Masking problem

I have had good and bad luck with masking. I would be most thankful to those that could share the good tips on masking from one color to another. Pulling paint off after a second coat that looks great is most aggravating. I have used the same tape on other jobs that did very well. But this time the same tape pulled off the base white coat in spots. I used Brodak med. silk with Brodak dope and sealer. Sprayed on 3 coats of Ultracoat primer, wet sanded and two more coats of primer. dryed 3days. Then 3 coats of Ultracoat White. Let dry 3 days, then a light sanding. It did seem that the white was dry after the 3 days, but maybe I should of waited a week, before I masked for the Ultracoat Red. As I pulled off the tape, the white came off in quite a few areas. But didn't on the maskind lines. That looked ok. I used the vinal greenish color tape, and some electrical tape, both stuck to good to the white when I pulled it. What tape is recommended. Is 3M blue painters tape the best? And where am I going wrong.

Hi Greg
I am quite bald for the same reason!

I found " Masking tape" and some low tack tapes
in Graphic supplier shops to be very good
They also do a gel but I found this to be
unworkable for straight lines.

There are many here who are real experts on this
subject , while I am a beginner

Best of luck with further efforts.

I am going to look at both the tape and the Ultracoat. Is this an enamel or epoxy type stuff? If so, and you use a dope base under it, even though Brodak dope is quite fast in drying, there will still be an element of time needed for it to "gas off" which takes a few weeks to virtually complete. This could be the start of your problems. If you use dope from start to finish, it can gas through. If you use something that skims over, the top layer can keep the bottom layers of dope from properly curing and it could end up just peeling off. So, that could be problem number one.

Next is your tape. There are some low tack tapes available. But electricians tape and some masking tapes are quite sticky. They work fine for house paints or paiting your car, but on our airplanes where the bottom layers are still curing, we need something a bit less tacky. So, one trick is to take the tape and sort of stick it to your Tee shirt, pull it off, and then apply it to your plane. This takes a bit of the tack off of it so it won't stick down as hard. Then, do not leave it on for any lengthy period of time. Put it on, spray your paint, and pull it off. The shorter the time that it is on, the better. Don't even wait for the dope to fully dry. And when you pull it off, do NOT pull it straight away from the surface. Bend it back so it is bent 180 degrees as you remove it. This puts the least amount of pressure on the surface beneath.

A little heat, like from a $cote heat gun, helps persuade the tape to come off smoothly. I delabel already used packages in this manner all the time, for ebay shipments.

And these labels are really stuck on.

There're lots of kinds of masking tape.
The best ones are made by 3M, and they have lots of varieties.
For masking over paint, varnish, or dope, try #2070 Safe Release Tape.
Don't leave it on more than 2 days.
Don't leave it on for than a layer or two of paint.

Where to find it? Maybe at a good boating supplies place
(somewhere that caters to the high-zoot varnish trade).

Having paid for it, store it carefully in a zip-lock bag.

Its called drafting tape. You can find it at a drafting supply store. Just clear it before you paint and there will be no problem.

I have been using this roll of Scotch, 3M FINE LINE TAPE Part number 0630l- it is 1/4 in. X 60 yards. I have had it or 6 years now. It is a low tack tape and have never pulled paint, yet. It is a vinyl and can be pulled around a curve. I also have a roll that is 3/16. There are small sizes so that you can pull around tight corners. Go to your automotive paint supplier--they detail cars with this stuff.

lenoard has the right idea but you want to take the strip and run it from one end to the other across your shirt or pant leg like pulling a string. just go back and forth 2-4 times and it will be a lot less tacky i have been painting autos for about 35 years and thats the way i do for back tapeing base/clear finish's they are kinda finicky but on silk it should work i really dont know for sure im just getting back into the sport after about 20 years also you might try the fine line thats blue in color and it feels like elec tape but a lot less sticky you just have to watch it sometimes some solvents will let the tape come loose so you have to check it over before every coat of color it also has good turn char for curves it comes in sizes from 1/16 up to 1/2 inch and made by 3m they also make a green translucent tape but i think it would be to sticky for the use your wanting but it is a lot thinner that the blue i would be intrested in your findings on this subject as i have been pondering on useing base/clear on some of my furture projects my son has a p-40 that was given to him and gonna try latex on that one as its gonna be a camo type of paint job

Outlaw

LAST EDITED ON Dec-04-03 AT 00:39 AM (CST)
 
The drafting tape works well, but the 3M blue fineline series #471 vinyl tape works best. You can buy it from any automotive paint store. It's not cheap, about $6-8 per roll (99feet). But, hey! What's a 20 point finish really worth anyways? It is available in widths of 1/8" p/n 6404, 1/4" p/n 6405, 1/2" p/n 6408, and 3/4" p/n 6409. On dope finishes, "de-tacking" it is a good idea. (rubbing on your clean pants) Dope finishes cure thru very slowly. Using a heat gun to remove the tape will most likely soften the paint, making the tape stick more! As a rule of thumb, try not to paint catalyzed topcoats over uncatalyzed (air dry) undercoats. It can trap solvents and cause a paint failure (peeling, bubbles, die back, etc.) If you have to, try and wait at least two weeks or more for it to cure throughly before top coating. I hope this helps!

I have found over the past several stunt planes I have built that a hair dryer (Not a heat gun) softens the tape glue & seems to make the paint separate from the tape. Stencils included. Ted Fancher gave me this tip.

If you are using a dope based primer and use several coats you need to shoot a coat or two of clear after sanding and prior to shooting color. Oddly , most primer sealers need to be sealed before applying color. Shoot a dry color coat ...ie dont let it get a glossy build up. It should be a fairly mat to flat looking finish. Your clear coats will give you the shine.

How you peel tape can lift paint also. If you roll the tape back on itself like a booger and slowly roll it off you will seldom get any lifting of the substrate.

John, I have never thought you had to spray a clear coat or two over the primer before the color coat, never heard of that, or am I reading you wrong? Can you give more details why?

I do this all the time, but forget why. It sure helps to keep the paint from pulling up with the masking tape. The only color I seem to always have some small pulling up with is white. I use the 3M blue tape used in autobody shops. 1/8" to 3/4" stuff. I'll never use the yellow stuff, it just does not do the job.

John, a booger?? Really??

>I have found over the past several stunt planes I have built
>that a hair dryer (Not a heat gun) softens the tape glue &
>seems to make the paint separate from the tape. Stencils
>included. Ted Fancher gave me this tip.

See Post #3. Currell

Here is what I like the best. Not too tacky, but really stays in place and I get crisp paint lines. I found it at a Scale Hobby store here in T-Town. Comes in four different widths. You can buy it with or without the dispenser shown. Great Stuff.

My local paint supply guy keeps telling me that he will "soon" have a new 3M tape that is orange and much more flexible and able to bend around curves. I'll keep asking to see it.....
Kelvin

let us all know when it's avalable. 3M orange? sounds good. the Tamiya looks interesting, I wonder if you can buy it on line?