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UkulelesRcooL
03-11-2017, 08:22 PM
Is this a method of spraying lacquer that would work well with Ukuleles??

High Volume Low Pressure....
It sounded really close to a vacuum cleaner and the hose that hooked up to the spray gun looked like a vacuum hose.
I spoke with a guy I know that rebuilds tube am radios...
The old ones with the wooden cabinets from the 30s and 40s..
He was spraying lacquer on one of those "tombstone" style radio cabinets in his garage and the days temp was probably 53 degrees Fahrenheit at the most.. Overcast skies.. I asked him if he had good success with spraying in those kind of conditions and he said because of the delivery method it worked great... Also he said that when he used to use his regular air compressor he would over whelm his garage with the spray.. it would get everywhere.. With the HVLP system its not a problem and he doesnt have to worry about the over spray as much.
In my limited experience Ive always used Nitro from a can.. and last year had horrible results once the temps started dipping..
He said the HVLP system gave him a super fine mist and he didnt have any issues with spitting..... Anyway.. I was wondering if anyone here has had experience with that method of application???
Thanks for any comments..

Allen
03-11-2017, 09:26 PM
It really would depend on the HVLP system. Some are much better than others, and if this fellow is spraying with lacquer and it's working a treat for him, then that's most likely a system to look at. Unless they have dropped in price considerably then they are going to be a sizable investment. Last ones I saw were $1,500+ but they were designed for automotive spray booths, where I worked for 35 years. We had plenty of systems demo'd over the years, but none where up to snuff for the job we needed them to do.

Turbine systems like the one you saw by their nature supply air that is warm, so if you are spraying in cooler conditions, this can be ideal. All they are doing is moving air and it gets heated up by the turbine action. In hot conditons though you are really going to struggle as your product is going to be drying the split second it's out of the nozzel.

Compressors act in a different way and supply compressed air that heats up as it's being compressed and cools as it expands out where it's needed. You have a lot more control of that supplied pressure and this is useful for all kinds of things.

Each has it's merits, but for me the only one to choose if you are going to spray something like ukuleles is the compressor and small HVLP gravity feed gun.

Compressed air is used so much in the workshop it would be like loosing an arm with out it there when needed. You just don't have that with a turbine system. However if money is no object, then you could get both the turbine and a compressor.

UkulelesRcooL
03-12-2017, 07:11 AM
Thanks Allen,

That really explains alot.. It makes sense why he would be able to spray in cooler temps with a heating of the air by the compressor... I was heating up my cans of nitro in a warm water bath
So they wouldnt spit last fall when the temps started dropping and that has its inherit problems.. So I struggled just trying to finish up the myrtlewood I was working on..
I was intrigued when I saw my friend spraying yesterday due to my own limited experience..
I believe he was using a cheap unit from Harbor Freight... Maybe 100 dollars.. So its along way down from what you were describing at 1500.
I didnt inspect the finishes on his radio cases very closely, from my vantage they looked good.
I like the idea of having a couple of different options as you stated using a compressor and a small HVLP gravity feed gun..then also having a small HVLP compressor for when the temps start to drop.
Im dont believe I will ever be doing this on a large scale but I would like to do it the most efficient way I could find that works the best.
Every time that can would spit on my Uke Id have a fit.. waiting for it to dry and sanding it again... It was like taking a step forward and 3 steps back..
I had a friend that was working on his tenor and he was french polishing and I thought that was another option,,,, I had tryed it but,, I had even more trouble with it..
Ill have to get some books and media on it I guess..
The folks here on the forums sure helped on that topic in a different thread which helped tremendously..
Thanks for the info Allen. It makes total sense to me now.

