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Hey guys.
Looking for a turbine system for nitro in 2018. Only a few guitars a year.
Thoughts on this?
https://www.thepaintstore.com/Earlex_Sp ... gItgPD_BwE


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What you have to do is determine the filtering of the air before it hits the gun. Filters should be very high quality to prevent crap from being shot with each coat. That used to be the BIG problem with HLVP.

Why type of contamination are you referring to? Since it is a turbine there is no water / oil issues inside a compressor.... right ?


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Crap in the air. You are taking in 500+ CFM.

Ah:)


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There is no free lunch - LVHP (compressor guns) are vulnerable to oil and water contamination, so it is more about whether the system is well thought out, put together, and maintained than whether the air source technology is turbine versus compressor. We have both in the shop, and use the four stage Fuji turbine for most work - dry, warm airflow, guns that are equivalent to current Iwata and SATA full sized conversion/HVLP guns, and identical results. Turbines extend minimum spraying temperatures by 5-10 degrees in cold weather and by 5% or more in Relative Humidity on high RH days.

All turbines use the same turbine technology so it's really more a case of getting the right size (e.g., number of stages of compression) turbine and a gun that handles well, can be cleaned easily, and is affordable. Look for a minimum of three stages in the turbine if spraying nitro or other clear finishes, availability of a 1.0 mm tip set along with the stock 1.3 or 1.4 mm (1.0 mm is the usual tip set for waterbores), and a gravity feed gun that has fan width controls. Minimum tip pressure generated should be about 6 psi (usually about 2 psi per stage).

On your linked system: the Earlex uses a gravity feed gun (harder to clean, limited fan width control), a single-stage turbine (finishes must be highly thinned for such a low pressure system - complicating nitro, which is easier to spray when minimally thinned), and supplies a hose set is about half the length that it should be to separate the turbine from point of application.

In terms of what we recommend to students leaving the shop and continuing to build:

- Good, all-around system for clear finishes that will not be Craigslist'ed in a year or two for about $650:
https://www.amazon.com/dp/B075RTSQLD/ref=sspa_dk_detail_5?psc=1

- Minimum budget system for clear finishes for about $425:
https://www.amazon.com/Fuji-2203G-Semi-PRO-Gravity-System/dp/B00D4NPPQY/ref=lp_8130965011_1_8?srs=8130965011&ie=UTF8&qid=1514288333&sr=8-8

- If money is not an immediate issue, $800 for a four stage system that will handle thicker finishes with minimal thinning (MiniMite 4)

Compressor installations and conversion guns are the standard for professional finishers for a reason - wide range of guns (clear coat, primer, touch-up, etc.), very controlled spraying conditions (spray booths manage both filtration and air flow for best application), and good range of accessory dryer/filter systems. These systems come at a cost - thousands for a spray booth that can safely handle solvent-based finishes, a minimum of a 60 gallon, 5 hp compressor (better 80-120 gallon and 7.5 or more hp), and an effective filter and drying system that can run several hundred for a decent system. For a home-shop builder without access to a booth, the portability of turbine systems make spraying nitro and waterbornes feasible with results that are equivalent to what pros achieve. We even have one ex-student that hauls his system to a neighbor's barn on winter days - the white, south-facing wall generates air temperatures in the low 50's on a calm, sunny 30 degree day.

_________________
For the times they are a changin'

- Bob Dylan

"Only a few guitars a year."

If you are only spraying a few guitars a year a cheap Harbor Freight jamb gun (about $15) and a small pancake compressor will work. They also have a small turbine system that works O.K., but the plastic cup doesn't allow you to keep solvent based finish in it between sessions.
The Earlex seems to get good reviews and I think some luthiers have had good luck with it.
The better (more expensive) systems generally do a better job for those needing an "off the gun - as is" finish. If you are going to be rubbing and buffing, then a less than perfect application is no big deal. With experience you can get decent results with modestly priced equipment.

I believe Brad Combs http://www.luthiersforum.com/forum/memberlist.php?mode=viewprofile&u=21855 has that system - maybe drop him a line and ask him how he finds it.
Also I know the Earlex is a 2 stage compressor (not single stage) and smaller nozzles (also in stainless for waterborne finishes) are available from Earlex. (I considered buying it before I spotted my Fuji MM3 used on Ebay)

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

I did not see any specification that suggests the OP's linked Earlex system is a two stage turbine, but I will defer to Mr. North's personal knowledge. That said, the Earlex HV5500 specs match up nicely with a single stage system - 650 watt, 42 CFM. and 2.2 psi. By comparison, Fuji two stage systems draw closer to about 1100-1400 watts, run the usual 100-110 CFM or so at the turbine output, and produce tip pressures of 4-5 psi. Either the Earlex specs are understated, or there is some turbine stage count 'magic' at work ("...pay no attention to me; look at my attractive, scantily-clad assistant!").

