HVLP question

Anyone here use a HVLA (high volume llw pressure) spray system to apply latex-primer/paint on thier painted projects?

i'm building a fireplace mantel w/ MDF and pine and was hoping to build it all up, then spray it with primer and eventually white paint (latex).

advice/suggestions appreciated...

Thanks! Fred

Reply to
FDawg
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i'm building a fireplace mantel w/ MDF and pine and was hoping to build it all up, then spray it with primer and eventually white paint (latex).

advice/suggestions appreciated...

Thanks! Fred

Reply to
FDawg

Are you set on using latex? My preference for MDF is lacquer systems. One or two coats of a high solids primer/surfacer, then two top coats, all can be done in a day.

Advantages over latex are: quick dry easy sanding of primer great coverage and filling of raw edges much harder, smoother finish - avoids the sticking problem that latex has initially easy to spray (less power and thinning required), more so for the top coat than primer not necessary to sand between topcoats - solvent based only

Disadvantages: odours/health - much more so with solvent based, spraying anything requires a good respirator IMO flammability - only solvent based need for spray booth - again more so for solvent based

that's all I can think of off the top of my head. ML Campbell and probably others make waterbased finishes that don't require a spray booth. For solvent based, try Sherwin Williams as well, that I know of.

Also, I like to prime some of the components as I go. Especially stuff like raised panels, columns and pilasters. This is because the smaller pieces are easier to handle, easier to sand, and fewer corners for the finish to sink into - keeps the details crisper. Consider that the top can be made separate from the mantel and set on during installation. Again smaller pieces are easier to handle, finish, transport. Fitting and installation are also simplified that way - fit the front, attach to wall, fit the top, attach. It's handy to be able to reach behind the mantle during installation and level the top separate from the front.

That would be a mantel in a nutshell. I kinda glossed over it, don't want to tell you stuff that you already know.

HTH, Jeffo

i'm building a fireplace mantel w/ MDF and pine and was hoping to build it all up, then spray it with primer and eventually white paint (latex).

advice/suggestions appreciated...

Thanks! Fred

Reply to
Jeffo

Reply to
nospambob

There isn't much to make in the way of suggestions. Use the right nozzle/needle combination and viscosity and spray away.If it is a turbine system the ideal would be a four stage but a three stage will work. I wouldn't want to try it with anything less.

Reply to
Mike G

Below you will find a summary of my results spraying latex with the Harbor Freight HVLP conversion gun. I originally posted questions about HVLP and latex in the rec.crafts.metalworking news group and then updated my post with results I got in use. There are caveats but I think for what you are doing it will work fine. I look forward to trying lighter finishes with my HVLP gun on future woodworking projects. Hope this helps.

Bill

An update to my Harbor Freight HVLP experience.

I thought I'd post an update to my OT post a few weeks back looking for input re HVLP systems and latex house paint. As is usual for this group I got several varied responses mostly warning me off HVLP for latex as being slow to use. Well, as with anything your milage may vary. I post my results to add further information to the collective ;-)

If you are painting large flat areas it's better to go airless. This is what most respondents said and I have to agree. My first use of the HF 7902 gun was to spray Kilz II latex primer on the ceiling of the new addition (around 450 square feet of floor space with slightly vaulted ceilings). I thinned the Kilz about 12% with water and added

12% Floetrol per gallon of primer (a pint of water and a pint of Floetrol per gallon approximately). Kilz is the consistancy of yogurt as it came out of the bucket and this dilution got me a thicker than heavy cream mix. Mixed well with a paddle and hand drill. I also ran the mix through a filter sock from the Ace hardware store and funnel into the cup to be sure I put no stray particles into the the 2 qt cup. I set my compressor (Devilbiss 25 gal. alledged 5HP and 8.8 CFM @ 40 PSI) to 40 PSI and set the pressure gauge at the cup to 10 PSI. I was unable to get a very big fan pattern with the adjustments (fluid and air) on the gun. Say about a 4 inch dia. circular pattern from 6 to 8 inches away. This is THE main drawback for large areas. It takes a long time and you have to be careful to overlap your swaths as you paint to avoid missing areas. It takes a long time to cover. It might help if a larger orofice tip were used but only a 1mm tip is available according to HF. On the up side even at 6 to 8 inches away I got no runs or orangepeel as long as I kept the gun moving. Also, at the low gun pressure, bounce back and overspray are minimal. A BIG improvement over my standard (no-name) spray gun. The compressor cycled normally, not excessively as had been my concern and was well able to keep up with the gun.

