Help! Alclad / airbrushing problem!

[Madoc]

Folks,

I need some help here.

I'm using Alclad paints for the first time and have run into some problems.  I put on a primer coat of Alclad's "honey" primer and that worked fine.  Yesterday I then sprayed on a coat of Alclad Duraluminum and it has come out looking and feeling "dirty."  That is to say, somewhat rough in texture and appearance.

Early in the day I'd put down a coat of Alclad steel without issue.  Same airbrush and all.

Any suggestions here?

I made sure to keep the model clean and I put the Duraluminum coat on lightly with repeated passes.

Your help would be appreciated!

Thanks,

Madoc

[Ian the Kiwi Herder]

Yep same thing has happened to me too.

I know this sounds corny, but if there is ANY moisture in the air, when you fare spraying then it seems to react with the lacquer and produce a surface like fine grade wet 'n dry.

I never spray ALCLAD if there is any hint of damp in the air.

It seems you have done everything right, the only other suggestion I could make, would be to use TAMIYA GLOSS BLACK acryllic as a base coat after you sand-back the rough Duraluminum - their rattle cans are fine for this. Then simply try again.

Always remember two coats at lo pressure.... NEVER try to do it in one pass !!

Best of luck

Ian

[John Howling Mouse]

I may not be comprehending but are you saying that Tamiya now has acrylic paint in spraycans?  I thought all Tamiya spraycans were of the lacquer type.

I'd sure like to try this out if a Tamiya spraycan product is compatible as a basecoat with Alclad.

[matrixone]

Madoc,

I have had success spraying AlcladII aluminum and white aluminum colors by using heavy coats instead of 'misting' the coats on. When I tried to paint Alclad by misting a few light coats on I also got the same result you described.

Heavy coats of Alclad work very good but ALWAYS keep that airbrush moving to avoid any runs from occuring from the Alclad pooling up.

Matrixone

[Ian the Kiwi Herder]

Strange isn't it... I have never had any luck trying to spray Alclad in one go - good for you MX1, I'm very jealous !!

Ian

[Jay Laverty]

All good advice so far, and the only thing I can add is that I always buff the surface primer to a shine before I apply the metallic laquers. these will show up any and all imperfections like a sore thumb.

Also John, Tamiya don't make the rattle cans in Acrylic, alot of people just assume that Tamiya=acrylic, because of the pots. They are indeed only the laquers in the rattle cans.

Cheers,

Jay  

[Ian the Kiwi Herder]

Also John, Tamiya don't make the rattle cans in Acrylic, alot of people just assume that Tamiya=acrylic, because of the pots. They are indeed only the laquers in the rattle cans.

Cheers,

Jay

I stand corrected - bows head to superior knowledge  

Ian

[jcf]

The Tamiya spray bombs are an Acrylic Lacquer.

The word Acrylic refers to the composition of the resin base...not to how the paint is thinned.
Acrylic paints can be water-thinned or solvent-thinned and in some cases they can be thinned with either...Tamiya acrylics spray very well if thinned with lacquer(cellulose) thinners.

BTW "water based" is a misnomer when referring to water-thinned acrylic model paints...none of them are water based, they are all Acrylic resin based, and should properly be called "water thinnable" or "water cleanup".

Cheers, Jon

[datguy]

The Tamiya spray bombs are an Acrylic Lacquer.

The word Acrylic refers to the composition of the resin base...not to how the paint is thinned.
Acrylic paints can be water-thinned or solvent-thinned and in some cases they can be thinned with either...Tamiya acrylics spray very well if thinned with lacquer(cellulose) thinners.

[SNIP]

Wow Jon,

I find this intriguing.  Do you have experience with other water-thinnable product lines spraying with lacquer thinners?  

In your experience is there ever any of the problem folks have had with cracking of the (water-thinned) acrylic over enamel undercoats when you take this approach?

I have lamented the passage of Floquil's lacquer based paints from the US market because I found them to be the absoultely best primer coats.  I am now tempted to try lacquer-thinned Tamiya from the pots as my primer coat, followed by the usual water-thinned paints.  Sadly my LHS doesn't carry the Tamiya paints...

BTW, I haven't experienced the rough Alclad problem, but my spray booth is in an air-conditioned area.  Given my otherwise utter ham-handedness with airbrushing, with a distinct skill for messing up any kind of airbrushed finish, this suggests that maybe moisture is the problem with rough Alclad.

DG

[jcf]

The Tamiya spray bombs are an Acrylic Lacquer.

The word Acrylic refers to the composition of the resin base...not to how the paint is thinned.
Acrylic paints can be water-thinned or solvent-thinned and in some cases they can be thinned with either...Tamiya acrylics spray very well if thinned with lacquer(cellulose) thinners.

