Doculam covering PRO's and PITFALLS.....

[Turbojoe]

I've had (and thrown away) a bunch of Doculam for at least a dozen years. It used to be included with every Mountain Models kit. I've only toyed with it a bit on stick built test boxes with paint on the adhesive side. Never covered a plane with it. It seems a few builders here have used Doculam and I'll bet a few more builders that haven't come forward yet.

I don't have any fear of its application. I know I can figure that out quickly. It's the painting/taping that I have questions about. I don't want to do a nice smooth wrinkle free covering and then screw it all up in the painting phase which I probably will. I need to know that the area I tape over won't lift when I pull the masking tape away. THAT is my biggest fear!

We can all learn from others good and bad experiences. I'm hoping to see lots of posts on the subject. Other brand covering prices are through the roof and out of my budget range when you factor in shipping.

My LHS are nothing more than Horizon Hobby pawns selling ONLY bARF's and what they are told to sell. They're virtually worthless to me as a builder and I refuse to support them.

Joe

 

[Bricks]

All you ever wanted to know about Doculam and then some, it gets a little off topic once in a while.

https://www.rcgroups.com/forums/showthread.php?274520-Doculam-Discoveries!

 

[Turbojoe]

All you ever wanted to know about Doculam and then some, it gets a little off topic once in a while.

https://www.rcgroups.com/forums/showthread.php?274520-Doculam-Discoveries!

No. That's a typical RC Groups thread and it gets WAY OFF TOPIC and impossible to follow after the first 20 or so posts. I'd prefer to hear from the crew here on FliteTest.

Sorry. Just not a fan of RC Groups anymore........

Joe

 

[TooJung2Die]

If you haven't tried document laminating film or are having problems using it ask your questions here!

I like document laminating film or doculam as its often called. It's great stuff. I covered four airplanes with 1.5 mil standard gloss laminating film from Laminator.com. It's thin and very light weight. It's very inexpensive. It's tough and puncture resistant. It's cloudy when it comes off the roll and turns crystal clear when heated. The shrink isn't strong enough to warp delicate balsa frames so it's a good substitute for balsa airplanes that are typically covered with tissue. It goes on a lot like other model airplane covering films but the less than average shrinkage turns off a lot of builders. I takes a lot more heat to shrink than standard films. I think many people try it and give up because they don't use enough heat. Heat guns are a big help. Heat that would blast right through regular film doesn't hurt doculam. My big epiphany was discovering that it can be stretched over complex shapes when enough heat is applied. I found that wrinkles that wouldn't go away by shrinking can be pulled out by stretching the film using a heat gun.

Most people use it to strengthen and protect foam model airplanes. It is very good as a covering skin on foam. It'll stick to foam without melting the foam. Use it instead of packing tape. Lay a sheet of doculam over the part you want to cover and work the iron on low heat from the center out towards the edges.

Here are the airplanes I covered with document laminating film so far.

The "So-Long", a 1/2A free-flight Old Timer converted to electric motor and 3 channel RC. The fuselage is doculam covered sheet balsa:

"Contest Commercial" A 1930's competition rubber power design converted to electric motor and RC.

Guillow's SE5A converted to electric motor and 3 channel RC:

Guillow's "Lancer" rubber power converted to electric motor and 3 channel RC:

The "Arena Rat", a 25" wingspan ultra-light indoor RC slow flyer. This is covered with 1 mil film. The film is left slack because the frame is very fragile.

I like the "bare bones" look you get with crystal clear covering. When you want color you can airbrush on a multi-surface acrylic paint. The film has to be cleaned thoroughly before painting to clean off the release lubricant that is put on the film during manufacturing.

Jon

 

[Turbojoe]

Most people use it to strengthen and protect foam model airplanes. It is very good as a covering on foam. It'll stick to foam without melting the foam. Use it instead of packing tape. Lay a sheet of doculam over the part you want to cover and work the iron on low heat from the center out towards the edges.

Jon

I had no idea you could use it on foam! I have a Multiplex Fun Jet that I started 'glassing years ago. It sounds like Doculam is a much better AND lighter option and may get me back to finishing that build sooner. I'd love to learn most about painting Doculam in a way that can be taped that won't peel the paint when the tape is removed.

The pictures of your builds are awesome!

