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I just got a T series gun and a m5plat but not getting that smooth of a finish. em6000.Currently have the fluid adjusting knob open 1 3/4 turns? What is the reason to adjust the hose ball valve?

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Mike McNerney

I can't say it's your problem, but I was having a similar problem because the air was too high (fully open) and the spray was "bouncing" off the surface leaving a "rough" finish on the top and back, but not on the neck and sides (I spray across the sides) which offer less resistant to the air flow.
Turning down the air (by about 1/3 - Fuji Q3 compressor) helped a lot getting a good finish off the gun.

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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.

One thing I've yet to understand with the MMs is what role does that valve on the hose play.
I think I am wasting/blowing more product than I need. I spoke with Derek at Fuji & he said that by closing it you will reduce the psi. Does anyone find they do this, if so how much?

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Mike McNerney

I close the ball valve between 1/3 and 1/2 way. You want just enough air to get good atomization but not so much that the finish bounces off the surface and into the air. If you are fogging up the booth then it is probably too much air.

Mike, like with any valve, its role is to control the flow. Closing it will restrict the flow of air.
This in turn reduces the air psi at the nozzle, as well as the air pressure in the reservoir pushing the lacquer towards the nozzle.
This will reduce waste of spraying medium resulting from overspray and "bounce-back"
You can actually lay down more product on the surface, more evenly and with less waste than if the air valve is fully open.
1/3 to 1/2 sounds about right.

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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.

This is all very helpful.But help me understand this.
For me to get a 3 mil wet coat, I have to open the flow needle 3 to 4 complete turns, which is fine if you have only a horizontal surface.
However I got a lot of rips when hanging it to dry.
I have a set up similar to the stew mac holder which holds the guitar (horizontal axis).
And I am currently spraying up & down with the fan set horizontally. fuji T series gun
I set the needle at a 1.75 turns for the sides.
And switch to a 2.5 or 3 complete turns for the top/back & let the top/back dry horizontally.
No drips & a nice thicker coat.
Today i experiment with the valve settings.

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Mike McNerney

I should report back. My relationship with the spray system has changed from "i want to smash it with a 10 pound hammer" to pure love.
I am getting nice results with these settings:

-lacquer diluted 50/50
-air valve at less than 1/2 (maybe just 1/3 open)
-fan at about 1/2
-needle open just 1.5 turns

Wet surface, zero holes or dry deposit, minimal sags (only if I overlap too much the same area). The orange peel is tiny too and if you look casually from a distance you could mistake it for a buffed instrument. I think about 8 to 10 coats are enough to deposit enough in the imperfections but also prevent sand through. It also seems, at least with this lacquer, that the drying time should be more than 1 month. On the first guitar I tried to buff after 3 weeks and didn't go very well. Waited 3 more with much better results, in the mean while there was a lot of pore sink (pumice/shellac fill). On current project I switched to epoxy.

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Build log

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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 don't own a Mini-Mite but I am trying to understand this post. Does the instructions for this spray unit indicate that one can more or less set it and forget it when it comes to pressure, flow, and needle settings? In my experience with other units I've used, be it conventional or HVLP -- the adjustments have everything to do with the viscosity of the coating and to a certain extent ambient conditions of the spray booth at the time of application. In other words the schedule is related to the product being sprayed and not the application tool.

For me knowing how to tweak the spray gun is one of the acquired skills required to get consistent results over a range of coatings.

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Ken Cierp

http://www.kennethmichaelguitars.com/

No, there is no set & forget. What you have acquired in spray skills will carry over. What hasn't been defined in this thread is what you did: there is no "Fuji MiniMite" schedule.

If you go from conventional to turbine, your learning curve will be much steeper than going from conversion HVLP to turbine. Once you get over how low of a pressure setting you need, meaning, reduce the air till its crap, then come back up from there, you'll be fine. After a few Gallons of Nitro, the gun pays for itself.
The other hill to get over is the lack of settings on the gun, or HOW you set the gun, specifically the air volume on less than a Q5 - there is no pressure setting. And heat, which determines if you buy the extension whip hose, or not. Don't take this the wrong way, the gun makes the system, IMHO.

Another "mantra": spray wet as a lake.
For me, that means a slower hand, which works for me. My measure is also how much material is over sprayed; relatively none.

Amen to that!

From what I've seem over the years, new comers cause themselves huge amounts of frustration and yes failure by misinterpreting the (sometimes misguided) requirements and process to end up with a reasonably thin finish. To that end I've seen efforts where a zillion dry thin coats are applied in hopes of "keeping the finish thin" of course this leads to all kinds of problems down the road when its time for final leveling. Its been said one way or another over the years --"its not what's sprayed on that's important, its what is left on that gets the intended results"

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Ken Cierp

http://www.kennethmichaelguitars.com/

Get the 1 mm tip. Also, buy the 3m PPS system (cup, liners, adapter). And slow it down. You are throwing too much material. My first 3-4 coats are light. Then I scuff sand level, then go heavier. Towards the end, I'm really laying it on. I do not hang my guitars anymore. Lay flat on a rotisserie style thing.

What I've learned about spraying is closer to Mr. Cierpilowski's recommendations than some of the others: thin as appropriate to the job (flash coat, repair to old lacquer, body coat on new guitar), always apply a wet coat, and be consistent on how the finish is applied. On the four stage Fuji, we COULD spray Mohawk straight from the can, but it lays down much better at about 25-30 percent lacquer thinner, and we still are putting on a 5 mil wet coat, which gives us about 0.6 mil dry (~17% solids x 0.75 x 5 mil)...a consistent wet coat lets me shoot the right number of coats to get the 5 mil dry film we want.

It took a while to get to the point where I was getting wet coats - the tendency when I was starting to spray was to go dry (lots more time sanding and slower film buildup) or to generate horrific runs (which if 'hot' could cause the earlier coats to separate). Getting the fan set, the distance correct, and the constant rate of movement needed to avoid either too thin or too thick helps a lot. A guitar shot with consistent wet coats takes less time to sand back, and can avoid intermediate sandings that seem necessary to get rid of 4-5 coats of overly dry, poorly attached material.

We pay about $40 per gallon of lacquer delivered, and I think I went through about $100 worth of material before I started seeing results that did not get a 'strip it and do it again.' If you can put a few dollars towards a 'wet mil gauge', it is money well spent, as the gauge will let you check how thick a just-applied wet coat is, which makes estimating coating thickness and number of coats required for final film thickness a lot easier.

A 1.0mm tip is our preferred for waterbased finishes and shellac, with the 1.3mm tip set for lacquer and catalyzed polyurethane.

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