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Sandy finish


Andy350

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I am using Humbrol Acrylic thinned down to about 60/40 paint/thinner.  Whenever I apply a sandy rough finish happens.  Have I thinned to much or not enough?  I did pick up a very cheap airbrush to replace the previous very cheap airbrush, the nozzle is tiny.  Also, I have had to strip this one down three times as it blocks up very quickly.

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a. some Humbrol acrylics are not good for spraying. Their pigment is too coarse. Its especially bad in their RLM colours

b. sounds like the paint is drying before it hits the model. More dilution and closer to model spraying will help

 

optional :

c. Try using Vallejo Model Air paints for spraying; They are ready mixed for spraying and have a good reputation for being sprayed.

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5 minutes ago, Black Knight said:

a. some Humbrol arcylics are not good for spraying. Their pigment is too coarse. Its especially bad in their RLM colours

b. sounds like the paint is drying before it hits the model. More dilution and closer to model spraying will help

 

optional :

c. Try using Vallejo Model Air paints for spraying; They are ready mixed for spraying and have a good reputation for being sprayed.

I'm going to have to buy a new airbrush and compressor.  I'm on the second airbrush and now that has give up, the internals are blocked by the paint that has turned to a rubber like substance and I cannot clean out.  I'm going to have to put a halt to this build until I have something better to finish off with.  Problem with airbrushes is, there is a lot of choice, I just need something that gives a good finish, will not require stripping down every ten minutes, and works.

I've been ok'ish with thinned down Tamiya paints, but this Humbrol has caused issues.

I do have some Vallejo Model air paints as a wheel and track selection, but not tried to airbrush yet.

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35 minutes ago, Andy350 said:

I'm going to have to buy a new airbrush and compressor.  I'm on the second airbrush and now that has give up, the internals are blocked by the paint that has turned to a rubber like substance and I cannot clean out.  I'm going to have to put a halt to this build until I have something better to finish off with.  Problem with airbrushes is, there is a lot of choice, I just need something that gives a good finish, will not require stripping down every ten minutes, and works.

I've been ok'ish with thinned down Tamiya paints, but this Humbrol has caused issues.

I do have some Vallejo Model air paints as a wheel and track selection, but not tried to airbrush yet.

You don't say how much you paid, or the make of your airbrush, but in my experience it is worth spending on a good brand, its a long term investment and will be worth the extra £'s spent. Also, watch some 'how to' videos on you tube. there are lots out there and cover airbrushing in various types of paint, and some its really worth watching, MIG for example airbrush much differently to tamiya. Airbrushing is a skill and takes a long time to master, I am always apprehensive when i get the airbrush out, I don't paint often enough and its like starting as a beginner most times!!Half hour later I am comfortable enough to paint the model! Work on it and save up for an Iwata or Harder & Steenbeck airbrush, it will be worth it!

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I'm going to be 'that guy'. Without actually being there and seeing what you're doing, it sounds to me like a paint issue. Humbrol acrylic is pants. Tamiya is good, but can be tricky to airbrush (hint, use Gunze Sangyo's Leveling Thinnner (note the one L in Leveling) to cure most of Tamiya's issues). Vallejo (and Mig and AK) are love 'em or hate 'em paints. Try them and see, but beware the use of incorrect thinner. My acrylic preference is Gunze Sangyo, followed by Tamiya and Xtracrylix (the last is difficult to get where I am).

 

Unless your airbrush is completely unusable, I doubt that it's your brush. I've used a few cheapies over the years and have found that they work; not always well, nor very controllably, but they blow paint in the right general direction. Which is all that's needed most of the time. I doubt that a new one, while nice to have, will solve your problems.

 

For cleaning your clogged airbrush, try an ammonia-based cleaner. Don't leave it to soak in the cleaner for too long, or you'll strip the chrome. It should however dissolve the paint gunk. Failing that, there's a number of airbrush cleaning solutions on the market that seem to work. If necessary, soft copper wire and wooden slivers can be used to pick and ream, with caution. NEVER use steel wire inside an airbrush, and be cautious if using cotton buds etc, they can leave behind filaments.

 

PM me if you want, although airbrush repairs by remote control are sometimes a little difficult!

