paint masking

[CanuckSigns]

I have a client who paints large industrial tanks for the petroleum industries, they asked me to supply a vinyl stencil for a tank they are working on, they need to paint a large logo 25' x 60' on the side. They are capable of applying the large vinyl sheets and painting.

I am seeking advise on materials to use, I can buy paint mask from my supplier, or I can buy standard removable vinyl, the vinyl is about 1/3 the price. They will be painting with urethane paints.

Is paint mask needed in this situation or will vinyl suffice?

 

[Johnny Best]

I like the print mask over vinyl. Easier to remove and weed. That is a large area to apply mask.

 

[TimToad]

Even though the 6mil semi-rigid vinyl is cheaper and has removable adhesive, I find the adhesive a little too strong for most applications. I do like it for sandblasting /etching glass.

Mounting and peeling off an area that huge would likely be proportionally more labor intensive to get off.

 

[Gino]

Personally, I'd rather use a pounce for something that size. Easier to put up and faster..... and costs a fraction of vinyl. I would use frisket, if I hadda make an adhesive backed material.

We just did one for a local paint company a few weeks ago. It was 24' tall and about 50' wide. They hadda do it twice, but using a pounce, they only needed one pattern.

 

[vincesigns]

Gino's tip is the way to go

 

[TimToad]

Gino's tip is the way to go

Except that it requires somebody to be able to either cut and fill everything in from the pounce lines, or apply some type of frisket or mask to every edge to be painted.

On a huge curved shape like a tank or with a complex logo that's easier said than done.

It sounded like the OP's client wanted him to only handle the masking off of the entire area and do the painting themselves.

 

[Billct2]

That is a big vinyl mask. Are they spraying it? It would help to see the logo. I have provided pounce patterns that large for jobs on tanks, never a mask.
If they are requesting a mask they must know what they want. So if they aren't open to other solutions, I would quote it using the right material, mask.

 

[GB2]

I agree, if they are asking for a quote on mask then provide it to them that way. Most likely they will be spraying the logo and then the mask is more appropriate, though extremely large and unmanageable. One thing to be careful of is that the mask material you provide is good for the particular paint they are using, otherwise the minute they spray the paint the mask will go flying off the tank.

 

[MikePro]

i've had questionable results using vinyl as a paint mask.... the edges bacon-collar and you get bleed spots. paint mask holds cleaner lines.

 

[CanuckSigns]

So this is a supply only job, the client is on the other side of the country. I spoke to the client and they have gotten these as "big self adhesive sheets" in the past and they apply them themselves, and paint.

The logo is just 6 letters, about 12 feet tall each, and a swoosh, nothing complicated.

I have given them the option and quoted both and explained the differences.

 

[Johnny Best]

So I have a question. If you are making a mask for 12' high letters and it looks like paint mask comes in 48" wide rolls. Are you going to cut these on a plotter or hand cut and then apply transfer paper to them to keep the inside, if any, of the letters in place. Seems like a lot of work plus shipping all of it.

 

[signbrad]

If polyurethane paints are to be used, I always prefer to roll on a liquid mask, such as Sign Strip, and hand cut it, using a pounce pattern to transfer the design.
It may be possible to do much of the rolling from the ground out of a five-gallon bucket with an extension handle on the roller.
If the tanks have many imperfections, such as welds or seams, a liquid mask will leave far fewer paint bleeds than a vinyl mask. False cuts or accidental pull-ups can be fixed with automotive masking tape, as the maskant resists re-adhering once it is lifted from the surface.
I also always lay a masking tape border around the entire area, with very generous margins of white space, before rolling the maskant. Then roll the maskant right up and onto the taped border, two coats minimum, using a heavy nap roller. The dried film needs to be a heavy coat or it will be difficult to remove (which is why I prefer rolling it rather than spraying it. I get a thicker film quicker with a roller).

