Protecting Decals... Some Tests

[D869Zest]

So finally... some results. Starting with Halfords matt lacquer.

As my experience on the slope sided mineral indicated, I found the result was not flat enough for my taste when finishing wagons. It did produce a uniform finish between the areas coated with gloss and those not.

Control wise the big Halfords rattle can is the least controllable of the bunch, hard to ensure an even coat while also avoiding flooding the surface.

There was no sign of any reaction with the Microscale fluids. It did a decent job of disguising the carrier but showed up the need for more attention with the Microsol and a pin or knife to persuade the decals into plank gaps and ensure every edge is completely down... this is not about the lacquer and the same was seen with the other products.

Surprisingly I did get a reaction with the paint finish on the parts of the van body where the gloss had been applied. Surprising because by this time I had used the Halfords stuff on three recent wagons with no such issues. I can't be sure but I am putting this down to poor adhesion between the old (really old) paint job and the plastic of the Peco body but the gloss is an essential ingredient too. If memory serves this van was bought secondhand and was not in any RTR livery so was perhaps a kit originally. Thinking about it after the event I can't even remember if it was me that painted it but quite possibly not.



After 24 hours I tried a couple of options for eroding the decals. One was to scrape with a No 15 curved scalpel blade. The other was to abrade with a fibreglass brush. My first attempt used a fine bristled fibreglass brush. This did not touch the decal at all so I think that says a lot about durability. I then deployed a coarser bristled brush which was able to abrade the decal. The black shading was first to go with the white proving more resistant. The result was a pretty heavily weathered letter. It was difficult to get in close to strapping. The scalpel was mostly 'all or nothing' so probably only useful for unlettering whole planks. None of this was controlled enough to produce light erosion.



I also attacked some of the plank gaps a bit further, trying a pin and a scalpel. The pin tended to break off flakes on either side. The scalpel produced a fine cut... which looks exactly like a fine scalpel cut. Neither of these techniques were very successful.

Next was another coat of lacquer to protect the eroded decals on one side only. After another 24 hours to dry some planks were picked out with a bare wood colour (brushed Humbrol) the model was then given a misted airbrush coat of Humbrol crud colour. None of this caused any ill effects.

After a further 8 hours some of the misted crud was cleaned off with Humbrol thinners and a flat brush, deliberately being heavy handed and continuing for a while after the crud was gone. The recoated decals were untouched by this. It did eventually pull some flakes off the eroded decals that had not been recoated but it took surprisingly long

No final picture sorry but the end result is a mess of different treatments with no serious attempt at realism.

 

[OzzyO]

Hello D869Zest,

if you can get Utube on your TV or computers have a look at some of the airplane modellers on there and some of the paints and varnishes that they use. Some of them may help you.

ATB

OzzyO.

 

[D869Zest]

Next the results for airbrushed LP23

For this test I dedicated a Peco mineral body and one van side as I had no prior experience with the product, the initial idea being that the van side would get just a single coat and would not undergo any abrasion so that I could assess durability.

I thinned this with Tamiya lacquer thinner, probably a bit more thinner than lacquer and sprayed at 25 psi. Naturally this was nicely controllable.

Flatness was good, as was the disguising of the carrier film. I'd say that the difference in flatness between glossed areas and those not glossed was slightly detectable after the initial coat but also that the coat was thinner than the Halfords so perhaps not like for like. I'm not sure that the photo really brings out the difference in flatness.

I didn't get any reactions with the Microscale fluids or with the old paint finishes.

A picture. Sorry about the awful repaint from my early years - about the time I figured out that colourful PO coal wagons didn't fit with late steam era locos. Now I am trying to figure out how to do... colourful PO coal wagons. Once upon a time I also thought that dirty thinners was the approved route to weathering



As with the Halfords test the finer bristled fibreglass brush made no impression on the lettering. Impressive! I then used the scalpel and the coarser brush with similar outcomes to the Halfords test. One point I omitted previously was that these treatments did produce a shiny appearance in the eroded areas (with both Halfords and Tamiya).

This is a better illustration of the way that the black ink is less durable than white.



No ill effects were seen from overpainting planks with brushed Humbrol or from an airbrushed mist of Humbrol crud colour.

