Masking with Latex

Because a big piece is missing on my Enterprise-C, I bought some liquid latex and hard plaster to make an attempt at making a mould and building a replacement part for it.

I have yet to start the attempt at making the mould, but today I fiddled around with the Latex, just to see how it handles and behaves on a model. I put some of it on some left-over sprue and covered a) a big piece of it with a thick layer, and b) several small protrusions to see if it removes easily.

(Normally, I'd prefer to use silly putty, as many modellers do, but - here in Belgium - I have yet to find it in a store. I refuse to pay $20-$30 shipping costs for a $2 egg of putty).

After several hours, it went from white to translucent. The big piece was easy to peel off. For masking a piece of your model to prevent it from being painted, it would certainly do the trick. The smaller parts came off easily with some tweezers. No latex was left behind, so no fiddling needed with a sharp knife, as you would have to do if you had used clay or something.

One of the purposes I'll use it for, is shown in the pictures below.

The first two pictures show the axles and road wheels of my M60. If I want to easily paint the tank and wheels, I need to paint them before assembly, but small connections like axles/wheels, antennas, ... usually have a bad bonding when glued AFTER painting. You can scrape away the paint where you want to apply glue, but my current experiment should be able to help as well, and a lot easier. Once I have painted the tank and wheels with all needed details painted, I can just use tweezers to remove the latex and have pristine plastic to glue the wheels in place.

The last picture shows the turret and the mini-turret for the machinegun (whatever its called). To avoid any friction or loose the ability to rotate the turret, I don't want paint in this area. Masking tape is far too big a hassle here, so again I am hoping latex will be the answer.

Conclusion:

• easily applies with a brush (use an old brush, that isn't used for painting anymore)
• CLEAN your brush regularly with soapy water, before it dries
• apply a second coat after 10 minutes, just to be sure
• it smells rather pungent and is indicated as toxic, so use gloves, maybe a mask (I didn't, but will when handling longer or in bigger quantities) and make sure the room is ventilated.
• easily removed by hand, with tweezers if necessary

Remaining tests :

• It's probably not suitable for masking on top of a layer of paint (e.g. when painting multicolour camouflage). I suspect it'll pick up the underlying paint when removed. (Will confirm or deny this later)
  --> Humbrol Maskol is confirmed to be suitable for this and is readily available in stores here.
• How well can it be used for making a mould? How thick does the layer have to be for a decent mould that will retain it's shape after removal from the original object?