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Airbrushing emergency! - Enough's enough - a new brush


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I know that there are other sections of the forum where this should really be posted but, this is a serious cry for help.

I find it difficult enough getting myself going to do some modelling and this weekend I have promised myself to get the Hawk I started months ago finished and to start on the 2 GB's I'd put my name down for.

However, I get home from work, head straight to my work bench, get out my airbrush and sit down to make my first attempt at pre-shading. Then just as I start it goes wrong! I've had very mixed results with airbrushing all along really. But just now and in my previous attempts I have started getting terrible problems with paint 'spitting'.

So, I'm using a Badger Crescendo 175 that hasn't seen a great deal of action since bought new 4 or 5 years ago. Just 4 completed models.

I'm trying to spray Tamiya flat black acrylic (XF-1) thinned with a ratio approximately 55% paint 45% Tamiya X-20A acrylic thinner.

The room temperature is a fairly low 13 degrees C. My compressor is set at about 15psi.

I'm keeping pretty square to the surface and I'm spraying from in the region of 2 to 3 inches - as I want pretty narrow lines.

In the picture you can see the results on the wing of a Mirage 2000 (my test kit) and on the Hawk's wing. The Hawk was primed ages ago using Tamiya XF-19 (as I'd seen done by Phil Flory) and that seemed to go pretty well in what I'm sure was a pretty similar set-up. The Mirage was primed with a rattle can primer - probably Halfords.

28fc5b89-e64b-40ca-b5e2-cafda67062df_zps

I know this sounds a bit melodramatic but I am feeling so riled by this - as I honestly can't see what I'm doing wrong - I feel like just chucking in the towel and selling the damned lot. All I want is to end up with something that looks at least a bit like the amazing work I see posted on here day in and day out but it just seems like a pipe dream. I've bought pretty good tools, I've read countless build threads and tips threads, I've watched dozens of modelling tutorials online and yet I can't even successfully spray a thin line of flat black acrylic paint.

I'll probably regret this rant when I've calmed down but still, any help would be appreciated. It's supposed to be a 'fun hobby' yet I'm pulling my hair out!!

Edited by Filler
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I would suggest you need to thin more like 75% thinner for preshading! and turn the wick down a bit, 10-12psi maybe (depends on the AB I guess). That splattering looks to be a result of the paint drying before it hits, which is probably a combination of paint too thick and pressure too high.

I now the frustration feeling, the above advice is based on hours of trial and error!

Phil

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As Phil said the paint looks a bit thick, also try adding a bit of Tamiya paint drying retarder to the mix, makes a lot of difference.

Edited by Stuck
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Cheers Phil and Stuck. I left the dismantled brush in a vat of IPA to soak while I've gone to my folks to cadge something to eat.

I'll try thinner and less force later. I never used to have these problems in my first brief period of modelling. Seems I've started to have problems on my recent return.

I know trial and error is an almost unavoidable part of the journey but it's hard not to want to match the RFI's on here right now, not in 10 years. I guess I need to learn some patience.

Edited by Filler
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When I want that effect, splatter, I drop the pressure give it full medium (ink,paint what ever it is I'm spaying) that's the way to get splatter. Otherwise I turn up the pressure and adjust the medium. The paint mix might be too thick, I've never used that paint though. I think your pressure is too low and too much medium button. I take it your brush is a double action.

How is your water trap? You could be getting some moisture as well.

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All seems to be ok-ish with pressure, ratios etc. Try closer to the surface and open the brush just a tad. Obvious I know but make sure the brush is clean. Let us know, good luck. Aidan

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It could also be a slightly clogged nozzle, or 'coated' needle.

Have a good look at the nozzle end under a mag lens if you have one.

Even with careful cleaning, it's surprising how much gunk can still be round the needle etc.

This will affect the air flow and paint flow.

I used to take the needle out occasionally, and carefully 'drag' my scalpel blade down the point all round now and again.

It made a world of difference.

Roy.

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I would suggest to turn the pressure up, low pressure and paint doesn't tend to work well, you need a higher pressure to atomize the paint. I tend to spray between 20psi and 40psi, depending what I'm doing and how the paint is thinned.

