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Old Aug 28, 2012, 10:40 PM
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Hampton, VA
Joined Mar 2009
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Da Good, Da Bad, Da Ugly

Listen to that inner voice. Da Good. Manage to get the sections of the plug cut today. And boy was I excited. Ready to get to the next step. Well, almost ready to get there. Took a couple of pics to show the progress and then decided to glue the sections together. Well, reach for one of my favorite glues, 3-in-1 Advanced Craft Glue. Then that inner voice said, "You have lots of scrap material. Check out a test glue joint." Then I thought, "I'm in a hurry to get this done. Don't think it's really necessary." Well, it was. As you'll see in the pics below, my favorite did a number on the Blue Foam. Lesson Learned!!! Tried to put the sections together using tooth pics, but the Blue Foam was too soft at the joints. So... I'll cut another set tomorrow. And the next glue I use, I WILL DO A TEST JOINT!!!

But all in all, I'm actually really happy. Now I know, it can be done. Question, what kind of primer is good to use for Blue Foam? I should be able to get the raw plug cut out and glued together tomorrow. Then sanded down. More to come.
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Old Aug 28, 2012, 10:51 PM
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Omaha Nebraska
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Ksqm,

That what happened. I bought 3-in-1 too, and shelfed it because it does the same to fff, and it's blue too though. For what you are doing, Elmer's rubber cement would be light and good. A single drop of CyA (foam safe) or Epoxy too, just right dab in the middle of each sections face would work too. You do not want glue to go to the edges, you only need it tacked in the middle. glue at edges makes sanding hard, or even causes damage sanding, and if you want to desolve the foam later, glue coving the whole section can inhibit the flow of solvent. I do this short stop glue thing even on full fuselages because later when I do filler, sealer, and other things, the sections will wick in enought 'stuff' to finalize the glue joints.

The ducts looked awsome though. Guess it was trying your patience! I'm sure the next set will go faster, and turn out better! Keep at it, you are a true craftsman and I appreciate you posting you work for us to see!

Fred

EDIT: Primer. Plane old Polycrylic by Minwax is good primer, and sands smooth. Otherwise Testors, or Tamyia. If you don't want to spend $$$ (Who does), craft paint, flat, works, and a bit of talc powder mixed in, or lightweight and some water thinned out, with some drops of craft paint also work well enough. Do practice on a scrap part first.
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Last edited by Freddie B; Aug 28, 2012 at 10:56 PM. Reason: Edit, edit, edit! Spelling and forgot stuff
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Old Aug 29, 2012, 06:07 PM
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Crystal River Fl.
Joined Jul 2008
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Ks,, like Fred, I've tried the Beacon,s and found the same problem, like Fred said, try the Elmer's rubber cement, get it at Wally for about$1.60 even comes with a brush on the lid, brush on a coat on both surfaces, let dry,, about 45 seconds and fit together, works like contact cement so nake sure you have your pieces lined up... Sands like it isnt there too,,, great stuff, give it a try.. His other tips are great too,,, I use the craft paints from Wally,,, cheap, any color you can imagine, very versatile.. I use an airbrush to spray them,, thin with winded, the surfactant in it helps it flow and dry...I use the for primer and final coats.. Good luck. W
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Old Aug 30, 2012, 12:03 AM
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Hampton, VA
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Freddie B and Waltjg,

Thanks guys. It's funny, I was holding a jar of Elmers, the day before, while shopping for school supplies. Well, I'll get some later today.

Ksqm
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Old Sep 02, 2012, 09:01 PM
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Hampton, VA
Joined Mar 2009
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Check in time. Well, we all have our learning curves when trying something new. Learned a bit about hot wire cutting (micro). Raw plugs are done. I've attached some pics to show what I've done and learned. Now for the next step, prepping and glassing.

