Airbrushing varnish: advice sought

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Guy Rixon
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Airbrushing varnish: advice sought

Postby Guy Rixon » Sun Mar 17, 2013 12:11 pm

I need to varnish some wagons and will later need to varnish coaches. Having had bad experiences with spray-can varnish in the past, I'm planning to use an airbrush. I've airbrushed paint with success but never tried varnish, so I'm seeking guidance.

Are there any differences between spraying paint and varnish? Maybe in the dilution? Different thinners?

If the stock has enamel paint, does it matter whether I spray enamel varnish or acrylic? And vice versa?

Are there preferred brands?

Should I spay one coat or more? If more, how long to dry between coats? What should I look for to tell when a coat is complete?

Some of these models are old friends, started decades ago and only now getting finished. I would hate to ruin them at the last step...

beachboy
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Re: Airbrushing varnish: advice sought

Postby beachboy » Sun Mar 17, 2013 6:24 pm

Hi Guy,

Many preferred methods in various modelling Hobbies.

For Enamel - I spray Humbrol brands, with Precision Paints specific branded Varnish thinners.
Acrylic - Ronseal Diamond Hard, with Tamiya Thinners. Humbrol are introducing a new Thinner for Acrylics.
I then overspray in required areas with Humbrol enamel varnish where I require a matt, or satin etc effect. ie roof canvas, or underframe areas.
Mix in a Thimble around 40/60paint, & empty into the Airbrush chamber. Spray close so the paint lands wet at 20 psi - Distance & pressure depending on which size Airbrush I use.

I prefer two thin coats in a warm enviroment. Have a heated Toolshed for the purpose of spraying, with extractor, a Daylight lighting. But tend to leave painting till warmer times setting up on the Workmate etc outside with a beer to allow relaxed approach.
When required I brush thinned Gloss varnish on where transfers to be applied, before the above.

With Enamels I recoat within the hour particularly gloss, or leave 24hrs B4 recoat. Acrylics - leave an hour 'tween coats
Thence leave model 24 - 48hrs plus to cure.

I have painted one coat only by brush many Gaming figures & sealed with the Ronseal out of the tin, then toned down with a mat etc varnish on clothing etc. Have done the same with wagons using artist brushes, but start to thin as the varnish thickens. Particularly with Acrylics. ProArte 1/8th or wider flat brushes for the say - sheeting or roof areas.
Some special effect paints like Metalcote loose their effect when varnished.
Prefer Acrylic as less toxic; & blends & mixes well. But may use both on a project.
Clean out with cellulose, like Rustins. Not sure if Halfords is genuine. A stainless steel tea strainer dish is ideal for larger mixes &/or s/steel ash tray ideal for cleaning or soaking smaller Airbrush parts.

Regards Steve.

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Guy Rixon
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Re: Airbrushing varnish: advice sought

Postby Guy Rixon » Mon Mar 18, 2013 5:18 pm

Thanks for that advice, Steve. I'll get myself some of Humbrol varnish and the special thinners from Precision.

bjuleff
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Re: Airbrushing varnish: advice sought

Postby bjuleff » Thu Aug 22, 2013 11:15 am

Seeking advice on varnishing, I have just seen this thread and I wonder if I could tease out a little more information from those in the know. I have experimented with a number of aerosol varnishes and have learned to be wary of those which attack my transfers. I have found Halfords and Citadel (Games Workshop) cans produce a good finish over the paint but wrinkle the transfers. On the other hand Humbrol satin varnish is excellent on paint and transfers.