Make sure also that your not getting pressure drop. (Do you have an air tank, or straight from the compressor?) Set the airbrush up without paint in and pull the trigger (at what ever you have set the needle) fully open and adjust the air so that you are actually spraying at 15psi, but when you let go of the airbrush the pressure will rise back up to 18psi/20psi etc. If you've just set it to 15psi and started spraying you will actually be spraying around 10psi(ish).

I might be wrong but the paint looks fine to me.

Hope that helps..

Edited by Radleigh
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hi pal. I had this happen with Tamiya paint.

the solution for me was to thin it to about 70 / 40. I also use revell aqua thinners. Running at 10psi i get a very fine mist that i can control by varying how far the trigger is set.

hope this helps.

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I would try thinning more as suggested and increasing the pressure, you can always turn it back down again if you feel you have too much. You have a test piece so don't be afraid to blast away at that. Preshading is a good time to practice with different mixes, pressures etc as ultimately it'll all but disappear.

Keep practicing, you'll get there (then wonder how so keep notes of mixes, pressures etc when it works the way you want it to).

Duncan B

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Thanks so much everyone for the advice. I've just finished having another go after taking on board all your suggestions.

The good news is that there was an improvement in the results - although there is plenty more room for improvement - most of which is probably to be made in my aim and trigger control!

So, I increased the pressure to 20psi. This was taking Radleigh's suggestion about setting the psi slightly higher than the intended spraying pressure. So i was looking for about 18psi. I thinned the paint to roughly 1 part paint, 2 parts thinner. I stuck with Tamiya's X-20A for now but added a drop or two of acrylic retarder. I also gave the brush a thorough clean before starting. I'm usually pretty fastidious with the cleaning but I suspected there might be some traces in hard to reach areas. I checked the needle under a magnifying glass as Roy suggested. Looked pretty spotless.

Maybe the biggest problem was something I never thought to check but bzn20 mentioned - the moisture trap. When I pressed the valve, there was enough water shot out to take out a railway line! I might have to look into an additional trap. I've seen those smaller ones that are fitted at the brush end of the line. That'll be one for Paul at Little-cars perhaps.

So here's the result of the first post advice attempt;

DSCN4046_zps4ec761c8.jpg

You can see the massively reduced splutter on the left wing line. A bit faint but that was mostly down to caution.

And the Hawk.....

DSCN4049_zpsd638c9bd.jpg

Ok, so it's pretty wild and inconsistent and yes, maybe I should have just painted it black and had done but, it's a start. I hope my aim and control will improve with practice and I will refine the mix and pressure over time.

So thanks again for all the advice and encouragement. I felt pretty despondent earlier but no I'm raring to get this Hawk finally finished and make a start on the JP and TR-1 in the group builds.

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Glad you've sorted it out. Go for the best water/moisture trap you can afford. You want the driest air you can get. I have an industrial trap, I've had "hobby" type efforts and the material spec and performance wasn't any good. You need a decent size "bowl/ water collector" otherwise it will fill pretty quickly depending on the air quality where you're using it.

As far as practise goes....more the better! Try spraying "panel lines drawn" on a toilet roll centre. spray numbers/letters/shapes on a sheet of paper. write letters and numbers on a sheet and try to follow/spray the pen lines. Try spraying a face free hand. use the cheapest medium possible to do it, not cheap acrylic paint tho' and not your expensive paints. I'd use WATER based artist acrylic ink from an art supplier (about £3) Obviously you'll need to practise with the paints you use, pressures etc. but if you get the basic control first and under your belt then paint/thinners mix and air pressure ratio sorted out you'll be flying!

Edited by bzn20
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I feel your pain Filler, I've been having the same problem preshading with Humbrol matt black. The paint comes out spattery and it's almost impossible to get a thin line.

I have tried thinning the paint to almost pure Humbrol thinners but I have an additional problem in that the brush WILL NOT respond consistently to the trigger position. It will mostly spray fine for about 2 secs then the paint flow will cut out. If I pull the trigger further I will get a huge spurt of paint and then a consistently large volume of paint. Thereafter it will be impossible to get a fine line, just bucket loads of paint (mostly thinners) comes out. This after repeatedly cleaning the brush. Is there a problem with spraying matt black? It's a Hansa 381 double action brush.

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I have this problem or similar caused by the following...

Paint not fit for airbrushing, pigments too big or paint not completely mixed. I got everything you mentioned.

Not enough thinner. You obviously didn't!

Paint drying in the brush, again I don't think you did.

