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Vinyl directly on alclad

B

Bevan

Well Known Member
I know it was briefly mentioned in another thread but no conclusive answer. What does the collective wisdom say about vinyl wrap being applied directly to alclad aluminum in terms of corrosion over the long term (10-15 years)? The alclad is designed to be corrosion resistant to some degree. This thread is to discuss the relative corrosion resistance of vinyl directly over alclad vs the same bare alclad. Is it likely to be the same, worse, better? If worse, should the aluminum be etched, alodined and/or primed first? My limited testing indicates the vinyl will stick very well. I tested with 3m 1080.

Bevan
 
Not sure I fully understand the question, are you asking if vinyl covered alclad will corrode more or less than bare alclad as in not painting the airplane at all?
 
As long as the vinyl is not porous and will not absorb mositure, such as the blue stuff that comes with the kits, then it would definately keep corrosion off better than leaving it bare. Be aware that if you put vinyl over a non epoxy primed airframe, you will have corrosion around the edges of the covering. The severity of the corrosion, and how long it takes the corrosion to start will vary with the operation and storage conditions that the aircraft is exposed to. If you go with this scenario you can pay extra attention to the edges of panel openings and skin joints for corrosion. If corrosion becomes an issue you can remove the vinyl and work the corrosion issues.

The best way to keep corrosion off of the airframe when wrapping with vinyl is to epoxy prime the exterior prior to vinyl installation. I stress the importance of using only epoxy primer on metal that will not have a paint top coat. All other types of primers and metal prep processes are designed to be top coated and will not provide adequate corrosion protection by themselves.
 
....qualifies for 'the never-ending debate' category?

Hey Bevan,
my plane is painted, but I wonder the same thing.....I'm surprised that we haven't found a guy that paints large aircraft, which use big chunks of vinyl, who can tell us what they find under vinyl years later!!! Really, it's hardly a new thing, I cut vinyl registration letters for our Jodel back in the 70's.
I can comment only what I've seen on 5052 aluminum, some strange things happen under vinyl.
MOST of this you can see is from moisture wicking in along seams etc., but some effects seem to be from the solvents in the adhesive as well ( mild oxidation, discolouration etc.)
If you are doing polished & vinyl, there are products to seal the edges of the vinyl, either thin clear tape, or essentially a liquid clear acrylic sealant, if the shapes aren't too complex.
If you are hangared, I think it's safe to say you'll have only 1 % of the effects you would outside.

The question remains unresolved in my view.
 
corrosion

Usually on a painted aircraft you get some indication of corrosion, a blister or crack in the paint.
What indication if any are you going to get with vinyl?
 
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Mike,

Much of the advantage (in my view) with vinyl is lost if one has to prep and prime first.

Perry,

I agree, good attention to sealing the edges is important. Use using proseal, it may be helpful to fill the seams where aluminum sheets join up and leave a "valley" for moisture to travel and get trapped.

Paul,

A blister will definitely show through the vinyl. A crack may show depending on the size but paint could also hide such a crack, so possibly no difference there.

Keep it coming.

Bevan
 
Vinyl wrap porosity

Bevan, All vinyl wraps will be porous. They have to be. Professional wrap installers use a water based lubricant under the wrap to enable it to be eased across the surface to final position. Over a number of days after application the moisture escapes through pores in the wrap. If you use clear wrap you can actually see the process taking place over several days.

I think it would be fair to assume that vinyls that let moisture travel in one direction would also allow it to migrate in the other direction as well.

Vinyl wraps and decals have been used on cars, trucks and aircraft for many years. BUT it has traditionally been applied over painted surfaces. You wont find any Boeing aircraft with wrap over bare Alclad.

Will the corrosion of bare Alclad be made worse by the application of a wrap? I think that there is some real possibility that it could be made worse. But I doubt that there is enough history of anyone applying wrap over bare metal for a definitive judgement to be made. People who want to take it on will be the beta testers.