As I would like to progress to airbrush work in the future, it would be useful to know what are the differences in the ingredients of these products. I am guessing the first two have a cellulose based thinner, but what sort of thinner is in the Humbrol tin? And is this an enamel or polyurethane varnish?
Bob

DougN
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Re: Airbrushing varnish: advice sought

Postby DougN » Thu Aug 22, 2013 11:37 pm

Bjuleff, I think you need to have a look at the Humbrol website. There are a number of Varnishes available and they can either be Enamel or Acrylic. So the answer to your question is yes, depending on which can you have purchased. May be ask at your local model store which one they would recommend. Though I would stick to "like with like" for varnish over paint, so Enamel with enamel. I have yet to use any varnishes but I will be using a Tamyia vanish over my meth fix transfers when I get a "round tuit".... Struggling with time at the moment :evil:.... and I can't exactly Varnish something with a can at a Exhibition tomorrow!
Doug
Still not doing enough modelling

beachboy
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Re: Airbrushing varnish: advice sought

Postby beachboy » Fri Aug 23, 2013 12:34 am

Stay safe, and use the same makers paint & varnish for modelling.
I've used Halfords for metal wheels OK, but would only use light passes on a model. It reeks of cellulose, or substitute.
Citidel works well, and is v poplular. GW figures, plastic, metal, resin, are suplied with waterslide transfers, & sprayed by the thousand.
Military guys voted for Testors, but its finding it. Tamiya with their thinners works well. The thinners is often used for AB use of acrylics.
Have often used Humbrol enamels for different effects on the model. Have heard of people being unhappy with recent stock.
Would not use cellulose paint or varnish with another medium. Other than mysty spray passes. Mix enamel & acrylics ok.
Often use variants of Ronseal acrylic varnish. Keep the lid clean, or the rock hard varnish will defy closing. Several thinned brush coats of Diamond Hard on areas where handling is useful
Vallejo have ready mixed paints/varnish for the AB. Windsor & Newton is v good.
Transfers need suitable surface prep. & sealed where maker recomends. Will lift or break up with age . Store in fridge. away frm frzr.

If you want a good companion to railway modelling painting etc, Ian Rathbones WSwan book has good advice on every page.
Steve.

williambarter
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Re: Airbrushing varnish: advice sought

Postby williambarter » Fri Aug 23, 2013 5:23 am

As to airbrushing technique, I find that a thin mix - at least half and half varnish and thinners, sprayed at low pressure, about 15 psi, with low rate of flow works for me. I tend tow ards thin at low pressure for paint anyway but for varnish find it essential.

As ever - try it out on a test piece, one of those old part-built kits that now never will be, for instance, until you have found what works for you. Test the flow by spraying into a tissue immediately before you start. Start spraying away from the model and move onto it once flow has started. Start work on an end, the inside or the underside on which an imperfect job might be tolerated, and not a side where any disasters will mean stripping and starting again. And make sure you have something to hold the model by as you work, often worth bolting a couple of long bolts into some hole or other to pick it up by.

William

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Jol Wilkinson
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Re: Airbrushing varnish: advice sought

Postby Jol Wilkinson » Fri Aug 23, 2013 7:18 am

If you are applying varnish over white or a very light colour I would avoid enamel varnish. It will "yellow" over time. I have found that from personal experience with Humbrol and have heard from the manufacturer that it will also apply with PPP enamel.

Humbrol Satin Cote or Matt Cote are claimed to be non yellowing. The Microscale products and Testors may also be worth considering.

Jol

bjuleff
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Re: Airbrushing varnish: advice sought

Postby bjuleff » Fri Aug 23, 2013 9:50 am

Many thanks to all who have replied to my post. Interesting reading.

Steve was saying stay safe use the same type of varnish over the paint. Well my paint was Halfords aerosol car paint, presumably with a cellulose type thinner and with the same range varnish it produces minute "crackling" of my waterslide transfers, indicating I need to match the varnish to the transfers. Strangely my experience of Citadel was not as good as yours, as I got the same "crackling" effect.

I do indeed possess Ian Rathbone's excellent WS book, but frustratingly he does not state in his chapter on varnishes, what thinners he uses with Ronseal polyurethane. I have had good transfer coverage with this, albeit spoilt by brush marks, hence my desire to move to airbrush. (Thanks for the technique tips, William).

Having checked the Humbrol website, Doug, I am sadly no wiser as to the difference in thinners between acrylic and enamel sprays. All I know is the enamel one is fine with the transfers, so it would be good to replicate this mix in an airbrush.

I was interested to hear Steve recommend keeping transfers (?) in the fridge. Have I got this right?