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59 minutes ago, sampanzer said:

You don't say how much you paid, or the make of your airbrush, but in my experience it is worth spending on a good brand, its a long term investment and will be worth the extra £'s spent. Also, watch some 'how to' videos on you tube. there are lots out there and cover airbrushing in various types of paint, and some its really worth watching, MIG for example airbrush much differently to tamiya. Airbrushing is a skill and takes a long time to master, I am always apprehensive when i get the airbrush out, I don't paint often enough and its like starting as a beginner most times!!Half hour later I am comfortable enough to paint the model! Work on it and save up for an Iwata or Harder & Steenbeck airbrush, it will be worth it!

The first one came with a small compressor without a cylinder.  Was about £25, then I picked up another cheap airbrush from Amazon for £10, they are not really branded as such, and are probably mass produced in China.  My wife will buy me one for Christmas inclduing compressor.  Too much choice out there.

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32 minutes ago, Rob G said:

I'm going to be 'that guy'. Without actually being there and seeing what you're doing, it sounds to me like a paint issue. Humbrol acrylic is pants. Tamiya is good, but can be tricky to airbrush (hint, use Gunze Sangyo's Leveling Thinnner (note the one L in Leveling) to cure most of Tamiya's issues). Vallejo (and Mig and AK) are love 'em or hate 'em paints. Try them and see, but beware the use of incorrect thinner. My acrylic preference is Gunze Sangyo, followed by Tamiya and Xtracrylix (the last is difficult to get where I am).

 

Unless your airbrush is completely unusable, I doubt that it's your brush. I've used a few cheapies over the years and have found that they work; not always well, nor very controllably, but they blow paint in the right general direction. Which is all that's needed most of the time. I doubt that a new one, while nice to have, will solve your problems.

 

For cleaning your clogged airbrush, try an ammonia-based cleaner. Don't leave it to soak in the cleaner for too long, or you'll strip the chrome. It should however dissolve the paint gunk. Failing that, there's a number of airbrush cleaning solutions on the market that seem to work. If necessary, soft copper wire and wooden slivers can be used to pick and ream, with caution. NEVER use steel wire inside an airbrush, and be cautious if using cotton buds etc, they can leave behind filaments.

 

PM me if you want, although airbrush repairs by remote control are sometimes a little difficult!

Hi Rob, I've had issue with everything I've put through them, Vallejo Primer, Tamiya Acrylic, Humbrol enamel and now Humbrol Acrylic, I only used the later because I was after EDSG.  I will try some ammonia based cleaner, but I feat it will only get clogged up again!  Thanks for the advice.

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Grab a bottle of IPA, put a few drops of the paint you used and some IPA into a shot glass (or whatever you have lying around) and see if it mixes properly. If it does just soak the airbrush in IPA (closed container) overnight and the next day grab some airbrush cleaning brushes and give it a good clean. The IPA shouldn't kill the rubber seals but you should take apart the airbrush as much as you can anyway so you'll be removing them. 

As a general rule IPA should be able to thin pretty much any acrylic paint without turning it into goo. Leveling thinner only works on some paints. Always do the mix externally if you're unsure of the compatibility.

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10 minutes ago, bmwh548 said:

Grab a bottle of IPA, put a few drops of the paint you used and some IPA into a shot glass (or whatever you have lying around) and see if it mixes properly. If it does just soak the airbrush in IPA (closed container) overnight and the next day grab some airbrush cleaning brushes and give it a good clean. The IPA shouldn't kill the rubber seals but you should take apart the airbrush as much as you can anyway so you'll be removing them. 

As a general rule IPA should be able to thin pretty much any acrylic paint without turning it into goo. Leveling thinner only works on some paints. Always do the mix externally if you're unsure of the compatibility.

I've tried thinning with IPA before and it just breaks the paint down.  I've had to use X-20A to think the Tamiya with.

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The sandy finish definitely sounds like a pigment issue and you probably won't overcome it by thinning. Try a different brand of paint. As for thinning ratios, forget them. What you should look for is consistency. I look for the consistency of milk. I find Vallejo Model Air will spray direct from the bottle without thinning and is my brand of choice. As for your airbrush, it is down to cleaning. Vallejo Acrylic Polyurethane Surface Primers can leave a congealed mess in your airbrush (regardless of make).  I flush with water then Vallejo 71.199 Airbrush Cleaner. If this doesn't do the trick its a strip-down job and out with SprayCraft aerosol Airbrush Cleaner. I have an Iwata HPCplus and a cheap Expo AB900 and my cleaning routine works with both.

HTH

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45 minutes ago, bmwh548 said:

As a general rule IPA should be able to thin pretty much any acrylic paint without turning it into goo.