Sticking mechanism and or "muck inside the works"

Build up in the nozzle.

Needle damaged, couldn't get a fine line.

Does your sprayed line (ever so slightly) go off centre or not exactly where you aimed it?

What happens when you just spray water? If you haven't, try it and see how it sprays on to news paper. That way you can easily see the line being sprayed.

Good luck, there is nothing worse than an airbrush problem you cant get 'round.

Edited by bzn20
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Also, sounds simple but make sure the aircap is tight, if it's loose it'll cause splattering too. But I reckon this will be due to paint not being stirred enough, I've done it loads. Even when you think it's mixed, it can sometimes need that little bit more.

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I feel your pain Filler, I've been having the same problem preshading with Humbrol matt black. The paint comes out spattery and it's almost impossible to get a thin line.

I have tried thinning the paint to almost pure Humbrol thinners but I have an additional problem in that the brush WILL NOT respond consistently to the trigger position. It will mostly spray fine for about 2 secs then the paint flow will cut out. If I pull the trigger further I will get a huge spurt of paint and then a consistently large volume of paint. Thereafter it will be impossible to get a fine line, just bucket loads of paint (mostly thinners) comes out. This after repeatedly cleaning the brush. Is there a problem with spraying matt black? It's a Hansa 381 double action brush.

Where do you mix the paint? I'm guessing you mix it in the actual paint cup of the airbrush. If you are then try mixing the paint in another pot or glass jar then transferring the mix to the airbrush.

I used to have the same issues and most of it was down to trying to mix the paint in the cup. I would find that some of the paint would form a plug in the paintway and this would cause the brush to block very quickly and to be very inconsistent. If I do want to mix a little paint in the cup now I use a paintbrush to add the paint rather than just pouring it into the thinners in the cup but generally try to mix the paint separately from the paint cup and add it once mixed.

Hope that helps.

Duncan B

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Duncan B's right about mixing the paint outside the airbrush. I used to mix it together with thinner in the colour cup, but started having problems similar to yours. I now use a ceramic mixing palette bought cheaply from an art supplies shop, but you can use anything that's easy to clean, and transfer the paint into the colour cup with a paintbrush when I'm happy with the consistency.

I had a gloopy bit of old paint that had found its way into the front of the airbrush behind the nozzle, (there's probably a technical term for that part). Soaking the airbrush in thinners would soften it but not remove it, and it had got pushed further back in the nozzle threads and impacted at the back of the thread, preventing the nozzle from screwing all the way in and seating properly. It caused a lot of spatter like you were getting until I poked it out of the thread with a bent over cocktail stick.

I also stopped stirring my paint in the jars, as Tamiya acrylics can get thick and dry, and lumps can find their way into the airbrush and clog it. Shaken, not stirred, is the way for airbrushing, I found.

Since following these methods I have had very few issues with my airbrush, and can spend less time trying to clean it and more actually using it. It's very frustrating when it's the other way round, so I hope you find a solution for your problem that works for you.

Cheers,

Paul

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hi pal. I had this happen with Tamiya paint.

the solution for me was to thin it to about 70 / 40. I also use revell aqua thinners. Running at 10psi i get a very fine mist that i can control by varying how far the trigger is set.

hope this helps.

70/40 ?? This must surely be a typo?

I use Tamiya with 90% of my builds and use the old "skimmed milk" mix with psi around 15- 18. Many on here dont use the pre set on their airbrush, I do and if you have one try using it. (set fine) I also think 2-3 ins away is a bit far for pre shading.. :2c:

A couple of examples on my test bed. There is a good chance that these are not up to the standards your after,they do however work for me. :poo:

P2110018_zps27f6abcc.jpg

P2110019_zpsd05e5abb.jpg
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Hello everyone. I'm back after losing Sunday and pretty much Monday thanks to a wedding reception on Saturday night. Although it I guess it was more due to booze than the reception itself but anyway...

I did have another go late last night and again with encouraging results. I went with two scoops Mr Color Levelling Thinner to 1 scoop Gunze acrylic paint and this ration seems pretty good as it was when I used Tamiya's equivalents. As Ancient Mariner mentioned, getting closer does seem to help with panel lines spraying.

After taking all the above advice on board I am pretty sure my first attempt went wrong thanks to a combination of;

Trace paint residue in the brush.

Gallons of water in the moisture trap (and need for a better trap).

