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Author Topic: Doculam for covering wings?  (Read 2454 times)

Offline Matt Piatkowski

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Doculam for covering wings?
« on: October 21, 2016, 04:43:19 AM »
Hello,
I got a roll of Doculam foil from the Oregon Laminations Company (www.oregonlam.com). The material is identified as 1C01.5G12x500, has 1.5 mil. thickness and is fully covered on one side with the heat activated glue. One side of the foil is glossy, the other dull. The dull side is covered with glue.

TESTS:
I have ironed the 12" long piece of Doculam to the medium density 1/4" thick 4" wide balsa plank using the maximum heat from my Hangar9 iron (280-290 deg.F). I had to use such high heat as, according to the Oregon Laminations Company, the glue activation temperature is~270 deg.F.

Material covered the unprepared balsa surface well, is smooth and there are no wrinkles. Peel test showed that the adherence is satisfactory but weaker than that for Ultracote that I normally use for wings.

Material shrinks very little, though, and the ironing must be careful and gradual in order not to leave larger wrinkles.

Then, I run the shrink test. I made a rectangular 5x6" cutout in larger piece of paper-foam-paper board (PFP, 1/5" thick foam board bought in Dollar Store) and attached the piece of Doculam to the edges of this cutout. I purposely created small (~1/32" high) diagonal wrinkles while attaching Doculam to check if they disappear when heated. They did disappear but slowly and only after six iron passes. The temperature of the iron was again ~280-290 deg.F.

The Doculam "window" created is drum tight and looks good but the foam core of the PFP was partially melted by heat so the PFP surface is sort of wavy.

I was told that, after roughing up the Doculam exposed surface with #200 sand paper, this surface can be primed and then painted with "everything". I do not know, though, what primer has to be used to avoid peeling, cracking etc.

I would be grateful for more information about Doculam use on balsa, covering the open cells and painting.

Questions:
1. Can the heat gun be used on Doculam to achieve higher shrinkage and better "accidental wrinkles removal"?
2. Will Doculam stay safely attached to the unprepared balsa after, say, two years? Some say the glue dries with time and Doculam will start peeling.
3. How to paint it and with what?
 
I am considering to use Doculam on the full size (62" total span) wing with six open cells per side. Cells size: ~5"x~3".
I will not even try to cover the hollowed soft balsa wing tips with Doculam as I do not think this material will cover properly the surface with 3D curvature.
Or maybe there is some neat trick to do it?

Thanks,
Matt



 


Offline john e. holliday

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Re: Doculam for covering wings?
« Reply #1 on: October 21, 2016, 09:42:12 AM »
Try it like Larry Renger does with SLC(super light covering from the Corehouse).   
John E. "DOC" Holliday
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Offline Fredvon4

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Re: Doculam for covering wings?
« Reply #2 on: October 21, 2016, 10:44:02 AM »
John good suggestion but it sounds like Matt got 12" by 500 feet of the doculam

and I doubt Phil Cartier's super light covering (SLC), alone, is strong enough for a 60"+ WS stunt plane without polyspan under it

I use doculam a lot, but on short lived combat wings so I have no idea about the long term durability of the adhesive

I would use doculam as is for a beater training plane (about all I build)

However, for a premier stunt plane with a superb long lasting (easy to repair) finish, I probably would not....in fact since I have had a shallow learning curve and I like SLC over polyspan

That, and the fact that SLC takes most paints well...that is how I would manage a lightweight, strong and hopefully 10 point finish

Matt... I think Bob mears has used the same product you got ----on some of his Nostalgia (combat museum) combat planes, I think he set the doculam top of polyspan...for a simulated silk and dope finish...I have seen them all and a very good (faster) alternative to silk n dope....

I know others who lightly spritz the underside (glue side) of doculam with color paint, and iron on for a already top coated glossy finish

The spritzed on paint must be very light for the glue to still activate and stick to the surface of what ever

I only use the stuff for durable top coat as much cheaper than most monoKote products

Since I fly slimy Nitro/meth/oil I still dope the basic balsa airframe and the doculam stick well to the 220 sanded LE/TE/Rib balsa areas

Heat temp to shrink doculam is too high for most RAW foam wings...but a wing with a layer of spackle fill/and good well dried Polyurethane perhaps even with a layer of tissue or polyspan...the stuff works well and the heat to shrink doesn't make a mess

While on the subject of doculam

I found a very inexpensive heat gun designed for solder re-flowing

Heaterizer XL3000
https://www.sparkfun.com/products/10326

and I made a spare set of flat duckbill pliers into a covering holding, stretching, tool====== by gluing 1/16th balsa to the inside of the nose/jaws, then shrinking a short length of heat shrink tubing. The balsa it to give some give n grip

The heaterizer is small, light,  and had a great spot heating zone... the pliers keep my fingers from getting burned--- and I can accurately control the stretch and adhesion of any compound wing tip
"A good scare teaches more than good advice"

Fred von Gortler IV


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