_________________
For the times they are a changin'

- Bob Dylan

I do have that one. I’ll defer to Woodie and Colin to fight out the specs on the turbine.

For me it was just economics. I got it for 100 bucks off.

I use it for spraying Endurovar. The 1mm tip is indeed key to a good experience. I like it but I don’t have anything to compare it to other than the harbor freight sprayer I tried and quickly chucked in the trash. I’m sure the HF would have been fine in more experienced hands.

The hose could be a little longer.


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Well, if I do go to a spray system... I’ll be stepping up from rattle cans of nitro sooooooooo pretty much all of it is an upgrade haha.
That said I don’t want something that will give me fits either


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Woodie' on seeing your post I did a quick search and found this https://muut.com/i/lostartpress/posts-that-dont-fit-anywher:soliciting-opinions-on-hvlp and another site I can't locate at the mment indicating a 2 stage turbine, but n looking again, other sites dont indicate this. (Earlex site is not functioning)
I would concur with your comments about the power and output of the 5500, it seems extremely doubtful it is 2 stages.
My apologies, and my regards to the assistant...

_________________
The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

Someone explain the importance of a 2 stage unit vs a single stage?
Does it just imply the ability to create more air pressure if desired and thus spray at a higher viscosity?
Pardon my ignorance. I’m also searching for this on google, but there isn’t a lot of info out there for this particular unit for some reason... at least not that I’m finding.



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Higher tip pressure equates to better ability to atomize finishes. Only very well thinned finishes will atomize properly at the sort of tip pressures a single stage unit will provide (~ 2 psi). Compressors of the type used in turbines are limited to about 2-2.5 psi per stage of compression, and more stages generally add less tip pressure with each additional stage, so a two stage unit will provide 4-5 psi, a three stage 6-7 psi, a four stage 8-8.5 psi, and a 5 stage unit 9.5-10 psi. At over 10 psi tip pressure, the gun is technically not an HVLP gun, so the EPA and Cal EPA regulations may be an issue in commercial use.

For most of the finishes we spray, more stages means less thinning, and fewer coats to apply to build to final desired dry finish thickness. Lacquer in particular 'hangs' on curved surfaces much better when minimally thinned, and for those spraying outside, fewer coats equates to lower risk of a mishap or issue with airborne debris, etc.

Practically speaking, two stage systems like Fuji's Semi-Pro will handle reasonable cuts of shellac, thinned lacquer, and thinned waterbased coatings. Three stage systems will handle minimally thinned lacquer, well thinned latex, and well-thinned primers with the right tip set. Four stage systems will shoot unthinned lacquer, lightly thinned latex, and moderately thinned primers. That said, the shop has separate compressor conversion guns for latex and primer - the T-75G guns are reserved for lacquer and EnduroVar.

Mr. Comb's comment on hose length reminds me that most turbines use the same end connectors, so an upgrade to a longer hose is usually just a matter of ordering a replacement Fuji or Apollo hose...the extra length can mitigate excess heat rise in summer use, which can make some guns too hot to handle. The Earlex Spray Port 6002 GUS comes with a 25' hose, so likely is available from dealers as a part to retrofit other Earlex systems.

_________________
For the times they are a changin'

- Bob Dylan

So the “semipro” will handle thinned nitro and the like. Does it have to be thinned to the point of losing the forgiveness of nitro?


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Thinning nitro is primarily an issue of additional coats - the material sprays well at 25% or even 33% thinner by volume. While an unthinned, wet coat of Mohawk instrument lacquer may go on at 6 mil wet thickness, a 25% thinner mix will apply at closer to 4 mil. After drying, an unthinned coat will end up at about 1 mil dry film thickness, while the thinned coat will be about 0.5 mil dry film thickness, so a 5 mil dry film finish (to be sanded and buffed to a 3.5-4 mil final thickness) will require 5 coats of an unthinned finish and 10 coats of a well-thinned nitrocellulose lacquer. Unthinned lacquer is fairly run-resistant on the sort of curves and vertical surfaces that builders deal with when spraying bodies and neck, but becomes progressively less so as it is thinned.

For a commercial concern, more time spraying is more labor and more material. For a hobby builder, more spraying means more opportunities for that suicidal gnat to make his or her death drive into your fresh finish, or an additional day or two of spraying when conditions are less than optimum (hot, muggy summer days and cold, damp winter days typically afford a narrow window of opportunity to get coats on an instrument).

Interesting reviews on the Fuji Semi-PRO 2 and the Earlex 6002 systems - worth a read-through prior to deciding.

_________________
For the times they are a changin'

- Bob Dylan

Thanks for your kind wishes - I have him in a thermal Speedo this season, so hope to avoid any missed performances due to the consequences of drafty stages

_________________
For the times they are a changin'

- Bob Dylan

I’m new to the site and have a similar question, as I’m thinking of a moderately-priced HVLP system for water-based materials. Thanks to all for responses and links: very helpful.


