How long should I wait until Removing masking tape?

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mr.T

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After using masking tape to mask off an area, how long do you usually wait until removing the tape? Should it be removed right away or is it preferable to wait until the paint is dry? I have tried both ways. I seem to get cleaner lines when I remove right away but I also have difficulty getting the tape up without touching wet paint that I shouldn't. Opinions?
 
I like to let the paint dry to the touch and then pull off the tape. I have used a hair dryer or let it heat in the sun to pull it off to avoid tearing. I also like the smooth to the touch so I'll go the extra elbow distance and use 1500 grit wet/dry and lightly sand. After the had ridge from the tape line has been almost knocked down, I switch to 2000 grit wet/dry load up on water and start lightly sanding again.

There are probably others that have other paths to the same goal but that's how I do it. And yep, it drives Ben up the wall when I am working to get one finished nicely.

...Howard

P.S. The sand paper I picked up at AutoZone. I think it was in a variety pack.
 
I've heard some people suggest waiting until the paint has set, but not dried to the touch. If you wait until the paint drys to touch, sometimes peeling the tape off causes sections of paint to peel/chip off.
 
I've heard some people suggest waiting until the paint has set, but not dried to the touch. If you wait until the paint drys to touch, sometimes peeling the tape off causes sections of paint to peel/chip off.
I have had the opposite problem: not waiting long enough caused the paint to tear and peel. I usually wait anywhere from 4 hours to overnight before removing the tape. In a couple of cases last year, though, I had to sand and repaint twice with one rocket and four times(!) with another because I kept getting peel-offs. Both occurred when I was using New Formula Krylon, but I have used the same stuff on other rockets and didn't have this problem. I would up waiting two full days before removing the tape from the first rocket, and waited four days before removing it from the other.

When I have tried to remove the paint mask and tape while the paint was still wet, I have gotten either mini-splashes of paint along the line, or bleeds across the paint line, or both. I haven't tried to buff down the ridge of paint at the mask line after everything has cured hard, but it's not a bad idea. I may start doing that when I resume painting in a few months.

MarkII
 
I tend to pull it off while the paint is still pretty much wet. I arrange the tape to allow this. I get less of a hard ridge that way, and almost never pull up the paint.

Second choice would be four or more hours drying first.

Of course, this is only true for current rattlecan paint; other paints might need other techniques.
 
I tend to pull it off while the paint is still pretty much wet. I arrange the tape to allow this. I get less of a hard ridge that way, and almost never pull up the paint.

Same here... I paint, walk inside, sit down and peel the tape right away... No waiting.
 
I typically wait about 20 to 30 minutes before I remove masking tape. Prior to peeling the tape back I run my hobby knife with a new blade lightly and carefully along the painted edge. Then I pull the tape back in a steatdy smooth motion. I hope this helps.

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The longer you wait, the more time the paint has to creep.
Paint creep? What is that?

I remove all forms of masking and tapes as soon as possible.
I always get messed up paint jobs when I try that. With that being said, though, let me add that I do prefer to remove the masking sooner rather than later. I don't know why I had so many problems with those two paint jobs that I mentioned before, but the only way to solve them was to really wait in those two cases. I did not see that happen in my other paint jobs earlier in the year or in any since then. (I only began getting serious about painting my rockets last year, and boy, do I ever have a backlog! :rolleyes: ) If I could get the tape off earlier without either making a mess or getting run-overs, I would do so.

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MarkII's Painting Dictionary:
Run-overs: when you remove the tape to reveal a clean mask line, only to see little fingers of the second color run over the line and flow into the previously masked area.
Related to, but not the same as splash lines - tiny whiskers of the second color that splash across the mask line when you pull off the tape while the second color is still too wet.

I've seen plenty of both!
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Question: I usually "undercoat" the second color by giving the uncovered area, especially the mask line, a shot of the base coat, and then I apply the second color as soon as it is safe to do so. Obviously, then, I can't remove the tape while the paint is still wet, because some of it has had to dry before I finished applying the second color. So if it doesn't matter that I have had to leave the tape on while the "undercoat" dried (or at least got well "set"), then why is it important to remove the tape while the second color is still wet?