Bob
Bob

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Andy W
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Re: Airbrushing varnish: advice sought

Postby Andy W » Fri Aug 23, 2013 1:28 pm

[quote="Jol Wilkinson"]If you are applying varnish over white or a very light colour I would avoid enamel varnish. It will "yellow" over time."

I know you spray in celulose Jol, but what varnish do you use on top of the transfers?
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Phil O
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Re: Airbrushing varnish: advice sought

Postby Phil O » Fri Aug 23, 2013 1:55 pm

I brush on Johnson Klear over the paintwork before applying the transfers if this is any help. I might add that Johnson's is no longer available but there are several threads on RMweb http://www.rmweb.co.uk which give the current alternatives.

HTH Phil

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Tim V
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Re: Airbrushing varnish: advice sought

Postby Tim V » Fri Aug 23, 2013 2:58 pm

Must be a very old tin of Halfords paint, all recent stuff is acrylic.
Tim V

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Jol Wilkinson
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Re: Airbrushing varnish: advice sought

Postby Jol Wilkinson » Fri Aug 23, 2013 3:25 pm

Ealing wrote:
Jol Wilkinson wrote:If you are applying varnish over white or a very light colour I would avoid enamel varnish. It will "yellow" over time."

I know you spray in celulose Jol, but what varnish do you use on top of the transfers?


Hi Andy,

in the past I used Humbrol, which is why I know about the yellowing.

More recently I've used Johnsons Klear but didn't really like it, so am about to try some Microscale Satin. That's part of a range used by aero modellers, who I usually think are a bit more advanced than we steam powered types when it comes to getting really good finishes.

Ronseal is also supposed to be very good but I haven't tried it.

I've also been persuaded to try Testors Dullcote, although that is in a spraycan and I prefer to use an airbrush.

Jol

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David Thorpe
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Re: Airbrushing varnish: advice sought

Postby David Thorpe » Fri Aug 23, 2013 4:16 pm

I've just been reading George Dent's book on airbrushing for railway modellers. For oil based varnishes he recommends Humbrol's synthetic enamel Clear Cotes, which he says dry to a "crystal clear" finish. For something extra special he might "upgrade" to Phoenix or Railmatch which he considers to be slightly more durable. He warns that all should be given at least a day or two to harden properly. For arcylics, he's still using the old-formula Klear he bought years ago, but he recommends Iwata's ComArt range which comes ready thinned for use in airbrushes. It's apparently very similar to the old Klear. One technique he mentions which I've certainly never tried but sounds interesting is floating waterslide decals onto a wet layer of acrylic varnish, such as Klear or ComArt, to achieve a painted-on finish.

DT

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Mike Garwood
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Re: Airbrushing varnish: advice sought

Postby Mike Garwood » Fri Aug 23, 2013 6:44 pm

I've also been persuaded to try Testors Dullcote, although that is in a spraycan and I prefer to use an airbrush.


Hi Jol,

You can get Dull cote in a bottle for thinning with cellulose for spraying. I have tried the rattle can and it covers really well and very matt. I have not plucked up the courage to spray the the bottled stuff, which given the fact that I spray in cellulose is a bit odd really!

Mike

Knuckles
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Re: Airbrushing varnish: advice sought

Postby Knuckles » Fri Aug 23, 2013 10:06 pm

Is Klear really impossible to get now? I've been wanting to try it as a varnish for a long time myself.

You may be interested in knowing what I used it for as a squaddie: Iron your trousers and shirt sleves, then spray a load of Klear on them and wait for them to dry 100%. If you don't wait until they are completely dry then you will permanently stain them when you iron them. So, once ironed hard with plenty of steam, Klear turns your creases into rock hard plasticky razor edges. Wonderful cheating result when wanting to be rigid with presentation standards. 8-)
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LesGros
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Re: Airbrushing varnish: advice sought

Postby LesGros » Fri Aug 23, 2013 11:01 pm

Knuckles wrote:
Is Klear really impossible to get now? I've been wanting to try it as a varnish for a long time myself...


