Airbrush Paint Finish

[drgj]

Is it better to spray wet looking coats and allow to fully dry for a few hours between them or just  to continuously build up the paint by spraying lightly? I tend to do the latter and if one sweep looks a bit too wet I dry it by blasting straight air at it. I use railmatch enamels and the finish looks a bit matt sometimes or even grainy.

 

I am using Railmatch enamels.

 

Dave

Edited August 21, 2020 by drgj

[Paul_in_Ricky]

No one else has jumped in here, so I'll add my thoughts.

 

" I dry it by blasting straight air at it" this isn't a good practice and is probably why a finished surface will be poor.

 

I either allow paint to FULLY dry before second coating, or follow the manufacturer's instructions for multiple coats. Usually that means putting on a second coat before the previous coat has started to dry to allow it to effectively become a part of the previous layer of paint. That allows it to dry as one solid layer of paint. The crucial part is not overloading the layer and getting runs.

 

[57xx]

I wouldn't say I'm an expert so stand to be corrected, but I think wet coats are what you need. However you need to build that up using light coats, not one big blast that drenches the work piece and causes runs. I think the graininess you are getting is from the coats being too light so you are not achieving proper coverage. It might be useful if you need that as an effect (maybe a dirty van roof for instance) but in general not what you need to be doing. Keep misting the paint on lightly until you can just see that wet sheen, then stop to let it dry the appropriate time before doing the next layer.

[Guy Rixon]

If you want an actual coat of paint (or varnish) then it needs to be visibly wet on the surface. If it looks dry then it's probably adhering in clumps. The latter is OK, sometimes, for weathering effects but doesn't often give a good finish in a base coat. I find this to be true even with matt finishes. It's also true for acrylics, more so than for enamels, and especially important if you want a gloss or semi-gloss finish.

 

Over-spraying while the coat is still wet is tricky. On the one hand, it may be better to strengthen the first coat rather than spraying another full coat after the first is dry and thereby getting too much depth of paint. On the other hand I find it causes runs more often and sometimes I don't get uniform coverage at the end. In general, I only now over-spray a wet coat if it's paint I've mixed myself; it removes the risk of getting a different mix for the second coat.

[drgj]

So is it alright to keep spraying to a wet sheen in one go as long as it doesn't run rather than waiting for one coat to dry?  Do proper enamel thinners dry more quickly? I have been using white spirit. 

 

Dave

[Pete the Elaner]

I was taught to thin paints when spraying other things, so maybe 25% paint & 75% thinners. I read somewhere this is too much for Railmatch. I have never used their acrylics but 75-80% paint to 20-25% thinners is more suitable for their enamels. After trying this mixture, I agree that it works well with this brand.

It needs to be stirred thoroughly too.

 

I think of spraying in layers & coats. A layer being a couple of passes of the airbrush, then leave it to partially dry for 5-10 minutes before applying the next layer. These can be built up until the colour is solid to form a coat, then left to dry & go hard for a week or longer before masking & applying the next layer, which is usually a different colour.

I like to do several models at once, so by the time I have applied a layer to the last one the first is ready for its next layer, otherwise i get tempted to apply the next layer too soon.

[57xx]

20 minutes ago, drgj said:

So is it alright to keep spraying to a wet sheen in one go as long as it doesn't run rather than waiting for one coat to dry? 

 

Yes, that's correct.

 

20 minutes ago, drgj said:

Do proper enamel thinners dry more quickly? I have been using white spirit.

 

I believe they do. I generally use white spirits, but also have some Humbrol thinners which smells a lot nastier, it has naptha in, and does seem to evaporate quicker

[heavymetalwagons]

 I to am no expert at all but was told less is more. The times I've been happy with the result is when I've said "leave it". 

I think the thing with airbrushing is we try to do it in one hit 

What about buying some Dapol unpainted wagon bodies and play with them 

I also put mine in the airing cupboard in a upside-down tub to dry 

[drgj]

Thanks for all the replies.  

 

Dave

[Torper]

I use Phoenix Paints and their quick-drying thinners.  As far as thinning goes, I've found that when I think I've got it right I should nevertheless add a bit more thinner.  Then when I spray a coach side, for example, I build the paint up in very thin layers, turning the coach frequently so as I'm spraying one side while the other is drying.  Sometimes I'll stop for a few minutes, then start again.  Eventually, when the opacity is sufficiently dense, I'll be spraying so as to leave a wet-look finish which will be the final coat.  I'm not sure that this method would work quite as well if I wasn't using quick-dry thinners, but I don't see why it shouldn't.

 

DT

[drgj]

Thanks for that, DT.