Opinions on Lacquer

[kcasser]

I had been asking this on another post, but no responses. Please help!

Spraying NitroCellulose Black Gloss lacquer with an Earlex 5000. Humidity is about 60%, Temp ~ 26 C. I'm spraying rectangular picture frames about 9" x 12", 1" thick using the circular pattern. Coverage is very good at about 8".

I've read two ways of doing things -
A) Spray, Dry 30 minutes, Light Sand, Repeat

B) Spray, Dry 10 minutes, Repeat (this one doesn't tell me if I should sand after the 10 minutes or not)

Which is it? And, if 'B', do I sand after 10 minutes or can I just spray immediately?

I'm getting very close, but not close enough. I'm still getting tiny pinholes in my finish. I think I need to thin it a little more. I added a good amount of thinner yesterday than what I had used the day before and the finish was noticeably better - but still some pinholes. With the viscosity cup, I understand water should be 10 sec, Lacquer @ 20 sec. I was measuring water at 12 sec, so I thinned the lacquer to 24 sec, presuming I didn't know the proper way to use the cup, but double is double no matter how you measure. Make sense?

Any opinions would be appreciated. I'll be practicing again today at 5 dst. Thank you!!!

Okay, I shot more paint thinned a bit more, about 16 seconds. Same results. Maybe a photo would help. Any suggestions? BTW, no, it shouldn't be dirt. I filter the paint into the cup and tack rag the frame before painting. It just looks like dry tiny specks.

[joe greiner]

I'm far from an expert on finishing, so take this cautiously.

According to my very imperfect understanding, succeeding coats of lacquer dissolve the receiving coat, so sanding is substantially pointless, unless there's foreign matter trapped.

To reduce trapping foreign matter, hang some wet towels in the spraying area. A small fan can provide a light breeze to keep dust airborne, or toward the towels. The breeze can also discourage bubble formation, by forming a local low-pressure area at the just-sprayed surface - similar to the top of an airplane wing. The lowered pressure may pop bubbles from within; this applies to most products, not just lacquer.

Aside from those suggestions, experimenting on scrap is advantageous to establish a spraying protocol, taking notes along the way; which you seem to be doing already

Best regards,
Joe.

[Mollywood]

Hi kcasser,

I no nothing of lacquering but I just googled the problem and found a site you could have a look at.
www.woodcentral.com (http://www.woodcentral.com)

The info is in -
Russ's Corner
Finishing Secrets
11. Lacquer.

Apparently direct sunlight causes air bubbles to form in the finish.

Anyway, there's lots of info on the type of finish you are using.

Hope this helps, and Welcome.
I'm a newie too.
:)

[Chipman]

Hi,

I am spraying nitro lacquer at the moment on a turned and carved bowl (Wattyl Stylwood) I have also sprayed steel frames for benches with the black version of it.

Now I don't have a cup or measure the viscosity, but what I have found is that.

You MUST use the correct thinner with your lacquer... check with the supplier
Assuming the frames are wood, make sure they are sanded to 240 grit (or 340 grit)..Apply a light first coat and allow to dry. Then sand lightly to get a really smooth surface (using the first coat like a sanding sealer) and give a very light sand to flatten off any nibs of wood.(fur). Now clean thoroughly and start applying nice even wet coats avoiding heavy build ups that may cause runs and sags. Make sure you allow it to dry between coats and their is no need to sand lacquer between coats. If you don't give a wet coat, the lacquer Will hit the surface as dried up dust and little lumps and when you go over it again you will get a rough surface finish (probably what is wrong with yours) Why not try on some scrap with more thinner, try adjusting the gun and your technique to give a thin moist coat.

If you are getting little pin holes where the lacquer seems to be pulling away (looks a bit like orange peel) you probably have little drops of water from the air compressor. You need a regulator and water filter/trap.

Now once you master this much, you can go to the next stage to get a truly mirror finish... Cut it back and polish it. I sometimes wet sand it back with 800 or 1000 grit and then give it a cut and polish..

