Sealed barriers for painting

[moon puppy]

I walked down to the garage today as part of my exercise and get back at it plan. I looked at a couple of projects that are on the bench, don't think I'm ready for that yet.

I looked at my Epic Failed Mighty Messerschmidt and wondered why all the coats failed except for the decal?

You can see where the lacquer thinner ate at the clear coat over the top of the decal but it didn't burn through all the layers and primer like it did in surrounding areas.

Now...what is it about the decal that seals against lacquer and could we take advantage if it?? :hmmm

 

[Swordsman]

Interesting ...... will take a little thinking here ...... need more input ..... ldguy

 

[moon puppy]

I figure it's a good time to pose this question because Chris would be :smack and tell me to keep my clear fluids sorted better.

 

[jknaus]

Why not mask the decal and reshoot the paint?

 

[ausf]

Maybe it's the film they screen on the decal that's resistant to your thinner.

When I did the Albatross wings, I sprayed a light coat of Vallejo Poly Primer (black, why didn't I go with a light color? ). Instead of paint, I went over that with a few coats of Future. I set the loz decal with MicroSol and let me tell you, that was the most tenacious bond I've ever dealt with. When I decided to pull the loz off the tailplane, I soaked it overnight in water, another night in straight vinegar, but the only way to get them off was physically scraping. And that was straight decal, not sealing with anything.

I know the same poly primer (without paint or Future on top) could be rubbed off with relative ease.

 

[moon puppy]

Why not mask the decal and reshoot the paint?

James that was not the only area impacted by my mistake. I was mixing Migs Nuetral Wash with lacquer thinner, as I spread it around it didn't just sit on top of the gloss clear coat, ate into it. What you see here is the result of my coming back after a while and using the same shot glass to try and remove the wash, which SHOULD have resulted in removal of the enamel based wash down to the acrylic clear coat. Mixing it with the lacquer took it to a completely new level. DEEP level.


So what is it with the decals, what medium are they printed in that seems to resist hot thinners?

 

[Heavens Eagle]

Hmmm! :hmmm

Never had much trouble with paints Bob. Always used enamels as base color (on external surfaces) then used acrylics and inks over that for detailing and weathering. Then with the old Polly-S or inks I could use a Q-tip or bit of paper towel with 409 to remove excess and blend. Once dry then more enamels or Testors flat clear over that. For decals I do't usually do a future or clear coat, I just use Walters Solvaset 50-60% with water on the model under the decal and 100% on top of the decal. Have very little trouble with that over flat & semi flat enamels (no future or gloss) and get no silvering.

The enamels I use are Testors and Humbrol. I use the Testors thinner for both and have no trouble. The acrylics are becoming Vallejo and some Games Workshop/Citidal paints. I thin the Vallejo with Vallejo airbrush thinner or water or a bit of both. Only other paints I use are some Floquil that I spray on as a base color straight out of the bottle, or some Alclad over Alclad gloss or flat black primers.

Only thing I have found a problem with is Solvaset on Vallejo can soften and damage that paint.

That's my 2 cents for what it is worth.

 

[Swordsman]

Here's what Wiki says ..........

Water slide decals (or slip decals) are water-mounted decals generally printed face up and rely on the dextrose corn sugar residue from the decal paper to bond the decal transfer to a surface. A water-based adhesive layer can be added to the decal to create a stronger bond or may be placed between layers of lacquer to create a durable decal transfer. The paper also has a layer of glucose film added prior to the dextrose layer which give it the adhesion properties, the Dextrose layer give the decal (lubricity) the ability to slide off the paper and onto the substrate.

Water slide decals are thinner than many other decorative techniques (such as vinyl stickers) and as they are printed, they can be produced to a very high level of detail. As such, they are popular in craft areas such as scale modeling, as well as for labeling DIY electronics devices, such as guitar pedals.

Until recently, water slide decals were professionally printed and only available in supplied designs, but with the advent of printable decal paper for color inkjet and laser printers, custom decals can now be produced by the hobbyist or small business. Even without this, decals have been made at home by modeler's. Gummed paper tape was used as a base and adhesive, with layers of hair spray (a shellac varnish) built-up to form the transparent layer. The difficulty with this in the 1970s was in printing the colored image neatly by hand, as this pre-dated accessible computer printing.

 

[moon puppy]

So it's the Dextrose based adhesive that seems to have protected the lower layers? Notice in my mishap that there's an irregular border around the decal that seems to have been protected. Would that be some of the adhesive from the transfer paper?

Could there be such a thing as a Dextrose based clear coat?? :hmmm

 

[Swordsman]

:hmmm ..... Could Be ..... ldguy ...... I'll have to do more thinking now ..... ldguy

 

[Heavens Eagle]

As to the decal composition Bob, I don't know for sure what the story is. It seems that there have been and are several different compositions for decal material. For example:

Many years ago I built a 1/24th scale MPC Stuka (Airfix kit). The decals were extra sharp and clear but NOTHING would make them soften up! Not Micro Sol, Not Solvaset, not paint thinner, I even tried Testors liquid solvent. Nada! They wouldn't even stock to the model, it was as if they were made from mylar which is pretty much indestructable. Ended up making masks and painting the markings.

Second odd decal kit was the ESCI 1/12 scale F-16 cockpit. hose decals were thin and would stick, but wouldn't soften with Solvaset. It took a little Testors Liquid solvent "just" wicked under the edge to make them settle down nice.

As to why your decals didn't damage from the solvent I don't know. It's one of those things about water and solvent solution stuff that you run in to with mixing odd thinners. Occasionally something is dissolved by more than one kind of solvent. I would never use a "hot" solvent over the top and would be hesitant on using it for a base color.

 

[Paulw]

Thats a good point, Paul.

 

[Old Dog]

I managed to splatter some lacquer thinner on a decal sheet once and without allowing the brain time to function I blotted it up. It took the top couple of layers right off the sheet. So your experience may only apply to those particular decals unless the act of applying them changes them some how from the state they are in on the backing sheet.

 

[moon puppy]

I think that is the case Gary, again I look at the border that seems unaffected by the hot thinner, maybe during the application of the decal the chemical make up of the carrier film or adhesive changes.

I'm sure I could take another washing of lacquer thinner and get that decal up but I'm just wondering what it was that sealed it to start with.

I guess best practice is to pay attention to what mediums you're working with, that's why I got that build sitting in front of me on the workbench.

 

[Barney]

Must be aliens.... :zen