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Blue Plastic or no Blue Plastic?

H

HighSchoolBuilders

Well Known Member
Hi All,

Reading thru several posts, there are builders dimple with the blue protective plastic on; but I was told not to during the EAA workshop.

If there is no real concern, I would like to leave the plastic on as long as I can, especially during dimpling, it often leaves a small ring of scratches where the die surface hits the side of the hole.

Would love to hear what everyone does...

Cheers!
Hank
 
Remove the plastic for a variety of reasons. It slightly distorts the dimple. Plus, the dimpling action often cuts the plastic at the dimple so that when you do remove the plastic, a bit is left in the dimple itself. Not good either for priming or for when you rivet. The 'scratches' you mentioned are very minor; if you are keeping the dies clean, then they should be smooth enough not to cause any real problem. You are more likely to make deeper scratches with the male die as you move from hole to hole (so be careful when you reposition). No corrosion will start at those rings and they will disappear when you either polish or prime.
 
I think you'll find that you get much better results when you remove the plastic over the dimples. There's other threads that describe the ways to do this.
 
Remove it

You can not deburr correctly with the plastic on. When you dimple you will embed the burrs and this could cause cracking at a later date.
 
Many of us use a soldering iron and a straight edge to remove the blue plastic just around the rivet lines. Here's an example:




I've heard lots of people have difficulty removing the plastic if it's sat there for over a year. I plan on removing all the plastic once I'm done riveting and then wrapping the parts in bubble wrap.
 
If you plan on painting the plane. Just rip all the blue off, the sooner the better. After its on there a while, it's tough to get off. I never had problems with scratches, it was the occational bang that left a little dent that hurts, whether you have the blue on or not, the ding will still get on there. My vote is to get rid of it all as soon as you can, take a scrippy and mark the part no. on it as you remove the blue. Taking time to cut strips on the panels can be spent on something else. My take.
 
Thanks! I have been removing the plastic like SGordon does, just that I've seen builders leave the blue plastic on and wonder if that's a good idea. It's crystal clear now that leaving the blue is not even an option :)
 
I removed the blue plastic along the rivet lines using the soldering iron along a wood yardstick technique. Because I'm not painting -- decided to polish the aluminum -- I left the blue plastic on as long as possible for 3+ years in some cases. It helps in preventing scratching the alcad. My plane was in my basement so I didn't have any problems with corrosion under the plastic. It was no big deal pealing the plastic off years later and the alcad looked as good as the day it arrived. I would have removed all the plastic if the parts were not stored in a climate-controlled place.
 
I leave mine on (mostly)

A few years ago, I took the EAA RV construction course, and it was taught by Ken Scott from Vans.

Ken, who is an excellent instructor, and knows a lot of practical lore told us , under no uncertain terms, to get that plastic off asap.

But that's not the story, the story is Ken's recent "Roll your own" series of interesting articles in Kitplanes on designing and building a teensy homebuilt. Check out the photos in the article. Ah-HA! Ken left the plastic ON!

My concern is deep scratches, so I left the plastic on most of the outer skin surfaces (except for the moving subassemblies such as rudders and elevators). And, I have some nice gouges in the plastic that did not penetrate to the skin (I hope). I've drilled and dimpled through the stuff with no problems.

Some have found corrosion beneath the plastic, so if you even suspect that, I'd yank it.

.
 
I leave the plastic on, using the soldering iron technique. I have not seen any good explanation of why it should be taken off, but one very good reason to leave it on: scratches due to handling. If there is corrosion under it, I believe the corrosion was already there before the plastic came on.
 
The corrisoin starts at the edges....

........and works its way under the blue plastic. I have some spare allclad strips with the blue film still on and some of it has corroded.

The plane, that has been sitting in the same garage, has no corrosion at all, due to the 15 micron of Akzo Nobel Aerospace FCR Primer on every alclad surface.

Regards, Tonny.
 
My vote is to get rid of the plastic from the get go. I removed the plastic after I drilled each skin and was ready to deburr/dimple it.

