adhesion problems with that Oded?

Share this post


Link to post
Share on other sites

No problems with adhesion.

I thin the ga with water and ox gall, which lowers surface tension and allows you to brush the gum arabic in a very thin coat without the gum crawling over the varnish, which it tends to do when it is thinned without some ox gall.

In the past if I didn't like the way the crackling looked I simply wiped it off and tried again but the varnish underneath was unaffected.

Oded

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.