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Old Jan 31, 2014, 12:29 AM
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United States, IN, Indianapolis
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To newsprint or not to newsprint?

I have been reading a lot about covering foam planes in newsprint with glue. I am wanting to do this at some point with my Dynam Skytrainer. The thing is a lot of what I have read talks about shrinkage and consequently warpage of surfaces. I do not want to take the chance of warping any of the surfaces of my plane.
Is there something else that can be used with Elmers/titebond that will not shrink as newspaper does but will be just as strong? Also, Is this a project you would recommend for a very handy noob? I am the type that has almost always been able to do something I have never done before.....but not always lol
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Old Jan 31, 2014, 06:44 AM
Build straight - Fly twisty
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Australia, QLD, Little Mountain
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What do you hope to achieve by covering your Dynam Skytrainer with paper?
Adding weight to a proven design is almost never a good thing unless there is a real need to address some specific issue.
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Old Jan 31, 2014, 06:52 AM
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Canada, QC, Montreal
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You can use coffee filters or even better some bamboo cofee filters.
I heard that they are great for covering planes.
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Old Jan 31, 2014, 07:43 AM
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Quote:
Originally Posted by Whiskers View Post
What do you hope to achieve by covering your Dynam Skytrainer with paper?
Adding weight to a proven design is almost never a good thing unless there is a real need to address some specific issue.
To learn something! is the main reason. Also I eventually would like to paint it so it would look different than every other one on the market
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Old Jan 31, 2014, 08:14 AM
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Southern Vermont
Joined Feb 2007
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Whiskers is absolutely right.

You will add quite a bit of weight by covering the whole model and painting and you will also move the center of gravity back considerably. Even if you just cover the wing and paint it the CG will move aft. To counteract that you will need to add even more weight forward.You will end up with a heavy plane. And the performance of your plane will suffer.

So if you consider the above, you've already learned something by asking! But to solve your real interests,

1.) Why not just paint over the planes trim colors with a different trim color -- using craft paint? Or add some other patch of color.

2.) I don't know what kind of foam this is, but if you object to a rough foam finish, you can use lightweight spckle with a few drops of water in it to fill the "grain" and sand to a smooth finish. It is lighter than papering the model, especially if you sand most of it off.

Be aware that paint is heavy and that it almost always moves the CG aft, which you must correct. So the less you can get away with and still find satisfaction in, the better your plane will fly.

2.)To answer your concerns about warpage, in paper covering, you should cover flat panels like wings and stabs on both sides at the same time. Then shrinkage is balanced. If you want to do a small section at a time, do that lengthwise, but on both sides at the same time.

3.) If you want practice at papering to learn about it, Make a foam wing out of some scrap foam and paper it to see what happens. What will it cost you, and how long will t take? Practically zero. And you might then have a start for a new design and plane of your own! This is the scratchbuilt foamie section of the forum, remember?

ps I tried coffee filters once, and found them heavier and harder to use because of the need to piece it up than 18 x 12 inexpensive drawing paper found in the art/drafting supplies section of Staples. The latter does a great job in a single wrap around piece for two panel wings up to 36". It seems just the right weight, and absorption rate.

However for smaller wings these days, I no longer wrap the whole wing anyway. I tend to paper the fwd quarter of the wing as a spar, and the dihedral wing joints get a strip. That produces a very light wing, and the rest is flled with lightweight spackle.
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Old Jan 31, 2014, 08:28 AM
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VTDIY Thank you for that! I do not want to negatively affect the performance of my plane, so I will hold off on doing this. The suggestion about building a foam with is a great one. I am really interested in building my own planes....I love the DIY side of just about anything. The knowledge you gain from DIY is worth the time you spend doing it, plus it usually saves money!

So, with that being said maybe I will delve into the wealth of knowledge in this sub-forum and go build be a wing!

Also, It's not that this plane looks bad the foam is nice and firm and all but I enjoy that nice glossy finish!
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Old Jan 31, 2014, 08:57 AM
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Well you're in the right place!

A smooth finish is pretty easy to achieve on foam when building from scratch if you first fill the foam with lightweight spackle diluted with a few drops of water, rubbed in well with a foam brush, then sanded off with fine wet or dry paper until back to foam (filled now), then a coat of Freddie B's "special sauce" -- basically a foam-friendly water-cleanup sanding sealer similar to what we used to use when adding talcum powder to dope (aircraft lacquer) for balsa IC planes.

Look up Freddie B. on this forum for always enjoyable, fun, and very informative reads -- It's just a mix of Minwax Polycrylic, lightweight spackle and talcum powder/baby powder (non-cornstarch, talc type) to make an easy sanding but hard no-absorptive undercoat for gloss paint. Sand that with your finest sandpaper and you're ready to paint. You can practice this also on a scrap foam practice wing. Probably you'll end up with an airplane as a result!
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Old Jan 31, 2014, 09:15 AM
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Southern Vermont
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One other important thing about paint and weight. You want to put as little paint on as possible, for the least weight. Makes sense, right?