[SNIP]

Wow Jon,

I find this intriguing.  Do you have experience with other water-thinnable product lines spraying with lacquer thinners?  

In your experience is there ever any of the problem folks have had with cracking of the (water-thinned) acrylic over enamel undercoats when you take this approach?

I have lamented the passage of Floquil's lacquer based paints from the US market because I found them to be the absoultely best primer coats.  I am now tempted to try lacquer-thinned Tamiya from the pots as my primer coat, followed by the usual water-thinned paints.  Sadly my LHS doesn't carry the Tamiya paints...

BTW, I haven't experienced the rough Alclad problem, but my spray booth is in an air-conditioned area.  Given my otherwise utter ham-handedness with airbrushing, with a distinct skill for messing up any kind of airbrushed finish, this suggests that maybe moisture is the problem with rough Alclad.

DG

The Tamiya is the only one I've used the lacquer thinner trick with...Polly S and MM Acryl use a different sort of Acrylic base and as I've had both respond badly at times to alcohol, I've not  tried them with the lacquer thinner.

As to cracking of acrylics over enamels its not something I've ever experienced and I always use enamel or lacquer as a prime coat. If you are spraying over a glossy enamel surface you may want to try roughening the surface slightly, give it some "tooth" for the acrylic to adhere to or waiting for the solvents to thoroughly off-gas...trapped solvents can cause bubbling of the much less porous acrylic coating. Acrylic paints literally produce a layer of plastic.

BTW the Floquil paints are still available in the Railroad colours and they were never "lacquers" but have always been an alkyd-oil enamel with a hot-solvent carrier...mostly a mixture of xylene and toluene. They changed their formula by reducing the amount of xylene in the carrier and their Dio-Sol thinner because of health concerns. You can easily get Floquil performance out of most enamels by thinning them with lacquer thinner rather than paint thinners. The "hotter" solvents in the lacquer thinner will give better spraying, faster drying and great leveling.

Both xylene and toluene can be purchased in bulk at hardware stores in the US if you want to charge up your old Floquil.

Paints consist of three primary components:
Base, Pigment and Carrier.

The most common bases are:
Natural lacquer...from plant sap; "hot" hydrocarbon carrier/thinner.
Cellulose Lacquer ...manufactured from wood and plant fiber; "hot" hydrocarbon carrier/thinner.
Synthetic Lacquers...Phenolic Resin (phenolformaldehyde popularly known as Bakelite) and Acrylic Resin. The Acrylic Resins can be used with "hot" hydrocarbon solvents or water/glycol/alcohol carriers depending on the formulation.
Epoxy...most use "hot"(and nasty) solvents but there are some primers that use water.
Urethanes...1 and 2 part, "hot" solvent carriers but also a couple of types that use water.

Natural Resin Oil...tung oil etc, "cool" hydrocarbon carrier/thinner.
Alkyd Resin...synthesised resin created by the reaction of alcohol and an acid, "cool" hydrocarbon carrier/thinner. The majority of "enamel" paints are alkyd oil based. The term enamel is properly only applied to gloss paints...they were called enamel when first developed in the 19th century because of their resemblance to "true enamel" which is melted glass frit. Flat or matte enamel is actually an oxymoron.

Carriers(a coating's thinner is usually the same as its carrier, or a major component of the carrier) are the various hydrocarbon solvents, the hot ones being things like acetone, toluene, xylene etcetera or combinations of same (generic lacquer or cellulose thinners are combinations of different solvents) the cooler solvents are turpentine, paint thinners/white spirit and naptha(Zippo fluid or white gas) among others. Naptha BTW is an excellent thinner for most model enamels.
The carriers for most "water-based" paints(a misnomer as the paints are resin-based) are mixtures of various sorts of glycol, alcohol and water. Water is the main constituent of both alcohol and glycol...thus the reason the paints can be thinned and cleaned up with water.

If possible it is always best to use a given companies proprietary thinner or reducer as it is matched to the formulation of their paint.

Apologies for the long-winded post but its info I acquired while researching coatings for a boat restoration project, and I learned some of it the hard way. :dum:

Cheers, Jon  

[datguy]

Thanks Jon,

That is simply the most cogent summary of paints I have ever seen.  I will be saving it in my techniques folder for reference.

With much gratitude,
DG

[Jennings]

I never spray ALCLAD if there is any hint of damp in the air.

Do you live in Antarctica?  And only spray in the depths of winter?

J

[Ian the Kiwi Herder]

Do you live in Antarctica?  And only spray in the depths of winter?

J

Yes  

I.

[John Howling Mouse]

Here is another good site of Q&A re: paint.  Although aimed at residential/industrial painting of buildings and such, the info is a good tutorial on what's in paint and what each element does and how they interact and react...

http://www.vansicklepaint.com/howto.htm