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HVLP

2104 Views 17 Replies 11 Participants Last post by ScottM, May 19, 2014

ScottM

Discussion Starter · May 16, 2014 (Edited by Moderator)

I just returned from HF with a new HVLP spray kit. This is my first spray unit and I thought I'd give ths one a try based on the price. It has gotten pretty good reviews so I figured what the heck.

My question is really about cleanup. I'm just finishing a project that I was figuring to be a bear to poly finish with a brush so that's why I popped on this sprayer. I'm going to spray water based poly. The can says 2 hours between coats. Do I, or should I, clean the entire gun between each coat or can I leave the remainder of the poly in the cup while I wait? Maybe just clean the needle and tip? Any thoughts would be helpful.

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b2rtch

· #2 · May 16, 2014

If you wait your poly will set in the sprayer just as it will do on the wood.
Empty the reservoir and spray some clear water until clean.
At the end of the job take the whole thing apart and clean it really good.

TheDane

· #3 · May 16, 2014

When I am spraying water-borne finishes, I don't clean between coats. Just make sure you do a thorough cleaning at the end of the day. I have an Earlex, but I would think the same applies to the HF unit you have.

ScottM

Discussion Starter · #4 · May 16, 2014

I don't mind removing the needle and tip and cleaning those between coats. I just don't want to have to empty the cup and then refilter and fill every 2 hours. I actually just finished a coat and I'm going to leave the cup as is with the remainder of poly in it, however, I did remove the needle and clean that. We'll see how it goes. Thanks for the info and suggestions guys.

Gerry, what size needle do you use for water based finishes? The unit I got came with 3; 1.5, 1.8, and 2.0. I tried the 1.5 last night and it sprayed extremely light so I tried the 1.8 today. Just curious what others go too.

TheDane

· #5 · May 16, 2014

The Earlex comes with a 0.08" fluid tip & needle … that is all I have ever used.

b2rtch

· #6 · May 16, 2014

I had a Earlex (not anymore more).
It had several needles,I used the 1.6 for latex and other waterborne products

TheDane

· #7 · May 16, 2014

The Earlex manual shows the needle sizes in SAE (0.04", 0.06", 0.08",0.10"). The needle supplied with the unit I have (0.08") is equivalent to a 2.0mm. I just check the viscosity, but haven't had to thin any finishes and have gotten good results.

ScottM

Discussion Starter · #8 · May 16, 2014

I may try the 2.0mm needle next. I'm sort of experimenting with the drawers of some nightstands that I built and I'm getting some orange peel happening.

InstantSiv

· #9 · May 16, 2014 (Edited by Moderator)

I've run gallons and gallons and gallons of polycrylic through that harbor freight sprayer. That thing is a beast and still runs like a champ, I've had it over a year.

I just wipe the tip dry between coats with a paper towel, outside of needle/tip without taking it apart. Sometimes I forget and it'll dry over so it's just a matter of scraping it off with my finger nail.

I've forgotten to clean up at the end of the day sometimes and there's no ill effects after sitting overnight, just the dried tip. I don't suggest that but just my experience.

--

I've had the best luck with the middle size tip.

On the orange peel, is the layer thin or thick. I started out with a orange peel like surface. I would spray a small amount and make my passes slowly. Now I get glass like surfaces. I spray mine on thick enough to where it looks like the surface of water. It's a little trial and error to get the right amount so practice. You want to open up the needle adjustment to spray a lot and make your passes really really quick. I do one pass from left to right and immediately go over that with a pass from top to bottom. There's a balance between too little(orange peel) and too much(runs).

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NiteWalker

· #10 · May 16, 2014

No need to clean between coats; just wipe the tip and you're good.
For extended waiting periods, a piece of tape over the cup vent hole prevents the finish from hardening.

ssnvet

· #11 · May 16, 2014

I think the point that your missing is that exposure to air is required for the polycyclic to cure. Inside your cup and gun, it is not exposed to air.

I've never sprayed it, but I have brushed several gallons of it, and in my experience it dries a lot faster than two hours.

pintodeluxe

· #12 · May 16, 2014 (Edited by Moderator)

I always drain the gun, and remove the needle and nozzle for a soak in thinner. Take the filter out as well, and drop it in the thinner (mineral spirits in this case). The tiny apertures in the nozzle quickly clog, and will affect spraying performance on the second coat. In fact, take the body of the gun and rest it in the thinner as well. This will keep the inner nozzle from clogging.
Use a pipe cleaner and solvent to clean the air vent in the top cap.

This entire operation takes 2-3 minutes, and the solvent is reusable (put some in a Tupperware container).

If you don't do this, I guarantee the spray pattern will suffer at some point.

FYI, when you remove the needle, the fluid cup will drain. There is no way to keep fluid in the cup with the needle removed.

dhazelton

· #13 · May 16, 2014

I wonder what would happen if you do what I do with a paint roller I don't want to clean between coats - put it in the refrigerator.

runswithscissors

· #14 · May 18, 2014

I have used my HF HVLP (the model with its own blower) with water based acrylic. Leaving the stuff in the gun overnight, or even longer, doesn't seem to be a problem at all.

shawnmasterson

· #15 · May 18, 2014

+1 for leaving it. I use the 12.99 HF hvlp guns, and I leave have left it in as long as 48 hours. The 2 hour wait time is kind of odd to me. I use minwax latex poly? I get it from menards.
This past winter I was finishing the cabinets for my living room. I stoked up the wood stove and had it 110* in the shop. I sprayed it 6 fine coats with about 15 minutes in between Then I let it sit overnight with the temp slowly descending. In the morning (still 80) I hit it with some 320 to smooth it down and laid one final coat. The came out perfect. The high coat count will soften the edges, and give the finish a nice depth. I have done this on many projects and never had a problem. I have even lit the stove in the summer just to cook a finish on.

BillWhite

· #16 · May 18, 2014

Which gun did you buy? Model, link?
Bill

shawnmasterson

· #17 · May 18, 2014

Bill I don't know if you were talking to me or not. I generally get the 67181 or 47016 They are the same as far as I can tell. also I run it well over 45 PSI. The instructions say not to. I just plug it into the hose (95 psi) from there I dial it down with the knob on the bottom of the gun. I usually spray it on a scrap until it is laying flat. I found if set the hose pressure at 45 there wasn't enough pressure to atomize the paint so it would lay down. you have to be cautious of the over spray.

ScottM

Discussion Starter · #18 · May 19, 2014

I have the kit here, http://www.harborfreight.com/high-volume-low-pressure-spray-gun-kit-44677.html

It's on sale plus I had a 20% off coupon so I figured I had to give it a shot.

As for the leaving it in the cup, I was just worried about how much air could get into the needle and tip and cause it to cake up. I finished spraying my tables this weekend and they came out pretty good. There's still a lot to be learned with a good spray finish. I ended up leaving the cup full most of the day and didn't have any problems. I'll post some pictures soon.

Thanks for all of the info and tips guys.

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