Help!! with spraying water base lacquer

[Ralph]

Help,
I am in the process of finishing my first guitar. This is a one piece ash body from Warmoth. It seemed to me that things were progressing well until I started getting some orange peel.
I sanded the orange peel out and moved on - had a few other problems but was making progress and the guitar was looking ok for a first time.

Then I got the spots in the attached photos! What a mess. The dots seem to be present in test sprays on scrap wood also so not something on the guitar??

Here is a list of my steps and materials used:

• One piece ash body from Warmoth
• Sanded with 220 and 320 Frecut gold
• Sprayed 2 coats of Target EM 1000 reduced 50% with distilled water***
• Pore filled with Colortone water based Ash filler
• Sealed with 2 more coats of EM 1000
• Light sanding with Frecut gold 320p
• 2 coats of EM 1000 thinned about 15% with distilled water tinted with Colortone Vintage Amber
• 1 coat of the above with 6 drops of Colortone medium brown added
• Got some orange peel - sanded and recoated with above vintage amber / medium brown
• Sprayed a coat of EM1000 with color tone medium brown and got the dots.

Spray rig Fuji Q5 Platinum with 0.08 air cap, needle and nozzle. Temperature 70ºF, humidity 45%

Any thoughts about what to do to fix this??

 

[Spud]

If the dots are on the test piece too I wonder if contaminants have infiltrated your spray gun? Or product itself?

Guessing as I have not those products personally.

 

[Ralph]

If the dots are on the test piece too I wonder if contaminants have infiltrated your spray gun? Or product itself?

Guessing as I have not those products personally.

Thanks for the reply. My next step will be to do a though cleaning of the gun and mix a batch of brown using all new mixing cups…….

 

[Spud]

Thanks for the reply. My next step will be to do a though cleaning of the gun and mix a batch of brown using all new mixing cups…….

Other thought is if something in the spray area got on the surfaces and contaminated them? Airborne crud? I have experience spraying cabinets, but only rattlecanned guitars. FYI

 

[Ralph]

Thanks Spud. I was using a room humidifier for about 24 hours before the “spot coat” because the heater in the shop was running. the humidifier was filled with distilled water. If I can not find any other cause I may try to see if this could cause the spots.

 

[Hendrix]

Contamination most likely from lubrication or accumulated sewage from the air pump .
we always put Air Preparation Filters on the output of compressor , on industrial automation and robotics system we design & build .


https://www.smcworld.com/webcatalog/en-jp/air-preparation-equipment/air-preparation-filters/

 

[Ralph]

Contamination most likely from lubrication or accumulated sewage from the air pump .
we always put Air Preparation Filters on the output of compressor , on industrial automation and robotics system we design & build .


https://www.smcworld.com/webcatalog/en-jp/air-preparation-equipment/air-preparation-filters/

Good thought, but I don't think this is a consideration with a turbine system. I am thinking maybe I got some water in the air passages in the gun while cleaning?

 

[Spud]

HVLP systems are not affected by separate air compressor problems.

 

[Hendrix]

If "some water in the air passages in the gun " , you will see problems in the early stages and stop . what you photo show likely the problem come in later stage , It takes time for the air pressure to build up to pull water droplets or grease in the hose or compressor over a distance to the spray gun.

Any way , Thorough cleaning and drying of the gun takes some work

Why Compressed Air Forms Water Droplets

 

[Spud]

If you are using a conventional system to spray guitars in home shop you are doing it wrong. IMO

 

[Ralph]

If "some water in the air passages in the gun " , you will see problems in the early stages and stop . what you photo show likely the problem come in later stage , It takes time for the air pressure to build up to pull water droplets or grease in the hose or compressor over a distance to the spray gun.

Any way , Thorough cleaning and drying of the gun takes some work

Why Compressed Air Forms Water Droplets

Thanks for the info, but it's my understanding that Turbine HVLP systems do not have these problems - no air storage tank or oil to get in the line...

 

[DuckBaloo]

My experience spraying water-based lacquer is nil, mostly because the pros and semi-pros, that have tried it, all share the same advice with me...don't use it. The common complaints are the finish often dries too soft; the layers don't melt into each other (like solvent-based nitro), so it leaves witness lines; and it doesn't seem to hold an emulsion as well, so the solids tend to clump together.

The pics look like what happens when water droplets hit a oil/solvent based paint and "push" it aside. Which wouldn't make sense with the materials you are using.

One question, why are you continuing with the high solid EM1000 sanding sealer and not moving to the EM6000 lacquer for your tint and clear coats?

 

[Ralph]

My experience spraying water-based lacquer is nil, mostly because the pros and semi-pros, that have tried it, all share the same advice with me...don't use it. The common complaints are the finish often dries too soft; the layers don't melt into each other (like solvent-based nitro), so it leaves witness lines; and it doesn't seem to hold an emulsion as well, so the solids tend to clump together.

The pics look like what happens when water droplets hit a oil/solvent based paint and "push" it aside. Which wouldn't make sense with the materials you are using.