Hope this helps,

Chipman

[kcasser]

Thank you all for shedding some light. I've turned down the material volume knob, and that seems to be helping. The coats are coming up a little duller, though, which I think is a good sign. I'll build up the finish and then try polishing it.

Joe, how long would you suggest drying before recoating? I've heard 10 minutes and I've heard 30. Is it possible to leave it overnight and recoat without problem?

Mollywood - thank you for the referral. I'll read more there later. I'm painting indoors, so no sunlight.

Chipman - thinner and paint are from the same source. When you say, "Apply a light first coat and allow to dry", have you used sanding sealer first? Or are you applying that first coat directly to the raw wood? How long does it need to dry for? (It seems to be dry very quickly, but still soft) Then, when "applying nice even wet coats", how long do you let it dry between these subsequent coats? Also, what is meant when you say, "cut and polish"? What does "cut" mean, and what do you use to polish it?

Oh, and I don't have a regulator or water filter/trap. The machine I'm using is the Earlex 5000 HVLP, and there is no air adjustment, and I don't know how to put a water trap in this machine. It's nice in that I have fewer adjustments - the only variables I'm dealing with are - amount of thinner - volume of sprayed material, a knob adjustment - and distance between the gun and the work.

I'm familiar with the "dried up dust" finish, and have gotten over that, I think. I got that when I was using a touch-up gun last year. But these spots appeared in my first wet coat, so I let it dry, sanded it all off and repainted. Again, in the first coat, this is the finish I would get. I've now lowered the volume of material, but I seem to need to be a little closer to the work to get a wet coat. I'll keep practising!

Thank you.

[adrian backx]

I had been asking this on another post, but no responses. Please help!

Spraying NitroCellulose Black Gloss lacquer with an Earlex 5000. Humidity is about 60%, Temp ~ 26 C. I'm spraying rectangular picture frames about 9" x 12", 1" thick using the circular pattern. Coverage is very good at about 8".

I've read two ways of doing things -
A) Spray, Dry 30 minutes, Light Sand, Repeat

B) Spray, Dry 10 minutes, Repeat (this one doesn't tell me if I should sand after the 10 minutes or not)

Which is it? And, if 'B', do I sand after 10 minutes or can I just spray immediately?

I'm getting very close, but not close enough. I'm still getting tiny pinholes in my finish. I think I need to thin it a little more. I added a good amount of thinner yesterday than what I had used the day before and the finish was noticeably better - but still some pinholes. With the viscosity cup, I understand water should be 10 sec, Lacquer @ 20 sec. I was measuring water at 12 sec, so I thinned the lacquer to 24 sec, presuming I didn't know the proper way to use the cup, but double is double no matter how you measure. Make sense?

Any opinions would be appreciated. I'll be practicing again today at 5 dst. Thank you!!!

Okay, I shot more paint thinned a bit more, about 16 seconds. Same results. Maybe a photo would help. Any suggestions? BTW, no, it shouldn't be dirt. I filter the paint into the cup and tack rag the frame before painting. It just looks like dry tiny specks.
G'day mate !! I dont know what an EARLEX is but "I love my name is earl !!",your problem is your lacquer is too thick, try using a retarding thinner for nitro lacquer !! and if your picture frames are made of MDF they MUST be sealed with an appropriate sealer at least 2 coats (cut back with 320 grit aluminium oxide paper NOT GLASS PAPER )no real need to thin lacquer any more than 5-10%, a conventional gun with a 1 litre pot 3/4 full lac>1/4 thinners,could also be the tip is too small on the gun !!,Retarder will slow your drying time but let the lacquer flow out easier (also stops chilling in cold weather & blooming in humid),you must sand between coats especially 1st & 2nd,remember GOOD PREPERATION =EXCELLENT FINISH !! and if you want a mirror finish you must cut and buff !!,......Trust me I'm a french polisher with 30 yrs experiance !!......CHEERS ADRIAN.

[kcasser]

G'day, Adrian!

