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scordatura

Varnish Retouching Questions

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Before I start, let me clarify that I am not saying that everyone should start retouching valuable instruments...

How many work dry with pigments (water color, transtint) without a binding medium (varnish) in their retouching approach? The reason I am asking is I want to avoid surface build up with every color layer. Working with very thin (very diluted) varnish is an obvious approach. I find however that it is easy to get too much retouching varnish surface buildup. The downside with working dry is that sometimes when you are applying varnish, it can pull up the pigment creating uneven color.

I use 1704 and JOHA retouching varnish. Any other suggestions?

Anyone use an air brush to retouch instruments that have obviously had varnish sprayed on when they mere made? 

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58 minutes ago, scordatura said:

How many work dry with pigments (water color, transtint) without a binding medium (varnish) in their retouching approach? The reason I am asking is I want to avoid surface build up with every color layer.

I like to pre-mix a colored varnish, when I think the original was done that way. To test and adjust the color and the color concentration, one can stick a piece of cling-film to the area to be retouched with a little oil or water, apply the retouching to the cling film, and see if it builds up in the matching succession of shades as the original, as more is applied. One can also let it dry on the cling film to see what the final varnish thickness will be.

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10 minutes ago, David Burgess said:

I like to pre-mix a colored varnish, when I think the original was done that way. To test and adjust the color and the color concentration, one can stick a piece piece of cling-film to the area to be retouched with a little oil or water, apply the retouching to the cling film, and see if it builds up in the matching succession of shades as the original, as more is applied. One can also let it dry on the cling film to see what the final varnish thickness will be.

Excellent suggestion with the cling film!

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39 minutes ago, scordatura said:

Excellent suggestion with the cling film!

That technique works VERY well!  Part of the beauty of that method is that you can work out and refine what needs to be applied without affecting what is already on the instrument, which usually results in increasing the area needing to be retouched.

I’ve not used the dry pigment method, but I know some do with great results.

Regardless of the method used, patience and restraint is paramount.

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The air brush is an incredibly useful tool, but there's a learning curve, and it would be helpful if you have someone who can show you how to use it. 

It works perfectly for what you intend: with a dilute solution and low pressure you can lay on a much finer skin of varnish for sealing vulnerable work in progress than you can with a brush, and do it without imposing a texture or disturbing your work, building thickness at a rate that's totally under your own control. That's for work like painting in grain lines and wood texture where it's missing, that kind of detail work, which is what I assume you are talking about.

It's also useful for large bare areas, like wear on ribs, and heels after neck sets. For this work it's fast, and there's often no need to sand for smoothing later, and sometimes it can almost be left from the brush with some minor anti-polishing to take off the extra shine. When things are going well, I can varnish a cello heel in less than ten minutes. If you have a situation where you want to leave a bare wood look without leaving bare wood in an area that needs to be protected but isn't actually too vulnerable, it's great for that, too, and it's handy for blending retouched areas with unretouched where there's a difference in shine at the end, or for quickly removing certain type of irritating reflectivity in low spots (like the junction of underedges or other inaccessible spots) while adding virtually nothing that couldn't be quickly polished off with a cloth. In fact, the biggest advantage of an air brush is it's ability to deliver minimal amounts of material in a controlled tight area with the minimum amount of sanding and polishing required after.

I have a friend who uses it with a mask to paint grain lines, which need to be sharp on one edge, feathered on the other. I have used it for filling cracks, at which it can be very tidy. All of this takes experience/practice, and knowing the right pressure, dilution, and technique--easy to demonstrate, harder to explain in words.

I use a small compressor with abaout a 3-gallon tank (tiny compressors without tanks pump in bursts), but for a start you can buy small air tanks which last reasonably long, and the only thing you'll waste if you buy a compressor later is about $10 for the special tank valve. This isn't always good for really delicate jobs, however.

Many of the people I know who use air brushes use this one: https://www.iwata-airbrush.com/iwata-eclipse-hp-cs.html  For about 1/3 less they make one without the backstop handle (which limits needle travel, and thus flow rate, with a fine adjustment) as the Revolution C, but I recommend the Eclipse model. An the prices on the website are full retail, of course, which no one pays.

It can be seductive to buy one of the finer ones, but with the materials we use they clog too easily, so just don't. .02 nozzle, no; .03 nozzle, yes; .05 nozzle, only for varnishing whole instruments quickly.

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Thanks for the detailed airbrush info, I have three cheap ones but haven't used them for varnish or re-touch yet. I have a Chinese student cello in the shop right now missing lots of varnish. Maybe, I'll try color matching with the airbrush and then finishing with a brush. It will be good practice.

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Saran Wrap is something I've used (at David's suggestion) for over 30 years. Great way to get color and intensity very close before touching the instrument with a brush.

I use a different approaches to retouch, depending on need.  If it's possible, I prefer pre-mixing varnish, but in a pinch layering (and sealing in) color can be the way to go.

