hi there, so today my Humbrol clear coat mat (acrylic) came in. I wanted to try it, so I gave it a good shake and put on the first layer of paint. After waiting for 10 minutes I noticed that there was coming up some weird kind of dust, so I decided to wait another 30 minutes. When I came back my model looked like this…
if you look closely the model has this white shade on it.
the paints underneath are oil paints from Revell, and the paint was applied in one thick layer at a room temperature of 20c. Before spraying with this product I cleaned my airbrush with thinner.
I already tried to wipe it of with water, that didn’t work so I tried some turpentine but that didn’t work as well.
So now my question is, what did I do wrong, why does this happen and what can I do to to solve this issue?
I can’t say specifically why this has happened (could be any number of things) but it sounds as if your flat coat was applied too heavily and it has “frosted”.
This can sometimes be fixed by applying a clear gloss coat over it (don’t forget to re-mask your canopy) and then reapplying the flat.
PS: I was going to suggest using isopropyl alcohol or windex to remove the offending acrylic flat coat as these wouldn’t affect an enamel based base coat but you have allready applied the decals and both of these solvents would most likely strip or otherwise damage them.
Thanks for your answer as well! I think I will add another gloss coat and I’m glad to Hear you haven’t met the same issue again, and that it isn’t the product but my fault
I experienced the same nasty frosty finish using MicroSol Clear Flat (acrylic stuff) on a Revell RF-4C Phanthom that I loved dearly. I think it was because I put it on too thick and with too much pressure.
I wish I could give you more encouragement. I tried the same remedies you’ve already explored without success. I ended up stripping it down to bare plastic and starting over.
First off, always stir your paints, especially flat clears to help disperse the talc Medium. It’s ok to shake, but always finish up by stirring. Second, never put on a heavy coat when it comes to flat clears, all you need is a light mist coat. Third, the most common thing to do when fixing a paint screw up is to wet sand it out. I’m sure a quick polish with fine sand paper would help.
Happened to me too, many years ago when I used Microscale’s clear flat on my F4U Corsair. Researched the problem, and answer I found then is in Paul Boyer’s Painting & Finishing Scale Model’s book. He listed the possible reasons as:
humidity, this is least likely
clear coat being incompatible with base coat resulting in crazing
(most likely) flat coat not being thinned enough, resulting in this ‘frosting’ which is actually the flattening agent
Do remember to stir well to properly disperse the flattening agent, and thin sufficiently (Paul Boyer recommends 50:50). With this, I did not experience the problem again.
If you want to remedy this, the frosted flat coat will need to be removed, if still possible (it should have cured by now). Otherwise, you might need to strip off and repaint[:'(]
Gloss does not contain flattening agent, so you should not encounter case of gloss coat frosting up. Assuming, of course, the frosting is due to the flattening agent. Whether it will clear up the existing frosting in your case, just give it a try I guess and do let us know the outcome.
Do note that if its semi-gloss, some flattening agent would be present.
Hope that helps.
Edited to add, thinning will not be the factor affecting frosting in the case of gloss. However do thin to be able to airbrush it well.
This is not a definitive answer because I haven’t used Humbrol acrylics, but I have used other acrylic paints (Tamiya, Gunze, Vallejo) fairly extensively.
Though many acrylic paints suggest that they can be thinned with water, I recommend against it. Whilst it does thin the paint to an extent, thinning with water generally decreases adhesion. It can also increase the surface tension of the paint, which can increase the tendency of the paint to bead and run.
For clear coats especially, I’d recommend using the manufacturer’s proprietary thinner.
In relation to your original problem, I came across this on the Humbrol site:
Tip: Humbrol Matt or Satin Products: Misting
The white misting effect which can occasionally be seen when using Humbrol Matt or Satin products is actually caused by deposits of the matting agent, usually caused by the product not being stirred thoroughly or regularly enough. However, this can easily be rectified by applying a coat of gloss varnish which will dissolve the matting agent deposits. A coat of Matt or Satin varnish can then be re-applied.
Please Note: All Humbrol products must be used at room temperature for them to mix and work correctly.
Well I guess I just created myself a weathering dummy…
I applied a gloss coat over the humbrol mat coat, but unfortunately it didn’t Work and I still got a spitfire snow diorama… ;D
I applied Alclad aqua gloss since this product did a great job on my Revell B-17G 1/48
It is not yet finished, still need to do some weathering and add yellow tips to the propellers. (Sorry for the mess in the background and the unfinished model…) I’ll also Upload a topic on this one later.
I don’t know what I’m going to do with the spitfire. I thing I‘ll finish it and use it as a test dummy for al my weathering processes, since I never done any weathering yet. This spitfire is my third model ever and the B-17G was my second
Shaken not stirred works for 007 but not when it comes to paint.
I NEVER shake my paints. Why? Just because of what hapenned to you. Shaking also gets the paint under the cap creating a mess specially with the tin lid from Humbrol so wipe them clean to help reduce paint buildup around the tin lip. I always stir for at least a couple of minutes using a wood coffee stirring stick making sure everything is blended specially the bottom where it usually clumps up. Shaking will not blend the thick clumping globs at the bottom of the container.
Most of the time spraying clear gloss like Future will get rid of that frosting and hopefully it will save your paint finish. This is part of the learning process of this hobby.
Yeah I agreed on the fact that it is a case of try and error. eventhough this model was a failur I still continued. I already applied some weathering using tamiya’s weathiring kit.
You might have to take a close look at the photo’s I made due to the flash on my model
I don’t mind this model being a complete failure, because I have many more 1/48 kits waiting to be build and this being a 1/72 scale, it didn’t Fit my collection anyway. Not that it isn’t s nice kit though. I also already have an 1/48 spitfire from revell waiting to be build…
Dutch, this may have been a failure for you but I think you solved a problem for me. I’ve been looking for a way to produce that very haze effect to replicate sun-baked paint. I’m going to give your “mistake” a try! And look again at your first picture - that’s one heck of a good looking combat weary aircraft
