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Best way to mask off the doors?


theianmonster

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Climb out the rear hatch... and tape it off last.

OR

I use 2" tape around the inside with 1" overlap. Have your paper cut close to size and start at the top sticking it to the exposed tape. Two sets of hands make this easier. From the top go around the door trimming and sticking, you don't have to do more than touch the paper to the tape.

Really the easiest way is to have the quarter windows and the windshield removed and work though the openings to get to the back side to push on the tape. When closing up the windshield opening and the quarter windows I tape from the outside since all of that will be covered with glass and rubber and a little of the old color won't matter, at least not to me.

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Depends on where your paint break line will be.

You only need to mask off what you don't want painted. That's obvious. What isn't obvious is if you are doing a color change or not. If you are, and you're only painting door jambs to match color, do you want the paint break line under the weatherstripping or at the edge?

Masking doors also implies that you have removed the doors, or are planning to keep opening and closing as you paint the jambs first, then block out the overspray on the outside or if you're going to blend it in while it's still wet.

Are the doors gutted? If not, are the door panels still in place? (You'd be surprised how often people try to REALLY short-cut the process for a good job.) Remember, you can mask it, but once you get paint on the masking, you have to be careful of what comes into contact with the masking. You don't want to spend a bunch of time masking the door panels if by doing so, the first time you close the door, in order to walk away or between shooting an exterior coat, you smudge the jambs because of the way you masked.

All of these "if's" are based on your experience in geting around the paint booth, and knowing what sequence to paint in.

Personally, if you're shooting jambs to match color, shoot them separate, allow to dry after having masked the EXTERIOR surfaces of the car. Allow paint to get to the edge. After paint's cured, remove masking, final prep the exterior and mask the door CLOSED using foam or 2" mask that you push up into. A paint line on the edge of the door is extremely easy to hide, and is usually invisible.

Now presuming that you haven't removed the quarter windows:

As far as masking, if you're hiding the break line in the seam under the weatherstripping, as Lance pointed out, use 2" Masking taped to the INSIDE of the weatherstrip flange edge. Lay your masking paper using the edges for straightness and push up onto the exposed masking adhesive. To trim edges, push lightly on the mask allowing the sheet metal edge to stand out and using a sharp blade trim the excess.

If you're hiding the break line on the exterior face of the weatherstrip flange, this time use the masking on the EXTERIOR of the sheet metal, putting the adhesive side TOWARDS the interior. This method allows for full sheets of mask to be used, with very little, if any trimming.

When "closing", you're basically "closing the flap" on the access hole you had been using to apply pressure front and back to the mask and the adhesive tape. On the "flap" fashion a loop of masking tape, and use this as a "handle". Pull on the handle - gently- and it will usually hold the flap up against your prior tape well enough that you should be able to exert at least ~some~ pressure. Top the seam off with a quick strip from the outside and you should be fine.

Enrique

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A paint line on the edge of the door is extremely easy to hide, and is usually invisible.

The guy that painted my car did the door jambs first and let them dry. He then used a neat trick to hide the line. Instead of using the tape flat as you normally would he rolled the tape into a loop so that there was no hard edge. Is that the way you do it?

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The guy that painted my car did the door jambs first and let them dry. He then used a neat trick to hide the line. Instead of using the tape flat as you normally would he rolled the tape into a loop so that there was no hard edge. Is that the way you do it?

I'm not sure what you mean.

Masking techniques are both taught/learned and developed/modified. That may sound confusing as all heck, but let me ~try~ to explain.

The "hard" edge that the method I described, and that you refer to, is simply that there will be a DEFINITE start/stop break line between the new paint/primer and the unpainted/old paint. There are times and situations where this is the simplest and quickest way of blending / mixing / hiding the paint break line. Because of it's simplicity/speed this is, in my experience, the method most commonly used.

To further explain it, let me offer this example:

To paint a flat piece of sheet metal on BOTH sides AND all the edges, without leaving marks or "imperfections" in the paint, it would be easiest to paint one side first, and then the other. If you could rest the piece on a stand, you wouldn't even need to mask the back side while you painted the front side. It is when you painted the BACK (or vice versa) that you would have to be careful of the paint break line.

(Let me digress and explain why.)