Joe

 

[TooJung2Die]

I'd love to learn most about painting Doculam in a way that can be taped that won't peel the paint when the tape is removed.

Using masking tape can be risky. Paint doesn't like to stick to doculam. It has to be cleaned thoroughly using a solvent. I haven't found a solvent that affects doculam. Even acetone won't hurt it. I read if you scuff it up with steel wool or scotch-brite paint adheres better. I had no problems masking the bottom of the SE5A with blue painters tape. I used multi-surface Craft Smart acylic paint that sticks to plastics. I played it safe with the "So-Long" and didn't mask. Simple two color paint job using ordinary Apple Barrel acrylic. I sealed the paint with a light coat of Krylon crystal clear gloss to seal it. That paint has a few scratches from transporting it in the car.

I haven't tried painting the adhesive side. People say it works but I worry about the paint reducing adhesion and smearing when it's stretched over complex curves.

If I bought another roll of laminating film I'd get the matte finish. It's more expensive but better for painting. I probably won't be buying any more. I have a 25" x 500 foot roll of this stuff. I'm going to have to leave most of it to someone in my will.

Jon

 

[speedbirdted]

I might have to try doculam again, seeing your builds. I realize now the reason I didn't like it at first is I didn't use a heat gun so the covering ended up going on very slack and wrinkly. How does it stack up weight-wise to something like Monokote or tissue paper? I've tried using Monokote to cover light indoor models and it just doesn't work because Monokote is far too shrinky, and tissue paper does work but it's messy and horrible and disgusting (and eze-dope is most definitely not easy on your sense of smell)

I wonder if it can stick to dtfb without causing the dreaded warping/bubbling issues that plague Monokote and pretty much any other heat-applied covering?

 

[TooJung2Die]

I don't know what doculam weighs per square foot or meter. It is a fraction of the weight of Monokote and heavier than doped Japanese tissue but not by much. It's on par with the thinnest heat shrink films if you use the 1.5 mil (38 micron). The 4 mil or more doculam is more like normal weight model airplane film. The old timer builders often layer doped tissue on top of the film after it has been shrunk. It must not add much weight. It gives the film color and the look of a tissue covered airplane with the strength of plastic film.

I used doculam on this 40 inch DTFB wing after stripping off all the paper. Just the top side. No bubbles. Get the iron just warm enough for the film to stick; 200F if I remember right. If you're getting big bubbles the iron may be too hot. Air in the foam expands when heated. This wing is getting old and you can see some stress wrinkling. The wrinkles will go away if I iron it down again.

Watch this guy cover a glider wing with 4 mil doculam.

Jon

 

[Turbojoe]

I'm really getting encouraged now! That video was impressive. I measured the Doculam I have last night and it's 1.5 mil. Years back I built some boxes from balsa sticks and painted the adhesive side of Doculam with different brands and colors. Those boxes are STILL pretty much wrinkle free and look like the day I did them. I'm not certain how well painting the adhesive side will work on an area the size of a wing though. Likely better to paint the outside. I'm going to watch closely for what methods others use for creative color schemes on Doculam.

Joe

 

[rockyboy]

I'm excited to give this a try too! I ordered enough for a plane or two from http://www.alofthobbies.com/ (thanks for the tip guys) to see if I will like working with it before committing to a full roll.

 

[TooJung2Die]

Rocky, give it a good chance. The best tip I can pass along is leave a generous amount of excess film overhang. Don't trim the excess until after all the wrinkles have been shrunk out. If there isn't enough shrinkage use more heat and pull on the overhang to stretch out the wrinkles and loose spots. Don't trim the excess off until after you're satisfied. I wasted a lot of film until I figured this out.

One good feature of doculam is it strips off clean if you screw up and want to do-over. Another thing I like about it is overlapping film is invisible. I've had to do some balsa repairs and film patches on the Lancer and Contest Commercial. The patches are invisible.

 

[Turbojoe]

The only thing I know for sure about Doculam is how beautifully clear it becomes when heated. I was finishing up my Willy Nillies Jr. Skylark yesterday and was using Solarfilm for hinging. It sticks pretty good but I started thinking that Doculam being crystal clear would be perfect for the job. I grabbed some scrap balsa and covered with Solarfilm. I then applied Doculam for hinges starting at 250 degrees. No good. Pulled right off. Went up to 300 degrees. It stuck better but still pulled off. Went to 350 degrees and it didn't like that temp at all. The Solarfilm started to curl and bubble. Keep in mind my Doculam is only 1.5 mil. Maybe I have it all wrong.

