How clean are paint thinners?

essdee
Posts: 380
Joined: Sat Nov 29, 2008 4:47 pm

How clean are paint thinners?

Postby essdee » Thu Feb 18, 2016 3:13 pm

Rather an odd query, but I have a bit of a puzzle here, which I am hoping has a simple solution that will occur to the more experienced painters among you all.

After considerable practice and experimentation with my Neo/Iwata TRN 2 airbrush - with which I am very pleased- I have a continuing issue with annoyingly frequent specks of very fine 'foreign matter' being sprayed onto test surfaces, which include various chassis components where a less-than perfect surface will be well -hidden by subsequent matt varnish and weathering. The standard of finish is still some way short of what I want for superstructures - I am comparing with Ian Rathbone's superb finishes in his book.

Now, these are apparently not bits of paint residue from within the airbrush body; I have gone through the phase of identifying such 'crud' arising from incomplete cleaning (worst when moving from enamel to cellulose, obviously). I am not using acrylic at all. So I am talking about an effect manifesting itself immediately upon using a thoroughly cleaned and thrice-flushed airbrush, using the set of small cleaning brushes from Eileen's.

My suspicion now falls upon the thinners, having already established that some Humbrol Satin Black paint was itself full of minute particles of junk. I note various threads and comment on RMWeb about paint quality. So I was disappointed when I found the problem greatly reduced, but not fully eradicated, by using Phoenix Precision enamel paint and their thinners. Similarly, a car-body-shop paint mixer's cellulose satin black gives a superb finish, but still marred by the too-frequent little speck (sprayed1:3 paint/thinners).

This does not look like dust particles drawn into the air supply tests with a dry paint cup; my test is to spray (dry, or with neat thinners) into a small steel bowl, which sits under a tea strainer. This test traps these particles around the side of the bowl (which has a sort-of 'brushed' surface texture), while the thinners gathers at the base, and is recycled to the paint cup again, after which I wipe out any 'crud' trapped in the cup.

An admittedly old bottle of Rustin's cellulose thinner produced a fair amount of 'crud', a fesh tin of Barrettine has been a considerable improvement and my standard thinner so far. Yesterday I bit the bullet and went into town for a tin of HMG cellulose thinners from the model shop, assuming that this would be topmost quality for airbrush spraying. Most disappointing to find that it contains more 'crud' than the Barrettine! Another small and expensive bottle of 'cellulose thinners' from an alternative shop, who admitted they decanted it from a larger supply themselves, proved unusable - when sprayed, the steel cup accumulated a puddle of murky liquid with numerous droplets of moisture within it, like an emulsion.

In view of Ian Rathbone clearly being able to get superb results using bulk supply thinners, as illustrated and referenced in his book, I am baffled as to this variation in quality of cellulose thinners in particular. For enamel, white spirit from three DIY suppliers and the Humbrol thinners themselves, also give similar effects.

Any ideas where these small particles are originating, anyone? All advice much appreciated as I am rather stuck.

BW

Steve

Knuckles
Posts: 1206
Joined: Fri Nov 18, 2011 9:15 pm

Re: How clean are paint thinners?

Postby Knuckles » Thu Feb 18, 2016 3:56 pm

I'm not a painting expert but happy enough with my finishes.

I find Hornby/Humbrol thinners to be fine although I always get kamikaze insects whenever painting...or mini dusties.

One thing I can say with confidance is I find Humbrol paint hit and miss. SOme apply beautifully and others are a bit of a bugger.

I agree with your view on Phoenix. I now use Phoenix Precision if I can find the shade I want. The extra cost is worth it as I haven't so far had a single tin that is dodgy and they have always been the best paints applying themselves better than others.

For varnishes I haven't cracked it yet. I usually apply a coat of Citadel Purity Seal Satin Varnish over the top of the painted model and I find that usually allows the other varnishes to layer on top smoother. It is an Acrylic varnish but it seems happy going on top of enamel and so far I have had no problems with it. The Humbrol Gloss varnish nearly always 'Giraffe patterns' itself and I don't know why. On top of Purity Seal it seems ok though.