Moore Bettah Ukuleles
03-12-2017, 07:50 AM
I've used a Fuji Q4, four stage turbine, for the past 10 years and much prefer it over compressed air. I don't have to worry about contamination or traps and as your friend mentioned the air around you is MIUCH cleaner. It sprays lacquer onto the object and not in the air, which also results in savings. I regularly spray in temperatures of about 80 to 85 degrees with no problems. Of course your material has to be thinned properly and I do add 5% retarder to my mix. You can also bring down the temperature of the fed air by doubling the length of the hose but I've never found that to be necessary. HVLP is not good for applying sunbursts as the particle size is too big but other than that it's the perfect machine for me. I wouldn't waste my time on anything less than 4 stages, they just aren't powerful enough to atomize properly. And to can get quieter machines; the "Q" in my Fuji Q4 stands for "quiet". I will probably upgrade to their 5 stage if and when my current one ever quits on me. But so far I have not had a single problem after spraying many hundreds of ukes.

Pegasus Guitars
03-12-2017, 09:41 AM
I'm only a few miles from Chuck, but with much cooler and wetter spray conditions. Been using HVLP for 20 years. On my 4th HVLP system and my 2nd Fuji system now. They are very good. Still using a 3 stage system, with no complaints, but maybe if I tried a 4 stage I would like it better. The main differences between Fuji systems is the type of gun you use. I switched from a cup gun, of which I have 2, to a gravity feed. The cup feed gun is far easier to clean and refill, but the gravity feed is light years ahead of it in the quality of the finish. I resisted gravity feed for years, but would never go back to a cup. Maybe that extra 4th stage helps with the gun type, but for lesser systems I would highly recommend gravity feed.

UkulelesRcooL
03-12-2017, 09:58 AM
I've used a Fuji Q4, four stage turbine, for the past 10 years and much prefer it over compressed air. I don't have to worry about contamination or traps and as your friend mentioned the air around you is MIUCH cleaner. It sprays lacquer onto the object and not in the air, which also results in savings. I regularly spray in temperatures of about 80 to 85 degrees with no problems. Of course your material has to be thinned properly and I do add 5% retarder to my mix. You can also bring down the temperature of the fed air by doubling the length of the hose but I've never found that to be necessary. HVLP is not good for applying sunbursts as the particle size is too big but other than that it's the perfect machine for me. I wouldn't waste my time on anything less than 4 stages, they just aren't powerful enough to atomize properly. And to can get quieter machines; the "Q" in my Fuji Q4 stands for "quiet". I will probably upgrade to their 5 stage if and when my current one ever quits on me. But so far I have not had a single problem after spraying many hundreds of ukes.

Thanks Chuck,
I truly appreciate the information as I dont have enough experience to know any of what You and Alan have shared..
I dont think I will ever be applying sunbursts at this point so I would probably get away with not needing that application.
The problem I have here in Eastern Washington is the fall, winter and spring.. I have a very small shop and if I spray, its outside... So part of fall, all of winter and part of the spring is a no go for me.
In my musing it all over I thought that French Polish would solve it but I think that will take alot more research and practice.. and Im sure it has it place but when I can spray, Id like to try the HVLP system and the fact that the turbine heats the air is a plus to me in the cooler temps.

Moore Bettah Ukuleles
03-12-2017, 11:55 AM
Thanks Chuck,
I truly appreciate the information as I dont have enough experience to know any of what You and Alan have shared..
I dont think I will ever be applying sunbursts at this point so I would probably get away with not needing that application.
The problem I have here in Eastern Washington is the fall, winter and spring.. I have a very small shop and if I spray, its outside... So part of fall, all of winter and part of the spring is a no go for me.
In my musing it all over I thought that French Polish would solve it but I think that will take alot more research and practice.. and Im sure it has it place but when I can spray, Id like to try the HVLP system and the fact that the turbine heats the air is a plus to me in the cooler temps.