Earlex is an HVLP system. You can see it athttp://www.woodcraft.com/family.aspx?familyid=20047, if you're curious.

The wood is Poplar. It was primed and lacquered by an experienced lacquer painter, but he left some nasty dribs on the frames, probably from fingermarks, and my customer rejected the job. So, I'm trying to do better:C

The tip is 1.5 mm. What means 'cut and buff'? What do you buff with?

Thank you for your help!

Ken

[adrian backx]

HI, Ken Cut and buff = sand with wet and dry 1200. 1400 then buff with buffing pad on drill or arbour using cutting compound (panel beaters ) until desired gloss is obtained (bit of an art) buff speed needs to be about 800rpm or you will burn the finish !!, but if you want the picture to stand out then dont bother !!or your eye will be drawn to the frame !!......AB.

[adrian backx]

Oh and THE HVLP OFF they are USELESS !!, a conventional gun sprays a lot better !!> IWATA W77 is my choice of weapon !!.....:)

[kcasser]

With all respect and appreciation for your advice, I'm hoping there are other opinions on the HVLP since I just spent US$325 plus US$75 delivery to get one.:o I didn't have any luck with the conventional sprayer the last time I tried this project, so I thought HVLP would be the way to go. So far I'm happy with the rig. I just have to find the right combination...:rolleyes:

[kcasser]

Adrian,

I hope I didn't tick you off with my last comment. I only hope I can salvage what I'm doing! I found this site too late in the game, but I am determined to learn this craft so that I can add it to my bag of tricks.

I took your suggestion and used a larger needle and turned down the flow, I added a bit more thinner and some retarder. It's getting better. :)

I'll try more tomorrow. For now it's time for me to go.

Thanks!

Ken

[Chipman]

I am not familiar with your sprayer, I use an air compressor and conventional spray gun. Cut and polish was explained by an earlier post. 1000-1200 wet and dry paper to give the lightest of sandings (water and a little detergent) then use a cutting compound with a wax in it and buff it up (eg kitten cut and polish or swirl remover). For small jobs, I just use a soft cloth and do it by hand and get an excellent finish (follow the directions on the container)

From the further info you have given, it seems like you need more thinner... Light coats and let it dry between coats (about 20 minutes depending on the weather) If you are going to sand heavily it would need to be left over night (My job from last night came out great... 6 coats of lacquer, just needs a light cut and polish now...will do it tonight)

Chipman

[joe greiner]

I'll defer to Chipman's more enlightened experience about timing. Like I inferred, I'm flying half blind here. Anywhere from 10 - 30 sounds about right, though, and overnight for sanding.

On a just revived thread ( http://www.woodworkforums.ubeaut.com.au/showthread.php?t=457 ), Neil (UBeaut) suggests EEE-Ultrashine for polishing instead of rubbing compound. Now known as simply Ultrashine because some of the upover gang didn't appreciate the pun (although I really liked it!). Penn State Industries is the Oosa distributor: http://www.pennstateind.com/

Interesting low opinion about HVLP. I had the impression it was the duck's 'nads. At the moment, all I use my compressor for is filling tyres and occasional dust clearance, so need more research before I take the plunge.

Joe

[kcasser]

Thanks, Chipman! Yeah, a bit more thinner seems to have worked wonders. I'll know more later tonight when I try again. It's confusing because in one place I read to use 60% thinner, 40% lacquer. Adrian suggests 5-10%, of course then he said 3/4 lacquer and 1/4 thinner which seems more like 25% to me:rolleyes:, but anyway, I think I'm at about 50/50 right now. It's also been suggested to use a thicker tip, but wouldn't that give me a heavier coat? I tried it but really couldn't sense much of a difference once I had it thinned enough.