The soldering iron thing is a complete and total waste of time that could be spent actually building the airplane. Plus, it looks silly when you see an unpainted RV taxiing around with lines all over it where the rivet lines have oxidized more than the rest of the airframe. The old school RV builders didn't do this. It's a relatively new thing that builders have started doing.

Also, I have seen several RVs that did the soldering iron thing that had...you guessed it...scratches all over it where they didn't round off the soldering iron tip enough or where they were too rough with it.

The first thing your painter is going to do is sand the airframe and get the surface very, very rough to promote paint adhesion.
 
Having just finished painting my RV-10, the 20 hours cutting stripes in the plastic was a huge waste of time. Time I could have used etcfhing the perfectly shiney aluminum in prep for conversion and primer. I stared at that pristine metal for a good minute before the alumaetch and scotchbrite pads took all that shine away.
 
Pilottonny said:
........and works its way under the blue plastic. I have some spare allclad strips with the blue film still on and some of it has corroded.
Click to expand...
That sounds like filiform corrosion which occurs when relative humidity is between 85 to 95 % and salt is deposited. If the parts are stored indoor, there is not much risk of this happening. Outdoor storage in a tropical coastal area on the other hand ;)
 
SvingenB said:
That sounds like filiform corrosion which occurs when relative humidity is between 85 to 95 % and salt is deposited. If the parts are stored indoor, there is not much risk of this happening. Outdoor storage in a tropical coastal area on the other hand ;)
Click to expand...

I had some corrosion on parts here in Kentucky:eek: quite a ways from any salt water:D. Seriously folks, unless you are going to go with the polished look, strip the blue stuff off and use your soldering iron time building. Opinion here:eek: but soldering iron thing is a total waste of time. Opinion....you get what you paid for it:D Did it both ways, will never waste my time with soldering iron if I am a repeat offender.
 
blue plastic

I see a lot of RV's in the local paint shop ,guys will spend 5 years building with blue plastic thinking it will keep the skins pristine. Paint prep with a DA with 150 put more scratches than you could do building it
 
I'm convinced...

I just finished my HS and did the soldering iron trick, mostly because everyone else seems to do it. It was kind of a pain in the arse, time consuming and I kept thinking this ISNT building. And then I thought, once you get ready to paint, the minor scratches will be a moot point since you scuff up the surface anyway. So I'm in agreement I would rather spend my time building. I am going to remove the plastic from my HS before storing it and discontinue the soldering iron thing from here on out...FWIW.
 
I may stop doing the soldering iron thing after the empennage. I only did it with the HS and VS skins (with all the stiffeners in the rudder and elevators it didn't seem to be worth the effort). All my parts will be primed with AZKO and I knew almost nothing about painting or polishing when I started. Only in the past few weeks did I research the paint prep process, and I didn't know the skins would be scuffed up anyways prior to paint. I doubt I'm going to polish.

To echo Don's comment, I agree that the blue provides a better contrast while drilling. Sometimes I go crosseyed when I'm trying to line up the drill bit with a hole in shiny aluminum. I remove the inside plastic right away to insure a good fit, but I've been leaving the plastic on until I'm done final drilling. I don't even cut the strips until I'm ready to deburr and dimple.

I am by no means an expert, nor do I play one on TV. Do what makes sense for you.
 
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That's what I discovered today fitting empennage fairing. The empennage was bought in 2006. If it looks like this


rust1.jpg



remove the film. If you don't it will look like that


rust2.jpg



All stored in dry place.
 
Plastic

Get the plastic off immediately after unpacking the kit, the plastic will promote corrosion over time. Dont worry about scratches unless you plan on an unpainted polished airplane.

Pat Stewart
 
I worked on the same parts as Vlad last night. In my case, the plastic came off easily (well, as easily as it did when the kit was fresh), and no trace of corrosion. I can't remember which kit the wing root fairings came in, but they can't be more than about 3 years old.

I do live in Central Texas, we haven't had any humidity in about that much time.