As I've mentioned, the heated air produced by HVLP has never been a problem for me even when spraying at 85 degrees F and would probably be helpful to you in spraying in cooler temps. Much of the success in spraying with any equipment, but HVLP specifically, is in knowing your mix. Because the particulate size is much bigger than with compressed air systems it will produce an orange peel surface more readily if you don't thin properly. A 50/50 mix is not too thin. (In my particular case with the lacquer I use I mix 50% lacquer, 45% thinner and 5% retarder.) It lays on very nicely and flat with minimal orange peel. Using the smallest tip available;ab;e is important as well. Again, I warn you not to be tempted by anything less than 4 stages. I used a 3 stage before buying my Fuji Q4 and it's a world of difference. BTW, if you are spraying outside your neighbors will thank you. No more nasty vapor clouds in the air. It does make noise though but that's why I got the "quiet" version. (I have no neighbors anyway.)

UkulelesRcooL
03-12-2017, 12:07 PM
I'm only a few miles from Chuck, but with much cooler and wetter spray conditions. Been using HVLP for 20 years. On my 4th HVLP system and my 2nd Fuji system now. They are very good. Still using a 3 stage system, with no complaints, but maybe if I tried a 4 stage I would like it better. The main differences between Fuji systems is the type of gun you use. I switched from a cup gun, of which I have 2, to a gravity feed. The cup feed gun is far easier to clean and refill, but the gravity feed is light years ahead of it in the quality of the finish. I resisted gravity feed for years, but would never go back to a cup. Maybe that extra 4th stage helps with the gun type, but for lesser systems I would highly recommend gravity feed.

Thanks for your input.. I appreciate all your advice and information.. I know you guys know what your doing and it helps me from making blunders that Ill regret later..

Moore Bettah Ukuleles
03-12-2017, 02:42 PM
I know you guys know what your doing and it helps me from making blunders that Ill regret later..

Don't count on it, you'll still make you share of blunders. Finishing is an art more than a science. I can advise 10 different builders on how to finish an uke and they'll all have somewhat different results. Besides, if you aren't making mistakes you're not trying hard enough!

resoman
03-12-2017, 07:15 PM
I've been using a DeVilbiss touch up gun for a couple of years now but the Fuji 4 stage is in my immediate future.
The Q model is probably out of my range but I want the 4 stage turbine for sure

chuck in ny
03-16-2017, 05:12 PM
i use iwata HVLP guns driven by a regular compressor. these are more or less what the auto body guys use and are top of the line.
if you have a good electrical supply, not all shops do, you are well served by bleeding for a legitimate compressor, and whatever piping, aftercooler, and moisture traps you will need. you then have the industrial heart of any shop and can run d/a air sanders and normal spray guns.
a lot of money is spend avoiding getting a legit compressor, in specialized sanding and spraying equipment. to each their own.

sequoia
03-16-2017, 06:41 PM
Finishing is an art more than a science. I can advise 10 different builders on how to finish an uke and they'll all have somewhat different results. Besides, if you aren't making mistakes you're not trying hard enough!

Boy is that right. Also just when I think I got it down pat, something weird happens. I do enjoy (mostly) the process. So nice when it works perfect....

Just a question ukesRcool: How many ukes do you plan on making? Chuck and the others are real luthiers who do a lot of production to high end standards and their finishing techniques might not be the right fit for the amateur or the low production facility. Time becomes key as time is money to a luthier trying to make a living. There is a substantial upfront investment to say nothing of learning curves. Their finishes are to die for, but I think for a small production output, shellac works as well at a fraction of the cost. Cost in money that is. Cost in time is something else and that cost is high. But if you have the time and don't have to kick out the ukes, try shellac again. Your first experience might have been bad, but it really does work. It really does. I think a lot of people tend to over think a basically simple process.

Kekani
03-16-2017, 06:51 PM
...
He said the HVLP system gave him a super fine mist and he didnt have any issues with spitting..... Anyway.. I was wondering if anyone here has had experience with that method of application???
Thanks for any comments..
I find it odd that HVLP system and super fine mist is in the same sentence. Of course I've only sprayed Fuji and Earliex, so take that for 2 data points.
Conversion HVLP I would agree (after spraying Sata and Iwata). Just saying.