Joe - EEE - it took me a while to get it, but I understand the pun:doh:

Regarding the HVLP, we really only have one negative opinion on it. I'm sure Adrian knows his stuff, and it does seem like everyone else is using a conventional gun, but I will say that I've been very happy with the unit. I like not having to deal with adjusting air pressure and air flow - it takes those two variables out of the mix. Also, it's really easy to clean and seems very well constructed. As mentioned, I tried lacquer before with terrible results using a conventional gun, but, it was only a small touch-up gun which may have been part of the problem. And, I knew much less then than now, and may not have thinned it enough. Also, I was working in an open garage where there were breezes blowing through causing the lacquer to dry prematurely. If I were to do it over, I would probably follow Adrian's advice and pick up a better conventional gun. It would have been cheaper since I already have a huge compressor here at work, and it probably would have been easier getting qualified advice. Oh well, I have what I have and I'll see it through to its conclusion. I'll let you know how we make out.

Thank you everyone for your support and advice.:)

Ken

[kcasser]

Joe,

I just learned one plus for HVLP - you don't need a water separater because HVLP eliminates the heating and cooling of the air stream. In a conventional system, the air is heated by the compressor and pushed into a tank. It cools down in the tank. Then, you go to spray with it and the air can be cooler than the dew point causing condensation on the work. HVLP blows the air directly from the turbine and it comes out warm all the time. There's no chance for it to cool before spraying so it stays dry. Very interesting. :)

[Chipman]

I have never used HVLP but have heard that it is very good. Must try it some time

Chipman

[kcasser]

I'll be the guinea pig. :roll:

[durwood]

I'm in the USA now (New Jersey) and its damn hot and humid. and the temp is a big factor you paint is too thick especially in the 85 F plus heat we have been having the last couple of months.

First lacquer needs to be thinned at least 60% thinner and 40% lacquer to start with and you can work right down to pure thinner ( even retarder if you know what you are doing) put on about 5 coats all up start with 60/40 for the first two then if the surface is not flat or has nibs in it rub it smooth with 320 and then thin the material further for the next 3 coats. (Check before applying the following coat and correct faults before you spray over them.) so add retarder as suggested. ( put about 5% in no more or it will take too long to dry) don't spray over the coat if it goes milky, you will trap water under the finish and you may get blisters in the paint. Keep any water far away from the paint spray in an open ventilated area preferably with a breaze.

In the hot weather leave 10 minutes between coats (not seconds) at least. it doesn't matter how long you leave it between coats but it does matter how short a time you leave.

If you are getting pin holes the paint is too thick and heavy. what happens is the lacquer dries so fast it dries on top before the thinner underneath can escape so the thinner bubbles up to the top.

When lacquer was used on on cars the finish always came off the gun, we did not have a buff in the shop. if it needed to be flatter we rubbed it flat with abrasive paper and then sprayed a really thin mixture of straight thinner (retarder in the heat) You don't need suoer fine paper such as 1200 to 2000 that is only necessary for acrylic lacquer ( entirely different material to spray)

Your gun is not really right for lacquer you need a bigger tip (1.8 to 2.0 mm) your gun is for enamel. HVLP was designed to reduce the overspray which resulted from the higher volume conventional guns its not designed for lacquer, in theory lacquer is old hat and environmentally bad and is banned in a lot of places. because of the solvent emissions.

you can't get enough paint for the amount of air, so you will need to keep the mixture thin and hold the gun a bit closer and move a little slower.

You may not get moisture from a turbine as you do from a compressor but lacquer takes the moisture out of the air which is a far bigger problem to your finish. If its coming from the air hose you will see it in the paint as you spray it as the two don't mix. Its the blushing ( milky finish) that is lacquers problem if its cold and wet its damn near impossible to use unless you have heaters. So it messes up when its hot and humid as well as cold and wet.

Unfortunately nitro cellulose lacquer has not been a normal finish for over 30 years and most who are now using it are guessing (and getting it wrong) as most of us who were brought up on it are dead and buried.

