Spraying shellac using Wagner spray guns

[barri]

I started another thread below using a cheap aerosol alternative called Preval but got no replies so I'll have another crack.

I make boxes and recently I've used an aerosol can of spray shellac to finish them ..... Rust-Oleum Zinsser 408 Bulls Eye Clear Shellac Spray - Shellac For Furniture - Amazon.com and the results have been great with minimal effort. I got the idea from this youtube video https://www.youtube.com/watch?v=Dm8xIf41jEE The finishing is at the end of the video.

The problem is they're hard to get and I have to order them on line. Also, they're about $30 delivered making them expensive in the long run. I've bought and used shellac flakes for less than that of which you can make over a liter. So what I'm looking for is a cheaper spraying system without going down the compressor path. There are so many mixed reviews on the Wagner airless systems. People either love them or hate them.

So are these a viable alternative? If so which one? Are they reliable? Easy to clean? Easy to get accessories? On Wagner's Australia site they have a large number of models ranging from below $100 to many hundreds. A little confusing. The fine spray models seem to suit what I'm after but I'm not sure. I guess what I'm really after is hearing from someone who mixes their own shellac and uses a Wagner system successfully, even people who use them successfully for spraying polyurethane could chime in here.

[barri]

A follow up. I rang Wagner and they didn't recommend any of their products for spraying shellac. How's that for honesty! They said what they have isn't fine enough. So going down the compressor path might be the go. I searched for a small cheap one, I'm only going to use it for spraying shellac and polyurethanes, and got completely confused.

Can anyone help?

[Cliff Rogers]

I'm watching with interest.

[ian]

... going down the compressor path might be the go. I searched for a small cheap one, I'm only going to use it for spraying shellac and polyurethanes, and got completely confused.

Can anyone help?

as I understand it, spraying a finish or paint is about
clean dry air
at the right pressure
delivered in an appropriate volume
matched with
the right sort of gun for the finish
with the right sort of tip
then you need to get both the viscosity and technique right

a small and cheap compressor may not deliver the volume you need at the pressure required.
years ago when small and cheap compressors first started appearing I asked about getting one for spraying finishes. The answer then was that the tank of a small compressor was too small to deliver enough air to do any useful spraying.


as for the other aspects, I too will sit back and watch.

[Glenn.Visca]

I too have just been down the spraying shellac path, on a reasonably sizeable job (refer https://www.woodworkforums.com/f187/s...89#post1900889 and later posts in the thread).

Final picture here: https://www.woodworkforums.com/f187/s...59#post1906659

To start with, Shellac isn't particularly fussy about the size or capability of the gun being used. Lets be honest, it can be laid on with a brush with pretty good results.

I went and purchased a "reasonable quality" gravity gun from my local auto paint shop. Was around $150 from memory. It has a 2mm tip, which to be honest, could be a little big I think. I pretty much had it screwed 80% closed I reckon. About a 600ml cup. I thought about HVLP and all the other good stuff, but thought I might just put a toe in the water first.

I already had a Scorpion B2800B belt drive compressor ... probably a 50lt tank ... trade quality unit as I understand it.

I went and purchased a line regulator that is attached directly to the gun so I could regulate pressure at the gun, rather than at the compressor. I am pretty sure I had the compressor set at about 90PSI, and the gun set to about 10PSI.

What I learned (which is not to say I am any kind of expert !!!) :

1. You need to retard the drying time - a wise person recommended around 6% n-butenol. A local scientific / medical supply place should be able to sort you out. This will let the shellac "flow out" better once its applied. Just as background, I purchased uBeauts hardened shellac mixture, and cut that 50/50 with pure alcohol, then added around 6% butenol.

2. Its easier to spray on a horizontal surface if possible.

3. One or two dust coats on first - just to lay down a bit of a base.

4. With that done - you can put the shellac on pretty thick - let it flow - and you will very quickly fill the grain. At one stage, I had the mix running that thick, the air pressure was creating "waves" in the surface. But - once I stopped spraying, the shellac flowed out and it created a pretty good surface. Honestly, that "piece" was probably sprayed "too wet" ... but what I am trying to say is ... you will go nuts trying to build coat on coat on coat.

5. Once you have a solid / grain filled base (depending on what type of surface you are trying to create), you can cut back with P600 wet and dry on a cork block, using a little bit of soapy water. You will notice dull sections, which are now dead flat, and glossy "pits" - which are the low spots. Apply more shellac and repeat the process as often as you want (or not .. as the case may be).

6. My final activity (having let it all dry), was to cut back with P1200 wet and dry - and then polish with EEE Ultrashine. Finish was sensational.

Now - back the compressor conversation. I had the luxury of a pretty big tank - so had no problems whatsoever. If you are spraying large pieces (table tops etc) - then I expect a big tank is required to keep consistent pressure to the gun.

But - for smaller pieces - I reckon you could get by on a cheap and cheerful unit from autobarn etc. You will know when the tank is running low - because the compressor will kick in. At this point, stop spraying until the pressure is back up ... then start again. I would also suggest that with a small compressor tank, release the air in the gun (ie. just spray air) until the compressor starts. Then start spraying liquid on you job - that way you know you have started with a full tank.

I hope that helps in some way ...

