Airbrushing issues

[Zadren]

Hi folks,

I recently made a return to my childhood hobby of aircraft modelling and decided to buy an airbrush kit and compressor. After some hunting around, I bought this set from ebay:

eBay - The UK's Online Marketplace

The two brushes have nozzle sizes of 0.3 and 0.35mm.

After spraying 2 models now, it seems that the brushes function very well, though I am encountering a few problems which I suspect may be down to my technique.

Firstly, the coverage seems quite narrow and I have to keep going over the fairly narrow lines again and again to cover the gaps. This results in pretty thick and uneven looking coats of paint.

Secondly, when the paint dries, the resultant paint job has a rough and powdery looking texture to it rather than smooth and even.

I'm having the same problems with both enamel and acrylic paints (Humbrol and Tamiya respectively).

I'm currently trying to paint a 1:48 Airfix Spitfire Vb and would like to resolve these problems before moving up to my Dragon and Hasegawa kits.

Any advice gratefully received.

Cheers

 

[dubster72]

Hiya & welcome to the forum! Firstly from looking at the link, the airbrush BD-128P looks rather like a single-action so I'd try to avoid using that one, except for large area coverage... maybe!

I assume the troubles you're having revolve around using the double-action. The width of the line you're airbrushing is down to the distance from the kit - the closer the AB is, the narrower the line. Therefore try moving further away as you go - wide areas work well at about 6 - 8".

A rough finish is often because the paint's drying before it hits the surface of the kit, it's known as 'tip dry'. Try thinning your paint a little more or using a retarder. This is very common with Tamiya acrylics, especially if you're using anything other than their thinners.

As with anything, as much information you can provide is helpful, such as the pressure you're using & how you thin the paint & what products you use.

Hopefully this might help a little.

Cheers

Patrick

 

[yak face]

Hi welcome to the forum. On the airbrushing problems, what pressure are you spraying at and how have you been thinning the paint? (what ratio and which thinners).A mixture thats ,applied at too high a pressure can cause the rough powdery effect, the paint drying before it hits the surface. If the paint is thinned to the consistency of milk (ie. slightly thicker than water) and the airbrush is clean and functioning ok , you should get a reasonable coverage at about 18 -25 psi. If the paint is too thick and not coming out very quick then the natural tendency is to get closer which could cause the narrow coverage and build up of paint . Just a few thoughts , hope this is helpful , cheers tony

 

[AVB99]

Hello and welcome

I'd agree with the previous gents. I too had to learn about spraying through practice. The thick and powdery surface is almost certainly due to too high a pressure and/or the paint being too thick. I experienced this a lot in my early days using acrylic paint of both Tamiya and Revell varieties. These guys will keep you right!

Best wishes

Aidan

 

[Zadren]

Thanks for the welcome and swift advice guys :smile:

Both of these brushes are double action, but I haven't got used to the technique of pulling the trigger back to regulate the paint flow.

I use Tamiya thinners with acrylic paint and Humbrol thinners with their enamels. I thin to a rough ratio of 50:50 so the paint looks like skimmed milk.

Rather tellingly, I have been spraying at about 35-40 psi (which may well be my problem!).

I'm not sure of the difference between the 2 brushes. The nozzles are very similar size (0.3 and 0.35 mm) so the spray pattern is almost identical. The only difference would seem to be that one is gravity feed and the other syphon. Why would I use one in preference to the other?

Thanks again

 

[dubster72]

The syphon one is single action, I have the same one as I bought an almost identical kit to yours! And 35-40 psi? Phew! I only go that high when cleaning!

You really never need more than 25psi maximum & really I'd keep it at 15-20, as you'll get much better control that way.

The gravity feed is better as it uses less paint & cleaning up those glass bottles is tedious. I also think the paint mixes better in a gravity fed airbrush.

If it's similar to my one, there's a screw at the back end that dictates how far the trigger can be pulled back & therefore how much paint is added to the mix. Try adjusting this so the trigger only goes about 1/2 or 2/3 of the way back, it will help as you get used to using the airbrush.

