Failed HVLP attempt, Advice?

[3PedalMINI]

Im spraying a cabinet using my Fuji MM4 and T75g gun. Using Emtech HSF5000 Primer. Tried with 1.3 and 1.8 and had a horrible time. It was confirmed a few times from the supplier and reading online that I did not need to thin the primer. I got a very blotchy spray (spitting isnt the right word, but kind of similar) I could not get it to lay nicely. Now the cabinet is "bumpy" Not a HUGE deal because obviously I have to sand anyway but the finish overall is terrible. My garage was 67 degrees and 50% humidity. Im thinking this did infact need to be thinned?

to say im a noob at spraying HVLP is an understatement. Im now really nervous about shooting the Emtech 6500 with HVLP. Thinking to finish this cabinet I should shoot it with my airless sprayer and practice getting the gun/paint viscocity correct on some scraps after its out of the shop.

I stupidly went forward with spraying hoping things would get better. Not a huge deal since it was primer, but now I have more sanding todo.

 

[Mike Goetzke]

I’m not an expert either but I’ve always needed to thin Target coatings finishes with my Q4. I’ve also had better luck with more airflow and smaller tip. I suggest practicing on a scrap board.

Mike

 

[3PedalMINI]

I’m not an expert either but I’ve always needed to thin Target coatings finishes with my Q4. I’ve also had better luck with more airflow and smaller tip. I suggest practicing on a scrap board.

Mike

Interesting. I guess I should have not taken the paint stores word and what I found online about thinning. Would you say what I experienced was due to not thinning? I’m trying to find a picture that best shows it. Maybe when I try again I’ll take a picture.

I did have some scrap plywood pieces to try first. I should have just quit and asked on here. It’s a project that is long overdue and im excited to finally be done with it.

 

[tjbnwi]

Put the gallon can in a pot of 100° water. Allow gallon to warm. Fill the cup, place the can back in the water, spray, repeat.

Tom

 

[Pnw painter]

I’ve found that things only tend to get worse and not better when I’m spraying.

Tom’s advice about worming up the paint might make a huge difference. The viscosity of some paints at can really be effected by cold temps.

On a recent project I’d leave a gallon of paint sitting on a heating pad over night to ensure it was ready to spray the following morning.

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[blaszcsj]

Check it with the viscosity cup that came with the gun and review the times against what it says in the manual. For doing thicker paints, the book also recommends removing the black ball valve for the incoming air at the bottom of the gun. It allows for no restriction and highest flow.

hope this helps. The manual recommendations actually work pretty good.

 

[mschmidt10k]

With a Fuji MM4, there's no need to thin the Emtech HSF5000 at all - I spray it with a 1.3 cap and it lays down easily. Did you try it out on a practice board beforehand so you could set the spray pattern/air flow?

 

[sheperd80]

Ive been spraying with my mm4 alot lately and found that all the factors you hear about do matter quite a bit. Material temp, air temp, tip size, viscosity, and how much you put on in one coat. When spraying onto a piece of scrap you wanna see a very fine mist around the edges of your spray pattern. If there are even small spots, somethings wrong. Viscosity will vary in different climates but timing your material in the provided cup will get you to the right tip size. For finer finishes i never want to use higher than the 1.5 tip, even with latex. Preferably 1.3 or even 1.0 depending on the material.

I recommend thinning to a viscosity that works with a finer tip. Once your spray pattern starts to look good (small mist, not splats) dry time is the next obstacle. Not familiar with wb lacquer but with pigmented precat i always add retarder to give the material time to flow out in my warm climate. If the material is dry by the time you sent the piece of side on a drying rack, that's obviously driving way too fast. It should look wet for at least a few minutes

And finally, make sure youre putting enough material down. This is a hard thing to judge and harder to describe. One way to guage this is to spray a vertical scrap piece until it just starts to run. Then do another slightly less until it looks like it could almost run, paying attention to how fast your passing over the piece. This is roughly the right amount for most paints. Then of course spray your parts horizontally whenever possible, aiming for that wet coat that would almost run if it were vertical.

Not an expert, but ive been hard at it lately and getting decent results. Hope this helps.