MarkII
 
i am assuming paint creep is where the paint seeps under the tape and you dont get a nice line... it happens alot to me probably cause i use way to much paint.
 
i am assuming paint creep is where the paint seeps under the tape and you dont get a nice line... it happens alot to me probably cause i use way to much paint.
During my long and sometimes difficult "rattle can apprenticeship" (before I got competent enough to attempt to paint my "good" rockets), one thing I learned very quickly was that if the tape wasn't down good and tight and the mask line wasn't well-sealed, it didn't matter whether you pulled the tape off right away or waited a couple of hours - you got bleeds (paint creep) either way. After I switched to using quality masking tape (Tamiya) and undercoating the second color with a light coat of the base color, paint bleeds became a thing of the past. Also, when I began repeatedly "misting" the rocket with paint (each "coat" consisting of several "mistings"), rather than spraying on distinct individual coats, it helped a lot too with preventing that problem as well as others.

At this point, let me recommend an excellent resource for the novice painter: John McCoy's (a k a Micromeister's) Painting Tech Tips, available at the NARHAMS web site. These detailed essays, packed with information were absolutely essential in demystifying the whole process for me. The biggest things that I got from reading them were 1.) that anyone can learn how to put really good finishes on their rockets; 2.) that putting on finishes is a multi-step process that involves simple, but essential steps and techniques, and 3.) that base prep is everything. Let me repeat that last point: base prep is everything. Read the Tips and you'll see why. I have since moved on to adapt and modify the techniques (as any good student should) to suit my own style and work process, but these essays were my foundation. I highly recommend them to any new rocket builder.

MarkII
 
During my long and sometimes difficult "rattle can apprenticeship" (before I got competent enough to attempt to paint my "good" rockets), one thing I learned very quickly was that if the tape wasn't down good and tight and the mask line wasn't well-sealed, it didn't matter whether you pulled the tape off right away or waited a couple of hours - you got bleeds (paint creep) either way.
MarkII

Exactly. The best way to get clean lines is to have the edges of the tape sealed completely. I always give my tape a good rub-down right before I paint.

On the subject of removing tape, if you pull off the tape slowly and at a sharp angle, you'll get cleaner lines. (By sharp I mean the tape is almost touching itself back to back.) This gives a shearing effect and "cuts" the paint.
 
I remove the tape right away, slowly, and (like Intruder said) at a very sharp angle.
 
I remove the tape right away, slowly, and (like Intruder said) at a very sharp angle.
You don't get bleeds over the mask line right AFTER you remove the tape, when the second color is still quite wet? Maybe it's just me, then. My second colors don't stay put until they have sat awhile. I don't spray heavy (in fact, I "mist") and the colors don't appear to be runny, but yet, I'll still see run-overs occasionally if I remove the masking before the second color has had enough time to start bonding to the layer underneath it.

BTW, I get the tape off just fine, quickly, with no hesitation, pulling it off at a sharp angle.

MarkII
 
If the paint is still pretty wet, you have to balance moving fast enough to "cut" the paint, and not moving so fast that it splatters or drags.
 
I hear folks talking about sealing the tape edges with a coat of base color all the time.

Please! think about is a moment. Any paint you apply contains Pigments, Pigments have dimension and mass. This means your Paint dam (build up of paint at the tape line) is going to be MUCH thicker then if you used a CLEAR paint compatable with whatever paints your spraying.
When I'm doing multi color Scale models it's a big help to use a matte or satin clearcoat as a tape edge sealer between color coats.
Be sure to burnish down the edges of all masking before this quick clear application. This ensures the taped edges are sealed to the underlying substrate and provides a minimum edge for build up and prevents seeping, creep or whatever you'd like to call it.

Why matte or flat? Because it flashes off the solvents quicker then gloss. preventing damage to the newly applied color(s) below and drying very very quickly.
For this type operation I normally use Testors dull coat, just because it's what I developed the technique with. Possibly other satin or matte clears will work but I can't say as it's not what i've used. This process works well with old formula Krylon paints, Testors, Pactra, colorworks, Duracolor, Duplacolor, Rustoleum, and lots of other rattlecan "brands". As a matter of fact to date I haven't found a rattlecan this technique hasn't worked with other then New forumla Krylon that doesn't even like itself LOL!!!

How do we remove maskings almost instantly after applying the next coat? 1) By providing pull tabs folded into the tape at specific points. These are usually set-up so they fall behind the forward edge line of whatever masking material your using.
2) Use of tweezers to pick-up your pull tabs.
3) Always pull tapes nearly back on itself as it's being removed, turning the model on a mandrel or paint stand stick away from yourself as you pull the tape off.