I'm about to put the wings on for the final time, and most of the plastic is still in place. The panels still peel easily, and no marks from the soldering iron. Rivet strips aren't noticeably oxided.

When I did the Van's factory tour, they said, just to strip off the plastic. At the time I thought that was great advice for them, they have all the parts they want.

All in all, I don't regret the extra time to keep as much plastic in place as I could. It was nothing when I had to wait on finances for the next kit anyway. I might do it again. I've seen what happens when painting, and a few scratches is nothing in comparison. I do like the reaction from some women, "Oh, it's such a pretty color blue!"
 
Unless you are polishing your plane, remove it ALL. I think it's total overkill to leave it on for protection, but that's just my .02
 
I have heard as many horror stories as anyone else yet took an entirely different tack to "conventional wisdom" when I built the -8. Conventional wisdom dictates removing the blue plastic as soon as possible and that is exactly what many builders do. I chose differently. I kept the covering on as long as possible to absolutely NO ill effect. Nada. zip, zippo. Some of the parts were clad in vinyl for (I'm guessing) nearly 6 years, particularily those parts in the empennage group, an assembly completed in 3 weeks and stored away for a few years in my basement before I got around to building the rest of the airplane. It's all documented in the VAF archives.

When I built the -6A an older design, some of the aluminum was clad in white vinyl. Now that stuff really WAS hard to remove! The point I am making is this. You have to ASSESS your own local conditions which includes the quality of the vinyl on your parts, and then act accordingly. I did not have any parts where the vinyl was all wrinkly as shown in post #21.

34si1cw.jpg
 
my experience - polishing

I am in the process of polishing my airplane now and I can definately say that I would take a little surface corrosion over scratches any day. The scratches are virtually improssible to remove while the bit of contamination I had after almost 5 years of plastic on was gone on the 1st pass with the Nuvite G6.

My 2 cents for the polishers out there...
 
"Take it off ... take it ALL off ..."

Back when I started building, the plastic wasn't blue. It was clear. And the conventional wisdom then was to leave the plastic on until the last possible minute, to prevent scratches.

I did the soldering iron bit, carefully removing all of the plastic where the rows of rivets went, leaving the bulk of it on until I was ready to fly the plane down to TX for the paint.

Looking back, I can't see any good reason to leave the plastic on the aluminum unless you plan to polish the metal. None. And, FWIW, some of the clear plastic had been on for nearly a dozen years and all peeled off with very little effort. Maybe the blue plastic is tougher to remove.

I'd strip it all off if I were to build again.
 
HighSchoolBuilders said:
If there is no real concern, I would like to leave the plastic on as long as I can, especially during dimpling, it often leaves a small ring of scratches where the die surface hits the side of the hole.
Click to expand...

I know the OP was over two years ago, but I didn't see anyone address the small ring of scratches issue.

My trick (which I shamelessly stole from someone else, maybe on VAF) is to put masking tape on the male dimple die.

I was worried at first that the tape would somehow contribute to a less-than-ideal dimple, but all my dimples are great, and I have no qualms about continuing this practice.

First picture is a skin dimpled with no tape (see the circles?)
Second picture is the tape on the die (right before I changed the tape.)
Third picture is skin dimpled with the tape, no circles! (I use this for the squeezer and the c-frame.)

But please keep in mind that this is insane to do. Even if you are polishing your airplane, these circles will come out the minute you wave the polisher in the general direction of the airplane.

Please don't be as A.R. as me.

1-13-10-004-large.jpg

1-15-10-001-large.jpg

20100711-117-large.jpg
 
Plastic on

I remove the plastic from the inside surface and debur from the inside. I leave the plastic on the outside while I dimple. Seems no matter how careful I was the male dimple die scratched the heck out of the skin. I don't see ANY difference in how the rivets sit in the dimple whether I leave the plastic on or not. Then I use a soldering iron to remove a strip of plastic before riveting.

Once a section is assembled I remove all the plastic, cover it with a sheet and put it someplace secure and dry

My $0.02
 
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