LumberJocks

desperately need help with cheapy HVLP

  • Advertise with us

« back to Finishing forum

Forum topic by sarahss posted 10-20-2012 10:43 PM 1118 views 0 times favorited 7 replies Add to Favorites Watch
View sarahss's profile

sarahss

254 posts in 1369 days


10-20-2012 10:43 PM

We made a bunch of door casing and decided to try to spray it with finish. Sanding sealer went on wonderfully. Waited couple hours and started to spray with Minwax Polycrylic satin. Initially, it started spraying fine, but about 1 hour into spraying—with NO changes to the gun setup at all, the thing started to clog up. We’re using a cheapy Cambpell Hausfeld gun—similar to the Harbor Freight knock off of the Earlex, I think—suction feed cup with small turbine system. We have 2 needles and spray tips—they don’t say in the book or on either set what size they are, but my best guess is that they are 1.5 and 2.0 mm. We used the smaller one for the sanding sealer, and no problem. We used the same one for the polycrylic, as the viscosity of it seems to be about the same as the Sherwin Williams sanding sealer that we are using. We cleaned the gun thoroughly after the sanding sealer and started with the polycrylic. After very little adjustment, it worked wonderfully. We got all the plinth blocks sprayed, and started the door casings. After about 4 casing pieces, the gun just started to clog up—there were visible chunks of the polycrylic on the tip of the needle. The troubleshooting in the book said clogging may be due to too small a volume of material being sprayed, so we upped it—no help—clogging continuted. The other suggestion was wrong needle size. We tried the larger needle and still got clogs. The only thing that changed was the ambient air temp. When we started, it was just under 70 degrees outside, and it was probably 75-77 when we started having issues. We were outside, as we don’t have a spray booth.

If anyone has any ideas about what might have caused this, I would really appreciate it. I just can’t imagine why it started to clog up.


7 replies so far

View huff's profile

huff

2807 posts in 2005 days


#1 posted 10-21-2012 12:51 AM

sarahss,

I’m not positive what your problem may be, and I’m not sure about your HVLP unit, but in general, the longer your HVLP runs, the warmer the air is that the turbine puts out. This could have an effect on the product in your gun while spraying. I now use an Earlex 5500 and I haven’t notice the temp change as much. Have you tried spraying again after everything was shut down for a while and you cleaned your gun?

When I used an Apollo 2 stage turbine HVLP, I noticed the temp. of the air flow from the turbine would change the longer I used it. Since I sprayed primarly nitroceluous lacquer, I never seemed to have a problem, so I’m not sure if that would affect polycrylic or not. I now use an Earlex 5500 and I haven’t notice the temp change as much.

Does your gun continue to push air thru the tip even when your not spraying? If so, when you set your gun down and you’re not actually spraying, then the air movement ( even if it’s not getting that much warmer) may be drying finish in the tip before you get to spray again.

Just food for thought. I’m sure there are other factors that could cause the problem. I’ve been spraying for years and every time I think I might know something about it, my gun, my HVLP or my finish will prove me wrong! lol

-- John @ http://www.thehuffordfurnituregroup.com

View sarahss's profile

sarahss

254 posts in 1369 days


#2 posted 10-21-2012 01:38 AM

John,

We cleaned the gun and will try again tomorrow after church. It does continue to blow air as you described. I hadn’t thought about the gun itself warming the air and drying it out. I bet you’re right Eventually i’d like a better sprayer, but since we have the cheapy, i thought it would be good for practice until we can afford a better one. Thanks for the help.

View sarahss's profile

sarahss

254 posts in 1369 days


#3 posted 10-21-2012 07:28 PM

still clogging when we started today. but it only clogs when the gun gets turned so the can is parallel to the ground. when the can is perpendicular to the ground, no clogs. it’s a one quart can, and slightly over 1/2 full.

View cutmantom's profile

cutmantom

295 posts in 1755 days


#4 posted 10-21-2012 07:41 PM

how about thinning it and/or adding a paint conditioner for latex paiint

View juniorjock's profile

juniorjock

1930 posts in 2486 days


#5 posted 10-21-2012 09:09 PM

Did you strain the poly?

View RussellAP's profile

RussellAP

2963 posts in 1007 days


#6 posted 10-21-2012 09:14 PM

If you had a build up, then it would have ruined the gun by now unless you have some strong chemicals to run through it. Sound like it probably thickened up if you had been spraying an hour. Use less and strain it. But first you may want to run some mineral spirits through that gun. If the gun is ruined, the Chicago sprayer at HF is a very decent gun for long term use. The motor gets a little hot though, so keep that in mind.

-- A positive attitude will take you much further than positive thinking ever will.

View sarahss's profile

sarahss

254 posts in 1369 days


#7 posted 10-21-2012 09:14 PM

problem turned out to be not enough material in the cup. I thought it was clogging, because there was a bit of material on the tip of the needle, so the troubleshooting said to increase material flow. I got to thinking though that it only seemed to sputter when the cup was turned sideways—and always after about the same amount of time, so I added more juice to the cup, and it sprayed fine straight from the can.

@ cutmantom—no-just used it as it was from the can, as i didn’t have any thinner on hand

@ juniorjock—used sherwin williams paint strainers after mixing well

Thanks for all the input and help—just can’t believe the problem was so simple!! it’s good when key learning happens and leads to success and doesn’t hurt—it usually involves cuts, bleeding and pain so this is a good thing. LOL

Have your say...

You must be signed in to reply.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics

HomeRefurbers.com

Latest Projects | Latest Blog Entries | Latest Forum Topics

GardenTenders.com :: gardening showcase