Paint after being blown out of the paint gun is "wet" for a given period of time. As the solvent in it evaporates it hardens. All obvious items so far. However, at the extreme edges of your paint gun pattern, you have the lightest and thinnest of paint coats, and the "driest" of the paint drops (because of the distance from the gun, and the fact that they don't blend/mix with other drops previously or additionally sprayed there). The further from the gun, the drier the paint drops are, to the point that at some point they become dust. Some of these drops are wet enough to stick, yet too dry to blend in with other drops that they land on top of and beside of. These drops, are what are referred to as a "Dry Line". They aren't too hard to get rid of, if it isn't a "Finish" surface (i.e. primer, under weatherstrip, or the masking material), but they are a literall ~B!TCH~ on a true FINISH surface.

On a LACQUER paint job, the dry line is almost unavoidable. The lacquer dries so quickly that it isn't unusual to see a dry line. Even using different thinners (Hi/Low Temp, Hi/Low Humidity), it is very difficult to eliminate a dry line. This is why you almost always wet-sand and polish a lacquer job to get the best shine.

On an ENAMEL paint job, however, the paint is viable (wet) for a longer period of time, and as such, with the proper paint technique you can eliminate the dry line ... OR ... hide it. (I've painted Tractor Trucks (10 wheel, 3 axle), both flat nosed and with hoods, and been able to blend or hide the paint line.) This does entail using the proper Reducer for the temperature and humidity, and also some very spirited running around, but you ~CAN~ do it. I'll wager that most painters would rather shoot another complete coat of paint rather than waiting to sand/polish a dry line out of an enamel paint job. (It can take as much as a couple of weeks or more, before the paint is hard enough to buff/sand/polish.)

With PRIMER on the other hand, a dry-line is not as problematic. You will ~usually~ be wet-sanding the primer anyhow (for a completely smooth finish). However, if you are using a Primer/Sealer or a non-sanding Sealer you also want to avoid a dry-line.

So, back to the masking......

In the example of the flat piece of metal, the paint that is being blown at the piece, will at the edges of the piece, curl back and impact the lower edge of the piece. When you're shooting the first side it doesn't make much difference since you'll be shooting more paint over the dry line there, BUT, when shooting the last side....you need to protect the front.

This is where the different techniques for masking come in.

I've seen a straight line break, as I mentioned, this is simply masking applied to the side you don't want paint to touch. This forces the painter to paint past the edge and push the dry line onto the masking (even if it's on the other side). When dry, the transition between the final coat and the previous coat is next to imperceptible. There CAN be an edge, if you apply the paint very thickly, but there are even techniques in removing the masking that will allow this edge to even out, OR you can "knock" it down. Knocking it down is where you literally sand/buff it off.

There are other techniques, which may be close to what your buddy did. I've seen masking tape bent at a 90° and taped to provide a "fence" which causes the air flow to swirl and not allow much of the paint to stick. Some does, but the amount is reduced significantly. Putting a foam tube, or as your friend did, a rolled piece of masking tape, also creates an air spoiler which won't allow the paint droplets to blow in there. (Note: the painter would obviously NOT aim directly at any of these masking lines, as that would defeat them.)

In fact, you can buy foam in long tubes with adhesive on one edge to put on the inside edge of the door jamb. This allows some paint to creep past the obvious sheet metal edge, yet fade away as it gets closer to the foam. Additionally, the foam prevents paint from blowing into the jamb area with the door / hatch / hood in place.

Hope this helps.

Enrique

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In fact, you can buy foam in long tubes with adhesive on one edge to put on the inside edge of the door jamb. This allows some paint to creep past the obvious sheet metal edge, yet fade away as it gets closer to the foam.

As always, thanks for the excellent and detailed explanation. I've never attempted to paint myself yet it's obvious that quite a bit of experience is required to do the job right.

The above quote is exactly what my painter did except he used tape formed into a roll lengthwise instead of a foam tube. The painted faded away as it got closer to the tape. I guess he was either too cheap to use the proper supplies or has simply been doing it this way for 30 years and before they had the foam tubes.

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What's the best way to mask off a door, when you've masked one side from the inside, but if you mask the other side from the inside, you're stuck inside, haha. Any ideas? I need to know pretty quick guys.

I know this is a little late, but I did the rear hatch, passanger door and front windshields first, and taped from the inside. THen for the drivers door I all the taping from the inside (I used old newspaper) but the last little bit in one corner had to be taped from the outside. I just used plenty of tape and made sure it was sealed tight ...

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