discussion Model Air best pressure.

[Remodel_Remake]

Hi Folks

Ok my first daft question. No laughing.

I used to always use enamels in the past, good old humbrol & Xtracolor, but these days I worry about all those fumes flying around & the strong thinners.

So I'm in the process of moving to use acrylics, probably mostly model air but a little tamiya ones to.

I've even bought a little spray booth from Amazon which in the long run will be fully vented in our summer house, once I've done it up which unfortunately depends on my recover time from a broken foot.

So in the mean time I'm just using the booth with the filters just vented in the room, which for acrylics I think is ok?

Sorry I'm waffling, what is the best pressure to spray model air at?

I'm using a new H&S evolution bought solely for acrylics, fitted with a 0.15 needle (also have a 0.4) ?

Thanks in advance.

Euan

 

[Guest]

Depends on what you are doing Euan.

This is with .35/needle/nozzle.

Model air I normally for an overall of the model with 25% approx thinners about 18SPI. About 150mm 6" form the model

For Vallejo Varnish about 25PSI a bit thick but I do not thin.

For more detailed work fine shading about 12PSI but it depends on how much I have thinned. Always test and if I get a bit of splutter I go lower in pressure. About 1.5" from the model

With a .2 needle nozzle for very fine shading with a medium and no thinner about 8PSI. About 1" or near touching the model

Think you will find out best yourself but this gives a starting point. A lot depends on the consistency of the paint ie paint to thinner.

Get an old platic water bottle and just spend an hour playing with PSI and paint mixtures. Do that every now and then to practice.

Laurie

 

[Ian M]

I don't wish to seem rude, but that is a question only you can come up with the answer to.

To many variables to put a figure on it Euan.

The best way is to "suck it and see" Start with a low pressure and see how it sprays, if need be, just turn up the air a bit at a time. It really is a question of playing around until you find what works for you.

So grab a bottle of paint, a couple of boxes to spray and get on it.

Sorry if it sounds "well that was really helpful" but it is the best way

Ian M

 

[Guest]

Just read about the .15 needle. That is to small for Vallejo. They do a .2 which may suit for finer work. For general work .4 I have used. Nice airbrush the Evolution and you will get good results with Vallejo Model Air.

By the way Tamiya pumps out lacquer fumes. Vallejo Air and model air is water based. Model Air is non toxic through out the range including the yellow. Model is non toxic for most but yellow and a small number of othere are toxic. They are marked on the bottle.

If you are recirculating the air Euan I would wear a filter mask as though non toxic you are going to breath in stray fine grounds from the paint.

Laurie

 

[BarryW]

Euan I also was going to say that 0.15 is too small. A 0.2 works well but I would recommend using the 0.4 and get used to the paint with that first. The larger size can do most jobs perfectly well.

I tend to spray at 20-25psi most of the time and sometimes reduce it to 10-15psi with thinned Air for detail work. It is best to play around and practice first getting the feel of the a/b.

 

[Guest]

Just to say that Tamiya isn't lacquer based from the pot. It's a synthetic acrylic & whilst not water-based (although some do thin it with water), it

isn't as harmful as oil-based paints.

For testing, I use the glossy photo paper, bought from a Poundshop. It's as close to plastic as you'll get & being flat allows for easy use.

 

[Guest]

I don't wish to seem rude, but that is a question only you can come up with the answer to.To many variables to put a figure on it Euan.

The best way is to "suck it and see" Start with a low pressure and see how it sprays, if need be, just turn up the air a bit at a time. It really is a question of playing around until you find what works for you.

So grab a bottle of paint, a couple of boxes to spray and get on it.

Sorry if it sounds "well that was really helpful" but it is the best way

Ian M

Probably the best advise, got my airbrush setup just before xmas, tried reading online, watched loads of youtube guides.... Too much differing advise, so i just started practicing on anything plastic.... Starting to find out what works for me, its definitly each to their own

 

[stona]

itisn't as harmful as oil-based paints.

It's not just the solvent(s) you should worry about, particularly given the low exposure making models and using a decent extractor and mask. There are just as many particulates suspended in an acrylic aerosol as any other type.

To make this visible try spraying something like Alclad in a sunlit room without an extractor

Cheers

Steve

 

[Remodel_Remake]

Thanks for the pointers.

I did wonder if the .15 would be to fine, I'll probably get a .2 at some point.

