Creating smooth finishes

[AndySG]

Hi. I’m new to the site and only been modelling a couple of years. My favourite interest is 1/72 and 1/48 WWII aircraft. My question(s) have a common theme with other newcomers but I’m still unclear with some of the techniques regarding painting/spraying smooth coats.

 

I’ve mainly used a paint brush till now but have now acquired a cheap airbrush. One thing I’m trying to nail down is an even smooth finish (brush or airbrush for that matter). Is it common practice to gently sand down between coats of primer and paint? With my airbrush I get a very slight grainy finish regardless of distance I hold it from the model or whether the paint thinned. If so what grade of mesh/sanding paper is ideal?

 

I use migammo paints and I understand that you start with light misting coats if airbrushing. How long between layers should I leave and do I strip clean my airbrush between coats? I have been cleaning the airbrush fully after each light coat and it’s quite a drag…how long can paint stay in the cup between coats before wrecking the airbrush?

 

I am tempted to go back fully to using a normal paint brush and if I do should I lightly sand between coats to reduce brush marks?

 

Apologies if these questions have come up before. So far I’ve had hit and miss results with a lot of my builds and I’m starting to get frustrated. Not helped by the fact that I have a tendency to over analyse!! I’d be happy to go back to paint brush but just want to get the best results possible. I’m not a fan of rattle cans  due to their toxicity.

 

Many thanks for all future replies 🙂

Andy

 

 

 

 

[Rob de Bie]

My best guess: your paint dries too much in the few centimeters from airbrush to model. The total surface area of all those minute droplets is gigantic, hence the drying in such short time.

 

You want rougher atomisation - larger droplets to decrease the total surface area, to reduce the drying. Lower pressure, decrease distance, pull the needle further back. I even bought a simpler airbrush (Paasche H) and was amazed what it did. That is with enamels though.

Rob

[Casey]

Migammo are water based acrylics right?

 

What are you thinning them with? Do you use any flow improver? Is the paint layer visibly wet when on model?

 

And yes I agree with Rob above that your paint is probably drying in the air

 

On the other hand, I had similar experiences with some Humbrol acrylics and it was the paint fault. No matter what I did I ended up with some sanding-paper-like finish.

Edited July 15, 2022 by Casey

[Casey]

Also just to make sure: smooth finish does not mean glossy for you, right?

Edited July 15, 2022 by Casey

[AndySG]

8 hours ago, Rob de Bie said:

My best guess: your paint dries too much in the few centimeters from airbrush to model. The total surface area of all those minute droplets is gigantic, hence the drying in such short time.

 

You want rougher atomisation - larger droplets to decrease the total surface area, to reduce the drying. Lower pressure, decrease distance, pull the needle further back. I even bought a simpler airbrush (Paasche H) and was amazed what it did. That is with enamels though.

Rob

Hi Rob. That’s my understanding of the problem and I’ve tried changing things up but unsuccessfully so far. 

[AndySG]

1 hour ago, Casey said:

Also just to make sure: smooth finish does not mean glossy for you, right?

Hi Casey. No, not glossy. Just smooth. I haven’t tried a flow improver though. Would a retarder help as well? Yes, Migammo are water based acrylics. 

[Casey]

Retarder, thinner and flow improver are different products but some vendor "thinners" contain sometimes all of those in good starting proportions.

 

Flow improver modifies surface tension to make it flow and atomize better. Too much will make paint go everywhere, like those panel liners products.

 

Retarder (also called extender) slows down drying time. Too much and you may need to wait days/weeks/eternity to make it fully dry and stop being tacky.

 

Thinner dilutes paint. Too much and it stops being a paint.

 

 

Edited July 15, 2022 by Casey

[Rob de Bie]

2 hours ago, AndySG said:

Hi Rob. That’s my understanding of the problem and I’ve tried changing things up but unsuccessfully so far. 

 

In that case, my last recommendation is to reduce the amount of thinner. I'm a bit reluctant to mention it, since I don't understand its effect on atomisation fully. I would aim for the minimum amount of thinner, that works for your airbrush.

 

Rob

[AndySG]

51 minutes ago, Rob de Bie said:

 

In that case, my last recommendation is to reduce the amount of thinner. I'm a bit reluctant to mention it, since I don't understand its effect on atomisation fully. I would aim for the minimum amount of thinner, that works for your airbrush.

 

Rob

Will do, thank you for the advice…I’ll give a go this weekend 👍

[AndySG]

2 hours ago, Casey said:

Retarder, thinner and flow improver are different products but some vendor "thinners" contain sometimes all of those in good starting proportions.

 

Flow improver modifies surface tension to make it flow and atomize better. Too much will make paint go everywhere, like those panel liners products.

 

Retarder (also called extender) slows down drying time. Too much and you may need to wait days/weeks/eternity to make it fully dry and stop being tacky.

 

Thinner dilutes paint. Too much and it stops being a paint.

 

 

Thank you. I’ll try fiddling around with thinner quantities as Rob has also suggested. I’ll try a flow improver on it own as well. 

[malpaso]

Also as you are local to me I think the current temperatures won’t be helping with paint drying as it sprays!  So if you don’t solve the issue now it may resolve in a couple of weeks.

