Can you spray "Scenic Cement" or diluted PVA with an airbrush?

LASteve · July 05, 2020, 08:13:30 AM

Probably a totally wacky question, but I've looked around the font of all learned knowledge that is the Interwebs and not found any mention of this.

I'm in my mental planning stages of weathering track, laying ballast and all that good stuff, and I'm wondering if I could use my airbrush to spray a super-fine mist of adhesive to set the ballast?

I'm considering using some weird stuff called "Chinchilla Dust" (per the good counsel of a member on here - sorry, I can't remember who it was) for the grungy grubby TMD mud/ballast/dirt that makes up the surface of a TMD/goods yard. The stuff is super-fine, and I can't see any way of fixing it without blowing it all over the room with a spray bottle or leaving it looking like a lunar landscape if I use a dropper. I'm thinking if I could load up the airbrush with "scenic cement" (50/50 PVA and water with some dish soap in there) and spray it on the lightest compression setting, maybe that might work?

Obviously I don't want to gum up the airbrush, but - any thoughts? Madcap idea?

BTW, whoever said in this forum "don't model what you've seen modelled, model what you see" was spot-on. Researching the TMD photos from the 80's I've seen that the surfaces are grungy, oily, puddled crappy dirt with bits of goodness-knows-what lying around and weeds. Plenty of weeds. Not a spot of pristine ballast to be seen.

Anyway, I digress.

Thanks in advance for your thoughts on the airbrush.

crewearpley40 · July 05, 2020, 08:26:22 AM

Steve @LASteve , can I call on @chrism up in coniston please who can if please around advise on chinchilla dust. I can confess I have never used an airbrush. There are threads on rail rust, painting track sleepers but I just use masking tape, a fine brush , diluted pva and sprinkled ballast then stain in oil and add coal stains

LASteve · July 05, 2020, 08:31:29 AM

Quote from: crewearpley40 on July 05, 2020, 08:26:22 AM
Steve @LASteve , can I call on @chrism up in coniston please who can if please around advise on chinchilla dust. I can confess I have never used an airbrush. There are threads on rail rust, painting track sleepers but I just use masking tape, a fine brush , diluted pva and sprinkled ballast then stain in oil and add coal stains

Thanks, Chris. It's the fact that the chinchilla dust looks just the thing for the depot ground dirt, but I can't imagine how you fix it unless there's an ultra-fine spray of adhesive that doesn't blow the stuff all over the room. I'm sure I could spend a couple of weeks with an eye-dropper, but that airbrush looks awfully tempting! I just don't want to experiment with it and end up ruining a $100 piece of hardware.

And if it works for the fine stuff, suddenly the mainline ballast fixing looks a lot more enjoyable!

Bealman · July 05, 2020, 08:33:15 AM

Likewise, I have no experience with an airbrush, never really thought the expense justified one - in my mind they were used for fancy artwork on surfer's panel vans (shaggin wagons) that were all the rage here in the seventies.

I can't imagine putting PVA into an airbrush does it any good though, even diluted.

crewearpley40 · July 05, 2020, 08:34:57 AM

Thanks was going to leave that to chris in coniston. But here we go on rails steve https://www.ngaugeforum.co.uk/SMFN/index.php?topic=37212.0 look forward to progress on moorpark

LASteve · July 05, 2020, 08:37:21 AM

Quote from: Bealman on July 05, 2020, 08:33:15 AM
I can't imagine putting PVA into an airbrush does it any good though, even diluted.

You just don't like hearing the word "ballast", George. Imagine how magical it would be if it worked?

Bealman · July 05, 2020, 08:40:02 AM

Wouldn't a very fine mist bottle get the same result? Could be harder to control, but a darn sight cheaper!

crewearpley40 · July 05, 2020, 08:42:25 AM

The type you may find in a garden centre ? I did think that idea through, my only reservation being the nozzle being clogged up

LASteve · July 05, 2020, 08:45:15 AM

Quote from: Bealman on July 05, 2020, 08:40:02 AM
Wouldn't a very fine mist bottle get the same result? Could be harder to control, but a darn sight cheaper!

I've got a very fine mist bottle, it's called an airbrush

Seriously though, all the spray bottles I've used don't really spray a mist, they more squirt. The Woodland Scenics one was the worst, it was like a water pistol. That was $8 of my life I won't get back.

I think the only thing for it is to give it a try with a bottle of hot water standing by if things get gummy to clean it out before it goes sausage-side-up.

Bealman · July 05, 2020, 08:47:41 AM

Quote from: crewearpley40 on July 05, 2020, 08:42:25 AM
The type you may find in a garden centre ? I did think that idea through, my only reservation being the nozzle being clogged up

Yeah but at a couple of dollars a bottle it ain't going to break the bank, and a wash of hot water will unclog it anyway.

LASteve · July 05, 2020, 08:48:44 AM

Quote from: crewearpley40 on July 05, 2020, 08:42:25 AM
The type you may find in a garden centre ? I did think that idea through, my only reservation being the nozzle being clogged up

At least it's a cheap clog. I remember years ago there were things called "perfume atomizers" that one's mother used. That's the kind of misting I'm looking for, but spraying glue and spraying essentially pure alcohol are rather different. I could try perfume, but I think the TMD's didn't smell that nice

crewearpley40 · July 05, 2020, 08:52:43 AM

Good point. Look forward to hearing more steve on the results

ntpntpntp · July 05, 2020, 09:00:57 AM

When I've worked with really fine grained stuff (finer than my usual Woodland Scenics ballast) I've still gone for the same technique as ballasting, using dilute PVA and a pipette and letting it soak in from the edge rather than dropping from above. I was happy with the result.

I would think an airbrush would have to be run at a very low pressure to avoid puffing the dust away, and would risk creating globules rather than a mist?

Bealman · July 05, 2020, 09:06:57 AM

Yeah, I think the tried and trusted techniques are probably the best, painful as they can be (to this railway modeller, anyway).

Regarding the smell, I have always used cheap no name brand hair spray as fixative on me trees. Smells OK for a while before it wears off.

Suppose if I was fussy I could use salon quality stuff

LASteve · July 05, 2020, 09:07:37 AM

Quote from: ntpntpntp on July 05, 2020, 09:00:57 AM
When I've worked with really fine grained stuff (finer than my usual Woodland Scenics ballast) I've still gone for the same technique as ballasting, using dilute PVA and a pipette and letting it soak in from the edge rather than dropping from above. I was happy with the result.

Hmmm. There's a thought. The "dust" wouldn't be a great depth anyway, maybe halfway up the sleepers, so maybe that would be a neat solution (excuse the pun). Food for thought.

BTW, @ntpntpntp which WS grade ballast do you use for the main lines? I used "medium" on the last layout, I liked the look but when I took photos it looked like the remains of a mountain avalanche - way too large.