Try this u-tube link: http://uk.ask.com/youtube?q=klear+floor ... Y&qsrc=472
LesG

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Knuckles
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Re: Airbrushing varnish: advice sought

Postby Knuckles » Sat Aug 24, 2013 6:23 am

Thanks for the link. That was really informative.
Guess I'll try a bottle then. If the new stuff dries clear (or Klear) then I guess it'll be ok, I can see application being a tad awkward in comparison though. Will look out for it.
“He who dares not offend cannot be honest.” Thomas Paine

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beachboy
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Re: Airbrushing varnish: advice sought

Postby beachboy » Sat Aug 24, 2013 7:36 am

Bob,

If you wish to spray Ronseal, mix with Tamiya XF20A acrylic thinners. You may buy some cheap from a closing down Modelzone.
Tamiya are quality paints.
I have sprayed & brushed this on waterslide, HMRS both types, POW Sides, & waterslide tranfers with no problem.
Do allow the paint etc the given time to cure for each application.
Humbrol enamel, Vallejo acyrlic, - & the older Johnsons Klear & others have all been fine.
I have found waterslide & HMRS transfers have not aged well, but lowering the storage temp. has preserved them well.
Otherwise they crack & wrinkle, or loose tack. POW need to be used sooner to obtain the best application.
I have sprayed Halfords paint, & had to use pure cellulose to stop blooming despite the metal being at 20c plus. On car panels, steel rail & metal kits post primed. Their Car Plan paint mixes are cellulose based. Their tins of brush paint need a lot of cell. thnrs. to ever be able to brush without instant drying.
Older yellowing varnishes would be authentic for older railway applications ?
Which puzzles me in that it is said the Grt Westn became a yellow & brown for their coaches because of this. But LNWR, & Caly which seem to use a pale whiter base colour did not. Paint mixes, lead values may be relavant, but is that correct, or is there a given reason?

Steve.

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John Bateson
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Re: Airbrushing varnish: advice sought

Postby John Bateson » Sat Aug 24, 2013 8:08 am

Les,
Very enlightening video - will add a bottle to the shopping list.
John
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Avoiding the soaps ...
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beachboy
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Re: Airbrushing varnish: advice sought

Postby beachboy » Sat Aug 24, 2013 9:14 am

Just a thought on varnish - why use it ?

I appreciate the given wisdom is standard proceedure is Precision 'X' colour and a coat of varnish, & its authentic.

Yes it protects, & a seal for transfers. Although enamel & acrylic paint can be quiet tough. But the varnish can be dirted by handling, or scratched.
Some modellers will not use it.
If you you like overcoming the lack of light reflection on a small model, and add highlighting with lighter variants of the given colours to bring life into a model. Varnish can negate these effects. I have also found some initial colours have lost their 'brilliance' after a relavant varnish.
I painted my take on the Wills cottage with this painting method with acyrlics, with highliting, blending & washes. Looked realistic. Although over highliting on a small model can look exagerated. After the varnish, the effect was significantly knocked back, to then require a paint revisit. I suspect the matting content. Gloss is usually ok on its own.
I know the Games Workshop of display figures are not varnished because of this.
I remember a guy who used to produce a lovely coachwork painting on his car, but refused to put on any varinish material.
Unfortunately, the lead effected his health. I cannot recall if wax polish then generally about then.
As I say, just a thought.

bjuleff
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Re: Airbrushing varnish: advice sought

Postby bjuleff » Sat Aug 24, 2013 10:51 am

Hi Steve,

Thanks for the useful info about thinning Ronseal for spraying. To take up your later point about why varnish at all, my prime reason is to put a protective layer over the transfers, rather than to protect the paintwork. But to get a uniform coverage the whole area has to be coated. Unless there's another way? I do take the point, however, that some varnishes will yellow over time.
Bob

dal-t
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Re: Airbrushing varnish: advice sought

Postby dal-t » Sat Aug 24, 2013 11:49 am

As someone who occasionally switches from modelling things on rails to things with pointy fronts and sticky-out wings, I'd like to throw in my two ha'puth on this one, please:-

