Problem with water based paints
Maciek Mastalarczuk
I am fairly new to painting and airbrushing, so the questions may be silly.
I am building a plastic model of an aircraft from a kit.
I picked water based paints over enamels because they are less messy to work
with. However no matter how hard I tried the results were horrible. I used
Gundze Sangyo paints, a cheapo airbrush and a cylinder with propellant
(though I don't think airbrush quality has anything to do with it).
Basically I had to apply about 15 coats of paint to get any decent coverage.
It might have been even more than that, cos I lost the count. Not
surprisingly the propellant was gone after painting about 1/3 of the model
and entire exercise took me a few of weeks to complete. In addition every
time I try to use a paintbrush on painted surface - the new coat seems to
dissolve the previous one. It is half a trouble if I'm applying the same
colour, but if it's different they mix up and the result is shocking. I left
the model to dry for about a week or even more before touching it with
paintbrush, so it should be dry as a bone.
The question is: has anyone had any luck with water based acrylic paints
while painting plastic models? Some colours (like the glossy ones) come out
OK after "only" 6-7 coats. But for example "H11 Flat White" is an absolute
nightmare to work with. The coverage is poor, you can still see plastic
through the paint on sharp edges and you cannot use paintbrush afterwards. I
wiped the surface with isopropanol prior to painting leaving it squeaky
clean. So I don't think it was greasy or something. I also tried using
less-thinned paint, but at a certain point it just clogs the airbrush
nozzle. If it is thin enough it just forms rain-like drops and does not
stick to the surface unless I apply extremely thin layers, but then it takes
15 coats to actually see the colour I am applying.
Is it a bad paint or a bad painter? Is there any special technique for using
water based acrylics? They also badly bleed through masking tape unless I
put 5-6 layers of tape. A few cylinders with propellant and a few reels of
masking tape per model make it quite expensive. Maybe all the mess with
enamels is simply worth it? What am I doing wrong?
Any help or comments would be greatly appreciated
Thanks and regards
Maciek Mastalarczuk
mac...@nospam.com.au (please replace nospam with iprimus).
Ron
Maciek Mastalarczuk wrote:
> I picked water based paints over enamels because they are less messy to work
> with. However no matter how hard I tried the results were horrible. I used
> Gundze Sangyo paints, a cheapo airbrush and a cylinder with propellant
> (though I don't think airbrush quality has anything to do with it).
First, a "cheapo" airbrush isn't worth bothering with, Paasche H's can
be had in the US for $41 and probably a similar amount down under.
Propellant cans are pretty much useless. You either need a compressor or
a bottle of either CO2 or nitrogen. Gunze is good paint but really needs
a primer and you shoild thin it with a 50:50 mix of distilled water and
90% ispropyl alcohol.
> Basically I had to apply about 15 coats of paint to get any decent coverage.
> It might have been even more than that, cos I lost the count. Not
> surprisingly the propellant was gone after painting about 1/3 of the model
> and entire exercise took me a few of weeks to complete. In addition every
> time I try to use a paintbrush on painted surface - the new coat seems to
> dissolve the previous one. It is half a trouble if I'm applying the same
> colour, but if it's different they mix up and the result is shocking. I left
> the model to dry for about a week or even more before touching it with
> paintbrush, so it should be dry as a bone.
It's not unusual to need two or three light coats of Gunze for good
coverage. Gunze and to some extent Tamiya do not brush well since they
tend to dissolve themselves. Polly Scale brushes better, Acryl is too
thin and Vallejo is the best for hand brushing.
> The question is: has anyone had any luck with water based acrylic paints
> while painting plastic models? Some colours (like the glossy ones) come out
> OK after "only" 6-7 coats. But for example "H11 Flat White" is an absolute
> nightmare to work with. The coverage is poor, you can still see plastic
> through the paint on sharp edges and you cannot use paintbrush afterwards. I
> wiped the surface with isopropanol prior to painting leaving it squeaky
> clean. So I don't think it was greasy or something. I also tried using
> less-thinned paint, but at a certain point it just clogs the airbrush
> nozzle. If it is thin enough it just forms rain-like drops and does not
> stick to the surface unless I apply extremely thin layers, but then it takes
> 15 coats to actually see the colour I am applying.