Paint Dams:
Every single type and color including clears leave some type of paint dam at the masking edge. These can easily be nearly completely removed with a little wet sanding with an Ultrafine Grey Scotchbrite #7448 sanding pad. used with LOTS OF Water.
I usually work over a 5gal bucket in the basement with a terry towel draped over the open top. Dipping the pad in fresh water to keep it sopping wet as I lightly circular sand the buildup areas. Rinse often with clean water and feel the area as you go. This well result in a completely smooth transition between colors and layers. It's also possible to smooth out hand painted lines and details the same way making your entire painted finish appear to be one flat surface. All thats needed is a coat of polymer (Nu-finish) or wax to keep it shinny and clean:)

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Excellent suggestions, Micro. Thanks for sharing!
 
All good advice John, but I have a question: doesn't Testor's Dullcoat impart a yellow cast to everything? I tried applying it to a set of decals once, which caused them to be totally unusable. I would be very reluctant to apply it to any paint, and quite frankly, I can't think of of any good use for the stuff at all. (Oh, wait - there's one: making your rocket look like it has been sitting up on a shelf for 30 years.) The new Krylon UV-blocking clear coat looks promising, though, and it might be a better choice to employ for that technique.

I have no problem grabbing the tape and pulling it off cleanly (I emply pull tabs, etc.). I just haven't had very good results whenever I have tried doing it when the second color was still quite wet.

I don't get very much in the way of paint dams anymore now that I apply the colors in thin coats. Learning to do that was probably the biggest breakthrough that I have made in spray painting models since I learned about base prep. I don't always use it (or need to) but I also use a liquid polishing compound (3M Scratch Remover, available at auto parts stores) sometimes to buff out rough areas in the paint job (almost unavoidable when you are painting large cylindrical tubes with a spray can), and this can help with smoothing down the line between two colors in the paint job. (I learned that trick from one of your Tech Tips. :D ) It also requires the application of a fair amount of elbow grease, but it works. I have even used it to salvage an orange-peeled paint job that I otherwise would have had to sand off. (It smoothed down the rough "peel" texture, so that I could just go ahead and apply another coat of paint onto it, and have the result be as smooth as if the peel had never happened.)

Just as with your Scotchbrite technique, you do have to keep the rag wet (in this case, with compound). Along with helping to float out the paint residue that you are removing (even with polishing you are removing paint), the moisture helps to keep the surface temp of the paint down below the point where it begins to really soften up. The friction from the polishing produces a surprising amount of very localized heat just under the point of contact, and this can lead to things like getting tiny pieces of the Scotchbrite (or ultra-fine steel wool, another polishing aid) embedded in the paint. (I speak from experience here...)

Applying auto paste wax to the completed (and well cured) paint job is something that Vern Estes was recommending all the way back in the early '60's. It's still a real good idea, and someday I'm going to do it, too. :rolleyes: :eek:

MarkII
 
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All good advice John, but I have a question: doesn't Testor's Dullcoat impart a yellow cast to everything? I tried applying it to a set of decals once, which caused them to be totally unusable. I would be very reluctant to apply it to any paint, and quite frankly, I can't think of of any good use for the stuff at all. (Oh, wait - there's one: making your rocket look like it has been sitting up on a shelf for 30 years.) The new Krylon UV-blocking clear coat looks promising, though, and it might be a better choice to employ for that technique.

Mark:
Testors Dullcoat; doesn't impart a yellow cast but has 0% UV additives similar to just about every other Spary can Clear with the exception of Krylon UV Clear and yellows badly very quickly under any UV source indoor or out.
However: it doesn't matter one little bit in this application as it's used only as a sealer between other coats of pigmented paint anyway. Once the tape is removed there is no part of the Sealant exposed to uv. but it dries to a film about 1/2-1/3 the thickness of any pigmented paint.
Actually this is one of the very best uses of Testors Dull coat.
Again: I do NOT recommend clear coating any model with any Clear rattlecan clear other than possibly 1305 or 1309 Krylon UV resistant clears. the jury is still out on them as well. but as a masking sealer between color coats it's a very good material. I thought this subject was covered in my Tech-tip series?? I guess i'm gonna have to go back and check , it's really a pretty important point in finishing multi-color models.
 
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At our house it generally goes like this:

First coat, we leave the masking tape on.
Second coat we take it off when it's dry to the touch--at least within 24 hours.
Third coat, carefully take the tape off within an hour.
Buff off any overspray with a Mr. Clean Magic Eraser.
 