I still rely heavily on my regular brushes, but I do love my airbrush. If layering, it's easy to control the finish thickness. If pre-mixing, you can adjust intensity with each pass (coat). With practice, mimicking the texture of old varnish is pretty easily accomplished. Pulling back a bit causes the varnish to dry just about the time it hits the surface, which can be a rather useful effect at times.  I was lucky to have an airbrush teacher from the community college to get me started with technique.

I most often use a .03 airbrush by Futo Seko (Richpen Phoenix 213C; when I bought mine they were made in Japan. I think they may be made in China now) and an Iwata compressor with a really good moisture trap.  The compressor is a "Cadillac" (nice size tank, two independently adjustable hook ups, and very, very quiet), but I've never been sorry I bought it. I think the Iwata airbrushes are great tools, but personally found the Richpen a little less fussy for regular use... and the price is/was good.  Both Iwata and Richpen are very good at low pressure.

I still use a brush (tiny one) for grain lines.  

 

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For those who use air brushes, by the way, the plague has taught me something. I made some hand sanitizer in the shop with everclear, water, and glycerine, since they were there. I have had trouble with the air valve sticking for the last 35 years, but the other day, when I cleaned the brush, instead of squirting alcohol down the trigger hatch I pumped in a load of that hand sanitizer, on a hunch that the glycerine might make a harmless lubricant (Lord knows, I've tried all the other possibities!) The valve is working great, for the first time--absolutely no sticking.

I had a compresser like Jeffrey's, but it wouldn't stay working, and the factory wasn't any help, so I  bought a $100 job at Sears. I've since learned that I should have taken it to a air conditioner / fridge repairman, since it's basically an overpriced refrigerator compressor.

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1 minute ago, Michael Darnton said:

For those who use air brushes, by the way, the plague has taught me something. I made some hand sanitizer in the shop with everclear, water, and glycerine, since they were there. I have had trouble with the air valve sticking for the last 35 years, but the other day, when I cleaned the brush, instead of squirting alcohol down the trigger hatch I pumped in a load of that hand sanitizer, on a hunch that the glycerine might make a harmless lubricant (Lord knows, I've tried all the other possibities!) The valve is working great, for the first time--absolutely no sticking.

Hahaha! Good idea!

 

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53 minutes ago, Michael Darnton said:

 

I had a compresser like Jeffrey's, but it wouldn't stay working, and the factory wasn't any help, so I  bought a $100 job at Sears. I've since learned that I should have taken it to a air conditioner / fridge repairman, since it's basically an overpriced refrigerator compressor.

Jeffrey's sure is quiet, though. Overall, refrigerator compressors are pretty reliable. What a shame that the manufacturer wasn't any help!

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2 hours ago, Michael Darnton said:

I had a compresser like Jeffrey's, but it wouldn't stay working, and the factory wasn't any help, so I  bought a $100 job at Sears. I've since learned that I should have taken it to a air conditioner / fridge repairman, since it's basically an overpriced refrigerator compressor.

Sorry to hear that...  mine has been running like a top for about 12 years.. the only problem I had with it was an oil gasket early on (the gasket sucked), but an upgrade was available from Iwata.  Once installed it's been fine since.

1 hour ago, David Burgess said:

Jeffrey's sure is quiet, though. Overall, refrigerator compressors are pretty reliable. What a shame that the manufacturer wasn't any help!

Yes it is!  It's directly above the Lawyer's office below me and he's never been bothered by it at all...

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My manufacturer was of help, but the service center was in Canada, and the compressor weighs, what, 50 pounds? The first time, I went for it, but not the second.

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I think I mentioned this on a thread years ago, but I have always used bottled, regulated compressed air, rather than a compressor.  They are absolutely silent and are easily & inexpensively re-filled.  A bottle would last me many months or even a year or more.

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On 3/14/2020 at 12:24 PM, Jeffrey Holmes said:

The compressor is a "Cadillac" (nice size tank, two independently adjustable hook ups, and very, very quiet), but I've never been sorry I bought it.

 

If it's still available, which model is your compressor Jeff?

I'm considering one rather than running a hose from the large one in my garage...

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1 hour ago, Mark Norfleet said:

If it's still available, which model is your compressor Jeff?

I'm considering one rather than running a hose from the large one in my garage...

Hi Mark!

Yes, it's still available.  It's the Iwata Hammerhead Shark.  If you don't need the capacity and the dual output, there are single output compressors available from Iwata but they may not be as quiet.  Prices are better through art supply houses.

Hammerhead Shark

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1 hour ago, Jeffrey Holmes said:

Hi Mark!

Yes, it's still available.  It's the Iwata Hammerhead Shark.  If you don't need the capacity and the dual output, there are single output compressors available from Iwata but they may not be as quiet.  Prices are better through art supply houses.

Hammerhead Shark

Thanks much.

That certainly looks nice, but my situation doesn't warrant spending that much to squeeze air and make sure it's clean and dry, especially as I already have a much higher capacity compressor.   I just have to make sure I have enough stored compressed air if I'm working late.

