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Painting problem

Posted: Thu Oct 05, 2017 11:57 am
by jon price
I'm part way through painting and lining an industrial loco and I have encountered a problem which I'm wondering if someone will recognize.

The model is a brass loco. It was thoroughly cleaned with Cif, then sluiced with water and left several days to dry. I later thouroughly cleaned the loco with IPA before undercoating with Halfords aerosol grey primer and left the paint to dry/harden for several days. I then cleaned again with IPA and painted with Halfords aerosol gloss Volkswagen Maritime Blue. Some black parts were then painted with Vallejo gloss black, and the cab interior with Valejo matt buff. I applied the first stage of (red) lining with Fox transfers on one side. I then began the second stage of (light blue) lining with Fox transfers. I instantly realised that unless I varnished the first stage lining I was heading for insanity as all the transfers would start to move so I stopped. At this stage everything was fine. A couple of days later I lined out the other side and left the transfers to harden. On returning to the loco I find that one side now has chalky marks on it.

Does anyone have any idea what these might be or how to get rid of them? I have tried to remove them first with water on a cotton bud, then similarly with IPA but I can't detect any diminution. Unless I can remove them I think I will brush over them with the Halfords gloss. If that doesn't work I would have to start again, which I am loth to do.

The photos show the side with the marks, and the side without (photos now edited to better show nature of mark)

Re: Painting problem

Posted: Thu Oct 05, 2017 12:58 pm
by John Palmer
You don't say how much drying time you allowed for the Maritime Blue. Presumably this is a cellulose paint, and as such should have been fast drying, so the drying time may well not be an issue.
Finishing problem.jpg
Finishing problem.jpg (184.65 KiB) Viewed 4205 times
There is a clear boundary to the chalky marks in the vicinity of the lining transfers - does this indicate some causal connection? I've not used Fox Transfers, so can't comment upon the composition or characteristics of their carrier film or backing sheet, but I wonder whether the chalky marks have been carried over from one or other of these.

I also note that where the light blue corner transfers have apparently been overlaid on the red lining, there is a perceptible change in the colour of the underlying lining, which has a pink hue rather than an orange, as illustrated on the attached fragment of your picture. Does this suggest that the light blue lining transfer is the culprit?

Have you tried giving the chalky marks a light rub with a cotton bud dampened with a little cellulose thinner? That might be enough to cut through the 'chalkiness' without breaking through the underlying coat of Maritime Blue.

Re: Painting problem

Posted: Thu Oct 05, 2017 1:31 pm
by jon price
Not sure about this. Fox transfers have no perceptible carrier film outside the paint area. I tried some extreme close-up photos and none of them are anything close to what I see using my (extreme close-up myopic) naked eye, so I suspect some of the colour change is an artefact of the slightly out of focus photo. Agree the mark follows the line of the transfer. I suspect this is to do with glue residue from where I placed the transfer before moving it into position which might explain any colour difference if it exists outside the photo

Re: Painting problem

Posted: Thu Oct 05, 2017 2:27 pm
by Le Corbusier
How depressing for you :shock:

Looking at your picture it appears that there is evidence of the 'milking' occurring on one of the footplate steps? This is quite far from the transfers and so would suggest not directly concerned with the application carrier. I could be wrong but it looks to me similar to what happens when water gets under a varnish coat? rather than something that's on the surface.

It might be an idea to spray up some scrap and try applying water etc to see if you can replicate ... rather than too much experimentation on the loco until you have established what is going on.

Re: Painting problem

Posted: Thu Oct 05, 2017 2:55 pm
by Andy W
when you painted the black areas was this sprayed and did you mask the blue? I had a similar experience when spraying an MR tank's smoke box. I sprayed the body with cellulose, masked it off and sprayed the smoke box etc with enamel. When I removed the tape I had small patches of discolouration on the red. This wasn't residue, it wouldn't clean off. It was like cloudy marks in the body of the paint. It needed a re-spray.

After a trawl of the web, I found others had suffered similarly. It seems that if the paint isn't allowed to dry thoroughly before you apply the tape then gasses can be trapped and cause such marks.