Many builders have commented on the corrosion they have found under the blue protective film supplied on Vans components. Generally these components have never been in the weather. They corrode indoors simply from moisture in the air. I found some corrosion under my blue film when it was removed. In particular it was prone to occur where the Alclad had been printed. No doubt the digital printing ink that they used was hygroscopic and therefore attracted moisture which was able to travel in through pores in the film.

Of course the worst corrosion is hidden corrosion and it might be very difficult to establish the extent of corrosion of bare Alclad under an opaque wrap until the wrap is removed. Conceivably that could result in a very nasty and expensive surprise.

Personally I'd be inclined to let others who are more desperate to save a dollar take the unknown risk.
 
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inspection issues

Bevan,
I've only seen a few wraps on aircraft; so take this with a grain of salt.

straight coloured vinyl is about 2 mil, if put down nice & tight, MAY show advanced corrosion. My opinion based on ugly aluminum sign cabinets I've stripped.
Wrap vinyl is usually at least 2.5 mil, plus the laminate to protect the print, so you are at 4.5 minimum...... the ones with air egress channels in the adhesive ( most) add a bit to the thickness as well. Even if installed perfectly, this stuff has some ability to hide.
I don't think you will be able to tell an imperfect rivet head from something happening under the vinyl.
As most folks will tell you, paint gives a much different reaction to movement, corrosion, cracking etc., as it's typically NOT elastic like the vinyl.
Let's say you do it yourself, invest 'only' $1000, ( half covered ) and get tired of it in 5 years...... Stripping it off might just be part of the long term equation for this particular finish process.
 
Good points all.

Bob,

The vinyl wrap of today goes on dry. At least with the 3M that I am testing with, has tiny "grooves" or air channels in the adhesive that allows the air to be squeegeed out and seems to make sort of a vacuum seal. It is down strong immediately once squeegeed. I would think it would get a little stronger in stick over time but that's only a guess. Hopefully not so much stick that it's too labour intensive to remove eventually.

Perry,

Do you agree that the vinyl of today is non-porous?

I don't expect a paint job to look good for ever. I also don't expect a vinyl job to last for ever. However, I do expect them to age differently. The paint will tend to fade and erode away. The vinyl will fade and likely start to lift around the edges at some point. I expect to pull it up and redo, or paint 5-10 years down the road. Perhaps there will be something different by then.

In addition, I plan to remove the vinyl on a small piece (ie: elevator or trim tab) after some underermined time (say two years) and inspect. If all is well, re-apply new vinyl. Then two years or so later, pull up a different piece to get a feel for any corrosion, and ease of removal, and repeat

PS. I plan to attempt the vinyl myself and the aircraft will be hangared. Otherwise there may be no paint for the forseable future.

Bevan
 
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NO-no-no

COMPLETELY INCORRECT

OUR VINYL WRAP IS DRY INSTALLED

Do you know how many bare aluminum aircraft use vinyl markings?

Sorry, but your statements are completely incorrect.

"Porous": of course not!
"Water based lubricant": of course not (maybe 10 years ago)

Respectfully.... What you describe is completely incorrect.

Regards,
Scott Farnsworth


Captain Avgas said:
Bevan, All vinyl wraps will be porous. They have to be. Professional wrap installers use a water based lubricant under the wrap to enable it to be eased across the surface to final position. Over a number of days after application the moisture escapes through pores in the wrap. If you use clear wrap you can actually see the process taking place over several days.

I think it would be fair to assume that vinyls that let moisture travel in one direction would also allow it to migrate in the other direction as well.

Vinyl wraps and decals have been used on cars, trucks and aircraft for many years. BUT it has traditionally been applied over painted surfaces. You wont find any Boeing aircraft with wrap over bare Alclad.

Will the corrosion of bare Alclad be made worse by the application of a wrap? I think that there is some real possibility that it could be made worse. But I doubt that there is enough history of anyone applying wrap over bare metal for a definitive judgement to be made. People who want to take it on will be the beta testers.

Many builders have commented on the corrosion they have found under the blue protective film supplied on Vans components. Generally these components have never been in the weather. They corrode indoors simply from moisture in the air. I found some corrosion under my blue film when it was removed. In particular it was prone to occur where the Alclad had been printed. No doubt the digital printing ink that they used was hygroscopic and therefore attracted moisture which was able to travel in through pores in the film.