The second job for the gun was to spray the eaves and fascia with the final color. I had sprayed them before the first stucco coats on the exterior walls with my old freebie gun. I'm glad the roof wasn't on yet because I got primer everywhere with the standard high pressure gun. The top of my extension ladder was completely covered (as were my glasses) with overspray and bounce back. For the finish coat I used exterior latex tinted to match the existing (they need re-painting too) eaves. Behr brand thinned the same way as mentioned above. I would guess there are 50 to 60 linear feet of eaves and fascia on the addition. The remote (about 4 feet of hose) cup made all the difference in doing the underside of the eaves and back (hidden) side of the fascia. In this case the small pattern is a plus as it is very easy to control exactly where the paint goes into all the nooks and crannies. It is, IMHO 'da bomb' for detail work such as this. Again minimal bouceback or overspray. The top of the extension ladder is still white from the primer as there was no mess from the brown I was doing with HVLP. Also since the HVLP is much more efficient at getting paint on the job and not eslewhere and combined with the larger cup I filled the cup only once after the initial fill and did all the new eaves and fascia as well as about 30 feet of fascia on the front of the house that needed paint. It's still not fast and I did two coats so it took most of the day including lunch break and coming down to consult with the guy installing cabinets inside. I am very pleased with this gun from HF. Was a little leery about buying it due to some of the bad reports about general HF quality but after using it I have to say it's well worth the money ($120 in the store, $99 on the web). Appearance of the gun is excellent with nice fit and finish. Too bad different size tips are not available but there might be tips from similar guns that would fit.

So in summary this Harbor Freight 7902 HVLP spray gun is excellent IMHO for doing detail work. It works well with thick latex paint thinned slightly with water and with Floetrol added even with a small

1mm tip. It is NOT reccommended for large flat areas due to the small fan I was able to get. I think it will also be excellent for lighter woodworking finishes such as polyurethane and shellac (I do a little wood work too) and will probably do a nice job with the oil base paints for metal (obligatory metal content) work as well although I haven't tried it for that yet. Hopefully my experience will help someone else who has similar paint jobs to do. By the way, I highly reccommend Floetrol as an additive to latex for rolling and brushing as well as spray. It seems to make the paint go on smoother and flow from the roller and brush better. No association with either HF or Floetrol except as a satisfied customer.

Bill On Wed, 18 Feb 2004 04:28:51 GMT, "FDawg" wrote:

latex-primer/paint on thier painted projects?

then spray it with primer and eventually white paint (latex).

Reply to
Bill Schoenbeck

I suspect that that gun is a clone of a binks gun. take it in to a good supply house and see if they have a cross reference

Reply to
Bridger

Good post Bill. Hope you don't mind if I add a note for those not acquainted with HVLP.

What Bill is using is a conversion HVLP gun rather then a turbine based HVLP system.

A Turbine system supplies a high volume of air at low pressure to the gun, a conversion gun takes the high pressure, low volume air from a standard compressor and "converts" it to HVLP.

To the best of my knowledge, with the proper compressor, there is no reason to expect a better or worse job from either method or, for that matter, a conventional system..

However, the conversion from high pressure low volume to HVLP can, depending on the gun and fluid feed system, put some high demands on a compressor so care should be taken to match the output of the compressor (CFM at specific PSI) to the needs of the gun. An under powered compressor may spray but the results will be far from optimal and could lead to frustration.

Reply to
Mike G

Here is a post I did sometime back for someone wanting to know about spraying latex. It should have some pertinent information for you.

I just finished spraying a bunch of passage doors this weekend. A very long weekend.

I have a Graco, 4-stage turbine HVLP with a 2 quart remote pot. Since latex is thick, I figured I needed a big tip to get the necessary flow, so I dropped $90 for a #6 (2.5 mm) set which calls for 26+ seconds on a Ford #4 viscosity cup. That is the biggest tip made for this equipment. I already have the #2 - #5 tips.

In hindsight, I then called Graco after buying the tip and talked to tech. Boy, did I get a lesson in spraying latex. I told him I had a #6 tip and would he please give me some guidelines on spraying latex. The first thing he said, was that he didn't think the #6 tip would work. Although with the remote pot, I could turn up the pressure and get a good flow, the turbine wouldn't be able to push enough air to atomize it. He was right and there went $90 down the tube. He suggested thinning the latex 10% and adding Floetrol. More thinning can change the sheen and bonding characteristics. Then start with a smaller tip. If I can atomize before I reach full air flow, then go to the next larger tip. When I get to a tip that won't atomize at full air flow, go back to the smaller tip. He said I would just have to live with the smaller output and subsequent slower coverage (it equated to a lot of time). I thinned the latex about 12% and added 8 ounces of Floetrol per quart of latex. That is the maximum Floetrol that supposedly won't change the sheen of semi-gloss or satin (I used satin), or change the color. Too much starts adding a yellow tint to the paint. I ended up with a #4 tip with a #3 air cap. The #4 tip is 1.8 mm. I went down to the #3 air cap because it is a higher velocity air flow for atomizing and does atomize a little better than the #4 air cap (this is a hint in the manual). It doesn't make sense because the viscosity suggested for the #4 is 20 to 26 seconds with the #4 Ford cup and the latex is so thick it would take minutes to empty the viscosity cup. I had already asked him about that earlier. He said that although the #6 calls for around 26 seconds, it could actually spray paints with viscosities up to 160 seconds. Also, all the tips can spray at much thicker viscosities that are listed in the manual. Although it will spray at higher viscosities, you must use a slower fluid flow so there is enough pressure to the air cap to atomize it. The viscosities suggested for each tip size is the optimal viscosity range for that tip; but it isn't the limit of viscosities that can be sprayed for each tip. Again, he was right. I could get good atomization, but I could only move the spray gun about 1 foot every 4 seconds or so. It took about

8-9 minutes for each door side. The material did have some orange peel and it splattered some as it went down, but with the Floetrol, it leveled out as it dried and I got a really smooth surface. I put it on pretty thick, so I could have easily gotten by with one topcoat, but I opted for two.

