> A couple of the models that I built a few months back, are experiencing
> their paint jobs turning into a powder.
[quoted text clipped - 6 lines]
>
> Any ideas?
What are the conditions in your home? I've never encountered that with
model paint.
Bill Banaszak, MFE
W - 06 Apr 2004 05:12 GMT
> What are the conditions in your home? I've never encountered that with
> model paint.
I started noticing it around Christmas, that is just before we started
having the 35C+ days.
The area that I currently have the models is rather cool even when it was
38C outside, and has very good ventilation - the air is never stale even
when the doors and windows are closed.
The only things I can come up with to explain the dusty nature of the paint:
1) Far too thin, but then it isn't because in one coat I can cover any
light/bright colour.
2) Paint was contaminated with some caking agent - this has been the only
time I have ever seen something that even closely resembles what I am
experiencing.
Stephen Leslie - 06 Apr 2004 10:38 GMT
Hi W,
I always varnish mine with Xtracolour matt/semi-matt after painting them and
have had no problems.
So that could be a solution, unless you are varnishing them and you are
gettting a bad reaction with the type you are using with Tamiya/Humbrol
paints.
Cheers,
Stephen
W - 07 Apr 2004 11:33 GMT
> Hi W,
>
[quoted text clipped - 4 lines]
> gettting a bad reaction with the type you are using with Tamiya/Humbrol
> paints.
I have not arrived at that stage just yet, but I do have intentions of
applying a finish to seal the paint.
Sounds to me like the paint was too thick or maybe the word should be dry-
it covered well - a sign of not being too thin. If it was too thick it would
dry on the way to the model and just lay on the surface. I once had a
problem where the paint dried on the way in and the surface looked like
tiny balls instead of smooth - easily rubbed off for a correct coat. Too
thin and it would lay on the surface and tend to run.
Two other possibilities - one surface preparation. Did you wash the mold
release off the model, and maybe later finger print oils, or you used the
wrong thinner and it did something strange of a chemical nature to screw up
the paint coat;.
This seems like a topic that needs more discussion - Hate to have it happen
to me - would be nice to know the reason - especially if its the basic paint
thats at fault.
Val Kraut
> A couple of the models that I built a few months back, are experiencing
> their paint jobs turning into a powder.
[quoted text clipped - 6 lines]
>
> Any ideas?
Rob Grinberg - 07 Apr 2004 03:44 GMT
I'm no expert, but it sounds to me as if the paint was missing one of its
constituent parts - some sort of binder, maybe.
RobG
> Sounds to me like the paint was too thick or maybe the word should be dry-
> it covered well - a sign of not being too thin. If it was too thick it would
[quoted text clipped - 25 lines]
> >
> > Any ideas?
Bill Banaszak - 07 Apr 2004 05:16 GMT
> I'm no expert, but it sounds to me as if the paint was missing one of its
> constituent parts - some sort of binder, maybe.
Can we assume it was well stirred? I've gotten uneven results on
occasion because Humbrol's wasn't as well stirred as I thought I had it.
I've never used Tamiya's paints so I'm no help there.
Bill Banaszak, MFE
W - 07 Apr 2004 11:41 GMT
> > I'm no expert, but it sounds to me as if the paint was missing one of its
> > constituent parts - some sort of binder, maybe.
>
> Can we assume it was well stirred? I've gotten uneven results on
> occasion because Humbrol's wasn't as well stirred as I thought I had it.
> I've never used Tamiya's paints so I'm no help there.
I use a battery operated agitator which works very well for the Humbrol mud.
Bill Banaszak - 08 Apr 2004 02:42 GMT
> > > I'm no expert, but it sounds to me as if the paint was missing one of
> its
[quoted text clipped - 5 lines]
>
> I use a battery operated agitator which works very well for the Humbrol mud.
Then that doesn't sound like the cause. I'm out of ideas now.
Bill Banaszak, MFE
e - 08 Apr 2004 04:16 GMT
>> > > I'm no expert, but it sounds to me as if the paint was missing one of
>> its
[quoted text clipped - 9 lines]
>
>Bill Banaszak, MFE
i whupped up a bahgun shaker. took the guide plate off my
'lectric jig saw.
i tape the paint or jar to the blade, lay it on the carpet
and block the trigger on with another bottle. ten minutes
and the clumpiest is smooth.
Rob Grinberg - 08 Apr 2004 04:45 GMT
Good idea - I've seen the same done with orbital sanders. Just make damn
sure that lid is on *tight*!
RobG
> >> > > I'm no expert, but it sounds to me as if the paint was missing one of
> >> its
[quoted text clipped - 15 lines]
> and block the trigger on with another bottle. ten minutes
> and the clumpiest is smooth.
e - 08 Apr 2004 06:30 GMT
>Good idea - I've seen the same done with orbital sanders. Just make damn
>sure that lid is on *tight*!
>
>RobG
tighter than a weldiggers....
W - 09 Apr 2004 02:11 GMT
> Then that doesn't sound like the cause. I'm out of ideas now.
I just got back from the workshop, I ran a white rag over the
surface...nothing. Not a smudge, smear, speck, spock of paint dust.
I am starting to sway my thinking in a different direction: soot.
I use a candle to nullify the vapours (yes I know, but it is on the other
side of the room, and at no point does it get that concentrated), and am
starting to wonder if there may be soot coming from it.
W - 07 Apr 2004 11:39 GMT
> Sounds to me like the paint was too thick or maybe the word should be dry-
> it covered well - a sign of not being too thin. If it was too thick it would
> dry on the way to the model and just lay on the surface. I once had a
> problem where the paint dried on the way in and the surface looked like
> tiny balls instead of smooth - easily rubbed off for a correct coat. Too
> thin and it would lay on the surface and tend to run.
The paint is touch dry after 5mins, but then I have noticed that black
always dries in under 30mins.
> Two other possibilities - one surface preparation. Did you wash the mold
> release off the model, and maybe later finger print oils, or you used the
> wrong thinner and it did something strange of a chemical nature to screw up
> the paint coat;.
I used dishwasher cubes with a toothbrush to clean the surface, with gloves
to prevent re-soiling of the surface.
> This seems like a topic that needs more discussion - Hate to have it happen
> to me - would be nice to know the reason - especially if its the basic paint
[quoted text clipped - 13 lines]
> >
> > Any ideas?
I think you will find Tamiya paints are Acrylic which means there isn't a
problem with the type of paint.
It probably is the paint drying into tiny globules on it's way to the model
and not being able to spread out once it hits the surface, try rubbing over
the surface with an old hankie and see if the "dust" comes off and leaves
the base colour still there. if that works then next time hold the airbrush
a little nearer the model or try not to use too much thinners.
good luck

Signature
Ted (happy modeller) Taylor
http://www.modelwork.freeserve.co.uk
http://www.scale-models.freeserve.co.uk
http://www.scale-model-aircraft.freeserve.co.uk
http://www.model-trucker.freeserve.co.uk
http://www.real-trucks.freeserve.co.uk
This message has been swept for viruses by Norton AV
> A couple of the models that I built a few months back, are experiencing
> their paint jobs turning into a powder.
[quoted text clipped - 6 lines]
>
> Any ideas?
W - 07 Apr 2004 11:44 GMT
> I think you will find Tamiya paints are Acrylic which means there isn't a
> problem with the type of paint.
In this case it is their enamal paint.
> It probably is the paint drying into tiny globules on it's way to the model
> and not being able to spread out once it hits the surface, try rubbing over
> the surface with an old hankie and see if the "dust" comes off and leaves
> the base colour still there. if that works then next time hold the airbrush
> a little nearer the model or try not to use too much thinners.
> good luck
The paint is touch dry in 5mins, I thought I had over thinned the pint, but
when it comes out of the bottle it covers even white very well.