Well paint is usually three things. Pigment, vehicle, and thinners. The main one you are interested in is pigment. If paint were all pigment (and still stuck well) that would be ideal. You could put a very thin (light weight) coat on an be done with it. Nice solid color.

But pigments are expensive -- especially the old really opaque mineral compound types. And some like the cadmiums and chromes are toxic.

Nowadays synthetic pigments -- organic dye types -- are cheaper, less toxic, etc. The main problem with them from a model aircraft point of view is they are usually much less opaque -- in fact nearly transparent, some of them. Well they're dyes, right?

So if you put them on over anything but a perfectly white surface, or brush them on, you are going to see uneveness through the paint. Putting more coats on helps but also darkens it with each coat. On the other hand if you want a dark color, putting it on over white requires lots more paint, and if brushed looks uneven until you've added a lot of coats.

Even worse, since pigment is expensive, cheap mass market paint tends to have less of it these days, so you have to paint even more coats to get an even coverage. What this all means is you're putting mostly vehicle (paint glue) on the plane, and relatively little pigment per coat

What I do sometimes, particularly for reds, which tend to be very transparent now, is use artist's acrylic colors in large tubes. The cheaper student variety seems to work well. It is much higher pigment ratio, so covers very well -- though it is kind of pasty to apply. But If you rub it in -- spread it out using a foam brush rather hard to it, to get it as thin as possible, you get very good coverage at minimal weight in one thin coat, or maybe 2, most. And if you've brushed it out well -- it will look even. It dries satin finish, which may be acceptable -- or you can overcoat lightly with polycrylic gloss if you want more sheen.
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Old Jan 31, 2014, 09:40 AM
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SE MI
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VT: do you have a upc code off the drawing paper you use? I am always up for trying new things, (though I do like my coffee filters!)

One of the nice things about any of the covering methods that incorporate minwax Polycrylic, is that you can pretty much use any paint for covering after you seal the foam surface. I use a lot of the dollar a can rattle can spray paint from Walmart. cheap and goes on relatively thin compared to rustoleum, et al. sprays.
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Old Jan 31, 2014, 01:33 PM
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Paper covered foam wings become so brittle that they will snap like a twig on impact.
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Old Jan 31, 2014, 01:42 PM
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Kaiapoi , New Zealand
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Quote:
Originally Posted by goldguy View Post
Paper covered foam wings become so brittle that they will snap like a twig on impact.
no more than a balsa covered wing will.
I have 4 foam news print planes and the oldest is 4 years all still flying and its a LIGHT and cheap way to build.
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Old Jan 31, 2014, 01:43 PM
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Southern Vermont
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Hey Springer!

Just found a package upstairs with the front label intact. It's Roselle, "Hands On", White Drawing Paper, 100 sheets 12" x 18" UPC 00671071347.

Weird, I looked it up on Staples website and it isn't listed. Yet I've been buying it for years at my Staples store -- I use it for a lot of things besides models. Printing plans, etc. It's inexpensive but quite good quality, no finish or filler so it absorbs glue well, and not too thick or heavy. A good white for painting over -- doesn't yellow or go brittle like newsprint.

I find it in the art and drafting supply section of the store, not the paper section. Looks like it is mainly marketed for kids.

Here it is on the Roselle company online catalog:

http://www.rosellepaper.com/products...g-paper-12x18/
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Old Jan 31, 2014, 08:51 PM
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[QUOTE=springer;27365695]VT: do you have a upc code off the drawing paper you use? I am always up for trying new things, (though I do like my coffee filters!)
/QUOTE]

MY coffee filters... Melitta cone type.. are quite Coarse filter paper.
Too coarse to consider, let alone use
The Toy airplane equivalent of Burlap IMO.
Can't comprehend any sane person using those as covering.
Although those basket type paper filters as used in the Bunnomatic coffee machines of yesteryear are quite thin.
Those then?
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Old Jan 31, 2014, 09:36 PM
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Southern Vermont
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Quote:
Originally Posted by goldguy View Post
Paper covered foam wings become so brittle that they will snap like a twig on impact.
My 54" WS Mambo took a direct hit on the paper covered wing into a two foot tall steel metal stake driven into the ground with a welded ring on it -- used as a guide to retrieve a glider tow line.

The dent was so small it's practically invisible -- the paper moved back out from it -- I haven't even bothered to repair it.

Any plain foam wing I have ever built or flown would have been smashed to pieces by that impact.

I don't fly EPP, so that might have survived I guess, but styro of any sort.........forget it.

I think aging really depends on your paper and your glue -- just like in any composite laminate.
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Old Feb 01, 2014, 08:31 AM
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Vt: sweet! Thanks for the info, gotta try it out. I did a little experiment with regular printer paper and titebond glue and found it made a very stiff section, but the paper buckled and separated when i bent the section (beam). That was if i soaked the paper. If i just applied the glue to one side like wallpaper, it seemed to retain better. I wonder if i got the viscosity wrong, or perhaps the other paper....

Bare: yup, you don't want the cone type. But rather the corrugated ones that open up and lay out as flat circles.
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