 

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1 hour ago, Mark Norfleet said:

Thanks much.

That certainly looks nice, but my situation doesn't warrant spending that much to squeeze air and make sure it's clean and dry, especially as I already have a much higher capacity compressor.   I just have to make sure I have enough stored compressed air if I'm working late.

 

Yup.  I understand.  It wasn't nearly as expensive 12 years ago (and I got mine from the air brush instructor who taught at Washtenaw C.C. at the time; he got them at quite a discount).  Having used it for this many years, I'd be prepared to buy another one if it ever poops out. 

One of the co-administrators at Oberlin has something similar from Iwata with a single output that's pretty quiet.  Smaller, less expensive (by quite a bit as I recall) and close to as quiet as mine.  Maybe he'll see this and list the model.

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9 minutes ago, Jeffrey Holmes said:

One of the co-administrators at Oberlin has something similar from Iwata with a single output that's pretty quiet.  Smaller, less expensive (by quite a bit as I recall) and close to as quiet as mine.  Maybe he'll see this and list the model.

At the time, I didn't have the Jeff slush fund for toys, so I bought the Power Jet Pro... they've updated the model now to include two hookups, hopefully it retains the quietness of the older version which isn't much louder than Jeff's. My workshop is small and I don't mind it at all when it's running, even when it's directly by my feet.  It's also a whole lot more portable, hence why it makes the trip to Oberlin: 

 Iwata Power Jet Pro

 

The fifth tile on this instagram post shows me using it, I think at the end the compressor kicks on.  neck heel/airbrush  I'm not showing good form by how I'm holding the the hose... or by not wearing a mask (really should mask up).   I often use the airbrush together with a paintbrush for heels.  

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I made my own compressor almost 20 years ago, being student with no income and every luthier supply was imported (meaning extremely expensive) I had to make almost all my tools. I remember how I cringed when I bought the switch, pressure valve and trap for unheard amount of money (something like $50) but the rest was pretty much free... together with one afternoon of work... Two old refrigerator compressors, one (not working) cut open and emptied to make a tank and other wired and connected with hoses together and mounted on a piece of plywood. After first try I learned I need to add valve to release pressure between the compressor and tank or the compressor won't start against pressure over 3-4 bars (I set it to start at 4 and stop filling at 8). There are pressure controller switches with built in valve for relieveing pressure, but I failed to know that, but somehow managed to retrofit the switch with old bicycle valve (schrader) that releases pressure when lever inside the switch moves and touches the pin and it had worked well ever since. you can hardly hear it running... I've  always wanted to build some casing to look more professional, but never had the time...

 

IMG_2632.JPG

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Hogo, you have always come across as a super-smart and very creative person.

Having known Norfleet for many years, I wouldn't want to hazard a guess as to whether he would prefer to fashion an air compressor from a refrigerator compressor, or a pump organ. :lol:

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48 minutes ago, HoGo said:

I've  always wanted to build some casing to look more professional, but never had the time...

I think it looks kinda cool as it is!

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Well, in my situation back then it was either you make it yourself or you don't have it... And with a bit of luck to know some skilled friends to help with some steps (the welding was done by my firend, my welding skills suck). Living behind iron curtain (or still shortly after it fell) had at least some positive effects... todays folks just go and buy whatever they want...

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16 hours ago, Jerry Lynn said:

At the time, I didn't have the Jeff slush fund for toys, so I bought the Power Jet Pro... they've updated the model now to include two hookups, hopefully it retains the quietness of the older version which isn't much louder than Jeff's. My workshop is small and I don't mind it at all when it's running, even when it's directly by my feet.  It's also a whole lot more portable, hence why it makes the trip to Oberlin: 

 Iwata Power Jet Pro

 

The fifth tile on this instagram post shows me using it, I think at the end the compressor kicks on.  neck heel/airbrush  I'm not showing good form by how I'm holding the the hose... or by not wearing a mask (really should mask up).   I often use the airbrush together with a paintbrush for heels.  

Hey Jerry. What airbrush do you use? Enjoying the Omo podcast by the way!

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1 hour ago, scordatura said:

Hey Jerry. What airbrush do you use? Enjoying the Omo podcast by the way!

Hi Scordatura!

I have two Richpen Phoenix airbrushes that I use. I got them because Jeff recommended them to me.  Both of them are the 213C model.  One has been modified to have a smaller nozzle and needle, essentially making it a 212C which wasn't an official product of the company, but a reseller was modding them that way.  Richpen Phoenix  I mostly use the stock 213C, the larger bore seems to work better for me.  I always use a combo of dyes and dry pigments, the pigments seem to have an easier time with the larger size.  

Unfortunately, it would appear is if they've been discontinued.  A trusted friend and colleague in Boston has recently gotten the Iwata Neo gravity fed dual action airbrush  .  They say good things about it, and it's very affordable.  

 

I'm so glad you like Omo!  We've shelved the next episode on Baroque set up for a later date in favor of some commentary from Ben Hebbert.  

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