Looking to spray Poly. Any tips? or good tutorials/ reference? HVLP?

[jdcrotteau]

Hi all!

Looking to step up my finishing game and add a new skill. Have never sprayed finish before.

Currently using Varathane Polyurethane. I have a compressor that's plenty big enough, and am familiar with requirements to remove moisture/oil from the air. as have done a bit of automotive painting.

Have any of you sprayed polyurethane from an automotive paint gun? I'd likely pickup a cheapo HF HVLP gun to learn with.

Does anyone have any good references or tips to get me going?

 

[Packard]

I have a HVLP sprayer (Turbine Products, Stage 4).  By all accounts you want a stage 4 or stage 5 turbine.  I’m using a gravity fed gun (also from Turbine Products). 

I have not sprayed poly.  Oil based poly, I use wipe on.  Done right, I think it is nicer than sprayed. 

My attitude about equipment is this:  If I am teaching myself how to use equipment, then I want to buy the best quality equipment that I can afford.  If I buy a cheap gun and my results are poor, then I don’t know if I am at fault, or if the cheap gun is at fault. 

Once I master the process, I will sometimes use cheaper grades if I don’t think it will degrade the quality. 

Cheap tools either do not work well, or do not last long.  If you know it works well, and you are wiling to deal with the shorter life cycle, then use the cheaper tool.

Turbine Product’s gun and turbine have proven to be very good.  It would be on my recommended list.  They sell direct and I think they are located in Connecticut.

The key, I have found, is getting the right viscosity.  A Ford cup is used to measure viscosity in paint, and is a very useful extra.  Also, you should always filter the paint as you are filling the cup.  Disposable filters are available from Amazon.  Also, clear disposable mixing cups are available.

If you get a gravity feed gun, you are going to want to get a spray gun stand.  It holds it stationary so you can fill the cup with paint.

I got the mixing cups, filters, and stand from TCP on Amazon.  All good stuff, all affordable.

 

[blues]

+1 [member=74278]Packard[/member].
The saying "I'm not rich enough to buy cheap" would resonate well within the walls of FOG.
I use the Apollo Precision 5 hvlp system and I highly recommend it. Their gun is a dream to use. Everything about the system is just fantastic - from customer service, to ease of use (during & after). Its made right here in the USA. Yes its expensive. You get what you pay for. The absolutely best thing i like about their system is scalability. There is nothing you can't spray from thick Renner coatings to thin stain. The end result is so good that every single time you use it makes you feel the money you have spent is worth it. Integrates well into the work flow of a small shop and adds value to the work you do for your customers. It gives you confidence to price your work accordingly. If you goof up you know it's not the tool . There are other companies that make good hvlp products as well. So do your research and good luck with your purchase.

 

[woodferret]

You don't need a turbine for clear poly.  People have been spraying poly out of Critters.  Obviously, don't use a Critter.  Since you've done autobody work, most rules apply except note that WB flashes off really quick - so watch out for dry spray too.  You usually can get retarders for more of the higher end stuff, which helps levelling.  Don't think there is one for varathane. 

Best of luck, and have fun.

*All said turbines are nicer when you get into this - less overspray.  But you do have to fight the heat more there :/

edit: Q-You say you've done auto painting.  I assume it means you're familiar with spray guns on that end - and not somehow referring to bomb cans? 

 

[Packard]

You don't need a turbine for clear poly.  People have been spraying poly out of Critters.  Obviously, don't use a Critter.  Since you've done autobody work, most rules apply except note that WB flashes off really quick - so watch out for dry spray too.  You usually can get retarders for more of the higher end stuff, which helps levelling.  Don't think there is one for varathane. 

Best of luck, and have fun.

*All said turbines are nicer when you get into this - less overspray.  But you do have to fight the heat more there :/

edit: Q-You say you've done auto painting.  I assume it means you're familiar with spray guns on that end - and not somehow referring to bomb cans? 

The heat and the noise.  Mine is quite loud.