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I have been shooting the Fuji system for years. Accuspray before that. Fuji has great customer support and continues to improve their products based on feedback.

With that said, nitro lacquer is the most forgiving hard finish one can spray. You can do nitro out of the can, frankly. Among other things, 1) we prefer thinner nitro finishes, 2) it is a finish that one block wet sands and buffs. So anything will work just fine for 1-2 guitars / year. A bit of orange peel isn't going to kill you - simply solved with a wet sand block. Buy what you can afford! And seriously ... good quality nitro lacquer out of a can works.

Andy

I use a high pressure jamb gun. It sprays unthinned lacquer without any problems. Being a jamb gun it has a smaller spray pattern and less output so is easier to control and with less overspray than a full size gun. Technique can also be a factor - I don't "hang" my instruments when spraying them, I spray them "flat". I will spray the (flat)back "heavy" and the (vertical) sides normally, then after it has set, turn it over and spray the soundboard heavy and the sides again normally. I will also "double coat" - allowing the first coat to flash off and then spray another coat behind it.
You can also elevate the work piece on nails for the first few coats so you don't have to wait for the finish to fully cure between flipping and respraying.
A cheap ($15) high pressure jamb gun and a small hundred dollar pancake compressor (which has a million other uses) is far and away better than rattle cans and is a low cost option for doing sprayed finishes. If you decide later you need something better, you haven't wasted much money.
I have used HVLP conversion guns and turbines for spraying cabinets and furniture, and for large volumes of work they have some advantages over high pressure guns (ease of use is not one of them). For a cabinet shop or commercial concern the the savings in materials (transfer rate) can make them cost effective and help meet EPA regulations. For small jobs in inexperienced hands the advantages are somewhat less.

I have a Fuji Mini Mite 4 with T75G gun and 3M PPS cups. I still get orange peel. Any ideas to lessen?

One reason some HVLP systems have less overspray is because they don't atomize the material as well as a high pressure gun. Larger droplets may not flow out as quickly and if the thinner evaporates before it does you will have orange peel. You can add retarder (butyl cellosolve) or go with a different nozzle size or spray thinner coats. You could also try heating the air to warm the material being sprayed.

I have been using the Fuji mini mite 3 stage turbine and it works well. It is however extremely noisy so you should take that into consideration when choosing. I imagine this will be true of other turbine systems.

I wished I had forked out that bit more and bought the silenced one from Fuji, called I think, Q3 Gold. It is however a lot more money.

Dave

At 1-1/2 turns open on the material knob and 3/4 fan width, with an 80/20 mix of lacquer and thinner, are you getting a nice wet coat? If not, check to see whether your cup seal is bad (metal cups only)...best fix is to go to the newer 600cc nylon cup. Atomization is not an issue on any HVLP gun we run - sounds like too much air and not enough material due to low pressure to the cup. Bad seals and issues sealing are a known issue with the aluminum cup/aluminum cap T-75G, which is why Fuji went to a 1/6th turn nylon cup and offers a retrofit.

To clarify some terms, a turbine gun is set up to use high volume/low pressure (HVLP) air directly - it does not need to convert low pressure/high volume (LVHP) air to HVLP, as does an HVLP conversion gun designed for use with a compressor. In terms of how they work, a turbine gun takes the 100-110 CFM flow of warm, dry air at between about 2 and 10 psi (~2 psi per turbine stage) and delivers that pressure and some portion of that 100 or so CFM at the tip...atomization is a function of tip pressure and airflow, with the usual practice to reduce airflow to the minimum necessary to fully atomize the finish. A conversion gun takes a much smaller volume of air (10 CFM or more for a full sized compressor) at much higher pressure (90 psi is typical), and converts that to HVLP airflow via something we might recall from high school physics: Boyle's Ideal Gas Law. Once that conversion is accomplished, both a turbine HVLP gun and an HVLP conversion gun will see exactly the same tip pressure and airflow at the tip in operation, although the temperature of the turbine flow will likely be higher, both due to temperature out of the turbine and the expansion of higher pressure air in the conversion process for an HVLP conversion gun and related cooling.

A third type of gun is a conventional spray gun which uses LVHP airflow directly, with much higher tip pressures and significantly lower airflow. Jamb guns are a good example of a conventional gun that we use for metallic paints - they are inexpensive and excellent for spraying Gold Tops; because of the near impossibility of actually cleaning the bronze power out of a gun, we dedicate a jamb gun to that job.

_________________
For the times they are a changin'

- Bob Dylan

In looking at systems since I posted the OP... I discovered another Fuji system that no one has mentioned. The Hobby Pro2 .. also a 2 stage turbine.
Here are the comparative specs....


It appears it that the difference is the gravity feed vs the hanging feed

Here are the 3 in the spec list above









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