Lacquers/polyurethanes

[John Saxton]

Amongst you folk out there using Lacquers etc,are there any particular types that give a natural look without detracting from the timbers natural patina.There are a number of brands available.What would be an ideal finish to use on either Jarrah or West Oz Sheoak in a spray finish.
Up until the present I have predominately used an oil based finish on my furniture but and although I still adhere to liking this, the time element now precludes me from always continuing along this path,hence the need to update to spraying.
Cheers and TIA


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Johnno

[Mac Simmons]

Lacquer is much easier to spray, then Polyurethane.
Lacquer is more appeallingto the eye and hand, then Polyurethane.
Lacquer is easier to sand, rub out, and polish up, then Polyuerthane.
Lacquer is easier to do repairs on, then Polyurethane.
Polyurethane is more durable and chemical resistant then Lacquer.
If these two features are needed for your type of work, then I would suggest you use a Precatalized Lacquer, this will increase those features in the finish.

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[John Saxton]

G,day Mac,thanks for that,I'm a new boy in the spraying arena and am still setting up an area to carry this out.I am getting together what background info I can as there is limited info at my library and what there was available contained little or nothing to utilising the various finish's in a spray format.
Cheers

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Johnno

[Mac Simmons]

Hi Johnno,
Thamks
It can't be to hard to learn, as Lacquer is the most commonly used coating.
I think the best library in the world is the Internet, just do some "searches".
If you have specific questions "post" them here, I am sure some one will have the answers for you.

Good Luck,

MacS


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[RETIRED]

Gooday.

John, I use n/c lacquers for most finishing. Come to think of it all finishing unless it goes out raw.

The method here may not be the right one but it works for me.

I am talking about a commercially (albeit better than most) acceptable finish. Not a gallery finish.

We use 30-50% unless requested by the customer(some like 95%). It gives a nice flat satiny finish that is comparable and a hell of lot easier than danish oil.

We only use 2 coats on most things except cabinet or table tops that have 3.

Sand down to 240 with a random orbital and then hand sand with 320. Blow and wipe all dust off preferably in the open air so it doesn't settle straight back on it.

Set the air pressure to 40PSI (you are using a low pressure gun? A high pressure gun tends to "dry spray) and apply a light coat moving away from you. OK, OK all you car spray painters n/c lacquer on furniture needs another approach. Because it dries so quickly you are virtually "melting" the previous coat to blend the next one in. It also keeps the overspray ahead of the coat and it "melts in" as well.

N/C relies on evaporation to dry so a light breeze is great and by the time you have put the gun down it is nearly dry. Now have a "" cuppa i.e. 20 mins.

This bit is the most important. Get a "Chux" scouring pad (they are the pretty little pink ones with a curve in them) and rub back the whole surface. I have found that the green "Scotch brite" pads are a bit harsh. Blow off all dust and check the surface, it should be like a baby's bottie (NO not wet and dirty, SMOOTH as ).

This serves 2 purposes, removes any grain raising and cuts the surface for the next coat to adhere to although lacquer can be built up as it partially dissolves the "undercoat", a fact to keep in mind if you get heavy handed. You will end up with more runs than Allan Border. So light coats is the way to go.

If you really want a good finish, cut it back with Ubeat EEE (do I get paid now, Uncle Neil ) to remove the plastic look although you won't get it as much as Poly urethane.

Happy spraying.

DO NOT USE ON WOMENS DRESSING TABLES without glass on top. The perfume dissolves the finish. It pays to wear respirators unless you want to have a real good day. Beats glue sniffing any day .


Apply your subsequent coats the same way

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Ian () Robertson
"We do good turns every day"



[This message has been edited by (edited 15 July 2000).]

[Shane Watson]

Geez ,

Your not just a pretty face eh

Actually you brought up a really good point relating to Automotive spraypainters. And just thought I would add to that..

Spraying a car is different to furniture, not only in the finishes that are used but also the technique employed to spray. I have found generally that furniture sprayers are much better at spraying than auotmotive sprayers. I did say generally.

Fact is, cars have large flat surfaces, yes they may be curved but there still reasonably flat and are approached that way.
Whereas furniture is made up of small flat surfaces and those that are curved are usually very curved and have to be treated that way. And probably the one big difference between the two is that furniture has many different angles and faces in a small area that need to be coated( take a chair for example ), and thats where furniture sprayers tend to excell over our counterparts.

