MMP paints and masking liquids

Hi Everyone,

I am wondering if anyone had some experience with using masking liquids, like Humbrol Maskol, on Mission Models Paints as my first try was quite a disaster so to speak.

I had a surface coated with Ammo One Shot Primer and on top MMP white. I thinned the paint roughly with 20% MMP thinner. I left the model to rest for days and when I got back to put on the masking liquid I noticed that it desolved the paint underneath. So I went to see if I can wash it off with water and all the paint came off without any problem. The primer was still on, that thing is tough as nails.
This never happened to me with Vallejo or Ammo acrylics, even against water they showed a bit more resistance after 24h of curing.

Did a second run but now I used 10% thinner and added 10% MMP polyurithane to it as well. It looks a bit more tougher now, but still the paint gets softended up by the masking liquid.

Even tried the Vallejo Liquid Mask as well. That seemed a bit less agressive as the Humbrol one, but still damages the paint. But it might be the polyurithane that helped at that point.

The only way I can think of fixing is to either add more poly and see if that makes the paint more tough, or to coat the paint with varnish and then mask.

Here is an update.

I’ve removed the second run. Seemingly the 10% poly is not enough to give durrability to the paint.
Did a third run with a fresh coat of primer, still Ammo One Shot and half an hour rest.
Mixed up 15 drops of paint with 4 drops thinner and 4 drops of poly, all from MMP. Bit more than 20% of both.
Thin wet coats as instructed and let it rest for 2 hours. I didn’t wait too much with the primer curing as I wanted to give as much grip for the paint as possible.
After the two hours I applied the masking liquid and let it dry and cure fully for roughly 4 hours.
Now it came off clean and the paint stayed on nicelly.
I did feel the paint getting a bit agitated under the liquid, but I think one needs to wait until everything settles down nice and cures back to its previous state.

So the moral of the story is:

  • More poly for durrable paint, minimum 20%
  • Nice fresh coat of primer
  • Wait for the paint under the masking liquid to settle again

Even with this initial headache with MMP, I do like their paints. No tip dry, beautiful coverage and nice self levelling. Also starting to get why they give the thinner/flow improver and the poly separate.

The Maskol if they have not changed the formula is pretty hot, it was formulated years and years ago when either you used Enamel or you used Enamel, with acrylics it is a bit of a risk.

I use MMP but since using them I have never tried masking liquid but last night when I read your message I did a couple of tests, I have my sherman guinea pig which has various layers of MMP and a couple of fresh spots of 2 days a go, I tested paint and satin coat with and without Thinner, with and without Poly and I replace the MMP Thinner with the UMP one, I put some Vallejo masking fluid blobs and I took it off this morning after about 8 hours without problems apart from only one spot but I think it was an area without thinner or poly, plus I brushed the MMP on an old and dusty base, this morning I put the masking again a bit everywhere, old paint, satin cote, etc … then I’ll let you know in a few hours, my masking is old and not very liquid anymore but I tried to scratch the surface with my fingernail and only in that spot did I affect the paint

Checked the second test, on the MMP Satin cote no problem tuff as nail, on the areas painted in 2 points the paint was softer, if I remove it with my finger nothing happens but with the toothpick I scratched the paint, in other areas instead no problem, some areas were painted more than a year ago but I also did some tests so I don’t remember where poly is and where not, however the liquid masking does not lift the paint but I scratch it with the tooth pick, and where the paint has softened after 15 minutes it was as hard as before without stains

Great tests, thank you for sharing.

I think my problem was that I took the mask off too early and the paint underneath didn’t had enough time to heal (re-cure?). Probably… just a wild guess here.
I did use Humbrol Maskol recently on a P-40, doing the camo pattern on it. The paint underneath was Vallejo Model Color thinned with its own thinner. And that didn’t have any problems whatsoever. never seen the paint soften up under the mask before, although the mask usually sits for a day or two before removal.

Also did a test on a separate piece durring my third run (which I haven’t checked yet). It’s a plastic cup being used as a small desk bin and paint doodle/tester. Just had a fresh coat of leftover primer from couple of days ago and I sprayed the MMP paint (20% thinner, 20% poly) on it what was left over. After roughly 4 hours that was tough as nails as well. Tried to rub it off with a wet finger and it didn’t budge at all, just like a primer.

And finally, my third try came out good. The paint (20%) stayed nice and dry after removal. No signs of softening whatsoever.

So if you want your MMP paint to be “forgiving” and you know that you won’t put on things like masking liquid on top, don’t put poly in it, or just a small amount 10% or less. If you want a sturdy finish which can withstand a beating add poly to it, 20% or more.

For one MMP has a bit more of a learning curve to it, but the results with these paints are great.

slightly hot all masking fluids are, latex does not dissolve in water a certain percentage of acetone or other solvents must be there, and maskol had problems with other paints too.

The poly certainly helps a lot, I’m very happy with the MMP system, I certainly find it simpler, more scientific, it is easier for me to count the drops than the classic “consistency of skimmed milk” which for me means everything and nothing, but they are very personal things I think.

One thing that I have learned to my detriment and that I have noticed now they have added to the FAQ on the site, is that if the paint has an “infinite” shelf life the poly is very susceptible to both low and high temperatures, me after 2 bottles in the trash,the supplier send me one for free the second time,now I keep it in the fridge of my man-cave where it remains stable.

Now to save money I have the Poly from Createx, same thing but it costs a little less, Createx 4030 Balancing Clear and I think I will also try the Createx thinner, I have the vague feeling that Createx itself produces the paints for the MMP … same bottles, same smell and both USA products, MMP certainly does not have a factory to produce but has others produce with their own specifications, like most of the modeling brands