Incorrect paint mix on the 'think' side.

Slightly under pressured spraying - especially as I am using a siphon feed colour cup.

Mixing the paint in the cup.

Spraying from a little too far away.

And finally, poor technique.

So all in all, about as wrong as it could possibly have gone. The only way is up!

Interesting how a few have mentioned not mixing the paint in the cup. I guess through a mixture of wanting less cleaning up and fruggleness, I always mix in the cup as it saves cleaning an extra vessel and I waste less paint. But then I often end up with more than I needed anyway. My procedure has always been to add the thinner by using a pipette to put it into a measuring spoon (the type that often come in a variety of sizes for baking - 1/4 tsp etc) and pouring that into the cup. Then I take a scoop of paint from the jar using the measuring spoon and tip it in to the cup. Then a good stir with a cocktail stick. I'll try mixing first in future.

So again, thanks to everyone for their help. Recently I've found it a little morale sapping on here due to the ever rising standards of WIP and RFI's. Don't get me wrong as i do enjoy seeing the splendid models that others produce but, this kind of response to those of us who are a little less gifted is an equal reminder of why this site is so awesome.

And burncpt, good luck solving your spraying issues too. I'm sure all the answers are here above us.

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I never mix in gravity cup, but always mix in a suction pot and if I need paint for a gravity type airbrush then I mix in a spare Tamiya jar and use a pipette to put into the AB.

Never crossed my mind to mention it..

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That sounds like a lot of washing up to me. I always mix in the airbrush gravity cup. Add the thinners first, do a test shot to make sure all is working OK then add the paint using one of those plastic semi-disposable pipettes and give a few squirts in and out of the pipette which gives it a very thorough mixing. You can gauge the viscosity of the paint as it squirts out of the pipette and add more thinners / paint if needed. It works for me anyway.

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Same here. Especially sice we're talking siphon feed here. Sure it is possible to mix the paint thoroughly in the jar before it is sucked into the innards of the AB.

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That sounds like a lot of washing up to me. I always mix in the airbrush gravity cup. Add the thinners first, do a test shot to make sure all is working OK then add the paint using one of those plastic semi-disposable pipettes and give a few squirts in and out of the pipette which gives it a very thorough mixing. You can gauge the viscosity of the paint as it squirts out of the pipette and add more thinners / paint if needed. It works for me anyway.

Nigel, I think the reason your method works (I know as I have done it this way too) is that you are not pouring the neat paint in and giving it a chance to drop through the thinners to the paint passage. Your method gives it a decent mixing so that's good.

I tend to mix in a glass pot as I'll keep the excess paint for the next model (as you know I build a lot of Luftwaffe stuff so use the same colours often).

Duncan B

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Following some improvement with my brushing after the advice on here, I seem to be back to square one already. At the Huddersfield show on Sunday I picked up an in line filter to add an extra layer of moisture protection but, unfortunately it seems that moisture isn't the problem as I still have this spluttering problem. Plus the filter partially obstructs the paint cup (bottom feed) but that's no biggie.

My Badger 175 Crescendo came with three needles and tips, fine, medium and heavy. I've up till now used the medium but on Sunday afternoon I switched to the fine parts in case I have a defect in one of the medium parts. Alas, I still have spluttering and this has occurred using both Tamiya and Gunze acrylics mixed with their own thinners. So I'm fairly sure it's a paint mix problem but can't entirely rule out an airbrush problem. I'm a tad suspicious of the PTFE needle bearing as maybe that has been damaged by the removing and particularly the inserting of the needle or has been attacked by some of the thinner or cleaning fluids.

But the other thing that has crossed my mind is temperature. I know a lot of people spray in sheds and garages and I'm spraying indoors but my flat is colder than the average garden shed in Siberia. Is there an ideal air temperature for airbrushing.

I'd love to sort this soon as it is seriously holding up any modelling progress at a time when I actually have some enthusiasm for doing some! My last resort is to buy a new airbrush and compressor with tank but, that's a huge outlay to replace fairly decent and little used kit. And I may still experience the same problem. Do fancy a top feed brush though. Bottom feed seems to require higher pressure, greater volume of paint in the cup (loads of wastage if just spraying a very small piece or area) and obstruct filters and airbrush holders.

Gone on a bit there but in summary; is temperature a significant factor in successful spraying of acrylics?

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