I think a lot of people tend to over think a basically simple process.
I'm guilty of that. I've never considered finishing a simple process, no matter what finish is used. From a time perspective, I can complete an ukulele faster than I can finish one. I guess this is why I started my finishing process during the build process. Solves some problems I didn't know I had, sort of like putting the nut in the fretboard.

Michael Smith
03-16-2017, 08:48 PM
Lord I wish there was an inexpensive robot that could do all finishing.

Allen
03-16-2017, 09:56 PM
I think for many, finishing is the single most difficult aspect of building, and certainly is if you are looking for glass like mirror finishes. Even as pro's I don't think you'll find many that truthfully say that they like doing them. Quite simply they take time and are an incredible amount of work to get right.

Also I'd like to second Sequioa's comments about using shellac as a finish. You only have to have a look at some of the top Spanish Guitar builders to see what absolutely astonishing results that can be had from using it. Can be brushed on, or with a pad, or a combination of both. You really don't need to make it complicated to get very nice results.

It's very low cost, about as non toxic as you are going to get, and quite enjoyable to apply. I would say it's learning curve is less than learning how to be a good spray applicator.

Rrgramps
03-17-2017, 12:43 PM
In 1967, while in the air force as an SP, the airman working in the armory took me inside to show me his carbine stock that he'd finished. It was so smooth and glossy, that I thought it was a thick coat of epoxy. He laughed, and told me it was Tru-oil, and he applied it without a brush. My Fender Jazz Bass didn't have that level of finish when it was brand new in 1964. I'm still thinking about how it dazzled me back then.

A few years later, I started using it on my rifles and shotguns. I've also seen many examples of Tru-oil on various instruments, including my own. It presents an admirable finish, and a close 2nd to French polishing in appearance; for a those who don't have access to spray equipment.

fungusgeek
03-20-2017, 04:40 AM
Not having either spray equipment, nor a place to spray things, I have been using Tru-Oil. I have worked out a process that is very simple, not at all time consuming, and yields a very nice shiny smooth surface, yet with a remarkably thin finish. (When scraping off to glue on the bridge the finish seems almost not there at all it is so thin.) I'm going to do a small write-up on my procedure in the near future. For now, here is a picture of the reflection of the banana trees outside the window, and me trying to take a picture of a shiny surface.9864598646

sequoia
03-20-2017, 07:02 PM
That certainly is an attractive finish if you like shiny and I like shiny. Lovely looking instrument. Looking forward to a description of your finishing schedule. Please do write it up and post.

My knock against Tru-Oil and reported here earlier is that I was a Tru-Oil applying slave during my father's dalliance in gunsmithing. It took forever to get a decent finish. Or at least it seemed that way to a 12 year-old. My other reluctance is what the stuff does to the sound of an instrument. Ukes ain't gun-stocks. I have no evidence it inhibits sound, but all that resin...Hell, maybe it enhances the sound. I don't know. Also I've never been able to figure out what exactly the stuff is made out of. As far as I can tell, it a propitiatory preparation of some sort of "resin" in a volatile organic solvent mixture which doesn't really say much. If anybody actually knows, please post.