Enamel/Acrylic/Cellulose The best advice is stick with one or the other, particularly if you're not sure what is compatible and what isn't. Remember cellulose attacks plastic, so needs a barrier coat, but it sprays wonderfully and gives a super finish. It's also toxic (most things we use are, one way or another). But whether it is worse, from an airbrush, than acrylic is a matter of opinion. Bear in mind 'acrylic' ends up, after reaction with air and water vapour, as a 'plastic' coating. That works in lungs as well as on models ... A general rule if you're going to mix types is make sure the first is properly dry before you apply the next. That means days, not hours.
Matt Finish My 'swears by' brand for enamels is currently Hannants Xtracolor FF , although now the Post Office won't let me get resupplies I shall be switching to Testors Dullcoat, as soon as my in-country source restocks (no trouble sending such things through La Poste, the French are more pragmatic about H&S). For acrylics, Hannants Xtracrylic XAFF works well too, I just don't use it as often.
Gloss Finish For enamels I use Xtracylix GG (note that's a 'type' crossover, but it has never given me any problems). For acrylic, I'd use the same thing (after all, it's made for them) but Ronseal is great too, can be thinned with water, and works out pretty cheap if you can stop the can drying solid.
Humbrol 'Cotes' I avoid them like the plague. I have a blue pointy thing (OK, it's a Tucano - so maybe 'paddly' thing) sprayed with Satincoat about 10 years ago. It still sticks to your fingers if you pick it up for more than a few seconds.
Johnson's Klear Sold, for anyone who doesn't know, as a floor 'finish', but actually an acrylic varnish. If I have used matt paints I always apply two or three coats before applying transfers (but usually by brush, as it's a beast to clean out of an airbrush). I don't personally 'float' transfers onto wet Klear, preferring to use Microsol/Microset, or decalfix, but many modellers do. Again, I seldom seal the transfers with Klear before using Extracolor FF, but many do as a matter of course. Note the reason Klear 'pulls' transfers onto surfaces is that like all acrylics it shrinks as it cures. This means if any coat below that finish isn't firmly attached it can be lifted and wrinkled. There has been much debate about whether the current Klear is as good as the original. The consensus seems to be that although it is slightly milky when liquid (the old stuff isn't) it does the same job and dries 'clear'! Luckily, I don't have to test this for a while as I still have one and a half bottles of the original to get through - that's an awful lot of dipped canopies, even in 1/48 scale.

Finally, the best advice is test anything on scrap first, before blasting a well-loved model. I appreciate it may be hard to replicate finishes that have dried for a number of years, but basic compatibility should always be proven before you spray 'in anger'. Remember manufacturers do change specs, usually without telling consumers - recent debate about 'new' Humbrol colours bears this out (as does, apparently, Halfords car paints - as Tim V says, they haven't been cellulose for a long time, all being, they claim, 'an advanced acrylic based formulation').
David L-T

charles davidson
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Re: Airbrushing varnish: advice sought

Postby charles davidson » Sat Aug 24, 2013 7:00 pm

Changing the subject slightly but picking up the point of old (ok 25+ years) transfers, I'm still using up sheets of Woodhead pressfix BR wagon numbering and PO liveries. No surprise that these now have zero tack and call for a different approach - I treat them as waterslide but using Carr's Transfix (usual disclaimer) instead of water. When dry and the tissue soaked away (with water!) they stick - removing a misaligned item is not easy, usually requiring scraping with a blade. I'm not sure how this process works but it does work - most times - items such as steel mineral end-door stripes are liable to fragment if repositioned. Larger characters in ex PO liveries sometimes need more than one coat of the solution. The crispness of the Woodhead material makes this worthwhile.

Charles

Knuckles
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Re: Airbrushing varnish: advice sought

Postby Knuckles » Sat Aug 24, 2013 9:08 pm

Don't know if this helps, but I too have some pressfix transfers (HMRS in my case) that I have applied as a waterslide instead. Always without bother.

I found it out by accident, for in my ignorance I originally thought the transfers were waterslide and it was only after reading them properly that I realised they wete pressfix...after I already used them with good results as a waterslide!

No idea why it works but it is a good bonus that you get application options, ay least that is how it has been for me, and I've never used Microsol or anything. I've always used warm water with a post varnish application.
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