I want to find a Gloss/Satin hybrid finish for that 'oily rag' polished look but I don't want to bother mixing my own. Suggestions?

I'll shut up now and let the more experienced answer. :thumb
“He who dares not offend cannot be honest.” Thomas Paine

http://www.shapeways.com/shops/sparksho ... eationsscc
Mostly offering Loco kits & bits in 4mm.
SCC Photon Resin Prints Price list
download/file.php?id=19320

dal-t
Posts: 621
Joined: Mon Jan 11, 2010 8:06 pm

Re: How clean are paint thinners?

Postby dal-t » Thu Feb 18, 2016 5:04 pm

How are you dispensing the thinners? I use a plastic pipette, but you have to be careful with one that has been used before, especially for paint, because it can dry inside and then be shed as spots of 'crud' if you squeeze too hard next time. I keep a different supply of pipettes for thinners (and for Klear) and always try to use a new one for the final coat. I also decant from the thinners tin into a glass jar (ex-yoghurt or fruit dessert) before blending the mixture to apply, so I can spot any obvious foreign bodies - although that's obviously more difficult with the paint itself. Many painters do filter both paint and thinners (apparently old nylons/tights work fine), but personally I've never found that necessary. In my experience it is more important to kill off dust in the atmosphere with a good douse of water spray before starting the compressor - but then I have always lived in houses full of cats and, latterly, dogs. Obviously covering the sprayed object while it dries is also important, and I tend now to leave it in the spray booth and place a sheet of cardboard across the front to deter air currents - this avoids the problem of closing the lid on a box and discovering later that it actually touched, destroying the perfect finish (yes, been there, done that, have several tee-shirts ..).
David L-T

User avatar
jim s-w
Posts: 1720
Joined: Wed Jul 30, 2008 5:56 pm

Re: How clean are paint thinners?

Postby jim s-w » Thu Feb 18, 2016 5:23 pm

Knuckles wrote:
I want to find a Gloss/Satin hybrid finish for that 'oily rag' polished look but I don't want to bother mixing my own. Suggestions?



Have you tried nuln oil from games workshop (http://www.amazon.com/Citadel-Shade-Nul ... B007RRDTAW)

HTH

Jim

User avatar
MarkS
Posts: 277
Joined: Tue Jul 22, 2008 1:15 am

Re: How clean are paint thinners?

Postby MarkS » Thu Feb 18, 2016 6:26 pm

Steve,
do you filter your paint mixture? I find that my (Iwata clone) airbrush will clog and or spit paint if the paint has even minuscule lumps from inadequate mixing. (I use a jigsaw to mix my paint - tape tin to a blade with duct tape, turn on for a minute)
Even then, I pour the paint through a mesh filter like this one.

http://www.amazon.com/Badger-Air-Brush-Co-50-2017-Paint-Filter/dp/B000BRMZE6/ref=pd_bxgy_21_img_2/176-3267168-2373956?ie=UTF8&refRID=0Q2BZ80A4RV39XYF2YWZ
Cheers,

Mark.
"In the end, when all is said and done, more will have been said than done..."

Knuckles
Posts: 1206
Joined: Fri Nov 18, 2011 9:15 pm

Re: How clean are paint thinners?

Postby Knuckles » Thu Feb 18, 2016 6:45 pm

jim s-w wrote:
Knuckles wrote:
I want to find a Gloss/Satin hybrid finish for that 'oily rag' polished look but I don't want to bother mixing my own. Suggestions?



Have you tried nuln oil from games workshop (http://www.amazon.com/Citadel-Shade-Nul ... B007RRDTAW)

HTH

Jim



Hi Jim, thanks for the suggestion. I've never heard of it to be honest. After reading the description and reviews though it seems more like a weathering type product so possibly not what I'm looking for.

Unless you have used it and know? ;)
“He who dares not offend cannot be honest.” Thomas Paine

http://www.shapeways.com/shops/sparksho ... eationsscc
Mostly offering Loco kits & bits in 4mm.
SCC Photon Resin Prints Price list
download/file.php?id=19320

essdee
Posts: 380
Joined: Sat Nov 29, 2008 4:47 pm

Re: How clean are paint thinners?

