Airbrush problems

[Cole4ord]

Hi all.

Imhoping for some advice. I have just bought my first airbrush (Harder and Steenbexk Ultra)
I used it the first time to do some pre-shade on panel lines and it seemed to work ok, apart from not being able to get a very thin line. I then stripped it and cleaned it.
Last night I went to use it for a second time and it will barely push any paint through. I have thinned it down about 50/50 or more like 60/40 but hardly anything coming through. I then stripped it down again but still the same.
I blocked the end and was able to get bubbles in the cup with just thinner as Paul advised in his video but still nothing.
I know it's a
Long shot but can anyone help?

[mep1954]

Hi Cole4ord,


I am no expert (far from it) but as your H&S Ultra is NEW and a fine airbrush, (so there shouldn't be any problems, wear etc), it sounds to me from your severly reduced paint flow issue, as though the needle chucking nut MAY not be fully tightened, or that the needle may not have been fully seated within the nozzle when you re-assembled the airbrush??

You said you have stripped it, and if, as you say, you are fairly new to airbrushes, stripping cleaning etc, is it possible, maybe??, that you might not have rebuilt it spot on?

Assuming that there is no damage to the needle & nozzle (hopefully!), when rebuilding, the needle needs to be (very carefully) pushed back into the airbrush until it comes to a firm 'stop' (fully seated within the nozzle), and then the needle chucking nut (the straight-nurled threaded nut with a conical 'tail' end) needs to be 'nipped up' (finger tight) to ensure that when you pull the trigger back that the needle is firmly 'gripped', and that it, too, is also pulled back out of the nozzle (to open the paint 'path', and allow the paint to flow).

If you have not pushed the needle fully 'home' to a firm stop, OR if you have not fully tightened the needle chucking nut, then the needle will NOT be drawn back out of the nozzle when you pull back on the trigger (or will be only PARTIALLY withdrawn from within the nozzle) and thus the paint will not flow at all, or you will only get a partial/reduced flow of paint.

This sounds to me (who is albeit very much still a comparative 'newbie') as what MIGHT be happening??

If you think any of this sounds plausible, there are plenty of "How to strip and clean your airbrush" tutorial videos available, (search for one on this ISM site, as I am sure Paul has done at least one, if not more!)

In terms of getting thin lines, you need the 'business end' of your airbrush to be CLOSE to your work to achieve this, need paint/thinning and airline pressure optimal, but above all, this is mainly a matter of practice .... practice ... practice. That's what they keep telling me, at any rate! lol

Hope this helps and might help you sort your probs. There are LOADS of airbrushing-related videos on this site alone. So if you are new to the wonderful (and at times, infuriating!!) world of airbrushing, go check some of them out. But above all, don’t let this little hiccup discourage you at all, and the H&S Ultra is a fine starter airbrush, so don’t be blaming that either. lol

Good luck, do lots of practicing, but mostly - enjoy your modelling!

Cheers, Mark

[Svenne009]

What is the paint and the pressure you are using?

[Cole4ord]

Hi both.
Thanks so much for replying. Extremely informative!

I have taken note of your points and given it a go. I have put it all back together very carefully so that the needle is up into the nozzle and the nut at the back is tight and that seemed to be correct as I test pulled the trigger without the back body on and I could see the needle move backwards.

The paint I'm using is Humbrol (actually this colour is one of the tiny pots of it that comes with a started kit) and I'm trying all psi's, from 15-40.

Could the paint be the problem. I managed to get it working slightly better for a short period of time tonight but the paint that was going on the model was far too watery (possible too much thinner?) so I put a bit more paint into the mixture in the cup and almost immediately I was getting nothing out the end again.
Are the humdrol paints no good for airbrushes? If so what would you recommend.
Another quick point is that I have been taking the needle cap out of the head for cleaning and there seems to constantly be paint inside it, even after soaking it in thinner to clean. I can gently push a pin into it and see tiny worms of paint coming out of the end.

Any further help would be great.

[mep1954]

Hi Cole4ord,
Sorry if my original post sounded as though I was ‘teaching my granny to suck eggs’ regarding stripping and re-assembling your airbrush. No offence intended!

Errrr... Humbrol supplied-with-the-kit paint pots!!! That would be the first thing I’d suspect. Not really all that good even for BRUSH-painting, probably even more so if thinned for airbrushing, although can’t say it’s something I've ever attempted.

Personally, my main ‘catalog’ of paints is Vallejo Model Air (designed/thinned to be used 'out of the bottle' for airbrushing, although some modellers advocate a little further thinning. A LOT depends on the paint, and even different colours of the same brand can vary in thickness/viscosity/ideal thinning ratio etc.