Since they took lead out of hobby paint, white, yellow and to some
degree red just haven't covered well. For white prime with very light
grey first, then spray the white in 3 or 4 mist coats, works for me (go
to the jets agllery at www.aircraftresourcecenter.com and look for my
F-16). By the way, a bottle of Gunze doesn't go all that far.
> Is it a bad paint or a bad painter? Is there any special technique for using
> water based acrylics? They also badly bleed through masking tape unless I
> put 5-6 layers of tape. A few cylinders with propellant and a few reels of
> masking tape per model make it quite expensive. Maybe all the mess with
> enamels is simply worth it? What am I doing wrong?
What kind of masking tape? El cheapo from the hardware store? That stuff
isn't meant for fine lines. Try Tamiya tape or parafilm. One trick you
can use to help stop bleed is spray either clear gloss or the base color
along the tape edge before spraying the new color.
Remember grasshopper, it take practice.
Wayne C. Morris
"Maciek Mastalarczuk" <mac...@nospam.com.au> wrote:
> I picked water based paints over enamels because they are less messy to work
> with. However no matter how hard I tried the results were horrible. I used
> Gundze Sangyo paints, a cheapo airbrush and a cylinder with propellant
> (though I don't think airbrush quality has anything to do with it).
>
> Basically I had to apply about 15 coats of paint to get any decent coverage.
> It might have been even more than that, cos I lost the count.
Shouldn't need more than 2 or 3 coats. Two probable causes:
1) You thinned the paint too much.
2) Most of the pigment had settled to the bottom of the paint jar, and
you didn't mix it back into the paint, so the liquid portion that you
were spraying had very little color. Sometimes the settled pigments are
so thick at the bottom of the jar that you have to scrape the gunk loose
with a stir stick and mash it up before it can be mixed back into the
rest of the paint.
> Not surprisingly the propellant was gone after painting about 1/3 of
> the model
Yep, that's the drawback of airbrush propellant in the aerosol cans.
Runs out very quickly. Big incentive to get a compressor as soon as you
can afford one. Note that the cans also lose pressure when they get
cold; if it's not completely exhausted, warming it in hat water will
restore the pressure.
> In addition every time I try to use a paintbrush on painted surface -
> the new coat seems to dissolve the previous one.
Yep, that'll happen with acrylics. It softens the old coat, so that
when you drag the paintbrush across the surface, it pulls up the old
coat and mixes it with the new. But if you just brush the new coat on
quickly and leave it, it'll be okay. Work fast, and if you need to
cover a large area, use a wider brush (I like to use a 1/2" wide
chisel-tipped artist's brush).
Also make sure you're not using too strong a thinner. Try windshield
washer fluid or rubbing alcohol, if you aren't already. If that's still
too strong, try a 50/50 mix of windshield fluid and water.
> The question is: has anyone had any luck with water based acrylic paints
> while painting plastic models? Some colours (like the glossy ones) come out
> OK after "only" 6-7 coats. But for example "H11 Flat White" is an absolute
> nightmare to work with. The coverage is poor, you can still see plastic
> through the paint on sharp edges and you cannot use paintbrush afterwards.
I get good results with acrylics, usually needing only 1-2 coats, with
both airbrush and hand brush.
White and yellow are the worst colors for getting complete coverage.
Make especially sure that the pigments haven't settled to the bottom of
the jar. It's also important to make sure it's thinned just right.
It'll also help to use a good primer first, and to apply white & yellow
before any other colors.
> I also tried using less-thinned paint, but at a certain point it just
> clogs the airbrush nozzle. If it is thin enough it just forms
> rain-like drops and does not stick to the surface unless I apply
> extremely thin layers, but then it takes 15 coats to actually see the
> colour I am applying.
Probably a combination of several things:
1) Too much thinner, causing poor coverage.
2) Not enough air pressure, forcing you to over-thin the paints.
3) Airbrush nozzle too small for acrylics, so it clogs quickly and
forces you to over-thin the paints. Try to get a larger nozzle &
matching needle for your airbrush.
4) Thinning with water instead of proper acrylic thinner, so the paint
has too much surface tension and beads up on the surface. Windshield
washer fluid will work better. A drop or two of "acrylic retarder" may
also help; you can find this in any good craft or artist's supply store.