Postby essdee » Thu Feb 18, 2016 8:22 pm

Thanks for the responses so far, guys,

Briefly, yes I use a glass pipette with detachable bulb, and clean both with cellulose thinners/tube brushes, so that they cannot contribute the crud that way. Also the glass decanting bottles and mixing jar are cleaned similarly, so there is never any dried paint anywhere to flake off into the mix. I use the airbrush to blow out all cleaned vessels, to evaporate the cellulose thinners and dispel any dust particles (or....am I thus introducing dust, surely not?!!) Obviously, I wear a proper filter mask and have the extractor fan running for all this.

I did initially use a stocking mesh - which clogged immediately - and a sieve to intercept particles in the paint, with no measurable effect. And it has since become clear from my experiments that the offending particles are present either in thinners, or the airbrush system, in the absence of any paint.

No one had any evidence of muck in their thinners, then?

Baffling...

BW

Steve

User avatar
Guy Rixon
Posts: 602
Joined: Sun Mar 27, 2011 6:40 pm

Re: How clean are paint thinners?

Postby Guy Rixon » Thu Feb 18, 2016 8:45 pm

How old is the air hose? Is it possible that it's shedding particles?

essdee
Posts: 380
Joined: Sat Nov 29, 2008 4:47 pm

Re: How clean are paint thinners?

Postby essdee » Thu Feb 18, 2016 10:55 pm

Thanks Guy - interesting thought. But I only bought it last May, and didn't start using it till December (!!!!), so I doubt if that's the source. Mind you, I recently invested in an in-line moisture filter; it didn't pick up any moisture from the 3m air hose run, but I might reinstate it and see if it affects matters.

So many problem sources!

Regards

Steve

User avatar
Andy W
Posts: 819
Joined: Thu May 21, 2009 8:11 am

Re: How clean are paint thinners?

Postby Andy W » Thu Feb 18, 2016 11:16 pm

Steve, have you tried spraying pure water? If that has specks, it's your hose. Or at least something to do with the brush. It's odd though, I've not experienced anything like it.
Last edited by Andy W on Fri Feb 19, 2016 9:22 am, edited 2 times in total.
Make Worcestershire great again.
Build a wall along the Herefordshire border and make them pay for it.

dal-t
Posts: 621
Joined: Mon Jan 11, 2010 8:06 pm

Re: How clean are paint thinners?

Postby dal-t » Fri Feb 19, 2016 8:39 am

I hate to be the one to suggest this, but could it be the washers within the airbrush itself breaking up? I don't have a Iwata myself (always been a Badger man!) but I've heard others report that the head washer is vulnerable (and expensive to replace - I think they only sell the whole needle assembly?). Since you mention the use of cellulose, which has the most detrimental effect on washers, it would be worth at least eliminating them as a possible cause by checking their condition.
David L-T

essdee
Posts: 380
Joined: Sat Nov 29, 2008 4:47 pm

Re: How clean are paint thinners?

Postby essdee » Fri Feb 19, 2016 10:08 am

Andy -good idea, thanks, will give that a try and report back, see if that is different.

David - in view of cellulose thinners, I had wondered, but no, the washers under the 60X lens appear fine. And the crud is generally pale, rather than black, some of it like fine fibres? I have checked it's not remnant of kitchen roll from cleaning operations too.

Regards

Steve

User avatar
David Thorpe
Posts: 818
Joined: Tue Oct 21, 2008 11:13 pm

Re: How clean are paint thinners?

Postby David Thorpe » Fri Feb 19, 2016 10:30 am

I have never before seen anyone complain about dirt in their thinners, and wonder if the effect you're getting could be something to do with the environment in which you're carrying out your spraying. Have you tried using the same equipment in a different environment? And your initial posting suggests that you've always had this problem when using your new airbrush - did you have another airbrush before the new one and, if so, did you experience the same problem?

DT

User avatar
jim s-w
Posts: 1720
Joined: Wed Jul 30, 2008 5:56 pm

Re: How clean are paint thinners?

Postby jim s-w » Fri Feb 19, 2016 12:38 pm

Knuckles wrote:
Hi Jim, thanks for the suggestion. I've never heard of it to be honest. After reading the description and reviews though it seems more like a weathering type product so possibly not what I'm looking for.