The clean off with thinners test was done on the van side, again being deliberately heavy handed. Leaving crud in the plank gaps did not damage the lettering so I carried on until the crud was completely gone, again with no visible damage. Carrying on again did start to pull flakes from the lettering

 

[paulc]

This didn't start out as a test - after reading some posts online a rattle can of matt lacquer was purchased from my local Halfords and applied to a slope sided mineral which had just received decals, starting with a very tentative thin coat. The result didn't ruin anything but was not as flat as I had hoped. Rather than using other wagons with more complex liveries as guinea pigs I dug out three old Peco wagon bodies from my odds and ends box to test things out on.

I had a spare set of private owner lettering from one of the recently lettered models so the wagons were given a coat of Humbrol gloss and the private owner letters shared out across six wagon sides with a liberal application of Decal Set followed by Microsol to persuade them into the planking. I left the gloss off the central door area to help gauge how well the products could restore a flat finish. From there onwards their paths diverged to experiment with different treatments and different ways to do weathering.

My shortlist of products for testing was as follows...
Halfords matt lacquer rattle can
Tamiya TS80 rattle can
Tamiya LP23 flat lacquer and Tamiya lacquer thinner. I also bought semi flat while I was making an order online but it wasn't part of the test.

Obviously from the suggestions made on this thread (for which, thank you) there are far more products out there. I have heard of the brands but not all of the products.

So what am I looking for?

1. Protect Alps decals from the sort of handling that locos and rolling stock endure at an exhibition.
2. Kill the gloss paint or varnish recommended for use below decals
3. Compatible with Microscale decal fluids
4. Suitable for weathering over with Humbrol enamels, and partial crud removal with enamel thinner a few hours later
5. Flat and semi flat options for grotty wagons and less grotty locos and coaches
6. Brush, spray and rattle can options ideally

The trickiest questions relate to ex private owner wooden minerals where I need to make the lettering look worn and also represent replaced planks either by scraping part of the letter off or by overpainting with wood coloured enamels, so a few ideas for doing that were included in the various treatments.

Be careful with the Tamiya flat lacquer , that stuff will curl up your transfers quicker than a curling wand if applied slightly more than thin . Sometimes once it has gassed off the transfers will lay down again but sometimes not . I have the tee shirt and it wasn't my loco that i was working on at the time .

 

[D869Zest]

Be careful with the Tamiya flat lacquer , that stuff will curl up your transfers quicker than a curling wand if applied slightly more than thin . Sometimes once it has gassed off the transfers will lay down again but sometimes not . I have the tee shirt and it wasn't my loco that i was working on at the time .

Oh dear! Do you know what transfers they were?

 

[paulc]

Oh dear! Do you know what transfers they were?

No as they were supplied by the guy who owned the loco . Fortunately in that case i only had to replace one side as the other flattened out after 24hours although another loco from the same person ended up with me replacing the transfers completely, again no idea of brand . After that time i just stopped using the Tamiya flat but i do use the gloss as a base for transfers but will replace that with another brand once it runs out .
Probably Mr hobby which is the brand of matt that i use now , see photo entry #5 .

 

[D869Zest]

And finally the TS80 rattle can.

This was only tested on a single van side and with fewer weathering treatments because I expected it to be an aerosol version of LP23. I expected wrong.

The first surprise was that the lid of the TS80 can has a sticker saying don't apply over decals. Oh. What should one do with it then? As usual other forum posts had no shortage of opinions on whether or not it would be OK but few if any spoke from experience.

This being a test I duly ignored the sticker and carried on with a thin coat. The Tamiya can gave better control than the Halfords but not as good as the airbrush. On inspection afterwards it was so thin that I did not get coverage in all areas.

The big suprise was that the decal carrier film stood out like a sore thumb, being obviously less matt than the surrounding paintwork.

Given the incomplete coverage and obvious carrier I went for a second coat a day or so later, thinking that there was a good chance of fixing both issues. That sorted the uneven coverage but not the obvious carrier film. Hmm...

Disguising the gloss coat seems OK to the Mk 1 eyeball but perhaps slightly less convincing in the photo. Shame about the carrier.

I carried on with the misted Humbrol crud coat and heavy handed cleaning off with thinners with no issues at all.

It was only when zooming on the photos ready for posting here that I think I figured out the reason for the obvious carrier film. The lacquer seems to have reacted with the paint resulting in a very fine textured surface that wasn't there before. This happened on both the glossed and unglossed areas but the decal film prevented the lacquer from reacting so the finish there was smoother. I can't blame insufficient hardening time, the Peco body had been overpainted at least 40 years ago.