Not saying that Vallejo Model Air is the 'top dog', by any means - (paint drying/accumulating on the needle shaft ('‘tip dry’) needing frequent needle tip cleaning is a quite common complaint with it. 'Fraid there isn’t really much of a short-cut to trying a few different brands, and finding out which works best for YOU!

Mr. Hobby Aqueous Hobby Colour, AKAAN, and Tamiya are well acclaimed and used by MANY modellers. So would suggest that you acquire a bottle (or three!) of any of these paints (that you can get hold of fairly easily) and give it a whirl.

As I said earlier, the PAINT, thinner, airbrush, air pressure and temperature/humidity all have an effect, quite apart from thinning ratios, the brand/type of thinner used, and of course, the skill of the airbrush user!

As regards a thinner to use. Get yourself some Ultimate Modelling Products Airbrush Thinner (and some of their Cleaner, while you’re at it!) Paul (Bretland) of this ISM site, & co-owner/director of Ultimate Modelling Products, and purveyor of countless highly informative YouTube videos, has gone to the trouble of producing a thinning ratio chart for a whole raft of different paints used with their thinner (do a search on this site, and you'’ll find it) The Ultimate will work well with virtually ANY (modelling-related!!) paint, and is increasingly the "go-to" thinner of choice for many many modellers.

Hope this of some help. And don't be discouraged. It's fun being on a learning curve, isn't it? lol You'll have it cracked soon, I’m sure!

Cheers,
Mark

[Cole4ord]

That you so much for all your help Mark and don't worry, no offence was taken.
I think I will take your advice and invest in some different paints and see if that does the trick. It certainly sounds possible.
Thanks again.

[SteveW]

Hi Cole4ord

Though I haven't tried the Humbrol paint you get with the starter kits I have recently tried the Humbrol Acrylics and have had the same issue. They seem very finicky about thinning. If you go to far they puddle and if you don't thin enough then it just block your brush. I wold go with Marks advise and try the more staple paints, Tamiya, vallejo Air etc.

[RobertK]

I don't like humbrol in an airbrush, but using the 0.4 needle it should work when properly thinned.

But, I have had some issues with my Ultra. I couldn't really spray properly from start and after some frustration I found the problem. It was leaking and therefor disrupting the airflow. I don't know what the part is called, but, it was leaking shown in the image



Apparently the the crown(or whatever it's called, haha) was just a tiny bit for big for the airbrush body so some air leaked through, I found out using soapy water and I could see some bubbles. I contacted H&S and they sent a replacement but I couldn't wait so I used some beeswax to seal the threads temporary and it worked perfectly.

[mep1954]

Hi Cole4ord,

Came across this thread (in case you hadn’t already located it!)

The Thinning ratio chart that Paul did is in there, and I’m sure there will be lots of interesting/relevant posts in there of interest to you.

http://intscalemodeller.com/viewtopic.php?f=55&t=3016

Hope it helps!

Cheers,

Mark


P.S. I should have added before now, that you can disregard my previous speculation relating to the needle not being re-installed FULLY home when reassembling the airbrush. Brain wasn’t in gear properly when I composed my original post, because if the needle is not inserted 'fully home’, of course the problem that this would give you is that you can’t fully shut OFF the paint flow (getting paint and/or lots of splattering) even with the trigger released fully forwards) which is the complete opposite of what you have been experiencing! Doh! on my part!

I didn’t make the distinction, either, between ACRYLIC paints and other types, (e.g. Humbrol enamel, Alclad lacquer etc). So, needless to say the Ultimate Thinner, and the vast majority of my comments to date relate to ACRYLIC paints. But there I go again, teaching my Grandma to suck eggs! Sorry!

Hope you’ve got a good, well-stocked modelling emporium conveniently close to you, as I suspect (!) that you may be frequenting them now and again!! lol

Have fun!

[Cole4ord]

Hi all.the info you have all given me has been a massive help, and thanks for the link. Will come in very handy.

I took your advice regarding the paint. I popped into a local model shop yesterday to get some of the recommended paint. Picked up a few colours from the Tamiya range.

On getting home gave Tiago with some thinned down but nothing. Just to ensure I covered all bases I stripped it down and gave it a full clean and started again but still nothing. However, I then blocked the head with tissue like you do when cleaning, got bubbles and from then on it sprayed perfectly. I can only assume there was a blockage I couldn't reach whilst cleaning. I have suspicion that this could have been from the poor quality paint that came with the airfix started set. Fingers crossed it weld from now on.

I have also noticed very slight leakage from around the crown so this is something I definitely need to watch too as it was very tight. I may just give the threads a good clean too though to make sure this isn't contributing to a leak.

Again thanks for your brilliant help all of you!

[Paul]

Yes the humbrol acrylic paints suck, by far the worst paints I've used and would just go straight in the bin