I still intend to try my hand at covering and painting a plane with Doculam. Either it just isn't good for hinging or I was going about it all wrong or maybe even using the wrong weight of the product. In any case I really like how clear it is when applied. Much better than clear tape or Blenderm. I don't want the hinging to show if at all possible and Doculam seems to be the only product that offers that if I can figure out the best temp for it to be viable as hinging material.

Joe

 

[TooJung2Die]

I haven't tried doculam for hinges. I never tried covering film for hinges. It doesn't seem like a durable solution. I like CA hinges made from Tyvek. On doculam covered airplanes with balsa too thin to slot for CA hinges like the Lancer and Rat I used clear tape. If the tape fails I'll replace it with sewn hinges.

 

[Turbojoe]

I haven't tried doculam for hinges. I never tried covering film for hinges. It doesn't seem like a durable solution. I like CA hinges made from Tyvek. On doculam covered airplanes with balsa too thin to slot for CA hinges like the Lancer and Rat I used clear tape. If the tape fails I'll replace it with sewn hinges.

Yep. The Willy Nillies kits are "to me" too thin to slot for Tyvek hinges though I have used them on countless other larger planes. I just don't trust myself to try to slot 3/32" surfaces. I'm sure many here are much more than capable of doing it though. I've also used covering hinges on planes as large as 60" wingspan and they're still holding strong after many years.

I love the completely clear of the Doculam but I just haven't yet learned how to make it stick properly for a hinge. I'm hoping for posts from those that made it work for them with the mil and temp they used.

Joe

 

[rockyboy]

So using the 1.7 mil doculam I got from Aloft Hobbies, I had a great experience covering my Willy Nillies GLH. (Most of the folks posting in this thread are following that build too, but I figured I'd cross post for anyone finding this from the covering direction.)

The airframe is pretty simple without any compound curves, and the covering went on very easily. I had my TopFlite iron cranked up to its heighest setting and it went on and tightned up just great.

My next adventure with this film is going to be painting. I want to leave most of the plane clear, but make the right wing distinctive for orientation help. I also got a roll of masking film for my vinyl cutter recently, so it's time to get a little fancy with the paint!

First I masked off the outer third of the right wing. Then I used 600 grit sandpaper to rub down the covering where it's going to be painted, and give it a final rubbing alcohol cleaning.

Then I lightly dusted on two coats of red, and once that's very thoroughly cured (a couple days), I'm going to add the masking film pattern, give another red dusting to seal the masking edges, and then shoot the white graphic layer on top.

Once the white cures for a day, I'll pull up all the masking and hope it's a triumph of a white star & checkers over a red background and not a tradgedy. Probably do a clear coat to protect the paint job too.

 

[TooJung2Die]

Great job with the film. Can't wait to see how the graphic mask turns out. The combination of crystal clear and color will look great. It that aerosol acrylic paint?

 

[Turbojoe]

Perfect timing! Can't wait to see your progress. I just found an uncovered wing I had scratch built for the Mountain Models SwitchBack. I also found fuselage sides I had cut out and is ready for bulkheads. This will end up being my doculam test bed. It'll take a while as I'm creating all of the bulkheads for 3D printing. Lots of trial and error with mostly error so far. I can't wait to put some of that doculam to use.

Joe

 

[rockyboy]

Thanks - yeah, that's the Sugar line of low-volitile acrylics - they cost a little more but are way easier on the lungs and matte finish too!

 

[Turbojoe]

I just checked my doculam and it measures 2 mil so it looks like what I have will be OK. I unrolled one and it's no less than 30+ feet long by 12" wide. I still have 5 rolls after throwing away tons of the stuff. Looks like I should have using this stuff a LONG time ago.

Joe

 

[rockyboy]

Pictures of the next two steps for posterity. A vinyl mask made from Oracal was applied using generic frisket paper and the red paint kept good adhesion when I pulled the frisket off. No paint pull-ups so I'm still optimistic! The mask adhesion is a little stronger than the frisket, but it too is meant to be a temporary adhesive.

And to seal the mask edges I sprayed another coat of red.

White coat coming later today...