Does matt Varnish go off? – Airbrush always getting blocked

[lawnor 25939xp 0]

TLDR My airbrush jams every time I use my matt varnish through it.  Any ideas why and if I can fix this?

For a while now I’ve been having issues with my airbursh.  It keeps getting blockages, even if I’ve just cleaned it.  I thought the airbrush was dying, but then realised it only happens with my matt varnish.  It’s reached a point where it basically happens the moment the varnish enters the up and spraying requires constant work to keep it moving.  It never used to do this.  The pot is older than I realised, and has about 1cm left at the bottle. This could still go a long way so I’d rather not waste it.  Given what I’ve got in my queue it’s possible this may last the year.

Has anyone run in to an issue like this before?  Has my varnish just gone off, and if so, what’s a realistic expectation of shelf life?  Are there issues with the Vallejo Mecha varnishes?  Can I do something to salvage what I’ve got left, or should I junk it and buy a fresh bottle?  Is persisting harming my airbush?

Vallejo Mecha Matt Varnish (200ml) – 27.702, bought May 2019, but possibly not opened right away.

[sundancer 42971xp 2]

If it is that old maybe it just thickened too much due to evaporation? Have you tried thinner?

[avernosKeymaster 33947xp 3]

poke the bottom of the pot, you may find a lot of precipitation has settled out. If that is the case then you need to add thinner and really mix it up to remove the precipitate so it is in solution again.

[lawnor 25939xp 1]

I always mix my varnish 50/50 with thinner before spraying,  and always give the bottle a good shake by hand before that.  I’ll give it a thorough stir as best I can for a tall thin pot with a narrow opening and see what happens.

[waywarddarkwolf 1219xp 1]

I’ve had issues with Vallejo varnishs in the past as well with.

As the guys have already said, I tried adding Vallejo thinners (think it was about 50/50) and that improved things.

Also added a drop of flow improver to the mix.

I played around with sizes as well and found that using a bigger nozzle (4mm) helped – there was less clogging.

And only put a little bit of varnish at a time into the cup, washing out with water and/or a little bit of cleaner before filling again, otherwise it started clogging the tip after a few minutes.

It seems to be less of a problem in the winter for me, so I’m guessing the humidity at this time of year has an impact on the varnish as well.

 

[lawnor 25939xp 1]

I’ve always used Vallejo varnishes, but this is my first issue and my first pot of their Mecha.  I do have a 4mm nozzle so next time I guess I’ll swap to that for varnishing.  Good thinking.

[horati0nosebl0wer 19645xp 2]

Evaporation can be an issue and tossing in some flow improver might help but your nozzle size is a better bet to work on. Considering that matte varnish is just gloss varnish with added talc precipitate added to give it a frosty look it is more likely the culprit for clogs. The dry tip problem with airbrush is easily addressed with a touch of glycerin for your acrylics but some mineral spirits would be the material for lacquer and enamel type paints. I haven’t used Vallejo varnish myself but that could be a consideration.

[zorg 18801xp 1]

As others have said the varnish may be to thick. but are you thinning it enough for the gun thin coats are better than no coats. It’s surprising how thin a mix you need for nice smooth coats on the models. Clean and stick some ball bearings in to help mix it up.

[lawnor 25939xp 1]

Hmmm.  I’ve a marble in most pots that size, but now you make me think: Was it rattling last night?  Does it need a marble?

[zorg 18801xp 1]

It will help if theirs not one in the pot/bottle to agitate the heavy particles from the base of the container.

[soapdodger 17313xp 2]

I have had that especially with Vallejo premium matt little bits at the top crystallise then fall into the main solution but They never seem to dissolve back into the paint and clog my brush after a longer period of time. Same thing happens with ultra matt but they are soft balls instead of sharp crystals. For both, either filter the remainder of the bottle through tights (you could use other fine mesh) wash the bottle and put it back in or sometimes I cut a small square of tights and close the bottle over it so it’s between the bottle and nib making a poor man’s in line filter until the bottle is done or I need to replace the filter after 3 months or so.

[zoidpinhead 12492xp 1]

I sympathise.  I have exactly the same happen every time I try to put matt varnish through the airbrush.  In the end I gave up and swapped to spray varnish.  Initially Testors and then when that was discontinued I use Mr Hobby Matt Topcoat.  Super flat finish without the constant airbrush cleaning.

[lawnor 25939xp 3]

Well, I thought I mucked up last night.  I get maybe 10 minutes free at home on Tuesdays and I used it to put a marble in the pot to mix it up.  I’ve done this with other bottles of this shape and size.  I found out why I didn’t do it for this pot.  The marble got wedged firmly in the neck and wouldn’t shift in either direction, no matter how much I poked it.  I thought it was all doomed for the bin (or at least I’d need a knife, a small funnel and an empty bottle), but Sarsons Vinegar bottles have forced me to learn a trick.  They changed the cap on their reusable glass table bottles so the cap won’t unscrew anymore.  The only reason to buy those bottles is to reuse them.  Youtube taught me to get the cap off by standing the bottle upside down in freshly boiled water.  plastic expands faster than glass.  I tried this on my varnish while making my morning coffee and the marble is now in the varnish.  Hopefully the heat has been good for the varnish too.  I’ll give it all a thorough mix and add some thinner to the bottle itself before I get the airbrush out next, and see what happens.  That might not be for a couple of weeks, though.

Thanks everyone for the feedback.  It’s been a big help.  I’m also super impressed that no one has told me to stop being cheap and just buy some more!

[sundancer 42971xp 2]

I’m also super impressed that no one has told me to stop being cheap and just buy some more!

 

Well this isn’t a G’Wullu forum now is it? *g* Also why waste perfectly good materials if the only thing they need is a marble and some action?

[avernosKeymaster 33947xp 2]

the hobby is expensive enough without replacing things that don’t need it 😉

I’ve a hex nut in mine and it still gets trapped in the much at the bottom, I’m toying with getting something like a badger paint mixer for mine…although without the hobby tax.

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