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Masking Tape Problem


ARTA_NSX
09-13-2006, 07:57 AM
Hi,

Hope anyone can advise. I've got a problem i always encounter, is the masking part. Whenever i take off the masking tape after painting, it will leave uneven marks on the smooth masked away surface painted before, making it dull. It gives me hard time polishing it untill smooth again. Even if i let the paint dry for a week and then mask, the same problem occurs. How do i avoid this? Do i leave it longer? Say, a month?

Also, after masking and spraying the next paint, the new paint tends to run down lines and gap like panel lines and such. It seems like no matter how many times i've checked the masking tape to make sure it's firmly attached, the same problem happens. How do i avoid this as well? Really need help! Thanks!

Veyron
09-13-2006, 08:01 AM
I'm not really sure what you mean about uneven marks....but as far as paint bleeding under the tape and running down panel lines... the best thing to do always on a multi color paint procedure is spray on a light coat of clear to seal the tape before you go to the next color.

ARTA_NSX
09-13-2006, 08:16 AM
Oh! clear coat! Thanks for the important tips! But wont the light coat makes the paint blur? i mean some mist or droplets might stick to some other surface in the process?

By the way, wat i mean is, the smooth surface which the masking tape sticks to always become blur (leaves uneven surface) or lost the shine after the tape is removed.

Veyron
09-13-2006, 08:20 AM
Oh! clear coat! Thanks for the important tips! But wont the light coat makes the paint blur? i mean some mist or droplets might stick to some other surface in the process?

By the way, wat i mean is, the smooth surface which the masking tape sticks to always become blur (leaves uneven surface) or lost the shine after the tape is removed.

As long as you are using alike paint types there shouldn't be any blurring.

I never get the uneven surface problem but then I always use Tamiya masking tape which has never given me problems.

ARTA_NSX
09-13-2006, 08:29 AM
I'm using tamiya's masking tape as well. How long do you leave it to dry before you do the masking?

ZoomZoomMX-5
09-13-2006, 08:55 AM
I'm using tamiya's masking tape as well. How long do you leave it to dry before you do the masking?

Tamiya tape (along with others) will cause damage to any paint that isn't thoroughly dry; paint may be dry and polished out on the surface (especially lacquers), but it might not be dry beneath and the tape exascerbates the problem, trapping the solvents and causing the tape pattern to etch itself into the paint. One week of drying at ambient temperatures isn't enough if you are having this problem. I also use the clear paint to seal the tape edges.

ARTA_NSX
09-13-2006, 09:06 AM
So how long do i have to leave it to dry before masking ? Also, if i was to paint acrylic over lacquer, should i use acrylic clear coat for that masking tape sealing?

ZoomZoomMX-5
09-13-2006, 09:23 AM
So how long do i have to leave it to dry before masking ? Also, if i was to paint acrylic over lacquer, should i use acrylic clear coat for that masking tape sealing?

I can't tell you how long since I always use a dehydrator. Paint a body, and test with tape. One week, two weeks, three, a month...find out for yourself.

Acrylic clear is okay over lacquer if spraying acrylic as a second color, but I only do that for black window trim. For a second color I'd recommend sticking with the same kind of paint as the base coat. Acrylic gloss paints can be very tricky to lay down and they can take forever to dry. Lacquers/enamels are far easier to deal with.

ARTA_NSX
09-13-2006, 09:28 AM
Hhm... maybe i should leave it a lil' longer... what dehydrator are u using anyway?

ZoomZoomMX-5
09-13-2006, 10:22 AM
I have a cheap no-name dehydrator w/o fan or motor, similar to Ronco. Any will work, though keep the temp. at 105 F or below. You might have to cut out the rack centers or make spacers tall enough to fit a body or paint cans.

ARTA_NSX
09-13-2006, 10:36 AM
i might have problem getting the dehydrator.. sigh.. w/o the dehydrator, how does it take for lacquer to dry out completely?

MPWR
09-13-2006, 03:26 PM
Ah, the great imponderables-

How long does laquer take to dry? How many roads must a man walk down? Can God make a tree so big he can't hear it fall in a forest (or something)?

I have bodies painted with automotive laquers more than a year and a half ago that if closed in a container for a day or so reek of solvents- appearently still outgassing now (but all were hard enough within days to polish). For a real answer, I think you need a much greater understanding of chemistry than I possess.

And I've had at least one Tamiya laquer finish eaten by Tamiya tape (although it had been painted pretty recently- a couple of days I think). I guess the best real world advise I can give is be patient and be careful. And you will likely never find anyone who will tell you "yeah, a so&so paint finish is completely dry after so many days at whatever temperature". Waiting periods are just guidelines, never guarentees.

Some more useful advise might be to minimise the amount of time that the masking tape is on the paint. Put it on, spray the next color, then get it off. A couple of huors is a good period of time to shoot for, overnight only if you have to- and certainly not longer if you can at all avoid it. Again, just guidelines, but the shorter the tape is in place, the less time it has to eat the pant underneith.

Jay!
09-13-2006, 03:55 PM
For the 2-tone paint work on the Prelude I've recently posted, I used Tamiya TS sprays over Tamiya primer and Tamiya masking tape (wow, do I sound like a whore!), but I live in an extremely warm, dry climate.

Ambient conditions in my work area (my patio) are probably better for drying paint than Bob's dehydrator. Through most of the summer, it was ~110° with less than 5% humidity. I actually have a dehydrator too, and don't even plug it in anymore. I just use it to hide parts from dust.

But for the tape specifically - It was not on the car body for more than 4 hours, max. As soon as I was done masking, I started spraying, and as soon as the paint had tacked up pretty well, I pulled all the tape back off.

ARTA_NSX
09-13-2006, 09:16 PM
But, to take into account of the time needed for the mask to stay on, including spraying on the light coat to seal the masking tape then wait for it to dry AND the actual spraying of the 2nd colour, wouldn't it take more than 4 hrs? Is there anyway i can get away w/o polishing it again? I wont be able to get the same shine as i have now after my polishing skill.

Hmm.. maybe i should let it dry in the sun more..?

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