Mark:
Testors Dullcoat; doesn't impart a yellow cast but has 0% UV additives similar to just about every other Spary can Clear with the exception of Krylon UV Clear and yellows badly very quickly under any UV source indoor or out.
Well, I sprayed two sets of decals with it to coat them. (The decal maker states that their products need to be coated before use. They recommend another product, but I was out of it, so I tried using the Dullcoat.) One set already had two coats of the recommended product, and only needed a light third coat, so that is what I used DC to give it. For the other set, I used DC for all three coats. Big mistake. The first set was still quite usable, but the clear portions of the decal show a definite yellow tint against the white paint that they are adhered to. The tint was apparent as soon as I slid them off the sheet and started applying them to the rocket. This was during the winter, and the decal sheet had not been outside and had been kept in a light-proof envelope right up until I used them. The completed rocket sits on my desk in a sunny room in my house now; I have brought it to several launches and I have even flown it a couple of times. The tint remains the same as when I applied the decals almost three years ago; it has not darkened at all (and it certainly has not faded, either).

I wish that I could say the same about the other set, the one that received three coats of Dullcoat. After I coated them, other things came to the fore and took priority, so I didn't apply them. I put them back in the packaging that they were shipped in (acetate sleeve, inside a cardboard insert, inside a cardboard Priority Mail envelope). Last year I took them out to check on them, and I was quite disappointed to find that during their storage, they had yellowed to the point of being nearly opaque.

So those are my experiences with Testor's Dullcoat, and they are why I don't have anything good to say about the product.

However: it doesn't matter one little bit in this application as it's used only as a sealer between other coats of pigmented paint anyway. Once the tape is removed there is no part of the Sealant exposed to uv. but it dries to a film about 1/2-1/3 the thickness of any pigmented paint.
Actually this is one of the very best uses of Testors Dull coat.
You are right about that, though; what was I thinking? I don't recall seeing the technique of sealing the tape edge with Dullcoat mentioned in your Tech Tips, but it has been a couple of years since the last time I read them. I don't have any issue with your basic recommendation, although I haven't tried it yet. It's just that when I saw you mention Dullcoat, it set off alarm bells in my mind.

Do you have any data to back up the claim that a layer of clearcoat is only 1/2 to 1/3 the thickness of an equivalent formulation of pigmented paint? Doesn't that depend very much on how each type of coating is applied? And wouldn't it vary (a lot) from one application to the next? Also, assuming that you could standardize what a "coat" means (and have that definition be meaningful anywhere in the real world outside of the lab), would this mean that transparent, or candy-colored, paints fall somewhere in between in terms of the "thickness" of their coats?

MarkII
 
That's an awful story Mark! Wow! in all the years i've been spraying all kinds of paints, finsihes and clearcoats that's got to be the worst story i've ever read!
You must have had a very bad or extremely old can of Testors DullCoat for that kind of result.

I've used testors gloss and dullcoat on plastic models for about 40 years. I assume the other product your not devulging for some reason is Krylon 1301 Crystal clear. which I highly do not recommed on any Decal for the same reasons plus it attacks the decal if not applied very very sparingly. While both do in fact yellow badly over time, it's been one of the ways i've saved OLD (30yr old) and older decals for use for ages, until the introduction of Krylon UV-resistiant clear, it was testors gloss and dull coat or NazDar Decal Clear silkscreen ink, that as been used on nearly all my custom made decals.
To be sure and let me be perfectly clear here again: I don't recommend ANY clear coat for use on completed models....nearly All yellow. But on dark color model or over alps printed decals it's usually OK. Personally now that Krylon has a UV resistant clear that is all I use on my alps printed decals reserving the dullcoat for tape sealant work.

Of coarse I have data; Do you think I just pull this stuff out of the air? You seem to be a bit of a doubting Thomas there Mark. I simply didn't feel its at all necessary to go into all the whys and wherefores in this thread as we're getting a good bit off topic. It doesn't take a lot of imagination to see that a clear dried paint film will be thinner than one containing color pigments with or without flattening agents. In any case the dried film will be at least .5 - 1mils thinner simply due to the lack of mass from the pigments involved, after all; Every paint is a mixture of vehicle(clear or white base), thinners and pigments. This can translate to a considerable difference in paint dam depending on how many layers are applied but even the thinnest WILL be thinner in clear only.
And that's what we're trying to get across here; Don't use a pigmented color to seal your masking Tapes. Use Any Clear to reduce the amount of paint dam and also save a tiny bit of excess mass in the process.
 
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No, John - actually the other product was Microscale Liquid Decal Film.

I stated this in my previous post, and let me repeat it here: I have no problem with your recommendation. I think it is a good one, and I plan on trying it when I resume painting in the spring.

Before I go on, let me also clear up something else. I have never advocated putting any brand of clearcoat onto a completed paint job or over applied decals. That's a straw man that you created entirely on your own. What I did suggest was to wax the rocket with automotive polish after everything was done.