My previous experience with airbrushes has been on a single action badger 200 & an old Aztek, which I mostly used for broad work not fine camos.

But your quite right practice is the best medicine.

I have sprayed Alcad in the past but always with a filter equipped mask,but even at that the room was toxic for quite a while.

It must be cause I've just turned 40 but suddenly the health & saftey elements of our pastime has come home to roost.

 

[Guest]

Just to say that Tamiya isn't lacquer based from the pot. .

Quite right Patrick, apologies Euan, I Should have checked the facts on my bottle.

But the same caution does apply. On my bottle it says. Flammable. Risk of serious damage to the eyes. Irritating to the respiratory system. Vapours may cause drowsiness or dizziness.

Laurie

 

[Ian M]

It's not just the solvent(s) you should worry about, particularly given the low exposure making models and using a decent extractor and mask. There are just as many particulates suspended in an acrylic aerosol as any other type.To make this visible try spraying something like Alclad in a sunlit room without an extractor

Cheers

Steve

So You've tried that as well then? Lol.

 

[Guest]

I have a Harder & Steenbeck CR plus with a 0.4 needle. After some practice I found 20 PSI was fine for Vallejo acrylics, holding the nozzle about 5 inches (12 cm) from the part. I hardly ever thin the paint. I always shake the bottle well with an M4 nut inside each bottle to agitate the paint well. If I have not used a bottle for a few months I take the spout off and make sure no paint has thickened there. Advice usually is that a 0.2 or smaller nozzle can cause blockage problems. In saying all this, I don't do fancy paint work like shading or fine lines. I just try to get a high quality smooth finish, and usually do.

 

[Remodel_Remake]

Thanks Stevekir,

It's interest that you mention paint agitation, I'm return to the hobby after a break oh 2 yrs or so & my paints were stored in a friends garage during that time.

Now I've got them all back in our new house I've noticed that the enamels have survived fine, but the model color seem not to mix as well, luckily the model air seem to be fine.

I liked your idea about an M4 nut popped in the dropper bottle, but wouldn't that be subject to rust? Would glass beads be an idea?

Regards

Euan

 

[Guest]

The nuts I bought were stainless steel. I got the idea from Phil Flory's site. The size seems too big to block the spout of Vallejo paints. (The 4 refers to the diameter of the screw thread in millimetres, so the outer diameter would be greater.) They give a satisfying rattle when the bottle is shaken.

http://www.westfieldfasteners.co.uk/A2_Nut_M4.html

View attachment 97277


With VAT and postage the cost os £6.48 = 13p per nut. (Smaller quantities are available down to 1 nut.)

It seems that gloss varnish needs very thorough shaking every time it is used. Matt varnish is different. I am told that it is gloss varnish with a matting agent. This is a white powder that presumably prevents a shiny skin forming. Last year I got white spots on the final (matt) coat on my Spitfire and I am guessing that the varnish was not shaken enough (although my arm nearly came off with the effort).

View attachment 210300

 

[Remodel_Remake]

That's great information, thank you.

I'd heard that some folks were dropping little lava rock beads in with some good results, but I bet those more expensive than good old nuts.

Thanks again for all your help it's really appreciated, at the moment I'm shocked about how much I've forgotten about... well everything

 

[Guest]

John's Shop stock these. http://www.scalemodelshop.co.uk/stainless-steel-ball-bearings.html

Laurie

 

[Guest]

John's Shop stock these. http://www.scalemodelshop.co.uk/stainless-steel-ball-bearings.htmlLaurie

Oops! I didn't notice that. (However, the shop charges as much as Westfieldfastners but with delivery still to be added.)

 

[Remodel_Remake]

John's Shop stock these. http://www.scalemodelshop.co.uk/stainless-steel-ball-bearings.htmlLaurie

Brilliant, I was going to order a few things this week so I'll add it to the list.

 

[Remodel_Remake]

Can I just say thanks to everybody for helping me with this.

The forum is simply the best place I've come across for help.

Have a good evening folks.

Regards

Euan

 

[Guest]

Oops! I didn't notice that. (However, the shop charges as much as Westfieldfastners but with delivery still to be added.)

Mmmmmm. Steve but they do not run the best forum not only in Model Making but anything else I have seen.

Just add to your order at the shop. Then leave and add things, as I do, until the order mounts and the post charge becomes not a liability. Plus you earn points and what do we need points.

Laurie