 

[Steve1]

My own view is kinda like Packard -- I am not skilled enough to get good results with cheap equipment. 
So I got a Fuji 5 stage and use GF High Performance poly.

But having said that, with the above equipment anyways, I find spraying waterbased poly is so easy to get nice results that perhaps woodferret is right that lesser equipment could readily be used.

Lots of good YouTube videos out there.  In particular, don't put your gun too far away from the workpiece.  Practise spraying water before you move to spraying poly.

 

[usernumber1]

if you've done automotive, wood should be dead easy. you can spray it LVLP or HVLP, thinned a little helps if you don't have pressure assist. you should be familiar how to get it to come out it will depend on temps and which PU finish you're using.

i don't think there's any rules some people like a thick finish some like super thin 'natural'.

 

[Packard]

One tip.  If you are a beginner, it is easier to get good results when spraying horizontal surfaces.  You don’t have to worry about runs and drips, and a generous coat of paint will benefit from gravity assisting with leveling.

Vertical surfaces are more difficult. Too much paint and you get drips.  Too little and you get orange peel. Cabinets can be painted in sections so that you are always spraying on horizontal surfaces.

Slower drying finishes level better as a rule.  Mask off surfaces that have already been shot.  Overspray will dust onto the other surfaces leaving a very rough texture.

For paint, I find the extremely slow drying and even slower curing Benjamin Moore Advance line of paints are very easy to get a quality finish from.  But slow with 16 hour recoat times.  A nice result though. Imperfections I see on the finished result are invariably the result of poor preparation, not from the painting process itself.

 

[jdcrotteau]

Thanks all for your feedback.

Have been going down the turbine rabbit hole. Not convinced I need a 5 stage, and have been looking at the Fuji Semi Pro 2.

Everyone makes this sound stupid simple. Thinking my wife may be able to utilize it as well for some of her furniture projects.

 

[Packard]

The only issue I found was getting the paint to the right viscosity.  A Ford Cup is effective in measuring viscosity.  It is basically a small cup with a hole at the bottom.  You fill the cup with paint and time it to empty.  Once you establish the ideal viscosity, spraying becomes easy.

I have a stage 4 turbine.  I have to thin Advance.  I’ve been told that if I had a stage 5 turbine I would be able to shoot Advance undiluted.  That would have been a blessing.  It takes time to accurately thin the paint to the right viscosity.

I paid about $10.00 for my Ford cup; i see them advertised for as low as $5.00.
https://www.google.com/search?q=ford cup&ie=utf-8&oe=utf-8&client=firefox-b-1-m

The original Ford cups were made from machined aluminum, and calibrated versions cost over $500.00 each.  You don’t need that kind of precision.  Any of the ones with a long handle will work fine.  The short handle ones will be problematic.
https://www.thomassci.com/Equipment/Viscometers/_/FORD-VISCOSITY-CUPS

 

[Steve1]

Not convinced I need a 5 stage, and have been looking at the Fuji Semi Pro 2.

I have not yet tried spraying paint with my Fuji 5 stage, but that is why I bought the 5-stage.  I really don't like my Graco Ultra airless gun.  Would be nice to use the Fuji for paint also, and sell the airless.

But for spraying water based poly, the 2 stage is probably fine. 
For paint, I would want more pressure.

If getting the Fuji, make sure you get the 6 ft flexible hose.

 

[woodferret]

Thanks all for your feedback.

Have been going down the turbine rabbit hole. Not convinced I need a 5 stage, and have been looking at the Fuji Semi Pro 2.

Everyone makes this sound stupid simple. Thinking my wife may be able to utilize it as well for some of her furniture projects.

Since furniture refinishing is being thrown in, I'll defer to Ray of Sunlight.  She's got a comparison of Fuji Q4 vs a few of the standalones like Homeright and Wagner. 

It'll at least give you a comparison on how well each class atomizes and how finnicky they are to viscosity of paint.  You _CAN_ do okay with 2 stage as the classic Earlex is basically that.  Shoots GF paints and the polys.  Heck, even Homeright can put paint on walls. 