> They also badly bleed through masking tape unless I put 5-6 layers of
> tape.
Shouldn't be bleeding through the tape. Under the edges, maybe, but
extra layers won't prevent that. To prevent bleeding under the edges,
apply a coat of either clear or the same color that's under the tape; if
any bleeds under the tape, it won't be noticeable, and it'll seal the
edges so that the new color won't bleed.
Maciek Mastalarczuk
Thanks a lot for your comments.
> First, a "cheapo" airbrush isn't worth bothering with, Paasche H's can
> be had in the US for $41 and probably a similar amount down under.
> Propellant cans are pretty much useless. (...)
My airbrush is Paasche Ez-starter, it is nothing sophisticated, but I was
having some success with glossy paints. It is a fair comment about
propellant cans, they really are useless and I guess I will have to invest
in compressor. Will I need to get a new airbrush as well or I can just try
with the one I have first? Bascially the question is whether you buy a
compressor for a particular airbrush type or they can be selected
independently?
> It's not unusual to need two or three light coats of Gunze for good
> coverage. Gunze and to some extent Tamiya do not brush well since they
> tend to dissolve themselves. Polly Scale brushes better, Acryl is too
> thin and Vallejo is the best for hand brushing.
Two or three coats almost seem to good to be true. Do you prepare the
surface in any particular way prior to painting? (I mean except cleaning it
up). I tried to gently sand it with very fine sandpaper just to roughen it a
little for better adhesiveness. It helps the first coat stay and the next
coat is usually very effective, but it is easy to ruin all the engravings
this way.
> What kind of masking tape? El cheapo from the hardware store? That stuff
> isn't meant for fine lines. Try Tamiya tape or parafilm. One trick you
> can use to help stop bleed is spray either clear gloss or the base color
> along the tape edge before spraying the new color.
I am using Tamyia and it bleeds through like hell. It doesn't if I put many
layers of tape. The model then looks like car crash victim and so does my
wallet. Maybe paint needs to be thicker or I should try different brand.
Will try your tick with gloss. I haven't tried parafilm either, I will give
it a go.
> Remember grasshopper, it take practice.
I will. Thanks again for the advices.
Maciek
Maciek Mastalarczuk
Thanks heaps for the tips.
> 2) Most of the pigment had settled to the bottom of the paint jar, and
> you didn't mix it back into the paint, so the liquid portion that you
> were spraying had very little color. Sometimes the settled pigments are
> so thick at the bottom of the jar that you have to scrape the gunk loose
> with a stir stick and mash it up before it can be mixed back into the
> rest of the paint.(...)
I stirr the paint up properly, until everything is dissolved and then I thin
it to milk-like consistency. But yes, I use water to thin the paint, so
maybe this is the problem. I thought about using alcohol as it has lower
surface tension and probably won't form drops, but I wasn't sure whether it
will not damage previous coats. It looks like it will anyway if I use
acrylics and paintbrush, so I will just minimise the use of paintbrush.
I also understood the ordeal with propellant cans and will get myself a
compressor.
What are you using as a primer? Just normal paint (like white or grey) or
something special? And how do you apply it - simply spray all over the model
or various parts have to be primed differently?
> (...) To prevent bleeding under the edges,
> apply a coat of either clear or the same color that's under the tape; if
> any bleeds under the tape, it won't be noticeable, and it'll seal the
> edges so that the new color won't bleed.
Ron (see previous reply) wrote about using gloss to prevent bleeding through
the edges. I will try it.
Thanks and regards
Maciek
Sam
(don't recall the name, available at the better hobby shops.) Also put a
couple drops of liquid dish washing detergent in the paint, stops the static
build up and lets the paint flow smoother on the plastic. Using distilled
water and alcohol will help the paint flow smoother and the alcohol quickens
the drying time.
"Maciek Mastalarczuk" <mac...@nospam.com.au> wrote in message
news:3ed9c...@news.iprimus.com.au...
William H. Shuey
Sam wrote:
>
> When using acrylics I use a plastic prep on the plastic before painting,
> (don't recall the name, available at the better hobby shops.)
Poly-S "Plastic Prep". It is basically an alcohol and detergent
combination in water that scrubs off skin oils and mold release agents.
