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sealing balsa before final sanding

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Old 09-09-2009, 02:13 PM
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alabamaflyer
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Default sealing balsa before final sanding

is it a good idea to fill the balsa with balsa filler before final sanding for appling monicoat? is there a problem with the balsa filer and the heat used to appie the monicoat?
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Old 09-09-2009, 03:16 PM
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Default RE: sealing balsa before final sanding

Hi everybody,

I have a question to add to alabamaflyer's question (it is similar). Somebody in our club said that you really want to get a smooth and good adhesion of either ultracote or monocote, use something like Kryon gray primer and sand it. Another person said that you can also use hairspray (extra hold) since it is a laquer. Any thoughts?

Happy flying and soft landings!
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Old 09-09-2009, 03:47 PM
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Default RE: sealing balsa before final sanding

Yes, you use the filler then sand, if you still have low spots fill some more and sand. Just watch out, balsa sands very easy and you can sand it to the point you can read through it.
The trick to getting a good covering job is making sure the balsa is clean and free of dust. I don't use anything special on the wood but I have tried the hair spray and it works pretty well, not needed but it works. I have never tried or heard of anyone using primer before covering so????
First blow off the plane with air, then I use a stiff paint brush and hit it with air again then wipe the plane realy good with a tack cloth, the tack cloth is found in any paint store or hardware store in the paint section. Now just cover. For the most part the covering sticks to itself so you want to have about a 1/4 inch of over lap.
I use the Ultracote and like it a lot better then the mono but that topic is like opening a can of worms here, it's also been debated to death, do a search and you will see what I mean.
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Old 09-09-2009, 03:54 PM
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Default RE: sealing balsa before final sanding

I'm sorry, I read sealing and my brain locked into filling, an old age Brainfart, my bad.
I have never bothered using sealer on the wood before covering but I do seal before glassing. No real reason for it for covering but if you do seal and sand no problem, the covering will stick with or without it.
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Old 09-09-2009, 10:02 PM
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Default RE: sealing balsa before final sanding

Don't use GREY primer. It changes the color of the covering. I put yellow over grey primer and it looks greenish. Where the primer was sanded down to the wood the covering looks yellow. Plane looks like heck but I'm not going back and change it.
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Old 09-10-2009, 05:31 AM
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Default RE: sealing balsa before final sanding

I like to use a sanding sealer just before final sanding with a very fine sandpaper. It makes the balsa surface just a bit tougher and more resistant to the little dings we usualy get. I now use a latex product available at Michael's Craft Stores (and other Craft Stores) called ModPodge. Works well for me.
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Old 09-10-2009, 06:18 AM
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Default RE: sealing balsa before final sanding

Quote:
ORIGINAL: Gray Beard

I'm sorry, I read sealing and my brain locked into filling, an old age Brainfart, my bad.
Not really your fault. The title of the thread is "sealing," but the first post straight off says "filling." These are not the same! When I cover a model with one of the plastic films, I make sure to fill low spots in sheeted areas, or dent's and dings, with white or tan spackle paste. But I see no reason to fill the grain of the balsawood in general. Sealing the balsa before the final sanding helps to get the fine fuzz off, and it does help the film to stick better, but I don't see it as essential. I've used hairspray or thinned white glue with a brush, and they both work fine. I wouldn't use a paint primer. In addition to the color problem already mentioned I think that would add too much weight and not enough benefit.

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Old 09-10-2009, 11:50 AM
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Default RE: sealing balsa before final sanding

Hi!
Adding anything to the balsa surface prior to using Oracover (Ultracote in the US) or any other plastic covering is useless and only makes it harder to fasten the film.

There is one exception to this though! And that is when you have a sanded, glass fiber covered, balsa surface where you have used polystyrene plastic to secure the glass fiber weave...then the plastic film stays put like crazy when you apply it with an iron (ironing is the best method when covering).
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Old 10-19-2009, 12:38 AM
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Default RE: sealing balsa before final sanding


Quote:
ORIGINAL: jaka

Hi!
Adding anything to the balsa surface prior to using Oracover (Ultracote in the US) or any other plastic covering is useless and only makes it harder to fasten the film.

There is one exception to this though!

What about fuel soak balsa?... could use [link=http://www.coverite.com/accys/covr2500.html]balsa rite[/link] for that our just sealing before covering.
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