Michael N.
03-21-2017, 03:11 AM
It's almost certainly an alkyd resin, not far from old fashioned copal or pine resin type varnishes. It's the 'modified oil' bit in the MSDS that suggests it's an alkyd. That, along with heat treated linseed gets you an oil varnish. No doubt there's an added siccative and perhaps a bit of turpentine like solvent. It's not the resin that is considered the problem, it's the oil content. Most violin makers refuse to apply an oil varnish directly on to the wood for fear of it dampening the sound.
I've done Tru oil in very quick time, 3 days from applying the first coat to the final rub out. I was brushing it on and I also have a UV drying cabinet, so I could brush a coat on every 2 hours or so. Rubbing it out so early means that it will shrink back and you'll likely get a softer looking finish, not as glass hard looking. I much prefer that type of finish anyway. You can get the same (or similar) effect with shellac by finishing with the cloth rather than going through all the grits and polishing compounds. It's more like the traditional method of French polishing. The cloth is effectively producing micro lines in the finish which has the effect of scattering the light. It's still a glossy finish, just not as glass like as one would obtain by going through the grits. I think it takes more skill to produce that type of finish. Going through the grits isn't that difficult, it's just more work.
I use shellac for virtually all my finishes but I do apply an oil underneath the shellac. That gives a slightly richer look to the wood grain, which is a little lacking with straight shellac. It's pretty close to an all oil varnish finish in terms of the optics. On the soundboard I don't apply oil, just shellac. That just gives me security. I've no idea if oil on wood is that problematic in terms of tone. I've tried it, a few times. Sounded perfectly fine to my ears.

fungusgeek
03-21-2017, 05:25 AM
I have read that Tru-Oil is "a polymerized linseed oil with other natural oils added." It seems to harden rather quickly (in fact, keeping it from hardening in the bottle is a bit of an issue) unlike plain tung or linseed oils. I wonder about your "all that resin" comment. I have found (from scraping bridge areas prior to gluing) that the finish is very very thin, certainly no thicker than a french polish. I always have a seal coat of shellac, and see no deep wood penetration as one might expect of a pure 'oil' finish. The Tru-Oil seems to be very much sitting on the top and is way thinner than any lacquer finish.

RPA_Ukuleles
03-21-2017, 05:39 AM
I like TruOil for its sound qualities. Not my favorite to apply, no finish is all that fun actually. But try this sometime: build and string up an unfinished uke, listen and remember what it sounds like, then TruOil it and listen again. It truly brings an instrument to life. The difference is quite remarkable. In my use it seems to really harden in the wood and has zero sense of the oil "dampening" the sound.

My preferred type is the spray can. I don't spray it on, but I spray a puddle into a cup, then dampen the application cloth in the cup. The oil in the spray can is much thinner than in the bottle (and it does not harden in the can). I feel like the thinner oil in the can penetrates into the wood better as well. Using TruOil from the bottle is problematic because it starts to thicken pretty soon after opening.

Michael N.
03-21-2017, 05:50 AM
The MSDS states 'linseed oil' and 'modified oil'. The 'modified oil' bit can mean a lot of things but Tru oil doesn't act like it's a combination of drying oils and drying oils alone. It acts much more like a drying oil with some sort of resin content. I'm no coating chemist but I believe that alkyd resins can be derived from oils, they are synthetic. It's not a natural occurring resin like copal, pine resin or amber.
It's not as hard as dewaxed shellac, at least it isn't going by my tests. I've tried this on ebony and on glass using the pencil hardness test. Dewaxed shellac is noticeably harder than Tru oil even after 8 months of curing. Having said that it's protective enough providing the instrument isn't abused.

https://www.birchwoodcasey.com/getattachment/Resources/Safety-Data-Sheets/23123,-23035,-23132-Tru-Oil-Saftey-Data-Sheet.pdf.aspx

sequoia
03-21-2017, 06:22 PM
Thanks Michael for the post. I just looked up "alkyd resins" and my head is still spinning a bit. Complicated chemistry here. Basically as I understand it, Tru-Oil is really a modern take on an old fashioned oil varnish where the alkyd resin acts as a dryer. Nothing necessarily wrong with this but it is an "oil varnish" and to my mind this is problematic with acoustic instruments. I've become oil adverse in my current thinking and maybe that is just me but I think it kills tone and brightness and dampens the wood. That being said, Antonio S. used basically the same thing as Tru-Oil (Old-Oil?) on his instruments in the 17th century and from what I hear they sounded pretty darn good. Finishing is such a black hole when it comes to lutherie. No wonder people find a method that works for them and they stick with it come hell or high water. Sometimes by trying different things I feel I am wading around in the swampy bushes trying to find the shore. Still looking for that finishing salvation.