One question, why are you continuing with the high solid EM1000 sanding sealer and not moving to the EM6000 lacquer for your tint and clear coats?

Thanks for the comments.
Here is what I found on the Target site:

Target coatings recommends using EM1000 for tinting and shading. I plan to use EM6000 over it for the clear coats. Here is some info on EM1000 from the Target Coatings site:
"

Ultra-Low VOC Universal Sanding Sealer & Color Vehicle​

The philosophy behind EM1000 Universal Sanding Sealer is to offer a truly clear, ultra-low VOC water based wood coating that allows the true substrate color to reveal itself while remaining multi-functional as a universal intermediate base coat. EM1000 water based sanding sealer is engineered to function as: a clear, universal sanding sealer, a pre-stain wood conditioner and a color delivery vehicle, i.e. special effects spray stain, shading/toning vehicle or used as a translucent stain when tinted with universal pigments or dyes.

EM1000 Universal Sanding Sealer is “water white/clear” in the can. This clarity benefits the finisher in two ways. It allows the natural wood color and image to react in a way that is very similar to solvent-based sealers, and it aids the finishers “color eye” when using the EM1000 for shading/toning and performing color matching duties as a mid-level coating in a multi stage wood finishing process. Whereas a traditional acrylic emulsion such as EM6000 Production Lacquer dries clear on wood, it can be difficult to add colors for shading and toning and to determine the true color value/strength when working in its liquid format. When using EM1000 water based sanding sealer, it is easier for the finisher to visualize the direction the color strength and value is proceeding in before taking the sealer directly to the wood substrate for further evaluation. Granted, all color matches must be performed and evaluated on the final substrate of choice, but having a color vehicle that gives the finisher a clearer visual reference point “in the beaker” makes the job that much easier and faster.

EM1000 can be tinted with ANY water-soluble dye. Also, custom pigment toning/shading colors can be made when the EM1000 is tinted with water-based UTC colorants."

And on the EM6000:
"

100% Burn-In Technology in a Water Based Formula​

EM6000 Production Lacquer (EPLv8.0) is an ultra clear, water based acrylic lacquer that utilizes advanced polymer resins and HAPS-Free solvent technologies to provide a unique, self-leveling wood finish designed for commercial and industrial applications. EM6000 water based acrylic lacquer is formulated for use in furniture, cabinet, interior architectural and custom woodworking applications, and provides a fast drying lacquer system with exceptional clarity, outstanding adhesion qualities and a nitrocellulose-type appearance and performance all in an Ultra-Low VOC (ULVOC), 100% water-based system.

Solvent Look and Feel​

EM6000 Production Lacquer features a unique adhesion characteristic that allows it to bond to a wide variety of properly prepared substrates such as synthetic wood panels, carbon-fibre, PVC, ferrous and non-ferrous metals. This feature gives great latitude of use for the finishing professional when working with EM6000 Production Lacquer.

When used as a self-sealing system EM6000 Production Lacquer offers fast drying and sanding features identical to those of traditional nitro-cellulose lacquers and CAB acrylic systems. EPL generates excellent clarity and color definition when used with other sealers or as a stand-alone production finish. EM6000 water based acrylic lacquer is non-flammable, low in odor and cleans-up with water.

EM6000 Production Lacquer can be fortified with our CL100 Cross-Linker to create a post-catalyzed type lacquer. The addition of 3 to 5% by liquid volume of CL100 will improve the physical durability of EM6000 by tightening the molecular structure of the cured resin. CL100 improves the resistance of the cured film against high pH cleaners, alcohols and slow evaporating household chemicals. See the TDS for CL100 Cross-Linker for more information.
"


I am new to water based stuff but just don't want fool with solvent based finishes.

 

[Spud]

As long as it sands without gumming up it outta be fine. IMO

 

[DuckBaloo]

I am new to water based stuff but just don't want fool with solvent based finishes.

You don't like spontaneous combustion in your garage?

Like I said, no real experience with water-based products, but it sure looks like the gun may be "spitting".

The only way to fix it will probably be to sand all the way back and start again. Been there, done that, tried to fix one run and it snowballed into me just sanding back the entire back.

But it fixed up fine...

 

[raystankewitz]

That really looks like "Fish Eyes" in the finish. That means you're pulling water from the surrounding air if you're using a turbine HVLP system. That moisture condenses in the hose, then it goes through the gun, spitting water that may well be contaminated by oils, etc. in the equipment.
I would go back to bare wood, then have the manufacturer validate your equipment choice, if they will and maybe what fish eye preventer you might use.
As an aside, I'm familiar with the Crystalac Brite Tone line and the Flipping Awesome colors. Water based poly(?) and I had no issues with it once I had a decent Paasche HVLP gun to shoot it with. I did, however talk to Dorinda (the owner) at length about the application processes. Some things mentioned were shoot on low humidity days and use a quality water trap or two, one after the other.