I may be able to offer some more advice if needed but try what I have suggested first as we are on the road and won't be home till the end of the month. Do a search in the forum as there is also better way to get a mirror finish, black lacquer used to be the paint used on grand piano's its so easy to work with if you do it right. If its sprayed on thin and flat onto a flat surface it will dry to a great glossy finish if it done badly you have to rub it flat, its not meant to be done that way

[Vernonv]

Oh and THE HVLP OFF they are USELESS !!, a conventional gun sprays a lot better !!
That is far from my experience. I personally think HVLP guns are great. I used to use a conventional gun and was pleasantly surprised when I moved to HVLP - and I have never gone back. The majority of my spraying has been lacquer and as Durwood has already mentioned use a bigger tip (although I can't remember if the one I use is a 1.8 or 2.0).

[kcasser]

Thank you all! I'm getting better and better. But, I thought that for thinner materials, like lacquer, you would need a small tip. Anyway, I couldn't tell the difference between the 1.5 and the 2.0, so I may as well go back to the 2.0 and will thin some more. I've been lucky with the weather. Humiditiy has been about 60%, temp about 80F. Even after the rains it dries out. More next week :)

[kcasser]

Durwood hit it right with his other post - us crazy people start out wanting to spray a beautiful lacquer finish with not a clue as to how to do it :D:D:D

Anyway, thanks to you all, I'm most of the way through the basic learning curve. I started one week ago fearful and frustrated as I had promised my customer a terrific lacquer finish, but couldn't get it done by others, and realized I would have to do it myself. (Actually several years ago I tried this project, but I gave up quickly after realizing I was in over my head). My first attempts last week were very frustrating, but thanks to the help on this board, I quickly was steered closer to the right direction, and by keeping at it I've achieved the following result:

80175

I don't think the photo does the work justice, but to me it's INCREDIBLE!:):):)

This frame still needs a couple of more coats, but at the moment it is pretty perfect - no drips or sags, no dry spots, no pinholes. Unbelievable. And, last night, I took another piece and did a little buff on it. It was like BUTTER. It felt like a baby's behind.

Thank you, thank you, thank you. I've gone from fearful and anxious to excited and proud in one short week. I know there is much more to learn, and I'll work more on it as time goes by, but I'll be able to satisfy my customer with very good work in a timely manner from now on, and a bit more profit in my pocket. I can't thank you all enough.

G'day, mates!

Ken

[kcasser]

For others out there who may be as confused as I was, here is what I think - you pros, correct me if I've got it wrong.

You can recoat after a minimum of 10 minutes, which you would do if the most recent coat is flawless. If it's not flawless, wait 30 minutes, do a light sanding to remove any flaws, then recoat. ie, you don't have to sand between coats, but if you need to, you have to wait the 30 minutes or more. If you need to do a heavier sanding, it's best to wait overnight. Then (my recommendation) hand sand only. If you try to use an orbital sander, the finish starts to ball up and makes a mess, and more work. 320 grit should take care of anything you need to take care of. Then, after building up 4 to 6 coats of depth, let the finish cure for 2 or 3 days. Then, if you want, you can buff it out and it'll look like butter. Oh, and don't let two pieces of lacquered work touch each other until fully cured. They'll stick together and make a mess. In fact, don't let anything touch the lacquer until it's cured. It looks hard but is still a bit soft.

[Chipman]

Kcasser,

You have it right.... only thing I would do is leave it longer than 30 minutes (guess it depends on the product) and only ever wet sand...

Glad it has all worked out for you,

Chipman:)

[kcasser]

Thanks, Chipman. One question - "only ever wet sand" - does that mean ever, or just at the end to buff it up? With my frames, I'm hesitant to get water in the rabbet.

[Chipman]

You don't need to flood it with water but it should be just wet and rinse your paper regularly.. I would hope that the rabbet is at leased sealed with one coat.

The wet sanding helps prevent "balling up" and other sanding problems. You can dry sand but you get a better finish with wet sanding and the paper is less likely to clog up.


Cheers,

Chipman

[durwood]

Wet rubbing gives a better finish (less scratchy) but its main advantage is it stops dust. Important in a shop if you are doing a lot of sanding. It will also be easier to sand if you use a neutral soap to lubricate the paper. In Australia we have sunlight soap but any soap will do, there is just no need for the perfume.