Unless you have used it and know? ;)


Hi

It's an oily glossy wash. Is it just the sheen you are after? If so you might want to try original formula Klear (floor polish). humbrol now do Klear too. Tamiya do satin and gloss varnishes too but the gloss might be too shiny for what you want.

Below is a DMU engine with a subtle application of klear.

Image

HTH

Jim

User avatar
jim s-w
Posts: 1720
Joined: Wed Jul 30, 2008 5:56 pm

Re: How clean are paint thinners?

Postby jim s-w » Fri Feb 19, 2016 12:42 pm

Hi Steve

If you decant your thinners into a clear jar can you see any fibres? What happens if you brush thinners on to a surface do you get them then? If the answer to both is no then it had to be the airbrush or compressor. Perhaps the compressor is sucking dust in that not filtered before being sent down the airline? One way to rule this out is to use a can of compressed air.

It sounds like a process of eliminating things until something changes TBH

Jim

Knuckles
Posts: 1206
Joined: Fri Nov 18, 2011 9:15 pm

Re: How clean are paint thinners?

Postby Knuckles » Fri Feb 19, 2016 1:04 pm

jim s-w wrote:
Knuckles wrote:
Hi Jim, thanks for the suggestion. I've never heard of it to be honest. After reading the description and reviews though it seems more like a weathering type product so possibly not what I'm looking for.

Unless you have used it and know? ;)

It's an oily glossy wash. Is it just the sheen you are after? If so you might want to try original formula Klear (floor polish). humbrol now do Klear too. Tamiya do satin and gloss varnishes too but the gloss might be too shiny for what you want.


Hi Jim. Coach looks convincing but from here at least looks matt.
I've been wanting to try Klear for a while as I have seen the results Tim Shackleton gets from it but if Humbrol sell it I shall have a look. I used to use original Klear in the Army for ironing my clothes - great stuff! Wish I picked up a few bottles now.

Spray it from a bottle, wait until there is no trace of dampness then iron it, if there is any trace of dampness when you iron it you permanently stain your garment. You'll get razor sharp creases and the clothes then feel like plastic. Wonderful!

I also shaved my beret with a razor, brushed Kiwi shoe polish into it and Klear ironed that too with a blob of Cyno' to keep the flap down. I had the sharpest beret out of the whole section for a while, until the BSM laughed on parade, took the piss and forced me to buy a new one. I was trying my hardest not to, can you tell!? :D
“He who dares not offend cannot be honest.” Thomas Paine

http://www.shapeways.com/shops/sparksho ... eationsscc
Mostly offering Loco kits & bits in 4mm.
SCC Photon Resin Prints Price list
download/file.php?id=19320

dal-t
Posts: 621
Joined: Mon Jan 11, 2010 8:06 pm

Re: How clean are paint thinners?

Postby dal-t » Fri Feb 19, 2016 1:47 pm

Be a little wary of the Humbrol 'Klear', Knuckles, people have reported a range of problems with it (particularly when using decal softners/settlers), so much so that Hornby are supposedly investigating. Others find it fine, so it may be a quality control problem, or incompatibility with certain temperatures/humidities. Hopefully Hornby will let us know (if they're still in business ...) i.d.c. The current Johnsons' Klear/Future however, despite being different from the original formula and looking slightly cloudy in the bottle, gets good reports. I'm waiting to find out when I have to, still got a full bottle and a bit of the original brew left. The benefit of klear, as you probably know, is that you can control the amount of gloss (within reason) by the number of coats you apply. Just a couple give a decent sheen, often smooth enough to avoid decals silvering, six or seven (thin) coats gives quite a good gloss. HTH.
David L-T

User avatar
jim s-w
Posts: 1720
Joined: Wed Jul 30, 2008 5:56 pm

Re: How clean are paint thinners?

Postby jim s-w » Fri Feb 19, 2016 2:30 pm

Hi Knuckles

Obviously there would be no oil on the bodyside (dmus in my era were cleaned with automatic cleaners rather than an oily rag) . You should be looking at the engine.

