Author Topic: Problem with my HVLP spraying  (Read 3869 times)

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Offline usatu

  • Posts: 121
Problem with my HVLP spraying
« on: December 24, 2016, 05:16 PM »
Merry Christmas!

I am a newbie with spraying and trying to spraying the kitchen cabinets. Today I test sprayed a few pierces of  wood and on paper with Kem Aqua Plus tinted and found the following problems.
1) I timed the viscosity of Kem aqua plus and it is over a minute but not as other suggested 30 seconds. I added a little Floetrol to it.
2) Then I used 1.5mm needle ,adjusted to a medium fan pattern and opened the air to halfway and  got a kinda splatter pattern. The pictures are attached. Is it normal?
3) When I opened the can, there are bubbles in the can even after stirred well. The finish showed some uneven surface and tiny bubbles as well.
4) I sprayed following the instruction as wet as lake, but mil is more than 4 [sad]

I am not sure where I did wrong. Before this, I tried superpaint on vinyl shutters and  it also was splattering a little but the final finish is pretty flat. Is the temperature causing it? My room is 60 degrees with fan facing to a open window. Outside is 40 degrees.

Please help me diagnose the problems. Really appreciate your advice.




« Last Edit: December 24, 2016, 05:20 PM by usatu »

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Online tjbnwi

  • Posts: 4717
  • Cedar Tucky Indiana
Re: Problem with my HVLP spraying
« Reply #1 on: December 24, 2016, 11:56 PM »
What spray system are you using? EDIT: I looked at the sanding post, found the system you're using.

Is it KA+ clear tinted or KA+ White tinted?


Flotrol should never be added to KA+. Flotrol is not a thinner, it is an extender, it is not compatible with KA+. You can use General Finish Enduro Extender, it is compatible. Other option is Butyl Cellosolve, you must mix this with water then add to KA+.

I use a 1.0 mm air cap set if I'm using the gun cup, an 0.8 mm air cap set if the gun is connected to a pot.

How did you stir the can with the lid on it? If you shook the can you need to let it settle about an hour. Don't shake the can.

"Wet as a lake" is not in the instructions. Wet film thickness is 4.0 mils, dry film build should not exceed 4.0 mils for the entire system. The term for the bubbles is "micro foaming", user error is the most common cause I have seen for this.

The temp will slow drying.

Tom

« Last Edit: December 25, 2016, 12:01 AM by tjbnwi »

Offline wptski

  • Posts: 354
Re: Problem with my HVLP spraying
« Reply #2 on: December 25, 2016, 08:14 AM »
Merry Christmas!

I am a newbie with spraying and trying to spraying the kitchen cabinets. Today I test sprayed a few pierces of  wood and on paper with Kem Aqua Plus tinted and found the following problems.
1) I timed the viscosity of Kem aqua plus and it is over a minute but not as other suggested 30 seconds. I added a little Floetrol to it.
2) Then I used 1.5mm needle ,adjusted to a medium fan pattern and opened the air to halfway and  got a kinda splatter pattern. The pictures are attached. Is it normal?
3) When I opened the can, there are bubbles in the can even after stirred well. The finish showed some uneven surface and tiny bubbles as well.
4) I sprayed following the instruction as wet as lake, but mil is more than 4 [sad]

I am not sure where I did wrong. Before this, I tried superpaint on vinyl shutters and  it also was splattering a little but the final finish is pretty flat. Is the temperature causing it? My room is 60 degrees with fan facing to a open window. Outside is 40 degrees.

Please help me diagnose the problems. Really appreciate your advice.
I think you are using a Fuji 4-stage but unsure which gun but do you mean the air flow valve at the base of the gun?  If so the air flow shouldn't be reduced till after you get a quality pattern/finish and want to try to reduce any over spray.  I think Tom stated one time that he has never used that air flow valve to reduce air pressure.  It's really not a pressure reducing valve to begin with but an air flow reducing valve.
Bill
Most Confused!

