Spray Finish Training

[phmade]

I've been spray finishing for a few years and I feel like I should have more confidence - but I don't.  I've never had any real training besides what I've read on here and anywhere else I can find information. 

I started spraying with a gravity feed gun and I was able to achieve some nice results but it was slow and fatiguing.  I upgraded last year to a CA Technologies AAA rig and it certainly helped with speed.  I love not having to re-fill the cup and spray without thinning.  And I've been able to achieve really nice results but I feel like I'm not using the right process. 

That being said, I've had a lot of issues with the AAA rig and I'm not sure if another sprayer would be better or if I just need training - or maybe my expectations are unreasonable.  I'm not really sure if I ever have the sprayer set correctly - the only scientific test I know is by testing wet mil thickness.  There always seems to be a big "wink" when the pump strokes and that's been frustrating.  Do other brands have this same problem?

Another problem I always seem to have is the cleaning procedure.  I'm spraying Target coatings waterborne products and I'm thrilled with their performance but cleanup is always difficult.  Target recommends using warm soapy water to clean but CA Technologies recommends using a waterborne gun cleaner from ML campbell.  I've tried water followed by Acetone and I still seem to get buildup in the hose (although the filter does catch it). 

I think by biggest problem is simply a lack of confidence and training.  I'd happily pay for a spray finishing workshop if one exists.  The sales and product reps have been a little disappointing; they just don't seem to have practical experience outside of demos...
I'd appreciate any advice anyone could offer.

 

[tjbnwi]

PM Scott B.

All of the positive displacement piston pumps wink between cycles.

Cleaning water bournes is an issue. I find that spray carburetor cleaner works best.

I spray with an HVLP system (Fuji). For large jobs I use a pressure pot.

I have modified my hose/gun so the cup gets full turbine pressure.

Tom

 

[KRKWW]

I understand your frustrations! All the literature and advertisements make it seem like you plug it in, aim and shoot. And whala! You have a perfect finish. My experience tells a similar story to yours.

I shoot water borne finish exclusively and have done so with an airless rig, a compressed air gravity feed gun and an HVLP/turbine set up. At $100/gal for the finish I use, I could not justify the extreme overspray with the airless assist rig. I switched out tips to try and find the right one and dial down the pressure but it still came out like from a fire hose.

The compressed air gravity feed was way too slow and my compressor setup took too much time to recover and the settings were quite finicky.

After much research I settled on an HVLP/turbine setup from American Turbine out of St. Paul, MN. I also use the 3M disposable cups. I really like this setup though it took time to get used to also.

I achieved excellent results with each of these rigs but they all had a high learning curve. Tip/needle sizing is very important with water born product. I had to go smaller than mfg. recommendations to get it to perform where I was comfortable.

Soap and water clean up only works if there is no dried buildup inside your equipment. For my HVLP setup, I use that solution for two or three spraying sessions then I disassemble the gun entirely and soak parts in lacquer thinner. I clean all parts well on the spot and use a little compressed air to ensure parts are dry and debris free. This has worked well. When I notice poor finish quality, I can usually attribute it to buildup inside the gun.

Application technique is also very important. There are plenty of examples you can google. But I learned through much trial and error that I had to slow down and really keep my tip at a consistent height above the piece.

Good tools do help us get better results, but I've learned that they are not always plug & play and do take time and patience to learn how to use.

Perhaps you have some specific examples of the challenges you are experiencing. We'll help if we can.

 

[chrisrosenb]

When I started spray finishing over 20 years ago, my brother ran the finishing department for an appliance manufacturing company.
I ask him to teach me how to spray finish. He asked me if I could paint with a spray can of paint. I said yes. He told me that there was nothing more he could teach me. He also told me that matching spray equipment & material to the job, is the biggest challenge & that has to be figured out as you go.   

 

[tiralie]

That being said, I've had a lot of issues with the AAA rig and I'm not sure if another sprayer would be better or if I just need training - or maybe my expectations are unreasonable.  I'm not really sure if I ever have the sprayer set correctly - the only scientific test I know is by testing wet mil thickness.  There always seems to be a big "wink" when the pump strokes and that's been frustrating.  Do other brands have this same problem?

If you haven't already check out the Woodweb finishing forum. You will see that many others have problems with all the sprayers. Some more than others. If you are having a specific problem you can post your question there as well.