Another option is t-cut

Cheers

Jim

essdee
Posts: 380
Joined: Sat Nov 29, 2008 4:47 pm

Re: How clean are paint thinners?

Postby essdee » Fri Feb 19, 2016 8:37 pm

Latest update, thanks gents for the further suggestions.

Looks like Davey T. has identified a major part of the problem; moving down to the kitchen (cushion flooring) I found markedly less crud, with a sequence of tests of Barrattine - HMG - Barrattine - HMG into the steel cup; the last two test runs were really good, provided I did not alter the trigger position; the latter clearly has some influence and points the finger at the airbrush barrel. Back upstairs to workshop aka spare bedroom (carpet) - return of crud.

I think an ultrasonic cleaner may be net on the shopping list?

So thanks Davey, for a big step forward; I am still not sure if these fine specks are drawn through the compressor, or drawn into the airbrush sprayjet. Anyway, I can take steps now.

Jim - no, there are no fibres visible in the thinners themselves; these are very small specks really -but enough to catch the eye on a satin or gloss finish. (Incidentally, love the superb Sherpa creations on your thread - brilliant!)

And thanks Morgan for PM, I composed a reply which seems to have evaporated like the cellulose thinners, but will get back to you later; very useful and much appreciated.

I think I can be confident about the absence of thinner contaminants now, other than in a minor role!

Thanks all, very helpful as ever,

Steve

User avatar
David Thorpe
Posts: 818
Joined: Tue Oct 21, 2008 11:13 pm

Re: How clean are paint thinners?

Postby David Thorpe » Fri Feb 19, 2016 10:01 pm

I suspect that the fine specks have nothing to do with the airbrush or compressor - I think that it's far more likely that they're just fine dust which it is difficult to avoid in a domestic environment. In a way, the carpet gives the game away - any hoovering or carpet cleaning, even in the cleanest house, will raise dust which will hang around in the atmosphere for some time. I think that these dust particles might well be in the air and the mere action of the airbrush in spraying paint draws them into the jet and deposits them on the model. Are you using a spray booth?

DT

dal-t
Posts: 621
Joined: Mon Jan 11, 2010 8:06 pm

Re: How clean are paint thinners?

Postby dal-t » Fri Feb 19, 2016 10:22 pm

David Thorpe wrote: ... dust particles might well be in the air and the mere action of the airbrush in spraying paint draws them into the jet and deposits them on the model.


Hence my comment about dousing with a fine water spray - or alternatively, take over a shower/bathroom (domestic authorities permitting), they are normally the least dusty places in the house.
David L-T

beachboy
Posts: 99
Joined: Thu Feb 18, 2010 4:35 pm

Re: How clean are paint thinners?

Postby beachboy » Sat Feb 20, 2016 8:17 am

Steve,

If my memory is correct. Judging by the spotless cleaning of your models. A downside, is the minute specs that will become unseen from cleaning materials, until the opening air spray lifts them, and they become every-where. But when mixed into paint, become visible.

If you tried spraying outside, in a warm suntrap, which even recently now has been possible, away from log burners, dust etc.
And blast the model with the airline to clean. Do the same with the AB, & store in an airtight bag.

When mixing your paint, put the carrier medium into your mixing bowl first, & check for clarity, before adding paint.

A bottle of Rustins etc, if left standing, can have particles at the bottom of the bottle. Which may be removed at the above mixing stage, if necessary. They can look similar, to corrosion, that may occur from the inside of the compressor air chamber, if this is stored in damp conditions. But should be visible in the moisture trap first, if checked. Rustins appear to now use plastic containers. Its good cellulose, and does not bloom, unlike some others, incl Halfords, etc. even when the air temp is good.

The one problem I have with the Iwata I sometimes use, unlike my old Badger, it cannot be easily striped down for a thorough clean. Thus there is a possibility of paint / clear varnish becoming traped at the Chamber rear when the needle is drawn back.
In my opinion, it does not have such a fine dual action movement as the Badger, which helps control fine spray fans & lines.

Regards,

Stephen.

essdee
Posts: 380
Joined: Sat Nov 29, 2008 4:47 pm

Re: How clean are paint thinners?

