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General control line discussion => Open Forum => Topic started by: Motorman on February 10, 2016, 09:39:33 AM
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I molded a leading edge and it didn't come out quite right. It's got a couple of low spots/indentations where some of the ribs were a little too small. I don't want to rip off the LE because it's glued on so tight so I want to fill the dents with something. It's on the bottom of the outboard wing so weight is not a big problem.
I was thinking Hobbylite balsa colored filler because it's cheap, easy to apply and sands very easy. I know it's not good for fillets but I'm going to cover the wing with polyspan and nitrate dope and wondering if it would cause a problem under there? Don't care about adhesion in that little spot but would it eventually blister up?
Really didn't want to pay $30 for Superfil only to use it once. The other option I have in the shop right now is Bondo.
MM
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Go with it. May take a couple of thin layers to build it up.
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It's good stuff. Can be seen through most any color silk job.
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I'd laminate on very light sheet balsa and sand down to shape. Cement or medium Cya would do the trick a lot lighter.
Dave
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I tried such products in the past and will never use them again. When I tried Model Magic (Model Tragic) and other such products they softened when dope was applied and then never re-hardened adequately. Although these products might be useful when another material is applied over them I still fear the the dope will reach them and the trouble starts.
I have used the Elmer's wood filler for filling in small areas that will be covered with polyspan or some other material. The Elmer's also softens from the dope but it seems to re-harden better. So far I have not had any problems with it. Even so, I rarely use the Elmer's or any water based filler anymore. I went with the Super Fil since I use it in many areas and it was worth the cost.
I would experiment first on some scraps before I committed to using the Hobbylite or other such products.
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I'd laminate on very light sheet balsa and sand down to shape. Cement or medium Cya would do the trick a lot lighter.
Dave
I just did this as a repair for my friends airplane. Sanded it, used aerogloss sanding sealer and covered back with 21st century fabric covering. Came out excellent.
Good call sir
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I'd laminate on very light sheet balsa and sand down to shape. Cement or medium Cya would do the trick a lot lighter.
Dave
This is where 1/32 balsa sheet comes in handy, glue it on and block sand to conform with the existing wood. No shrinkage and lighter than any filler.
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I molded a leading edge and it didn't come out quite right. It's got a couple of low spots/indentations where some of the ribs were a little too small. I don't want to rip off the LE because it's glued on so tight so I want to fill the dents with something. It's on the bottom of the outboard wing so weight is not a big problem.
I was thinking Hobbylite balsa colored filler because it's cheap, easy to apply and sands very easy. I know it's not good for fillets but I'm going to cover the wing with polyspan and nitrate dope and wondering if it would cause a problem under there? Don't care about adhesion in that little spot but would it eventually blister up?
Really didn't want to pay $30 for Superfil only to use it once. The other option I have in the shop right now is Bondo.
MM
Ok in very small quantities and not around butyrate dope. All of these lightweight latex-based spackle compounds are incompatible with butyrate dope. The original CG "Model Magic" was renamed "Model Tragic" because of the issues.
If you just have rare small need, red air-drying automotive filler, or Testor's contour putty, is a reasonable alternative.
Brett
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I have also used Elmers Carpenters Wood filler, it dries much harder than the balsa filler and sands really easily
Fred
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What about spackling compound?
MM
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It's the same stuff only white
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I use Ambroid and balsa for this sort of thing.
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If you buy the Super Fil you will use it more than once, it's great. I need to order more since my "lifetime supply" is almost gone (in 3 years).
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What about spackling compound?
I actually don't know about regular "heavy" spackling compound. I would expect it to be better but I don't have any experience. This is the stuff I used before I had Super-Fil:
http://shopforpaint.com/Nitro-Stan_Red_Glazing_Putty_tube/category_id/209.html
It's pretty heavy and still shrinks some, but it generally works, and you shouldn't try to fill large areas anyway, so the weight impact is minor.
Brett
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If you buy the Super Fil you will use it more than once, it's great. I need to order more since my "lifetime supply" is almost gone (in 3 years).
Tom, your not supposed to build the fuse out of the stuff for cryin out loud LOL
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Way back I used plain old spackle. It works fine. I even made large fillets on pattern planes with it. Tight ones, not so good! Filling low spots should work but, as mentioned not recommended. I might go back to it for ding and minor imperfection work. Sands good and only shrinks once. This is the USG green label. The light weight stuff (blue)was the one that got attacked by dope. Now, there are multiple grades but I believe the green is still the same. I only use it on my walls now. I had graduated to Micro balloons and now super fill.
Tom