I use a cotton ball soaked in it to wipe down the model.
> Also put a
> couple drops of liquid dish washing detergent in the paint, stops the static
> build up and lets the paint flow smoother on the plastic.
Another good alternate additive is Liquitex low viscosity Acrylic
Airbrush Medium. Available at Michael's.
> Using distilled
> water and alcohol will help the paint flow smoother and the alcohol quickens
> the drying time.
This is essentially the mix sold as Poly-S thinner.
William H. Shuey
Sam wrote:
>
> When using acrylics I use a plastic prep on the plastic before painting,
> (don't recall the name, available at the better hobby shops.)
Poly-S "Plastic Prep". It is basically an alcohol and detergent
combination in water that scrubs off skin oils and mold release agents.
I use a cotton ball soaked in it to wipe down the model.
> Also put a
> couple drops of liquid dish washing detergent in the paint, stops the static
> build up and lets the paint flow smoother on the plastic.
Another good alternate additive is Liquitex low viscosity Acrylic
Airbrush Medium. Available at Michael's.
> Using distilled
> water and alcohol will help the paint flow smoother and the alcohol quickens
> the drying time.
This is essentially the mix sold as Poly-S thinner.
>
William H. Shuey
Sam wrote:
>
> When using acrylics I use a plastic prep on the plastic before painting,
> (don't recall the name, available at the better hobby shops.)
Poly-S "Plastic Prep". It is basically an alcohol and detergent
combination in water that scrubs off skin oils and mold release agents.
I use a cotton ball soaked in it to wipe down the model.
> Also put a
> couple drops of liquid dish washing detergent in the paint, stops the static
> build up and lets the paint flow smoother on the plastic.
Another good alternate additive is Liquitex low viscosity Acrylic
Airbrush Medium. Available at Michael's.
> Using distilled
> water and alcohol will help the paint flow smoother and the alcohol quickens
> the drying time.
This is essentially the mix sold as Poly-S thinner.
>
Pawel Zabza
[...]
> Basically I had to apply about 15 coats of paint to get any decent
coverage.
I'd attribute your problems to certain Gunze colors (aka "ten typ tak
ma" ;). I've had the same weird experience with their H51 (Light Gull
Grey) - only I gave up after three layers, when virtually no trace of
the color I was applying was visible on the model. But most Gunze colors
I tried worked very well, even if I'm not a big fan of gloss or
semi-gloss paints.
[...]
> In addition every
> time I try to use a paintbrush on painted surface - the new coat seems
to
> dissolve the previous one.
Sounds strange. Flat acrylics I use with a paintbrush - Andrea
Miniatures, Vallejo, Polly Scale - dry so fast that blending of colors
is not really possible.
OTOH it's a pretty good reason to buy a compressor and switch to
airbrushing ;).
[...]
> Is it a bad paint or a bad painter? Is there any special technique for
using
> water based acrylics?
Hard to tell. I've had good results with their H6x, H3xx and H4xx
paints, at least performance-wise.
If you have access to Vallejo Air paints (don't confuse with other
ranges of Vallejo), give one a try - they are thinned for airbrush use
and you could use it as a reference point. If not, try any flat Tamiya
or Polly Scale paint, thinned for example 6:4 (paint:thinner) airbrushed
in a few light coats - if that doesn't make any difference, there's
something wrong with the painter ;).
I prefer airbrushing a color in 2-3 light ("dry") coats, using hair
dryer in-between to speed things up, and then leaving the model alone
for a day or two. The paints I use (the few AeroMaster colors I have
left, Polly Scale, Vallejo Air, Gunze - H6x, H3xx and H4xx colors) cover
well enough for it to work. When a paint forms a "rain-drop" or runs on
me, it's a sign of it being too diluted or me applying too thick a coat
of it.
> They also badly bleed through masking tape unless I
> put 5-6 layers of tape. A few cylinders with propellant and a few
reels of
> masking tape per model make it quite expensive.
That's strange as well - the only problems I had with Tamiya tape were
result of me not burnishing the edges. Maybe in your "quest for Came^W
coverage" ;) you did put on too thick ("wet") coat?