Michael N.
03-21-2017, 11:43 PM
No, alkyds acts as a resin, it gives a harder surface to the finished film (over drying oils alone).
The Strad varnish was probably a cooked oil varnish, linseed oil and pine resin. They come under the term of natural resin oil varnishes. Copal oil varnish (copal resin + a drying oil) was a popular varnish for furniture and woodwork, sometimes referred to as coach varnish. In the 20 th century alkyds slowly replaced the natural copal varnishes which in turn were replaced by the modern urethanes. All of these types of varnishes still exist but the natural resin varnishes seem to be limited to violin makers and fine artists (painters). Alkyds may still be used in some of the boat varnishes but they are virtually non existent for general woodwork. Then there are the phenolic resins which I think the original Behlens rockhard contained. Rockhard was the hardest and the easiest oil varnish that I've ever used. I didn't care for the smell and it gave a horrid greenish cast to light coloured inlays.

sequoia
03-22-2017, 06:37 PM
Apologies that this thread has been semi-hijacked, but I find this stuff interesting... So what about "spar varnish"? A related product it seems to Tru-Oil but different. It was developed to be extremely tough and hard to resist the elements on masts of sailing ships, but at the same time had to be flexible or elastic and not crack when the masts or spars bent in the wind. This would seem to be perfect characteristics for a musical instrument and yet I see little use of "spar varnish" on ukuleles. I've worked on boats and I'm more familiar with the stuff than I ever want to be again, but hesitate before trying it on an uke. Has anybody had experience with "spar varnish" as a strnged instrument finish (the old style stuff, not the modern equivalent)? My gut feeling is that it is too hard and too stiff. A strummed D chord is not a stiff wind... Below a Wiki description:

Spar varnish was originally developed for coating the spars of sailing ships. These formed part of the masts and rigging, so suffered a hard life in service. They were flexed by the wind loads they supported, attacked by sea and bad weather, and also suffered from UV degradation from long-term exposure to sunlight.

The most important condition for such varnishes to resist was the mechanical flexing. This required a varnish that was flexible and elastic. Without elasticity, the varnish would soon crack, allowing water to penetrate to the wood beneath. At the time, varnish production was rudimentary and had only simple materials with which to work. It pre-dated the development of modern polymer chemistry. Spar varnish was a 'short oil' varnish, where a small proportion of a finishing oil, universally boiled linseed oil, was added to a majority proportion of varnish (see Danish oil for a 'long oil' finish).[1] This gave flexibility,[2] even though its weather resistance was still poor and relatively frequent re-coating was required.

In modern times, 'spar varnish' has become a genericised term for any outdoor varnish. Owing to modern varnish materials, their weather resistance is likely to be good, but the original requirement for flexibility has largely been forgotten.

Michael N.
03-23-2017, 04:59 AM
Not sure that the wiki thing is making sense. Short oil varnish refers to the proportion of oil to resin, so a 51% resin, 49% oil content would be a short oil varnish. 51% oil and 49% resin would be considered a long oil varnish. More oil = soft & flexible. More resin = hard & brittle.
For spar or marine oil varnishes Tung oil is often used. It has a better reputation (than linseed) for withstanding the rigours of the wind and the rain. Varnish formulations for boat applications have to take into account the environment, so they normally aren't too hard - otherwise they would tend to crack when subject to varying weather and direct sunlight. I wouldn't call them hard, although they aren't that soft either. The word 'tough' usually has a specific meaning when it comes to varnishes. It doesn't always mean hard, more an ability to take the knocks.
There are some guitar makers who use marine varnish. Epifanes isn't uncommon. Some add more resin to make for a slightly harder finish than the standard Epifanes.

Pete Howlett
03-30-2017, 08:16 PM
Crimson Guitars in the UK have cloned Tru-oil. You could ask them what it's made from rather than all this speculation...