Now I leave the initial coat at least three days to cure fully, I also remove the tape asap, plus I use plain paper and Post-its to mask the majority of the surface, and only use the tape to secure the edges.

Try a little T cut applied carefully with cotton buds, but I fear you may need to re-spray. You may get away with using wet and dry on the affected areas and taking it back to the undercoat (if possible) rather than taking the whole paint job off.

Re: Painting problem

Posted: Thu Oct 05, 2017 3:00 pm
by jon price
All useful information. The black was brushed on and no masking tape was involved.

The paint is gloss so no varnish coat, so I'm not sure if there is anything for the water to get under.

I may try cellulose thinners, but I will test it on a bit of paint that isn't on the loco first.

Re: Painting problem

Posted: Thu Oct 05, 2017 6:26 pm
by Andy W
Before trying thinners I'd rub a small area with T Cut and/or a car wax like Turtle. Did the marks appear some time after the paint had dried? If it were the transfers causing the problem then both sides would be affected. Was the loco laid on the marked side for a while?

I'd leave it for a while in case the second side also shows the markings.

At the moment the worst case scenario is that at least you will only have to paint one side tank - and not the whole loco. Not much consolation I know.

Re: Painting problem

Posted: Fri Oct 06, 2017 9:55 am
by buckie5507
Did you use any decal softener - microsol or similar, wonder if this has reacted with the varnish/gloss layer.

Halford's car paints are now all 'acrylic', and can take a long time to polymerize. The can of satin black I've just looked at advises allowing 2 weeks for the paint to fully harden

A polishing compound like T-cut or Tamiya compound - fine, would certainly be worth trying


Re: Painting problem

Posted: Fri Oct 06, 2017 11:17 am
by jon price
No Microsol etc used, but I wasn't aware of the two week wait for full polymerisation. Probably left the first side for a week, so re earlier post on varnishes it is uite possible then that this is water damage

Re: Painting problem

Posted: Fri Mar 30, 2018 2:37 am
by Allan Goodwillie
Jon, :)

I have only picked up on this one by chance, but interesting none-the-less Jon. Since you have not posted for a while on this I am assuming that either it has been resolved or the loco is sitting on the back shelf somewhere.

One of the early things you learn as an artist is that when oil painting you have to be very careful when using lakes as if they are used in lower layers of paint they can in time leach through to the upper layer. The reason is that crimson lake for example is made using dye stuff where the particle size is miniscule. It is as part of the process of production attached to a carrier whose particle size is closer to the size of the particles of paint produced by grinding down pigment. Unfortunately it can break down and the tiny particles work their way to the surface between the larger particles and appear as ghosts of previous painting.

Now it strikes me that the composition of Cif is similar in some ways in that it is made from micro-particles and they may just be behaving in a similar fashion working their way up through the different layers. I have never used Cif for cleaning my brass locos, so have never had this kind of reaction. If the acrylic takes so long to settle you can imagine the Cif working its way up and through.

Only a theory - would have to see if anyone can back this up. In an oil painting it is very difficult to remove - almost impossible in fact, I am sorry to say.

Allan :|

Re: Painting problem

Posted: Fri Mar 30, 2018 9:49 am
by jon price
Thanks Alan. I'm conscious that all cleaning products may contain problems and so after use I sluice the loco with water to get rid of any residue. I polished the paint, then varnished, and everything turned out fine. You can see the results on the CRAG thread for Feb 2018.

Re: Painting problem

Posted: Fri Mar 30, 2018 3:02 pm
by Allan Goodwillie
Hi Jon :)

That's great Jon,thanks for letting me know and I am really pleased that all turned out well in the end. I am very careful with the product when using it, but have never used it for cleaning metal prior to painting.

Your lovely industrial loco will give you hours of pleasure in operation. Many of my favourite engines were the small ones which often inhabited small yards - I had a favourite which used to shunt trucks in Lawson's coal yard in our town (Leven), it was a J72 built early BR period. It only went about a couple of hundred yards outside the yard to the shed at Methil for servicing or to collect /drop off more wagons.

Looking forward to seeing it in action sometime. :thumb

Allan :)