HTH,
Pawel
Mark Schynert
"William H. Shuey" <whs...@starpower.net> wrote:
> Sam wrote:
> >
> > When using acrylics I use a plastic prep on the plastic before painting,
> > (don't recall the name, available at the better hobby shops.)
>
> Poly-S "Plastic Prep". It is basically an alcohol and detergent
> combination in water that scrubs off skin oils and mold release agents.
> I use a cotton ball soaked in it to wipe down the model.
>
> > Also put a
> > couple drops of liquid dish washing detergent in the paint, stops the static
> > build up and lets the paint flow smoother on the plastic.
>
> Another good alternate additive is Liquitex low viscosity Acrylic
> Airbrush Medium. Available at Michael's.
>
> > Using distilled
> > water and alcohol will help the paint flow smoother and the alcohol quickens
> > the drying time.
>
> This is essentially the mix sold as Poly-S thinner.
Not quite--there's ethylene glycol in there as well, which I presume is
there to retard a bit and also to break surface tension. I've been told
the formula can be duplicated by:
10% isopropanol
25% blue antifreeze (glycol)
65% distilled water
Since I buy the stuff in the bottle, I have no idea if that's actually a
correct formulation, but it's certainly a starting point for the
experimentally minded.
Mark Schynert
Jim
"William H. Shuey" wrote
> Another good alternate additive is Liquitex low viscosity Acrylic
> Airbrush Medium. Available at Michael's.
****** Hi Bill, I picked up a bottle of this stuff as a result of
previous postings on the subject. Haven't tried it as yet. Would you have
any guide lines on how much of the Medium to use in relation to any amount
of paint? ie: 4 drops/squirts/spoon fulls/bottles per 8 fl oz of paint?
I'm aware that I'll have to try it to get it but I'm just looking for a
starting point......... :-) Cheers and thanks - Jim.
[The x's in my address are Spam Stoppers - I hope!]
William H. Shuey
Jim wrote:
>
> "William H. Shuey" wrote
> > Another good alternate additive is Liquitex low viscosity Acrylic
> > Airbrush Medium. Available at Michael's.
>
> ****** Hi Bill, I picked up a bottle of this stuff as a result of
> previous postings on the subject. Haven't tried it as yet. Would you have
> any guide lines on how much of the Medium to use in relation to any amount
> of paint?
I use about 15% to 20% medium. Seems to work fine.
Bill Shuey
Jim
"William H. Shuey" wrote >
> I use about 15% to 20% medium. Seems to work fine.
****** Great Bill, just great. Now I have a place to start. All I have
to do is get started building something so I can give your formulae a try.
Much appreciated. cheers and thanks again. Jim.
The Old Timer
>> "William H. Shuey" wrote
>>> Another good alternate additive is Liquitex low viscosity Acrylic
>>> Airbrush Medium. Available at Michael's.
>> Jim wrote
>> ****** Hi Bill, I picked up a bottle of this stuff as a result of
>> previous postings on the subject. Haven't tried it as yet. Would you have
>> any guide lines on how much of the Medium to use in relation to any amount
>> of paint?
>"William H. Shuey" wrote
> I use about 15% to 20% medium. Seems to work fine.
Jim -- You might want to stop by a hardware store and pick up a couple of 1/4"
ball bearings (brass, bronze or stainless steel to retard corrosion). Drop one
in your paint jar and shake the dickens out of it to stir up the paint. This
saves you time with the stir-stick, and keeps the paint inside the jar while
its being aggitated. It can really extend the life of a jar of paint as well.
-- John ___
__[xxx]__
(o - )
--------o00o--(_)--o00o-------
The history of things that didn't happen has never been written - Henry
Kissinger
Jim
"The Old Timer" wrote
> Jim -- You might want to stop by a hardware store and pick up a couple of
1/4"
> ball bearings (brass, bronze or stainless steel to retard corrosion). Drop
one
> in your paint jar and shake the dickens out of it to stir up the paint.
This
> saves you time with the stir-stick, and keeps the paint inside the jar
while
> its being aggitated. It can really extend the life of a jar of paint as
well.
******* Thanks. I've heard of that before but never got around to giving
it a try. Thanks for the 'nudge' in the right direction. I'll be sure and
get some next trip to town. Much appreciated. cheers - Jim.