As to drying time.

lacquers dry by evaporation of the solvent (thinner)

the hotter it is the faster it dries out

the longer between coats the drier each coat becomes.

So if you have time leave it as long as possible between coats.The longer each coat dries the less solventu underneath the following coat gets trapped.

5 coats put on over a few hours dries quicker an harder in a few days than 5 put on in less than an hour.

Obviously if you want to put on more than 5 coats its important to leave longer between coats. Hot rodders often put on up to 40-50 coats yo get a mirror finish (it only works if you do this over a period of weeks)

[BrettC]

Some great info in this thread thanks for sharing :ok:

[kcasser]

I agree with Brett :) Your help has been tremendously, well, helpful!

Durwood, I've seen other references to using the soap with the wetordry. How does one get the soap off the wood after sanding if one doesn't want to flood the wood? I guess a wet rag would work, then let it dry, then tack rag it?

I also want to say that the detail you put into your responses makes the process much more understandable. This is really getting to be fun. Thank you! :U

[durwood]

You only need enough water to allow the abrasive paper to be lubricated while you are rubbing. On a small object like your frames all you need to do is dip the paper into water and remove it. There should be enough water on the abrasive to allow you to rub. You can only rub one bit as a time so there is only a need to wet that actual area before you move on.

Only a small amount of soap is needed. If you are doing a small area and intend using you fingers to rub just rub the wet paper on the soap with your finger behind it and get yourself a dime sizes smear of soap. A small block of rubber or a piece of flexable plastic can be used to form the shape of the area if needed.

Only ever rub surfaces which have some area ( such as the width of the frame, Don't go near edges. ) They don't show faults , are usually thinner with less paint on them and easily rubbed through ,stay on the large surfaces where the reflection takes place..

If you were sanding a large flat surface (say a table top or any flat surface,) you should always use a flat block as a backing NOT your hand.Doing so means only the contact points of your fingers will rub and you will get grooves in the surface. Usually a flat rubber block that fits a quarter sheet of paper is used.

What you are doing is similar to using a plane on wood to get a straight edge, the block touches the high spots and removes them. The paint goes dull as you have scratched it and if you wipe it off ( use a thin sweegee rubber you can buy or a soft plastic straight edge) to wipe away the water (just like claning a window) you will see the dull rubbed spots and shiny ones where rubbing has not taken place. Keep rubbing till the whole surface has no shiny spots. Its then flat.

You wipe away the water with a rag or a sponge like a wetex cloth (or old Chamois) and use compressed air to make sure all the water is dried away especially if you have joins etc in the area As there was no dust you don'r need to tack rag. Just proceed with the next coat. If you wan to make sure it is really clean wipe again with a wet cloth and blow dry.

If you are going to compound or polish remember that the paper has scratched the paint surface, if you have worked towards thin coats as you build the marks you needed to rub should be small and therefore you can use fine paper this will make the removal of scratches easy if the paper is too course yoy will have to rub them out ( in other words rub away all the paint till the surface is flat the depth of the scratches.

There is no need to rub unless somethig is wrong and needs removing. What one would do is apply thick coats first (60/40 mix - 2 -3 coats rub to flatten and remove any peel which is usually present from thicker coats. once flat follow with thinner coats to melt down and fill the scratches and add more material and if sprayed properly the finish should not need much if any rubbing except for minor marks and with fine paper.

Watch using a finger to remove a speck of dirt etc if you rub the speck with a soft finger behind the paper you will rub a dip in the surface, possibly rub through as your finger being soft will ride over the imperfection and rub material from around it which is less in height than you dirt.

Finally you should not be getting water on or in the wood, if it is coated with colour or clear it should be sealed off from the wood, Thats why you paint to protect the surface first and decorate it second..

You don't want to get the timber wet if it is and you paint over it the paint will peal off the surface. Only ever wet rub if you know the wood is not going to get wet from contact with water . If you aren't sure ( maybe it can get into the mitre joints) of your frames -rub it dry.