Another problem I always seem to have is the cleaning procedure.  I'm spraying Target coatings waterborne products and I'm thrilled with their performance but cleanup is always difficult.  Target recommends using warm soapy water to clean but CA Technologies recommends using a waterborne gun cleaner from ML campbell. 

I use Franmar brush and gun cleaner on all my spray equipment. I also use Target products, and it removes dried coatings from my gun as well as everything else I manage to get spray on.
I have and have used the ML Campbell waterborne gun cleaner, and it's ok but doesn't seem as effective as the Franmar product.
You can order the Franmar product from Lee Valley in quarts only if you want to try it out but it's way cheaper to order directly from Franmar. I get a couple gallons sent to me at a time. Franmar is really great to work with, particularly shipping into Canada.
I also use nylon cleaning brushes from Lee Valley.
Of course a good spray gun cleaner kit is also very handy.

I think by biggest problem is simply a lack of confidence and training.  I'd happily pay for a spray finishing workshop if one exists.

PM Scott B.

Agreed.

Here in Canada Mcfaddens Spray school is an excellent way to learn and they also sell and support CA Technologies equipment. The paint specialist at McFaddens is very familiar with the equipment. You might call CA and ask who else is giving similar courses in your area.
If you can't find a course enroll in the one here. With the American dollar at 1.40+ Cdn. it'll be cheap. It's nice in the summer, cold now.
Tim

 

[tjbnwi]

Thanks for the heads up on the cleaner Tim. I'll have to give it a try. (I tried the @ thing, your name did not come up.)

[member=9364]phmade[/member], I going to be spraying various items and products next week. Some KA+, both clear and pigmented, Wall and Wood primer and Pro Classic Alkyd. You're welcome to stop by, I'm in Cedar Lake, IN. just east of Chicago.

Tom

 

[junk731]

PH I recently got the CA Tech new H20 rig and find that there is a bit of a learning curve after using their Gravity guns for the last 8 years. Have you call and talked to them about any of your issues? I talked to them at length at AWFS this year and got a lot of very useful info and was told to call if I had any concerns or issues. They also told me that a good flushing with warm water was enough for the H20 rig because of it design specifically for waterbournes.. Another tip was to have a separate fluid feed line for clear and pigmented finishes. What issues are you having?

John

 

[phmade]

Wow - the FOG never disappoints! 

Tom- Thanks for the tip on carburetor cleaner - I'll give that a try on some stubborn parts.
I'll also take your advice to PM Scott B.  I've read an awful lot of his articles / threads. 

Krkww - yes I fully agree that good tools help but you have to understand them.  Without previous finishing experience - I can admit that I don't fully grasp the concepts.  But then again, I usually make things more difficult than they are.

Tim Raliegh - I'll definitely check on the spray school -  thanks.  I've been on woodweb many times and there are some good guys on there but I always prefer the FOG first.  I'll also check out the Franmar brush cleaner.

 

[phmade]

So now for the specific problems I'm having with the spray rig.  First off, it's the CA Technologies H20 - just like yours kcufstoidi. 

#1 - General setup procedure: the CA Tech video recommends starting with Fluid Pressure only and gradually increasing pressure until the tails disappear.  Then he adds air to better atomize it.  When I crank up my fluid pressure to get rid of the tails, I'm spraying a lot of material - I feel like too much.  It's very difficult to lay down a 2 mil wet coat.  Then, I'm not really sure how much air to add - I think I'm using too much because I'm definitely getting bounceback. 

#2 - The cleaning procedure: CA Tech made it sound like I never really had to disassemble anything other than the air cap to clean it.  They just recommended flushing the lines with water or gun cleaner and dropping the air cap into a jar of solvent.  Currently, I disassemble the air cap (o ring, insert, and the TINY cylinder that fits inside the tip).  I've been brushing these off with water and then storing them in xylene or laquer thinner or acetone.  As far as the pump goes, I just flush it with warm water and then leave waterborne cleaner in the lines until the next use.
Should I take off the air cap between coats and put it in solvent?  I usually only wait 45 minutes between coats.  How long can I leave finish in the lines?  A full day? Overnight?  I currently never leave it without use for more than 8 hours.

#3 - Vapor Lock issue: I'm having great difficulty after I flush the system and the siphon hose is empty, it won't suction any finish up the siphon tube.  I have to remove the siphon tube and put a bucket directly under the pump to "prime" it.  It's happened several times and I don't think it's normal.  CA Technologies said it was rare but it does happen... Anyone else having this problem?

