Masking tape times?

[foz75 93]

Just wondering, once window masks and Tamiya tape are applied to the inside of a clear shell, do they stay stuck for quite a while (a few days)? Or worded another way, how long can I wait between applying masks and painting? And what about removing them? How long should I wait, and how long might be too long? I need to mask and then paint 2 colours, but I can't seem to find enough free time in the same day to get it all done, so need to spread it out over a few days or maybe a week

[sosidge 624]

Bigger issue for me is that the longer the mask is on, the more likely the adhesive is to degrade, leaving nasty marks behind. Try and keep the masks on for the shortest time possible.

[Tamiyabigstuff 831]

I put window masks on a body shell and left it a few weeks before painting - after eventually painting the shell I removed the masking tape and found some adhesive residue on the window areas - a drop of olive oil soon cleaned that off.

[foz75 93]

Ok,I know as short as possible is best, I guess a few days is fine? More worried about possible bleeding under the tape from lifting than glue residue

[sosidge 624]

Days is fine, weeks is what I'd worry about.

[Juggular 4964]

19 minutes ago, foz75 said:

how long can I wait between applying masks and painting? And what about removing them?

Tamiya window masks they supply in the kit have little glue (or whatever the sticky substance on the tape).  It can stay there for months.  I often have to reapply pressure on the edges right before I spray, even though I cut it only minutes ago.  So Tamiya window mask?  Fine for weeks.

Seeping happens immediately as you are spraying.  To prevent it, you need to have the edges stick very well.  I wash my hands before I peel them off the sticker sheet. (of course, the body shell is washed too)  I still try not to touch the sticky side as I apply the mask. Once applied, if you are not going to spray right away, leave the body right side up. That way, dust wouldn't get between the shell and the masking tapes.  Reapply pressure on the edges right before you spray. Otherwise, you might have the paint seep through.  

If you are using a regular masking tape? They can be sticky; the quality of those vary greatly.  Some would leave nasty residue after hours, some would be fine for weeks.  But I have not seen any masking tape that's as light-duty as Tamiya stuff. I should think that a week to 10 days until waiting for good weather wouldn't be a problem for Tamiya stuff.  Almost all the time, I wait days to spray.  I can't remember if I had waited weeks. But I do remember saying things to my wife, "I thought I could paint today, but it's too humid. Now that it rains, I'll have to wait until next week." I don't remember if that was Friday to Tuesday (days), or Monday to next Friday (weeks).  

However, I would not wait weeks to peel them off, after paining.  The paint becomes almost rock hard on the edges after weeks.  You would have to really score hard on the edges. Otherwise, you might pull the paint off as you peel the tape. After months, the tape gets encased, embedded and entombed in the solid paint.  Depending on the weather, 12-24 hours is the sweet spot. Even so I score lightly, if the paint looks 'chewy.' 

[On a hot and dry day (like 30C, 30% humidity), you can touch the paint in minutes. But I would not peel the mask for hours because of the layers.  If you spray several layers in succession, the fume from the lower layer gets trapped. I spray 3 layers of the color, then 2 layers of white, and maybe 1 layer of gray. That's 5-6 layers.  If I tried to pull the tape in 3 hours, it could pull a string of gooey paint from the edges. So I wait at least 12 hours to a day.  

 

[mtbkym01 4008]

left the window masks on my 40th Anniv 934 for a couple months, no issue at all

[GeeWings 2830]

3 hours ago, Juggular said:

[On a hot and dry day (like 30C, 30% humidity), you can touch the paint in minutes. But I would not peel the mask for hours because of the layers.  If you spray several layers in succession, the fume from the lower layer gets trapped. I spray 3 layers of the color, then 2 layers of white, and maybe 1 layer of gray. That's 5-6 layers.  If I tried to pull the tape in 3 hours, it could pull a string of gooey paint from the edges. So I wait at least 12 hours to a day.  

 

That's good to know. I have struggled to get masks off cleanly at times and think it was probably because I was too hasty. I also tend to run a new clean blade gently along the edge now which really helps keep clean lines.

[Howards 456]

Paint is put down too thick if you are having issues with it sheering when you remove a mask.