 

Keep persisting as airbrushing will give a good finish once you discover the right technique for you / your airbrush / your paint choice.  It took me six months to a year to consistently get reasonable results.  Even so getting a decent glossy finish for cars is a challenge each time for me!

 

If you can get to Romsey IPMS any 1st or 3rd Wednesday of the month you can get plenty of advice face-to-face.

[Rob de Bie]

4 hours ago, AndySG said:

Will do, thank you for the advice…I’ll give a go this weekend 👍

 

One more tip: don't get stuck with one brand of paint, testing it until you drop. Try other brands too.

 

I'm speaking from experience: for many years I was completely focused on making Humnbrol enamels work for me. When I tried Model Master II enamel, I was amazed how much nicer that came out.

 

Much later I tried MRP (Mr Paint) acrylic lacquer, and was sold immediately. It's been my paint ever since. I finally had a paint that give me this without any tricks, secret mixes or troubles, at the first try:

 

 

 

 

 

Rob

 

 

 

Edited July 15, 2022 by Rob de Bie

[AndySG]

9 hours ago, malpaso said:

Also as you are local to me I think the current temperatures won’t be helping with paint drying as it sprays!  So if you don’t solve the issue now it may resolve in a couple of weeks.

 

Keep persisting as airbrushing will give a good finish once you discover the right technique for you / your airbrush / your paint choice.  It took me six months to a year to consistently get reasonable results.  Even so getting a decent glossy finish for cars is a challenge each time for me!

 

If you can get to Romsey IPMS any 1st or 3rd Wednesday of the month you can get plenty of advice face-to-face.

Thanks for that. I did wonder whether the current humidity levels etc might effect it. I’ve seen the club in Romsey and like the idea of visiting one evening, I’ll be sure to come along. Thank you.

[Peter2]

I read a tip years ago on preparing your paint before airbrushing [I think it might have been in a magazine called "Scale Models Extra: Model Colour" which was a 66 page special issue of "Scale Models" devoted to tips on painting models, published possibly in the late 1970s; I notice back issues can be purchased on the Internet.] Gradually add your thinner to your paint until the paint reaches "the consistency of milk": you will know your paint is ready when a drop of it placed against the side of the mixing jar flows down "leaving a strong 'tail' of colour behind it". I can still remember that advice because it seemed to work. Hope it's of some value to you. [Next nostalgia tip: How to combat rising inflation these days by reviving a Second World War recipe to bake a sponge cake using liquid paraffin instead of unavailable butter etc. due to shortages. Yes, that actually was one British wartime solution in the 1940s! The side effects are unrecorded ...]

[spruecutter96]

7 hours ago, Peter2 said:

The side effects are unrecorded ..

Chronic stomach-ache, vomiting and time spent in hospital, perhaps...? It's a lot like watching anything on ITV, for more than 30 seconds. 

 

Cheers. 

 

Chris.  

[Casey]

7 hours ago, Peter2 said:

(...)bake a sponge cake using liquid paraffin

That must be the most unique response for an 'how to make smooth layer of paint' question... You made my day!

Edited July 16, 2022 by Casey

[Black Knight]

To help get a smooth paint finish I use automotive painters prep pads.

They are like pot scrubbers but better. (the pads, not the painters!)

I use a new mild grade pad on rough-ish paint jobs, mainly to remove dust specks

I have several bits of worn pads which are a lot less abrasive and I wipe the paint job over with these in between coats and before final varnish (not going over decals though)

[Steve Noble]

You don't need to take your airbrush apart to clean it between coats of paint, or when changing colours. Simply spray out/remove the excess paint from the colour cup, add airbrush cleaner of your choice and spray through the airbrush. You can also 'backflush' the airbrush by adding cleaner to the colour cup and holding a piece of paper towel tightly over the airbrush tip, press the trigger and the thinner will flush through the airbrush and clean it. You will get bubbles in the colour cup to show it's working. Do this method until your thinner/cleaner is clear and then finally, flush a little clean thinner through the airbrush to remove any final residue. All this should take no more than 30 seconds to a minute and the the airbrush will be perfectly clean afterwards. No need to dissassemble the airbrush everytime, over zealous cleaning can cause excessive wear of the parts and is unnecessary. Only take the airbrush apart if you have a blockage that can't be cleared by regular cleaning or when you want to do a more thorough strip and clean. I maybe do that once every 3 months or so.

[AndySG]

On 17/07/2022 at 21:53, Steve Noble said:

You don't need to take your airbrush apart to clean it between coats of paint, or when changing colours. Simply spray out/remove the excess paint from the colour cup, add airbrush cleaner of your choice and spray through the airbrush. You can also 'backflush' the airbrush by adding cleaner to the colour cup and holding a piece of paper towel tightly over the airbrush tip, press the trigger and the thinner will flush through the airbrush and clean it. You will get bubbles in the colour cup to show it's working. Do this method until your thinner/cleaner is clear and then finally, flush a little clean thinner through the airbrush to remove any final residue. All this should take no more than 30 seconds to a minute and the the airbrush will be perfectly clean afterwards. No need to dissassemble the airbrush everytime, over zealous cleaning can cause excessive wear of the parts and is unnecessary. Only take the airbrush apart if you have a blockage that can't be cleared by regular cleaning or when you want to do a more thorough strip and clean. I maybe do that once every 3 months or so.

Thanks for your reply, sorry mine's a bit late but your response much appreciated!