Offline usatu

  • Posts: 121
Re: Problem with my HVLP spraying
« Reply #3 on: December 25, 2016, 09:05 AM »
Thank you guys so much for helping  [thumbs up]

I used kem aqua plus white tinted and stirred with the stick. I didn't shake but lifted the can from the ground to the table. I will try again today with Fuji Q4. The gun is the one comes with it. Please give me suggestions about my plan. 1) Will fully open air valve. The overspray is a little crazy though. 2) Will try a different size of air cap and needle. I don't have 1mm, but 1.3mm, 1.5mm and 1.8mm. 3) Put the can in the hot water and raise the temperature as I feel the thing is still thick which may cause the splatter. I don't have anything on hand appropriate to thin the material now.

Microbubbling is not too much after it dried.

Btw, wet as lake is from the fuji website. :)
Hope I can improve today.
« Last Edit: December 25, 2016, 09:13 AM by usatu »

Offline wptski

  • Posts: 354
Re: Problem with my HVLP spraying
« Reply #4 on: December 25, 2016, 09:21 AM »
I have a Q4 as well with two Gxpc guns.

I had a 1.0mm needle cap set in one.  I experimented just using water and a simple motor speed to slow the Q4 down like what's done on the Q5.  One can easily see the spray droplet size increase with reduced motor speed or pressure.  I'd think if it was done to extreme, it would sputter or spit.
Bill
Most Confused!

Offline usatu

  • Posts: 121
Re: Problem with my HVLP spraying
« Reply #5 on: December 25, 2016, 09:26 AM »
I have a Q4 as well with two Gxpc guns.

I had a 1.0mm needle cap set in one.  I experimented just using water and a simple motor speed to slow the Q4 down like what's done on the Q5.  One can easily see the spray droplet size increase with reduced motor speed or pressure.  I'd think if it was done to extreme, it would sputter or spit.

I have experienced the sputter as well. Just like choked suddenly. I thought it is close to the end of the paint. Thanks for clarifying that.

Online tjbnwi

  • Posts: 4717
  • Cedar Tucky Indiana
Re: Problem with my HVLP spraying
« Reply #6 on: December 25, 2016, 09:51 AM »
You can get the piece to look wet without having the product on over 4 mills.

Your testing viscosity with a Ford 4 cup (the one that comes with the Fuji) not a Zahn 3 (I'm assuming you didn't spend a few hundred dollars on a Zahn 3). 30 seconds on a Zahn 3 is about 70 seconds on a Ford 4.

With a 1.0 mm air cap set my needle setting is about 1 turn backed off from seated (T-70 gun).

Tighten the fan pattern slightly and back off the gun a little to reduce the rebound. With the 1.5 in the gun the fluid flow would be less than 3/4 turn from seated. Once you get the delivery under control you can dampen the air flow slightly.

Try the 1.3 needle/nozzle with the 1.3 air cap, try the 1.5 air cap on the 1.3 needle/nozzle.

Tom

Offline Scott Burt

  • Posts: 1942
  • painter/writer/educator
    • Prep to Finish
Re: Problem with my HVLP spraying
« Reply #7 on: December 25, 2016, 03:16 PM »
You can get the piece to look wet without having the product on over 4 mills.

Your testing viscosity with a Ford 4 cup (the one that comes with the Fuji) not a Zahn 3 (I'm assuming you didn't spend a few hundred dollars on a Zahn 3). 30 seconds on a Zahn 3 is about 70 seconds on a Ford 4.

With a 1.0 mm air cap set my needle setting is about 1 turn backed off from seated (T-70 gun).

Tighten the fan pattern slightly and back off the gun a little to reduce the rebound. With the 1.5 in the gun the fluid flow would be less than 3/4 turn from seated. Once you get the delivery under control you can dampen the air flow slightly.

Try the 1.3 needle/nozzle with the 1.3 air cap, try the 1.5 air cap on the 1.3 needle/nozzle.

Tom

Likely the best online diagnosis I have ever seen.

Merry Christmas Tom

Offline usatu

  • Posts: 121
Re: Problem with my HVLP spraying
« Reply #8 on: December 25, 2016, 07:15 PM »
Tom and wptski,

I sprayed again based on your suggestions and think it looks better now. Please comment on the pictures. Please let me know how I can improve my techniques especially on not flat surface like moldings(last picture) and cabinet doors.  I compared the results and the 1.3mm air cap needle combination is better than 1.3mm needle with 1.5mm air cap. I opened the air valve about 85-90 pct and fan width about 4-5 inches and move the gun a little further to a 6 inches range. It definitely helped the atomization although I  can see both big and small droplets on paper.

The microbubble still exists and I found the bubbles in the KA+. I didn't move the can at all this time. I took a picture as well.

When I measure the mills, should I do it only on woods not papers?

Do I need wear google to spray it? I can definitely feel some mist to my face when the air valve opens wider and spray close to the objects.

Thanks again and happy holidays! You guys are so kind  :)




You can get the piece to look wet without having the product on over 4 mills.

Your testing viscosity with a Ford 4 cup (the one that comes with the Fuji) not a Zahn 3 (I'm assuming you didn't spend a few hundred dollars on a Zahn 3). 30 seconds on a Zahn 3 is about 70 seconds on a Ford 4.

With a 1.0 mm air cap set my needle setting is about 1 turn backed off from seated (T-70 gun).

Tighten the fan pattern slightly and back off the gun a little to reduce the rebound. With the 1.5 in the gun the fluid flow would be less than 3/4 turn from seated. Once you get the delivery under control you can dampen the air flow slightly.

Try the 1.3 needle/nozzle with the 1.3 air cap, try the 1.5 air cap on the 1.3 needle/nozzle.

Tom
« Last Edit: December 25, 2016, 09:54 PM by usatu »

Online tjbnwi

  • Posts: 4717
  • Cedar Tucky Indiana
Re: Problem with my HVLP spraying
« Reply #9 on: December 27, 2016, 08:23 PM »
Here are some photos of KA+ White, Mid Gloss tinted SW Garret Gray.

The high gloss photos are wet, 4 mills. Other 2 photos are after about an hour of dry time.

Tom

Online tjbnwi

  • Posts: 4717
  • Cedar Tucky Indiana
Re: Problem with my HVLP spraying
« Reply #10 on: December 29, 2016, 04:11 PM »
Surfacer.

Wet off the gun.256142-0

45 minute air dry. 256144-1

MDF edge not sanded. 256146-2

MDF edge sanded 256148-3

Face sanded, imperfections very visible. 256150-4

Tom

Offline usatu

  • Posts: 121
Re: Problem with my HVLP spraying
« Reply #11 on: December 29, 2016, 09:27 PM »
You made me wiping my screen so many times  [big grin] It is so hard to tell any imperfections in the last picture. Guess you are perfect. I sprayed on the maple door and mostly not too bad but there are some cracks in the thick edge and orange peel when the layer was too thin(?). Will sand and spray another coat.

Thank you and hope you have a wonderful new year!

Online tjbnwi

  • Posts: 4717
  • Cedar Tucky Indiana
Re: Problem with my HVLP spraying
« Reply #12 on: December 29, 2016, 09:38 PM »
You made me wiping my screen so many times  [big grin] It is so hard to tell any imperfections in the last picture. Guess you are perfect. I sprayed on the maple door and mostly not too bad but there are some cracks in the thick edge and orange peel when the layer was too thin(?). Will sand and spray another coat.

Thank you and hope you have a wonderful new year!

The goal is to be even and consistent. Takes gun time to get good at spraying.

Learn to listen to what the gun is telling you.

Tom

Offline usatu

  • Posts: 121
Re: Problem with my HVLP spraying
« Reply #13 on: December 31, 2016, 08:54 PM »
Hi- Wish you all have a wonderful 2017!

I got a few "technique questions" after sprayed the first layer of surfacer. There are some shadows (or missed parts) especially on the profiles. How do I avoid that wisely? I tried to spray those missed areas but material is too much for those crannies and paint started to run. I wiped the extra paint and sprayed another layer. Helped a little but the result is not as smooth as the rest.

Can I use bondo to fill the small gaps on the door?

I wish to know better how to handle them when I start to spray kem aqua plus. Couldn't find the right solution on internet. Please advise if you know. Do I spray the edges of doors and profiles inside doors and finally spray the whole door and also in different angles? Will that be too much for some areas?

Another problem I encountered is in the middle of spraying one door, the spray gun starts to sputter because of low volume of paint. Do you stop the job and fill up or try to move the can to make it work?

I have so many questions but can't figure out the answers. Please chime in as you can. Thank you all especially Tom. I learned so much from you.

Online tjbnwi

  • Posts: 4717
  • Cedar Tucky Indiana
Re: Problem with my HVLP spraying
« Reply #14 on: December 31, 2016, 09:09 PM »
Hi- Wish you all have a wonderful 2017!

I got a few "technique questions" after sprayed the first layer of surfacer. There are some shadows (or missed parts) especially on the profiles. How do I avoid that wisely? I tried to spray those missed areas but material is too much for those crannies and paint started to run. I wiped the extra paint and sprayed another layer. Helped a little but the result is not as smooth as the rest.

Can I use bondo to fill the small gaps on the door?

I wish to know better how to handle them when I start to spray kem aqua plus. Couldn't find the right solution on internet. Please advise if you know. Do I spray the edges of doors and profiles inside doors and finally spray the whole door and also in different angles? Will that be too much for some areas?

Another problem I encountered is in the middle of spraying one door, the spray gun starts to sputter because of low volume of paint. Do you stop the job and fill up or try to move the can to make it work?

I have so many questions but can't figure out the answers. Please chime in as you can. Thank you all especially Tom. I learned so much from you.

Hope you have a good 2017 also.

For the profiles tighten the fan and reduce the material output. At this time spray the edges with the same setting. The Syslight shines (no pun intended) for lighting the edge while you spray. Comfortable to hold in one had while you spray with the other. Eventually you'll figure out how to spray edges by manipulating gun angle. To much is under your control.

If your spraying over "cheep" MDF it may not be smooth to begin with.

Bondo or automotive glazing.

I don't recall which gun you have. The advantage to the PPS system on the gun is you can flip it over and turn a bottom feed into a gravity feed when you have to get that last little bit out of the cup. With the surfacer stopping, filling the cup and restarting is not an issue. Monitor cup volume so this does not happen with the top coat.

There is no substitute for gun time.

Tom

Offline usatu

  • Posts: 121
Re: Problem with my HVLP spraying
« Reply #15 on: December 31, 2016, 09:41 PM »
Lightening reply, thank you! Please see the pictures below. It is little hard to tell from pictures, but one side is raised panel one side is mitered joint, I always missed some parts. Should I hold my gun straight all the time?
I have a siphon one which I kinda of regretted.
« Last Edit: December 31, 2016, 09:45 PM by usatu »

Offline usatu

  • Posts: 121
Re: Problem with my HVLP spraying
« Reply #16 on: January 01, 2017, 07:38 PM »
Anyone has tried not to use the siphon filters with the spray gun? Will that damage or decrease the life of gun? BTW, I have a Fuji Q4 hvlp.

Offline wptski

  • Posts: 354
Re: Problem with my HVLP spraying
« Reply #17 on: January 01, 2017, 08:14 PM »
Anyone has tried not to use the siphon filters with the spray gun? Will that damage or decrease the life of gun? BTW, I have a Fuji Q4 hvlp.
Gravity and side mounts don't even have a filter, it's an added protection to keep the gun from plugging up.  You should strain everything first anyway.
Bill
Most Confused!

Online tjbnwi

  • Posts: 4717
  • Cedar Tucky Indiana
Re: Problem with my HVLP spraying
« Reply #18 on: January 01, 2017, 09:30 PM »
You really don't have  siphon gun, you have a bottom feed gun. The Fuji guns are positive pressure fed, not siphon fed (used this term to make life simple).

You don't need the filter.

You do not have to keep the gun "straight" in your situation try to keep the gun parallel to the surface being shot. Tighten the fan, decrease material feed, spray the details, spray the balance of the door.

Move to the PPS system, they have filters in the lids.

Tom

Offline Tim Raleigh

  • Posts: 3398
    • Oakville Cabinetry
Re: Problem with my HVLP spraying
« Reply #19 on: January 02, 2017, 03:17 PM »
Face sanded, imperfections very visible.

Can't see any imperfections

Offline usatu

  • Posts: 121
Re: Problem with my HVLP spraying
« Reply #20 on: January 02, 2017, 08:43 PM »
Brilliant advice always! Thank you
You really don't have  siphon gun, you have a bottom feed gun. The Fuji guns are positive pressure fed, not siphon fed (used this term to make life simple).

You don't need the filter.

You do not have to keep the gun "straight" in your situation try to keep the gun parallel to the surface being shot. Tighten the fan, decrease material feed, spray the details, spray the balance of the door.

Move to the PPS system, they have filters in the lids.

Tom