Postby essdee » Sat Feb 20, 2016 1:30 pm

Daves, T and L-T, and Beachboy, (Morgan, will again try to PM )

Thanks for these; yes the floating 'motes' are clearly a bigger issue than I thought, even though I was convinced the problem was emerging from the airbrush nozzle; so I shall be trying the bathroom, adjacent to the workroom, as well. But - downside - it's carpeted....... Anyway, the kitchen will be used for the spraying onto the loco and tender bodies - once Mrs. essdee is safely away to work and I have a day to clear the resultant fumes; even with using an extractor booth.

Beachboy; yes I have been wary of the cleaning deposits, as Ian R. warns, to the extent that I do my liquid soda crystals wash/immerse after the shiny sinks abrasive treatment, not before, as in Ian's book; the good news here is that when I blast the airbrush at crevices, I am only getting clean water, with no white abrasive residue. No evidence of remnant flux neutralising, after the liquid soda wash, as Ian warns against - probably because I have rigorously washed out all soldered work immediately after assembly. I also air-blast all components immediately before trying to prime or paint; I do this well away from the paint booth, obviously.

No, the problem deposits were not appearing on a test model piece, but on a plain 6" sheet of nickel silver on which I practise. However, I take note of your warning and will be carefully watching for trouble as I tackle the model itself.

'Warm suntrap'...yers, hmmm. I am well aware of my old mate Tim Venton's preference for outdoor, summer, spray sessions - lovely, down in sunny Bristol. Just to remind you, I am at 750ft above OD, on the east side of the Pennines.....!!! But I will be giving it a go, if I am home on whichever day Summer 2016 happens to occur up here.

Checking for 'crud'; yes I pour some thinners from the tin into a cleaned glass jar to enable a visual check, no problems there yet, from recently purchased tins. The old bottle of Rustins did indeed have a whitish deposit at the bottom, and has been avoided after initial tests. I always avoid disturbing a stood bottle/tin of thinners and use the glass pipette to withdraw thinner to the glass jar; latterly tilting the tin but still avoiding disturbing 'bottom sediment' too much. Very useful to know that Rustins is actually quite a quality thinners - will re-stock with fresh.

Your comment re your Iwata's inner inaccessibility is significant; I am sure this is quite a factor with the Neo TRN2. I have gone as far as leaving the front-stripped body immersed in cellulose thinners to soften internal deposits (but not overnight, more like 15 minutes?), but am loth to risk stripping the trigger mechanism for routine maintenance. I use the smallest cleaner brush and wiggle it around into corners of the body as far as possible, but no doubt there will still be deposits left; as I remarked earlier, sounds like an ultrasonic bath is needed.

I found Mick Bonwick's article in the ground-breaking and much-lamented Finescale Model Review of Bob Barlow & Co. very helpful, in establishing cleaning regimes. So it was fairly chastening to be still getting unacceptable levels of 'crud' deposit during painting trials. However, with the various advice passed on in this thread, I am now getting a considerable improvement, so many thanks to all for your contributions. If you think of anything else, keep them coming!

Regards

Steve

beachboy
Posts: 99
Joined: Thu Feb 18, 2010 4:35 pm

Re: How clean are paint thinners?

Postby beachboy » Sun Feb 21, 2016 1:55 pm

Steve,

Its worth stacking up the models for warmer days.

If your going to purchase more Rustins. Consider two bottles, possibly the smaller version, & keep it solely for dunking your needle in, then wipe across a flat K.Towel surface.

Another thing I often see is people prime bare metal with Halfords/Games WShop & similar 'Primer'.
Bear in mind its not a surface prep. But a Basecoat - hence different colours shades so as not to impair the top coat colour tone.
A car body panel would be prepared in say a twin pack, akin to a more economical sized product like Precision supply. But you need at least twice the amount of 'Thinners'. The benefit its ultra thin for a small model, & thus allow for a fine basecoat, etc. without losing the detail. But check your Mask filter is up for it first.
I have seen many metal models at Exhibitions with clean chipped roofs, paint worn away from handling, & so on.
Nice to just paint it the once.

Regards - Stephen.


Return to “Painting and Weathering”

Who is online

Users browsing this forum: No registered users and 0 guests