I do find that I can spray oil base paints to a really smooth finish much easier than latex with about 15% mineral spirits and 15% Penetrol. The sheen and adhesion don't seem to be affected. I use a #4 tip for that, too.

From the finishing newsgroup at Woodweb

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you might pose your question there), I get the idea that a conversion HVLP spray gun will handle heavier viscosities better than a turbine HVLP. I guess that is because you can get more atomizing pressure. For the conversion guns, it seems the consensus is Asturo or Kremlin. But be prepared to drop $400-$500 for the gun alone. However, with the conversion gun, your "spray rig" isn't very portable with a big compressor.

Obviously, for latex, the airless is still the way to go, but it is not very good in the shop for finishing cabinets and furniture.

BTW, I wouldn't even try to spray latex with less than a 4-stage turbine. It would take too much thinning or a way bunch of time.

Hope this helps, "FDawg" wrote in message news:5SBYb.287$P11.27442@attbi_s54... Anyone here use a HVLA (high volume llw pressure) spray system to apply latex-primer/paint on thier painted projects?

i'm building a fireplace mantel w/ MDF and pine and was hoping to build it all up, then spray it with primer and eventually white paint (latex).

advice/suggestions appreciated...

Thanks! Fred

Reply to
Preston Andreas

Thanks so much for taking the time to repy; this group is awesome!

i'll do more research on my end usinh the info gathered here...it doesn't look like my $59 CH gun is going to do the trick after all...

Thanks again! Fred

Reply to
FDawg

Bridger, Thanks, I'll give a look see for a local place dealing in Binks here in San Diego. Even though HF claims to have no other size tips it looks to me as though tips from some of their other guns might also work. Of course I don't need to spray latex for now as the addition is done. I think the smaller tip will work fine for lighter finishes when I get an opportunity to try it.

Bill

Reply to
Bill Schoenbeck

Fred,

Take 'nospambobs' advice and look at the Target Coatings products. Jeff Jewitt sells them through his Homestead Finishing site, and you can buy them direct from the manufacturer. I'm currently in the process of refinishing an old built-in kitchen piece with the PSL (premium spray lacquer) product. Initial trials went very, very well. It is water based, sprays through just about any gun you want to try it with, and unlike latex, it does not block.

What is blocking you say? Latex, no matter how long it has dried, always remains slightly tacky, and this situation only gets worse with increased humidity/moisture. Take something smooth, like a book with a nice slip jacket, set it down on a latex surface on a humid day, let sit a few hours, then try to pick it up. You will likely tear the slip cover. Blocking is even worse if you let two latex painted surfaces come in contact with each other.

Don't get me wrong, modern latex coating make great house paints, but are lousy bookshelf, kitchen cabinet, wear surface paints. Use either oil based, a solvent based lacquer, or one of the modern water based lacquers, like the Target stuff.

The Target PSL stuff can even be wet sanded and buffed, which would look primo on a high visibility piece like a mantle. Do a little wet sanding with 400 and then 600 silicon carbide paper, being very careful to stay away from the edges, then do a final buff to semi-gloss sheen with a worn gray scotchbrite lubed with a bit of baby/mineral oil. Will be as smooth as the proverbial babies bottom.

Best of luck, David Glos

Reply to
DLGlos

Fred,

Take 'nospambobs' advice and look at the Target Coatings products. Jeff Jewitt sells them through his Homestead Finishing site, and you can buy them direct from the manufacturer. I'm currently in the process of refinishing an old built-in kitchen piece with the PSL (premium spray lacquer) product. Initial trials went very, very well. It is water based, sprays through just about any gun you want to try it with, and unlike latex, it does not block.

What is blocking you say? Latex, no matter how long it has dried, always remains slightly tacky, and this situation only gets worse with increased humidity/moisture. Take something smooth, like a book with a nice slip jacket, set it down on a latex surface on a humid day, let sit a few hours, then try to pick it up. You will likely tear the slip cover. Blocking is even worse if you let two latex painted surfaces come in contact with each other.

Don't get me wrong, modern latex coating make great house paints, but are lousy bookshelf, kitchen cabinet, wear surface paints. Use either oil based, a solvent based lacquer, or one of the modern water based lacquers, like the Target stuff.

The Target PSL stuff can even be wet sanded and buffed, which would look primo on a high visibility piece like a mantle. Do a little wet sanding with 400 and then 600 silicon carbide paper, being very careful to stay away from the edges, then do a final buff to semi-gloss sheen with a worn gray scotchbrite lubed with a bit of baby/mineral oil. Will be as smooth as the proverbial babies bottom.

Best of luck, David Glos

Reply to
DLGlos

I am looking for a #7902 hvlp Central Pneumatic paint gun. Dont need the cu p. New or used. Please send picture to snipped-for-privacy@gmail.com

Reply to
alumaclear

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