Of course the worst corrosion is hidden corrosion and it might be very difficult to establish the extent of corrosion of bare Alclad under an opaque wrap until the wrap is removed. Conceivably that could result in a very nasty and expensive surprise.

Personally I'd be inclined to let others who are more desperate to save a dollar take the unknown risk.
Click to expand...
 
Bevan,

If you are at oshkosh this week please come see our examples on the field. We'll help you out "going it alone".

We've developed a very specific install process.

Please disregard post from others discussing "unknown to us" vinyl and install techniques that are not used. :confused:

Bevan said:
Good points all.

Bob,

The vinyl wrap of today goes on dry. At least with the 3M that I am testing with, has tiny "grooves" or air channels in the adhesive that allows the air to be squeegeed out and seems to make sort of a vacuum seal. It is down strong immediately once squeegeed. I would think it would get a little stronger in stick over time but that's only a guess. Hopefully not so much stick that it's too labour intensive to remove eventually.

Perry,

Do you agree that the vinyl of today is non-porous?

I don't expect a paint job to look good for ever. I also don't expect a vinyl job to last for ever. However, I do expect them to age differently. The paint will tend to fade and erode away. The vinyl will fade and likely start to lift around the edges at some point. I expect to pull it up and redo, or paint 5-10 years down the road. Perhaps there will be something different by then.

In addition, I plan to remove the vinyl on a small piece (ie: elevator or trim tab) after some underermined time (say two years) and inspect. If all is well, re-apply new vinyl. Then two years or so later, pull up a different piece to get a feel for any corrosion, and ease of removal, and repeat

PS. I plan to attempt the vinyl myself and the aircraft will be hangared. Otherwise there may be no paint for the forseable future.

Bevan
Click to expand...
 
AircraftWraps said:
Bevan,

If you are at oshkosh this week please come see our examples on the field. We'll help you out "going it alone".
Click to expand...

Thanks. I'm on the west coast and don't plan on Osh until sometime after the RV7 is done. I would like to wrap all the pieces before final assembly, so the wrap (or paint) will get done before it flies. However, any online assistance is greatly appreciated. I'm sure there are many others here who could benefit from your knowledge also. If it was discussed here where you advertise, you could benefit too.

Could you comment on 10year+ corrosion control when 3m is applied directly to alclad? ie: Moisture wicking from the edges, moisture getting into the seams from the inside of structures etc.

Thanks

Bevan
 
Bevan said:
Good points all.

Bob,

The vinyl wrap of today goes on dry. At least with the 3M that I am testing with, has tiny "grooves" or air channels in the adhesive that allows the air to be squeegeed out and seems to make sort of a vacuum seal. It is down strong immediately once squeegeed. I would think it would get a little stronger in stick over time but that's only a guess. Hopefully not so much stick that it's too labour intensive to remove eventually.

Perry,

Do you agree that the vinyl of today is non-porous?

Bevan
Click to expand...

Bevan, I must admit that I've been out of the game for well over a decade so there have obviously been technological changes to the process. Sorry about that. In the past a water based "slip aid" was used for the application of wraps but obviously that is no longer the case.

However some protective films are still wet applied including clear protective films such as 3M Scotchguard Paint Protection Film. Car window tints are also still wet applied. The residual moisture then migrates out through the film.

The point however is not whether wraps are wet applied or dry applied. The point is whether they are porous or not. Scotchguard Paint Protection Film is perhaps 4 times the thickness of your typical wrap film but it is obviously quite porous as it allows the water used during application to migrate out through the film.

Are "dry applied" wrap films porous. Well I would suggest that they probably are, and that it is just a matter of degree of porosity.

Maybe if you are intending to wrap your RV you might consider degreasing and alodining the aluminium surface first. Alodining is cheap and it is no big deal to apply and it will passivate the surface under the wrap to inhibit possible corrosion creep. It will also give you some modest degree of protection in the numerous areas where you will not be able to apply the wrap. :)
 
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