Airfix Logo

Humbrol Logo

The Airfix Tribute Forum was established in April 2006 to discuss the making of Airfix models.

Email: admin at airfixtributeforum.co.uk

It is currently Tue 19 Sep 2017 16:13 pm

All times are UTC [ DST ]




Post new topic Reply to topic  [ 11 posts ] 
Author Message
 Post subject: Tamiya Matt Varnish
PostPosted: Sat 08 Oct 2016 10:42 am 
Offline
Yellow Star
Yellow Star

Joined: Mon 18 Apr 2016 13:46 pm
Posts: 50
Location: New South Wales (ex-Bristol)
: --------------------
I'm just about to complete my first kit in decades, I've tried a few new things and it's been going very well all things considered (other than awful brush marks across the kit). However, when I applied a final matt coat across the kit this came up:

Image

I used Tamiya acrylic Flat Clear XF-86, thinned with water - I was trying to avoid leaving brush marks on the final clear coat and have read a few posts suggesting that thinner coats help with this problem. No ratio used, I just winged it to see how it'd turn out.

Is it repairable, or have I stuffed it? If the latter, what is it that I did wrong?

_________________
Instant expert - just add internet


Top
 Profile  
 
PostPosted: Sat 08 Oct 2016 11:41 am 
Offline
Red Star
Red Star

Joined: Sun 10 Feb 2013 20:08 pm
Posts: 381
Location: Sevenoaks, Kent
Hi,
This is a common problem and in my humble experience can be caused by a number of things.
1) My first thought was did you do a sealer layer between the paint and the matt coat?. I find that using Klear prevents reaction between the two.
2) I wouldn't have thinned with water. It can contaminate and affect the consistency resulting in the fogging. If the matt coat is supposed to be thinned, Tamiya would produce a propriatory solution.
3) Did you use a setting solution for the decals? Again, if it hasn't dried sufficiently, it can react with matt coat. So a sealant layer is a good idea.
4) Humidity can cause this problem (although unlikely) and avoid quick drying, for example near a radiator.

You could try a clear varnish coat, thoroughly dried, then apply the matt coat again, this might reduce the appearance of some of the fogging but wont get rid of the worst, unfortunately.

Hope this helps


Top
 Profile  
 
PostPosted: Sat 08 Oct 2016 11:59 am 
Offline
Silver Star
Silver Star

Joined: Sun 26 Oct 2008 19:29 pm
Posts: 1011
The white streaks are the matting agent in the varnish. It's usually caused by not stirring the varnish enough. Although some brands will react with damp decals, as I've found to my cost. If your using Tamiya acrylics then they should be thinned with isopropyl alcohol (eg Tamiya Acrylic thinners) not water.

I found Decalfix rubbed on with a cotton bud fixes the problem. Other people have used toothpaste

_________________
US Fighters project. Built - 22. Budget £220. Spent £187.91


Top
 Profile  
 
PostPosted: Sat 08 Oct 2016 14:54 pm 
Offline
Two Gold & Bronze Stars
Two Gold & Bronze Stars
User avatar

Joined: Thu 13 Dec 2007 02:47 am
Posts: 6792
Location: Minnesota, USA
: Model Portfolio
Ummmm.... drtemplar is correct. The "matting agent" is something like silica powder (ground glass). It's mixed into a clear carrier ("varnish") to produce a clear material that dries flat. When the quantity of matting agent in the mix is too high, you get white fog or streaks. I mix my own to avoid this problem. If I get a little of the white stuff showing up, I just add more clear "varnish" and re-coat. Cutting it with water won't help because the water evaporates. You need a clear acrylic resin--like, say, Tamiya clear GLOSS. Mix a little clear gloss into the clear flat and test it. It should end the problem. If you end up with something that's too glossy, you can get some Tamiya Flat Base to mix in to restore the "flatness." Experiment! Finding the right balance can be tricky and requires great peace of mind...

_________________
“Build what YOU want, the way YOU want to, and above all, have fun.”
- Al Superczynski (1947 - 2007)

dancho's model collection dancho's blog


Top
 Profile  
 
PostPosted: Sat 08 Oct 2016 23:07 pm 
Offline
Yellow Star
Yellow Star

Joined: Mon 18 Apr 2016 13:46 pm
Posts: 50
Location: New South Wales (ex-Bristol)
: --------------------
Hi guys,

Thanks for the swift replies, I appreciate it. To follow on:

1) I put a coat of Humbrol acrylic gloss over the paint before applying decals as we can't get Klear in Australia...!
2) Don't thin with water, use the proper product - advice noted and to be promptly acted upon, thank you. Most of my paints are Humbrol with only a few Tamiya - do you know if the Tamiya acrylic thinners work as effectively with Humbrol paints or should I buy both brands?
3) I used Micro Set & Sol to fix the decals - with rubbing them over with one of these help remove the white marks instead of Decalfix (which I don't have)?
4) I never would have thought to mix gloss to the matt, thanks. I'll give it a go.
4) Slightly away from the main point, I thinned the coat in the first place as I read elsewhere on the forums that this method can 'hide' brush marks in the paint. Does this actually work?