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[sheperd80]

My current project. This is only the 2nd coat. Obviously still has some defects and wood grain showing but the third coat should look pretty good.

Rudd duracoat precat, 4% retarder.

This is shown from a harsh angle, under harsh light. From Straight Ahead this looks nearly perfect
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[sancho57]

I do what Tom suggested on colder day using my W/B finish. So if yer having a issue with the finish not flowing, I would try warming it. If its to warm out side then you may want to try a retarder to slow the drying of the material. When I spray thicker material like Behr outdoor seal stain sealer I use a much larger air cap, nozzle ad needle. (apollo) It would be a C air cap for thick material and a 2.0 ( could be larger havent used it for a while and Im still chilling in the quiet of the morning ) nozzle and needle.

So my suggestion is to the customer service of the gun yer using and ask them what N/N they recommend for tht material. You may not need another one but it doesnt hurt to check . At least thats what I would do

 

[krudawg]

Im spraying a cabinet using my Fuji MM4 and T75g gun. Using Emtech HSF5000 Primer. Tried with 1.3 and 1.8 and had a horrible time. It was confirmed a few times from the supplier and reading online that I did not need to thin the primer. I got a very blotchy spray (spitting isnt the right word, but kind of similar) I could not get it to lay nicely. Now the cabinet is "bumpy" Not a HUGE deal because obviously I have to sand anyway but the finish overall is terrible. My garage was 67 degrees and 50% humidity. Im thinking this did infact need to be thinned?

to say im a noob at spraying HVLP is an understatement. Im now really nervous about shooting the Emtech 6500 with HVLP. Thinking to finish this cabinet I should shoot it with my airless sprayer and practice getting the gun/paint viscocity correct on some scraps after its out of the shop.

I stupidly went forward with spraying hoping things would get better. Not a huge deal since it was primer, but now I have more sanding todo.

I have the exact same system you have.  Before I sprayed my first thing I watch about 20 YouTube videos on paint thinning.  A good resource on YouTube was Charles Neil.  I thinned the Sherwin Williams acrylic Latex a lot thinner than I thought I should.  I used the #4 Ford cup and kept timing until it ran out at 55 seconds.  The consensus was 40 seconds.  I used a 1.5 Aircap and started at about 2 turns on the fluid control (I'm using the 3M pps 1.0) and adjusted on a cardboard box until the spray looked "right" to me.  Then I sprayed the plywood and it blew me away how well it turned out.  I lightly sanded between the coats and then put 3 coats of General Finishes HIGH PERFORMANCE over the Latex.  It looked like a pro did it and it was only my 3rd time spraying.  Watch those  videos  and go out and shoot it.

 

[todd_fuller]

I don't know about this specific gun, but check if you've assembled it correctly. I have an Apollo 7500 and if you make a mistake reassembling it, the spray is terrible.

 

[Mike Goetzke]

[member=17435]3PedalMINI[/member]  Hopefully you figured things out but was thinking back when I had an issue with the output of my Fuji pressure assisted gravity fed gun surging it ended up being the pressure feed line. Make sure the check valve is working and you have no air leaks.

[member=4105]tjbnwi[/member]  For pre-heating finish was just thinking those Sous Vide food heaters are reasonable enough to use for this (use a water tub and place the paint can in it).

 

[Michael Kellough]

I’ve heated stuff up to 95*f with the can sitting in a bucket in the slop sink running hot water and stirring continuously while checking with an infrared meter.

 

[gunnyr]

Hah!  I've struggled with HVPL also.  I have a Fuji MM4, after trying to thin based on percentages I finally learned to use a Ford cup to thin to the proper viscosity.  I can now say I can spray SW Emerald with some level of success.  Without reviewing my notes I would give inaccurate data.  I visited with the Fuji folks at IWF in Atlanta and they validated my use of the Ford cup. 

I'm sure you've figured it out by now, but I wanted you to know that you're not alone in your journey! [big grin]

 

[butzla]

I've had my share of troubles spraying paint but never primer.  I've always used BIN shellac based primer straight out of the can, no thinning.  I've never warmed it but I've never sprayed below 65 degrees F.  Goes on like water, sands easily and smoothly by hand and every latex based paint I've top coated with sticks like glue.