The big disadvantage of a liquid mask is that it cannot be used outdoors in cold weather. And you must never let the product freeze. If it freezes it will not come off in big sheets like it's supposed to but will have to be picked off in little pieces.
Of course, spraying polyurethanes in temperatures less than 60 degrees is usually unwise anyway. The 2-stage polyurethanes I have used (such as Matthews) require warmer temperatures to catalyze properly. And once the catalyzing stops, it doesn't start back up. It dies.

Brad in Kansas City

 

[signbrad]

So this is a supply only job, the client is on the other side of the country. I spoke to the client and they have gotten these as "big self adhesive sheets" in the past and they apply them themselves, and paint.

The logo is just 6 letters, about 12 feet tall each, and a swoosh, nothing complicated.

I have given them the option and quoted both and explained the differences.

Since you are not doing the actual masking job, it makes sense to simply give them what they want, once you determine which vinyl to use as a mask. Ship it and move on to the next job. If your client is experienced at applying a large mask, they are already familiar with the problems associated with it (for example, cuts not lining up in tiled pieces perfectly. Not all plotters are equal).

Which material to use?

What many do not realize is that types of vinyl react differently when used as a mask for polyurethanes. Polyurethanes, or urethanes, are paints that generally use very aggressive solvent systems. We have found out the hard way that some vinyls (Gerbermask is one) leave adhesive residue behind when used as a mask for these paints. Other vinyls leave little or no residue. Sometimes, the length of time the mask is left on the surface after spraying can make a significant difference, too.
Ideally, send the customer the material they have used in the past. If they can't tell you what it was, I would experiment first. I would not use price as the only determining factor. If the material you sent does not work well, they may blame you whether you are at fault or not. Customers are not always reasonable.

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Variations in Vinyl

There are only a certain number of vinyl manufacturers. Yet, there are a larger number of brands, including a number of house brands. If you know that a certain house brand of calendered intermediate is made by a certain manufacturer, say, 3M, you may believe it to be exactly the same as the 3M branded intermediate. This is not necessarily true. House brands are sometimes custom ordered from the vinyl maker. The buyer may specify a particular adhesive for their house brand, for example. So, the two intermediates may not react the same way in every situation, even though they may be made by the same manufacturer.

My point is that it may not be accurate to generalize about "vinyl versus paint mask." I think the only surefire way is by experimenting on samples.
Of course, it's not always easy to say "let's experiment" with a deadline looming. I once knew a sign shop boss who, faced with anything that would delay a job, said, "We don't have time for that!" Sometimes this included proofreading. In contrast, he always found the time to re-make a misspelled job.
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So, I woke up to an inch of snow on the ground. I had almost forgotten what it looked like.
Brad in Kansas City

 

[Johnny Best]

I think whoever is doing this wants mask made, they install masks, paint them and strip off masks. I also wonder if they applied large masks before why not go back to the company that made them before.
Seems it would be cheaper to hire a sign company to letter it on that has access to lifts or bucket trucks to paint it.

 

[signbrad]

I think whoever is doing this wants mask made, they install masks, paint them and strip off masks. I also wonder if they applied large masks before why not go back to the company that made them before.
Seems it would be cheaper to hire a sign company to letter it on that has access to lifts or bucket trucks to paint it.

I agree, Johnny.
My guess is that the crew that paints the tanks is already in place for painting the graphics. So the customer may believe it to be the cheaper option to have them do the work. And they may want the long-term durability offered by an automotive grade paint. Most sign companies would use One Shot or a similar single-stage enamel.
.................

I once asked a Matthews rep about the expected life of a Matthews polyurethane finish. They said that Matthews is considered a "five-year finish" without a clear coat, except for certain colors, and an "eight-year finish" when cleared with Matthews clear.
Lettering colors, of course, cannot match this type of durability.

Not many paints last longer than polyurethanes. The next step up from polyurethane in exterior durability on metal surfaces is fluoropolymer (polyvinylidene fluoride or PVDF). Kynar 500 is a proprietary name of one of the resins used in this type of paint. It is quite expensive. The metal roofing industry is a big user of PVDF paint.

Brad