#4 - Spraying waterborne and solvent finishes: Can I mix and match after thoroughly cleaning?  I liked the idea about having one dedicated hose for clears, and one for pigments... Do I need to do the same for waterborne and solvent? 

I know these are a lot of questions - thanks for all of your time! 

 

[tjbnwi]

I don't have a C.A.T. pump so take all of this with a grain of salt.

#1--I believe the fluid pressure is causing the rebound. Fluid pressure is straight towards the piece, air to the air cap is a side flow.

#2--I end up disassembling my guns every 25-30 gallons. These water bourne products build on everything.

#3-- I've heard of it and recall reading the solution, I'll try to find it.

#4--I use my equipment for all the products. Seeing as your pump is designed for waters, not sure if the solvents will hurt it. I do my best to avoid solvents and conversions.

Tom

 

[junk731]

PH, the typical pressure settings for spraying Target Coatings that I use are 20 lbs. fluid pressure and 20 psi air with the trigger pulled. These are the settings recommended right from C.A.T. and give a spray similar to their gravity gun. The right orifice size is also critical it will influence everything. If you want that size I'll post it later today. I leave the lines charged all day when I'm spraying with occasional orifice cleaning and brushing off the tip with a tootbrush with ethanol or lacquer thinner. The most problem I've had is when the orfice gets plugged but the tip cleaners from C.A.T make short work of that. When cleaning I do a complete flush with warm water usually about 3/4 gallon and leave the suction submerged in water until next use. I have not yet had a charging problem. Make sure the lube dam is full. I really enjoy using the system on larger jobs but still use my gravity gun for small jobs.

John

 

[phmade]

Thanks again guys.  I'm going to be spraying more this weekend so I'll try some different pressure settings.

John, could you let me know what tip you're using? I'm using a 411. Just making sure we're comparing apples to apples.  Also are you flushing with 3-4 gallons or 0.75 gallons?

Tom, wow- how much do you spray? 25-30 gallons is a lot! I'm not sure I Spray that in a year. I typically Spray 1.5-2 gallons in a batch. And I only do that every couple of weeks.

 

[phmade]

John, I forgot- what Target products are you spraying? We're spraying mainly superclear 9000.

 

[junk731]

The nozzle size is the same. I spray EM2000, EM6000 and EM9300. all with the same nozzle. I clean with .75 of a gallon of warm water and I should have added I leave the line charged with water as this was recommended.

John

 

[tjbnwi]

Tom, wow- how much do you spray? 25-30 gallons is a lot! I'm not sure I Spray that in a year. I typically Spray 1.5-2 gallons in a batch. And I only do that every couple of weeks.

I have posted a video of doors I was spraying. 480 doors, 16,000 square feet of surface, 1 coat of stain, 2 coats finish.

Over this and next weekend I'll go through about 10 gallons of primer, paint, surfacer and finish.

In May we should start the prep for a July install. Between the trim, cabinets, cabinet doors, and decorative panels about 10,000 square feet of surface to be finished, 2 coats surfacer, 2 top coats of finish.

Tom

 

[tjbnwi]

Phil,

I just read the instructions for the CAT system. In post 7 #1 you state you that you increase fluid pressure until the tails disappear, per the instructions you set the pressure to just see a fan at the tip, then use atomizing air to get rid of the tails (I did see you can use pump pressure, that's not their first recommendation).

Give that a try and see if your happier with the results?

Tom

 

[Scott B.]

Hey All

Sorry I missed this.

I haven't been on the fog so much lately. We are preparing to travel Prep to Finish to Orlando, New Orleans and Providence in the next 8 weeks, so lots of preparations and planning being finalized.

We have added a newsletter for folks who want to be aware of training clinic announcements and speaking events.

Here is a link to subscribe..

Hope everyone is having a great new year so far.

 

[griph0n]

Sorry, what tip size in mm are you using for the target finishes?

 

[tiralie]

Sorry, what tip size in mm are you using for the target finishes?

What system- HVLP turbine, HVLP compressor, AAA etc. and which Target product?

 

[junk731]

Sorry, what tip size in mm are you using for the target finishes?

In my CAT gravity guns I use a 1.3mm or 1.5mm depending on viscosity and /or weather/time of year. I try to keep my shop at 65 degrees in the cooler months with a 45% humidity.