Thanks again, I'm relieved to know that I can at least reduce the streaking. I was pretty annoyed when it came up.

Matt

_________________
Instant expert - just add internet


Top
 Profile  
 
PostPosted: Mon 10 Oct 2016 13:28 pm 
Offline
Blue Star
Blue Star

Joined: Tue 20 Sep 2016 09:55 am
Posts: 515
Location: Scotland
: --------------------
Gloss-o! :P

1) "Klear" is called "Future" in some markets. Any help?
2) Tamiya (and Gunze Sangyo) acrylics are resin based, and need to be thinned with an acrylic thinner. Tamiya make one. They also don't mix (at least well) with Humbrol, Revell, Games Workshop and Vallejo water-based acrylics.
4) Mixing gloss varnish into a matt works by reducing the proportion of the flat base in the varnish. It works, but makes the varnish less matt.
5) Thinner paint usually brush marks less, but at the possible expense of less covering power.

_________________
"Is there anything I can do to help you?"
"Yes. Give me a staffel of Spitfires!"


Top
 Profile  
 
PostPosted: Mon 10 Oct 2016 15:53 pm 
Offline
White Star
White Star

Joined: Mon 03 Feb 2014 10:25 am
Posts: 31
Location: Canterbury
: --------------------
I now use Tamiya matt spray TS-80 gives a very flat result with no fogging.


Top
 Profile  
 
 Post subject: Re: Tamiya Matt Varnish
PostPosted: Tue 11 Oct 2016 08:52 am 
Online
Bronze Star
Bronze Star

Joined: Mon 19 Mar 2012 11:40 am
Posts: 945
Location: Cambridge
I'm not sure that rubbing the decals with Microsol or Microset will remove the white powdery marks, which as others note is an overabundance of the matting agent. I don't think either of the decal solutions is a solvent for the resin in the varnish and so won't dissolve away the marks. I would worry that you risk tearing the decals. I'd paint over the marks with the matching gloss vanish as already suggested, then reapply the appropriately thinned matt varnish.

I've had white streaking on and around decals using many matt varnishes and now attribute it to incomplete drying of the decal-setting solutions. These days I apply such solutions sparingly only to the area of the decal itself and allow to dry thoroughly before varnishing - it appears to have solved the problem for me. Good luck!

_________________
My Portfolio My Work in Progress


Top
 Profile  
 
 Post subject: Re: Tamiya Matt Varnish
PostPosted: Tue 11 Oct 2016 12:30 pm 
Offline
Yellow Star
Yellow Star

Joined: Mon 18 Apr 2016 13:46 pm
Posts: 50
Location: New South Wales (ex-Bristol)
: --------------------
I did try rubbing it over with Micro Set and Sol yesterday, just to see if there would be any effect - Microset did nothing much but I gave it a good rub over with Microsol on a cotton bud and it cleared it up beautifully without any damage to the decal. Useful to know.

I also learned that the bottles are as easy to knock over as others on these forums have noted :roll:

I don't think my particular problem was caused by incomplete drying as I'm a pretty slow builder and leave it 24 hours between coats / decal fixing etc, most likely inadequate stirring beforehand. Having said that, the second coat was very well stirred but gave the same problem albeit to a lesser extent. I'll have a play around with mixing and thinning and see what works. Learning curves are a pain in the behind...

I did check Klear and Future but no joy, sadly. I'll have to ask my parents to post some over from the UK next time I'm due a birthday, from what I understand from ATF and other random forums it's almost a requirement for modelling success.

_________________
Instant expert - just add internet


Top
 Profile  
 
 Post subject: Re: Tamiya Matt Varnish
PostPosted: Tue 11 Oct 2016 12:51 pm 
Offline
Blue Star
Blue Star

Joined: Tue 20 Sep 2016 09:55 am
Posts: 515
Location: Scotland
: --------------------
By the rate I'm using it at, one bottle of Klear will last at least 10 years.

_________________
"Is there anything I can do to help you?"
"Yes. Give me a staffel of Spitfires!"


Top
 Profile  
 
 Post subject: Re: Tamiya Matt Varnish
PostPosted: Tue 11 Oct 2016 23:25 pm 
Online
Bronze Star
Bronze Star

Joined: Mon 19 Mar 2012 11:40 am
Posts: 945
Location: Cambridge
MattNSW wrote:
I did try rubbing it over with Micro Set and Sol yesterday, just to see if there would be any effect - Microset did nothing much but I gave it a good rub over with Microsol on a cotton bud and it cleared it up beautifully without any damage to the decal. Useful to know.

Yes indeed - thanks for the tip!

MattNSW wrote:
I also learned that the bottles are as easy to knock over as others on these forums have noted :roll.

Aren't they? After some annoying spillages, my bottles now have a piece of Blu-tac stuck on the bottom...

_________________
My Portfolio My Work in Progress


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 11 posts ] 

All times are UTC [ DST ]


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Jump to:  
Powered by phpBB® Forum Software © phpBB Group

The Airfix Tribute Forum

The Airfix Tribute Forum - Est. 2006 | Make a Donation


modelsforsale.com