I proved this theory while training at a Brisbane TAFE. Basically I got bored with the Furniture as I new what they were trying to teach, so I thought I would go see what the Automotive boys could teach me. I found them trying to paint something that they couln't because of the size and complexity of the piece. So I offered to spray it for them, they just laughed, I mean a lil' ole' French Polisher couldn't spray auto. Well lets just say I walked away laughing and they came back latter thanking me for getting them top marks! I won't go into trying to describe what happened when I let them spray a chair

But in saying all that, the boys did teach me some useful techniques that I still use today that helps me obtain a flatter more even finish when spraying. In otherwords We both helped each other become better sprayers!

Just my lot of dribble for the day, hey I only just crawled out of bed...

Cheers

Shane...............

[John Saxton]

G,day Mac,,Shane,thanks for all that valuable info that you have imparted.I will print this out and put it on my clipboard in the workshop as I'M about to try some trial runs to see my gear pans out!!
, I do not whether or not the gun I have is a low pressure gun or not but I guess it must be somewhere close as it came all together with a 20litre spray pot and long hoses that I bought recently before GST, came in from my local bloke for 400 bucks,but it does reccomend a max air pressure of no more than 50psi.Is this what you mean by a low pressure gun?
Cheers

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Johnno

[Shane Watson]

Damn guys, were gonna be published authors!!

Johnno, Mate sounds like you've got yourself a pressure pot spray system. Could be wrong but when you mentioned the 20L pot?
These things are great for continuous spraying... But pretty much a pain for small amounts of spraying. Although you can get a little 2L pressure pot..

Anyway, probably just gonna confuse the situation now

Hey, I'll tell what is great for a lot of spraying, and thats an airless system... Havn't used one much, but I have fun when I do......


Cheers

Shane

[Peter R]

Hi Chaps! can I come in on the spraying forum please, with some questions?? I have been using Wattyl Stylewood to finish spray over stains on furniture. I am a complete mug at the game but I have had mediocre success on the stuff that I build. What I need to know is how do you determine viscosity and what pressure should be used for the viscosity selected. Is there a scale? I would be interested in other products like stylewood (quick drying) if they are in the same price range.

Peter R.

[Peter R]

Yes, it is silly to answer my own question but in the excitement of having a forum to ask the experts I did not pay much attention to the advice already available.
I asked about viscosity and thinning of Stylwood ( I spelt it Stylewood). I had tried to access information on the web but I guess my spelling caused a failure in that area.
To cut the story short, I took advice from the other contributers of this forum and contacted the local Wattyl Trade Depot and was given two pages of fact sheet on Stylwood.
Another interesting facet of this was that I was told that the drying times and thinning was the manufacturers recommendation, and that it stayed well inside actual usage. Try and experiment was the advice.
I will read before I jump next time
Peter R.

[Kev-in Melb]

Hi Peter,

You can buy a cup to measure the viscosity, basically you pour the liquid through the cup and the amount of time it takes to empty will tell you the viscosity.

There are some good books out there on spray finishing

[Peter R]

I thought that everyone had died on this thread. Thanks for your advice about the cup, did know before as I had bought a Little Beaver (remember them?) years ago and it came with a viscosity cap.
There seems to be the same learning program for spraying as there is for welding, have a go and learn by the mistakes.
The information from the Wattyl Trade depot was better than good as the manager rang me afterwards to tell me to go see a local painter for more advice. Watch out! here comes and expert, which we all know is a little drip under pressure.

Peter R.

[Kev-in Melb]

Hello again Peter,

I used to do all my finishing by hand but now spray most of my work. But decided to get back into spray finishing after years of absence. It can take a little bit of trial and error to get the desired results. I use a HVLP gun (for a compressor) with a 2 mm tip, I find that this will handle most lacquers with out the need of viscosity cup or thinning.

Find your self a good supplier they can be worth their weight in gold for advise and information. A good book to get is “Spray Finishing” by Andy Charron (Taunton Press), if you can’t get hold of it locally try Taunton direct, Fine Woodworking or Amazon Books. You will find it’s cheaper to order it from the USA anyway.

Good luck,

Kev