That's a bit too generalised, if I may say so. :) There are a number of acrylic brands that will turn to rubbery goo when brought into contact with IPA (Isopropyl Alcohol/Isopropanol), as they're latex-based and entirely incompatible (Vallejo, Xtracrylix, LifeColor to name a few).  The only thinner that seems to work with all acrylics that I've come across is Ultimate Thinners and Ultimate Airbrush Cleaner.  They do contain a portion of IPA, but it is formulated not to cause the rubber goo syndrome.

 

You need to get into a routine of cleaning your airbrush properly at the end of each session with an appropriate cleaning fluid to your paint, learn to backflush before each colour change within a session, and choose your paints wisely to suit your nozzle size and aspirations of how fine a line you want to airbrush.  As some have already said, Humbrol acrylics have a bad rep for consistency and quality, and a very coarse (read cheap) pigment grind.  Gunze have a good fine grind, and spray very well, as do Tamiya and a few other brands.  If you use Mr Leveling Thinner (sic), you'll get a nice smooth and robust finish, but always spray closer to your model or in cooler conditions if you're getting orange peel or a gritty finish, as that's due to the paint drying on the way to the model.  There's a lot of trial and error with getting your paint and airbrush working well together, but start off with a decent bit of kit and you'll have an easier time.  I'd recommend Gunze airbrushes (very similar to Iwata), as they're awesome, well-priced and robust.  Speak to Martin @ Air-craft.net (@Jetblast) if you need any advice, or peruse our review section as we've played with a few :)

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20 minutes ago, Mike said:

That's a bit too generalised, if I may say so. :)

 

I agree, which is why I added that when unsure he should always try it in a clear cup to check what happens with the mix.

I've used IPA for Revell, Tamiya, Gunze, Green Stuff with no issues. I remember trying it with Agama many years ago (when I first got my hands on an airbrush) and I remember the paint didn't like it (although the Agama thinner had the specific alcohol smell). Then again, I do have a tendency for lacquers and enamels so I'm not up to date with all the acrylics that came up these past few years. 

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45 minutes ago, Mike said:

That's a bit too generalised, if I may say so. :) There are a number of acrylic brands that will turn to rubbery goo when brought into contact with IPA (Isopropyl Alcohol/Isopropanol), as they're latex-based and entirely incompatible (Vallejo, Xtracrylix, LifeColor to name a few).  The only thinner that seems to work with all acrylics that I've come across is Ultimate Thinners and Ultimate Airbrush Cleaner.  They do contain a portion of IPA, but it is formulated not to cause the rubber goo syndrome.

 

You need to get into a routine of cleaning your airbrush properly at the end of each session with an appropriate cleaning fluid to your paint, learn to backflush before each colour change within a session, and choose your paints wisely to suit your nozzle size and aspirations of how fine a line you want to airbrush.  As some have already said, Humbrol acrylics have a bad rep for consistency and quality, and a very coarse (read cheap) pigment grind.  Gunze have a good fine grind, and spray very well, as do Tamiya and a few other brands.  If you use Mr Leveling Thinner (sic), you'll get a nice smooth and robust finish, but always spray closer to your model or in cooler conditions if you're getting orange peel or a gritty finish, as that's due to the paint drying on the way to the model.  There's a lot of trial and error with getting your paint and airbrush working well together, but start off with a decent bit of kit and you'll have an easier time.  I'd recommend Gunze airbrushes (very similar to Iwata), as they're awesome, well-priced and robust.  Speak to Martin @ Air-craft.net (@Jetblast) if you need any advice, or peruse our review section as we've played with a few :)

Thanks Mike, very helpful.  Just to clarify, can you use Mr Leveling Thinner with Tamiya Acrylics?  I will speak to Martin as well.  Cheers.

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59 minutes ago, bmwh548 said:

Yes you can. And they clean up very nice with cheap lacquer thinner. Also works on Gunze's acrylics.

...and Vallejo's RealColors, plus a few others that I can't remember.  Usually anything that's called "synthetic acrylic" that can be thinned with water, their own thinner, or cellulose thinner.  MLT is a cellulose thinner with additives, and although per ml it's quite expensive, it's not as hot as others, and smells a damn sight more pleasant.  Just don't waste it on cleaning your airbrush.  I use Liquid Reamer, but you can use any brand of cellulose thinners, just be cautious that it doesn't soften your seals. :)

 

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