I've got a MiniMite 4.  Strong enough to push some primer and lacquers.  When you really need a 5-stage, you're very straddling the line into airless territory (at least for trim/cabinets).  The swaying factor for me of 5-stage vs airless is cleanup.  It's immeasurably easier to clean the HVLPs especially if you use a PPS style system.  But volume is silly small unless you use a pressure pot, and then you've lost that cleaning advantage.

 

[Packard]

Also consider Turbine Products
https://turbineproducts.com/

Stage 3 kit. $460.00

Stage 4 kit. $560.00

Includes:

siphon fed sprayer
25’ hose
Wall mounted cup holder
Tools
Cleaning kit

It is ready to use out of the box.  Just buy the paint.

I find the 25’ hose very handy.  I never have to reposition the turbine.  If you are shooting two or three cabinet boxes, the 25’ hose allows you to walk around the boxes.

The manufacturer has been helpful and they always come to the phone if you have questions.

I have the stage 4 for about 5 years.  I have had to replace the air filters, and I like their gravity feed gun more than the siphon feed gun.

I always completely disassemble the gun to clean after use.  That might be overkill. But by now it is part of my routine.

Note: Both the gravity fed and the siphon fed guns carry the same price.  If you call they might allow you to substitute the gravity gun in the kit.

 

[jdcrotteau]

Thanks all. Am still shopping, but am set in getting a HVLP turbine set up.

A question for you all, my first project will likely be garage cabinets out of baltic birch. Would you spray prior to breaking down sheets? or once fully assembled?

 

[Packard]

If the cabinets are large and heavy, I prefer to spray while it is KD, and assemble where I am going to use it.

It requires some prep as you have to mask off the glue areas. 

Spraying the inside of a cabinet is a hassle.  I have bought plywood with a clear finish on one side (I painted the outside).  That made life easier. 

 

[woodferret]

Easier to spray piecemeal as Packard says.  Or oversized breakdown parts if your paint has edge puddling issues.  8x4 is too painful to spray as you need to overreach across the 4ft span (the other dir is too long and you'll very likely lose your wet edge). 

If your assembly marrs the surface, spray after.  Make the back slot-in/removable.  Or you can go the route of prefinishing the inside, but learn to mask cabinet openings for spraying the outside.  3M handmasker is your friend.

 

[sancho57]

if your compressor is large enough capacity you can go with a conversion gun instead of a full turbine outfit.
I went with a turbine set up.
how ever what I say below applies to conversion guns and turbine driven guns in the case of conversion guns its the compressors capacity

regardless of what  set up you decide to  get, you should get the best gun you can afford with it.

there are a lot of good quality guns on the market.

I use a apollo 4 stage ECO turbine with their top of the line 7700 spray gun.

as long as you stay with in the limits of the turbine youll be fine.

my set up is a chevy turbine and a ferari gun, I can spray 90% of the products I need to.

Its the gun that will determine the finish not the turbine/ compressor, they will determine the products you can spray.
As I said, I can spray 90% of the product I need to, water base finishes, under coaters etc

its when you get into paints that it gets a little tricky.

Also be sure you have the proper nozzle and needle set up for the product you want to spray. most guns comes with a basic N/N set up that will do a good job spraying things like poly.

but if you go with thinner/thicker material (some water base finishes are thicker than others) you may need to adj the N/N.

Im no expert but this is what Ive learned over the years

 

[krudawg]

My own view is kinda like Packard -- I am not skilled enough to get good results with cheap equipment. 
So I got a Fuji 5 stage and use GF High Performance poly.

But having said that, with the above equipment anyways, I find spraying waterbased poly is so easy to get nice results that perhaps woodferret is right that lesser equipment could readily be used.

Lots of good YouTube videos out there.  In particular, don't put your gun too far away from the workpiece.  Practise spraying water before you move to spraying poly.

I spray with a Fuji HVLP MiniMite4 and the GF High Performance sprays well out of my fuji.