The following is a very nit-picky point, and it doesn't change anything about your recommendation. Basically, I think that your recommendation is good, but not for the reasons that you state. Anyone else besides John who doesn't want to read a trivial little discussion about a point that doesn't actually have any practical consequences can stop reading this now.

OK, here's what I'm thinking:

Yes, someone might be able to demonstrate that when they are applied on identical surfaces under identical conditions, precisely metered amounts of equivalent formulations of clearcoat and pigmented spray paint produce coatings with slightly different thicknesses, but that finding will only hold true under tightly controlled laboratory conditions. In a real world scenario, spraying either one from a typical spray paint can, all anyone has to do is linger for a fraction of a second too long over a particular spot while spraying, or press a fraction of a gram too hard on the spray button, to negate any differences that there might be in the comparative thicknesses of these two types of coatings.

But it doesn't really matter, anyway, because an actual difference in layer thicknesses is likely to be produced for an entirely different reason. As a way of explaining this other, more likely reason, let's look at what someone is trying to accomplish by spray-painting an object with a pigmented paint, versus spraying an object with clearcoat.

When someone is applying actual paint (with pigments) to an object, the person is trying to change the surface color of the object. When the person uses spray paint, the new color is deposited on the object's surface in minute drops of varying sizes. In order for there to be any perceptible change in the surface color, there has to be enough of a build-up of the drops to cause them to overlap and completely cover the surface. Any particular spot on the object's surface also usually needs to have a few layers of those drops piled up on it before it appears to change color. In practical terms, the person has to keep spraying on more paint until he perceives a change in color.

This is true even if the painter is only trying to put on a very light coat, or is painting over one coat with another coat of the same color. In either case, he has to keep spraying until he can see that some desired amount of paint has been applied.

Now think about what someone is trying to accomplish by spraying an object with clearcoat. The person is not trying to alter the surface color of the object, because clearcoat has no color. The person is merely trying to insure that the surface has a layer of clearcoat on it. A little bit of clearcoat does not look very different from a lot of it, and the person isn't expecting to see any change in the appearance of the object. He will likely to consider his job to be done when he knows that he has put a spray of clearcoat over every portion of the surface that he wants to coat.

So the conclusion is that when a person is spraying something on to seal the edge of the masking tape, it is likely that he will simply spray on less if he uses clearcoat as opposed to spraying on another layer of the base color. It has nothing to do with whether or not clearcoat, under ideal, controlled conditions, leaves a thinner coating than paint. It has everything to do with the fact that the person will probably just put on less of the clear spray.

So your tip is a good one, but not for the reason that you stated.

MarkII
 
Well Man Oh Man... I wish I knew the best way to say Mark without sounding like i'm trying to be a wisesguy which I'm not: What your thinking, Though it may "Seem" logical is about far from what actually happens while someone...Anyone is applying sparycan paint as one can be. I almost don't know where to begin.

Fact is; The wet material we are applying to whatever substrate isn't what makes the surface of the object change color. It's the platelets of pigment suspended in the vehicle and thinners...After they settle to the surface of the substrate, interlock and dried with the binder(base). This is why most "paints" dry a shade or two darker then when wet. WHY? because we're looking through and seeing light coming through the clear & thinners between the tiny platelets that haven't settled and interlocked yet. Further this is why its almost impossible to get an "Even" coat of transluscent (Yellows as example) or transparent Candy coatings by "eye" when wet.
Nearly all the thinners and much of the vehicle evaporates away leaving and interlocking overlaping platelets of pigment forming the dried film adheared together with a small amount of very thin clear vehicle(Binder base). This is what heppens in Paints, Inks are a completely different chemistry...but let's not muddy the waters anymore then needed.
Fact is; The more paint we apply the Thicker the dried film will become and/or to the point of causing a run. But it is only thicker because we are ADDING additional layers of pigment platelets and vehicle on top of one another. Clear Coatings remove the pigment platelets completely leaving only the thickness of the vehicle (binder base) which by it's chemical nature dries about 1/3 or less in thickness of the pigment platelets themselves.
As we can see this has very little to do with How or Where the material is applied. It is automatic regardless of who or how the material is applied.
Clear dried flim is by it's chemical nature, REGARLESS of how thickly applied, Thinner then any amount of Dried Pigmented coating. Unless of coarse you apply successive coats of clear after each is allowed to set to tac.
Turely Mark: it's the Paints chemical makeup and physical properties, Not who or how applied that make the difference in dried film thickness. and why just about any clear can NEVER dry to the same film thickness as any pigmented paint.
Hope this helps explain the process. but my tip stands correct exactly for the reasons orignially stated.
 
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