Cheers

Patrick

 

[Zadren]

Ooh, I was under the impression that the syphon feed was double action as you have to pull the lever back to get the paint to flow. I'll relegate that to 'other uses' then :smile:

Is there anything I can do to smooth out the rough paint job on my Spit? It looks like its been covered in oil and rolled around in sand at the moment. Most of the panel lines have been lost beneath the paint, too. But it would be nice to try and salvage it before I try the advice you guys have kindly offered.

 

[tecdes]

Ooh, I was under the impression that the syphon feed was double action as you have to pull the lever back to get the paint to flow. I'll relegate that to 'other uses' then :smile:Is there anything I can do to smooth out the rough paint job on my Spit? It looks like its been covered in oil and rolled around in sand at the moment. Most of the panel lines have been lost beneath the paint, too. But it would be nice to try and salvage it before I try the advice you guys have kindly offered.

Hi Zadren

Syphon is where the paint is pulled through the airbrush. Gravity is where the paint is fed by gravity.

Single action & double or dual action have nothing to do with the above.

Single action when you pull the trigger air & paint are delivered with no means of control ie it comes out the same every time.

Dual action the amount you pull the trigger back controls the amount of paint that is released. Full back max paint half back much less. Experience will only tell you how much. This having tried both is the best way double action gravity feed. I use a .2 needle/nozzle which I have found with experience to be the best for my use. Aircraft 1/72 & 1/48. Tried .4 but found this a bit lumpy. Again all this is found by trial & experience.

Practice more practice on a plastic water bottle until things start to look right. Try different distances to see the results. I am getting results where for larger areas I am about 6" form the model. Where intricate I can be very close. All to do with the amount of paint released. Keep the brush parallel to the model all the time moving smoothly backwards & forwards.

Not yet had to remove acrylics but others will give an answer on this. Sounds as though you will have to remove the whole paint film if the panel lines & detail have disappeared. If they have then the paint thickness applied must be grossly in access.

My choice of paint is Vallejo which I have found to be so easy to use & so forgiving. But I have not used Tamiya yet.

Just cannot give better advice than practice until it is really boring. It is worth it as it brings great rewards. You will get some great finishes guaranteed.

Laurie

 

[Cooperman69]

There is a paint remover called Purisol (I believe) which I've used to good affect for stripping tamiya acrylics. It just dissolves the paint without damaging the plastic and you can rinse it away.

Atb, Colin.

 

[dubster72]

Ooh, I was under the impression that the syphon feed was double action as you have to pull the lever back to get the paint to flow. I'll relegate that to 'other uses' then :smile:

Munch munch munch! That's me eating humble pie!

My apologies! I've just looked at the syphon feed AB that's the same as yours & it is indeed double action!! What a surprise, I've had it 3 year's and never realised!

I'd still relegate that one to minor use though & stick with the gravity feed one.

Cheers

Patrick

 

[tecdes]

Munch munch munch! That's me eating humble pie!Cheers

Patrick

I like that Patrick. Munch munch munch. Will use that with your permission in future to admit my short comings.

Zadren remembered after writing a reply that you talk of using enamel & acrylic. I s this on the same model & perhaps over the top of one another ?

Just to warn that mixing the two can be a problem. There is a hierarchy which I have forgotten but one should not be applied over the other without problems occuring.

Also if you have mixed then the procedure for removal is different for enamel essentially oil based & acrylic water based.

As yet, but waiting the day (without excitement), not had to remove paint & others will advise on this.

Apologies Zadren for seeming to make this all complicated but it is all relevant.

Laurie

 

[Zadren]

I haven't mixed acrylic and enamel (I guessed it would be a bad idea). After using the little pots of acrylic paint that came with this kit, I realised that acrylic was much nicer to work with, didn't stink the house out and was much easier to clean up. So I'll be using acrylic much more in future.

After scratching my head for a while, I've tried going over the paint with very fine grain sandpaper and it's smoothed it out nicely. The panel lines are now much more visible too. A very light recoat (at the correct pressure! :1newwink should tidy it up nicely, before I mask for the camouflage).

The kit was a pain in the neck from the start and had more gaps in it than Watford. The Airfix mould was made in 1976 apparently, so I wouldn't be surprised if it ends up looking a bit gash. It's something to learn with before I take the plunge with more expensive (and better quality) kits. :redface: