Localised white deposit after matt varnishing

[Stevekir]

I airbrushed a final matt varnish, Tamiya Flat XF-86, undiluted, 20 PSI, 0.4 needle, (which is on Tamiya Clear Varnish which is on Xtractylix RAF Dark Earth and RAF Dark Green). The result is very good except for a white deposit in several panel lines which was not there before the matt varnishing. (I have not applied any weathering to this model.) I tried to remove it gently with a pin but no luck. Please see the photo.

I have hidden the white by painting with a minute brush loaded with the (water) thinned appropriate camo colour (hoping for it to wick but it didn't) and all now seems well, (except for the area (in the picture) which is a bit messy where I used the pin.

Any ideas why the white deposit please, and why just here and there?

View attachment 64401 (There is a hair near the bottom of the photo !@%$£&*)

View attachment 65604

 

[Ian M]

My bet is that its just where the varnish has pooled in the line. The solids in the varnish can link up if there is a pooling.

It is more normal to see the effect if not stired or shaken enough.

IanM

 

[Stevekir]

Thanks. I read that Tamiya Flat should not be shaken. The bottle says to stir well. I turned the bottle over and back while rotating it this way and that until it had a consistent grey look. The panel lines in this model are quite deep. I sprayed to a continuous wet look, more than the stage where the surface looked dry and granular. Next time I will spray a little less generously. If the result is granular I will respray, hoping that will help.

Is Tamiya Flat more prone to deposit white than other flat varnishes?

 

[Adrian "Marvel" Reynolds]

My thoughts are pooling also, I only use the Tamiya rattle cans for varnishing my models, the flat clear I find better if I just mist several coats on rather than try to cover the whole model in one session.

Adrian

 

[BarryW]

I would agree with Ian's assessment - I found that Humbrol was also prone to that specially if not stirred enough. Now I use Vallejo's varnish, airbrushed thinned about 20%, with a 0.4 needle. I always use very thin coats and need 2-3 coats to either gloss-up or matt-down.

 

[tecdes]

Yes I also agree with Ian's summing up had this mself.

If you dry a drop of Vallejo Thinners it leaves a residue. Vallejo thinners is used in the varnish & I would imagine it is the same with Tamiya.

Vallejo do a new Poly varnish & I have not used it sufficiently to gauge it but so far so good & better than the original stuff. From memory it takes a little longer to cure well.

Laurie

 

[tecdes]

PS Steve. Where did the hair come from.

Not the Tamiya varnish I hope ?

Laurie

 

[Stevekir]

PS Steve. Where did the hair come from.Not the Tamiya varnish I hope ?

Laurie

I don't think so. It was probably one from my own fair head. It has been doing that for several decades.

You also said "Vallejo do a new Poly varnish". I assume by "poly" it is a polyurethane varnish. How new is it? Since January last?

I started using their polyurethane varnish in January but could not get on with it (blocking). But with more experience, and if it is a new (since Jan.) product perhaps I should try Vallejo again with my 0.4 needle, thinned etc. as Barry does.

 

[tecdes]

Still got a few follicoles to go yet Steve. Came to the conclusion early in life it is either you lose your teeth & keep your hair or vice versa.

That is the same Polyurethene I mentioned Steve.

I used a .4 as a trial with it & did not have a problem. I probably used 22PSI as I up it a bit for varnish but I did not thin. Not sure which Vallejo varnish Barry was alluding to.

Seems that airbrushes have characters of their own. I use H & S and have found they work best with .4 needle/nozzle. Other types seem to get on well with a .2 needle/nozzle. Varnish also has other disaster properties added to the ordinary paint ones. Like leaving varnish to dry in the brush bunging up the airbrush so that even the most potent laxitive available will not budge.

Laurie

 

[Stevekir]

Varnish also has other disaster properties added to the ordinary paint ones. Like leaving varnish to dry in the brush bunging up the airbrush so that even the most potent laxitive available will not budge.Laurie

I recommend Senna Pods. The original 1940s seeds in a pod, not the wussy tablets the chemist sells today. Soaked in a 2 lb jam jar on the window sill for several days, gradually darkening to a grey, ominously. Then the Matron (I was in a boarding school for several years) announced that IT WAs TIME. You had to drink a cupful. It tasted like dried mould. I will NEVER forget it. It would scour out an AB like lightning.

 

[tecdes]

Blinking Heck Steve.

You have lived in the land of Dripping & Bread & packet dried eggs like I have.

Laurie