[barri]

A great post Glenn

I mainly make small boxes, as a hobby and the compressor you described seems overkill in my case. You mentioned getting by on a cheap unit. Supercheap auto have the biggest range but I'm still confused as to what constitutes a basic unit that will do the job.

[Chief Tiff]

I take it you are referring to an electric airless sprayer? I have one of the lower spec'd Wagners and have used it to spray thinned down varnishes and oils with no problem. You will also need to buy a flexible extension so you can spray in different directions because unlike a normal syphon type spray spray gun you have to hold the Wagner pretty much horizontally all the time; the flexible extension allows you to point the nozzle where you want.

Downside? Rather messy as it is pretty much all-or-nothing, and fornicatingly LOUD!!! You WILL be needing earmuffs and deaf neighbours.

What hasn't been mentioned by those who prefer to spray with air, is the moisture and oil carry over which will destroy your finish. You must use a mist eliminator/water trap directly after the tank, and a dedicated air hose that is only ever used with spray guns.

Lastly; shellac, nitrocellulose or epoxy based paints and varnishes are really, really flammable when sprayed as an atomised mist. From a spray can it's a fairly small "cloud" and the warnings on the can is a bit of a hint but using a Wagner or a spray gun is best done either outdoors or in a sheltered space like a garage where you tend not to recognise the risk of rapid eyebrow loss. Static electricity from synthetic fibre clothing is enough to make you deeply regret ever wearing those paisley patterned nylon jocks...

[ian]

A great post Glenn

I mainly make small boxes, as a hobby and the compressor you described seems overkill in my case. You mentioned getting by on a cheap unit. Supercheap auto have the biggest range but I'm still confused as to what constitutes a basic unit that will do the job.

as I understand spraying, after clean dry air and the right gun for the finish, what you need most is enough air (measured in volume) for the task.

The volume of air required required is driven by the size of the pieces you are spraying and how long it takes to complete one coat.
Stopping and starting because there's not enough air is the last thing you want to have to manage.

justifying inadequate equipment on the basis that it's only a hobby, is, IMO, a false premise. It's like saying "I don't need to keep my chisels sharp, 'cause I'm only a hobbyist."

Hopefully, someone will jump in and advise how much air (per minute) is needed to spray each sort of finish.


Also, don't forget your and (and your family and neighbour's) safety.
Most of what I've read about spraying volatile finishes require the use of some sort of booth vented to the outside through an explosion rated exhaust fan.

[Ubernoob]

If you can't afford a big compressor you can find small ones with dud motors quite easily. All you have to do is use the dud as another tank for a more steady airflow. A small touch up gun should be enough for what most people do.
I need to modify some lines on my compressor as they are too restrictive to get decent pressure at the gun.

[barri]

I take it you are referring to an electric airless sprayer? I have one of the lower spec'd Wagners and have used it to spray thinned down varnishes and oils with no problem. You will also need to buy a flexible extension so you can spray in different directions because unlike a normal syphon type spray spray gun you have to hold the Wagner pretty much horizontally all the time; the flexible extension allows you to point the nozzle where you want.

Yes I think I'm referring to airless electric although Wagner has many models. Some mention turbine, some mention HPLV. It is confusing. I thought they were all airless electric. Its interesting that a "knowledgeable" person from Wagner doesn't recommend any model and yet you have successfully used one. Which model do you have? Link? I'm fairly keen on not going down the compressor path if possible. Also, I'm assuming Wagner sell flexible extensions.

Was that Wagner easy to clean and reuse and is thinning needed for these airless sprayers?

[barri]

It's like saying "I don't need to keep my chisels sharp, 'cause I'm only a hobbyist."

My analogy would be more of the line "As a hobbyist I don't need a full blown high HP cabinet saw as a hybrid will do the job". And it does perfectly.

Thanks for the advice on safety. I didn't realize that. Now you're scaring me

[Sam]

The belt driven supercheap compressors go on sale every few weeks, like 200-400 off the price.

[ian]

you might find the information here DeVilbiss, Anest Iwata, Asturo AOM, Sharpe, Astro Pneumatic, Binks - Spray Guns & More useful

[TongueTied]

A compressor is actually a very useful thing to have in your shop and I would suggest getting one with a large tank ~about 50L. The larger the tank, the less frequently the compressor motor will turn on and the more powerful the motor, the faster it will fill the tank. In the trade-off between tank size and motor power, I'd suggest the larger tank size takes priority. Once you have the compressor, you will find it is very useful for lots of things other than just spraying. An air drill will give you the cleanest holes you could imagine in sheet metal and most brad and nail guns run off air. I also have a Schrader valve adapter which makes inflating car and bike tires a snap.

[Chief Tiff]

The Wagner electric model I have uses a small recipricating piston to suck up and spray; the piston going back and forth 50 times a second makes a bit of a racket; hence the comment about earmuffs. I have no idea about a "turbine" model, but HVLP work by pressurising the paint and forcing it through the nozzle; the same principle as a spray can. Traditional spray guns work by releasing a jet of air, the paint is sucked out of the reservoir by the venturi principle.

Whatever system you pick will have a specific range of viscosities that will work; go outside of these and the finish will look rubbish. My Wagner will spray oils and shellac quite comfortably; it's a W140P model.