Ksqm
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Old Sep 02, 2012, 10:03 PM
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United States, OH, Dayton
Joined Apr 2004
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Ksqm,
Not sure how important that molded ducting is to you but for the F-20 airframe you could save some weight by simple using the fuselage walls as your ducting and still be pretty efficient. You are dealing with a small airframe and Au117 really taught me the importance of weight savings. His f-35 also has some ducting compromises to minimize weight and I personally think it was worth it. It's still goes 60mph and lands at a crawl.
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Old Sep 02, 2012, 10:47 PM
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Hampton, VA
Joined Mar 2009
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Pdawg,

I have to admit, you have a good point. My 22mm build did not have any inlet ducting and flew pretty good. In fact, I increased the length of the fuse walls from the original plans of this build, for just that reason. The only problem though, most of my electronics would be exposed to the air stream.

I also have an ulterior motive. I'm planning, for me, one of my dream builds. And it will require inlet ducting. I figured this would be a good trial run. If the ducts weight too much, I can still just go with the fuse walls. But seeing Hover Or Die do his ducts, well, I thought it was time to give it a try. Also, I got started using a hot wire cutter. Which opens up a whole new world and makes the dream, a reality. Right motivation, wrong build, who knows. More to come.

Ksqm
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Old Sep 03, 2012, 12:42 AM
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Freddie B's Avatar
Omaha Nebraska
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Ksqm,

First you have really big hands! Or you are making a really tiny model! LOL. Pdawg has a valid point on weight, but I am so like you and a great build is always going out on a limb and trying some new stuff, usually as you stated, for a future project. Pdawg sure did with his Electrolite, and it is very heavy by my standards. He was a master (and NC) for getting it to fly, and fly good, but not without huge challanges. I think we all learn by things that others do, and Pdawg is giving us good advice to keep the weight down. However if I can test something now for future projects, so be it! I am liking what I see, and you never know what you are capable of coming up with until you try it.

So as I continue to add many cool factors and ideas too my builds, all the time I am learning to get these bits and pieces lighter and lighter. I don't think you would be happy if all your intake and exit air was flowing around servos and such so if you ever change to that idea you would have to move stuff or add some splitters.

So far so good. I am liking what you are doing. Keep what Pdawg said in mind and always think light. Light is a builder goal! I think you are doing that, and Hover-or-die showed his results, so we will see where this comes out too! Keep up the great work.

Fred
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Old Sep 09, 2012, 10:02 PM
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Hampton, VA
Joined Mar 2009
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Quick update. Little building time. Managed to get nose and conopy rough sanded. Just put first coat of Freddie B's "Secret Sauce" on the inlet plugs. Once it's dry, I'll sand and do a thicker coat, then sand again. First coat was a bit too thin. Cut down a GWS 30mm rotor to ~25mm, but still need to do final sanding on it.

A bit disappointed with available time. It didn't help I spent all day under the hood of my Mazda6. Was planning to barbeque and get more done on the F-20. No joy. This one pic sums up progress. More to come.

Ksqm
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Old Sep 10, 2012, 11:12 AM
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Ahhhh.... The Bar-b-que time is most important. So is your Mazda6, but we don't like to do that kind of work. Looking good. A thought on secret sauce. It won't melt away as good as straight foam will if you use chemicals to rid the foam after glassing (lost foam method). If you are digging the foam out, much will release, but bound to have some residue. Since a smooth inside surface is desireable, some type of peel away release agent best (plastic film or tape), but not always possible with complex shapes. Maybe if the secret sauce is painted, then glassed, then chemical melt, and the paint melts away, you at most would have some light tinting left on a smooth inner glass surface. Just thinking out loud sitting here miserable with another Summer Cold!

Craftsman ship loking great and best to not rush working on the airframe until you free up some time. You will get a better product that way. It's hard to be patient, but recommended (trust me I tell myself this often, even today!)

Fred
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Old Sep 10, 2012, 02:34 PM
it wasn't me flying that plane
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United States, NC, Wilmington
Joined Mar 2011
705 Posts
Its crazy the way those ducts look big until I back up a few post and see you holding it in your hand and i remember we are working with MICROS...lol..
I'll tell ya those things look good..wax them as many times as you can stand and you will have much less hassle getting the foam out with either technique..lost foam or slitting the length..
After the have hardened well and you have the carbon wrapped(if you plan to)you can take a carbon stick and glue or tape some light sandpaper to the end and go in there and scrub the tubes out..a little acetone and the same stick/sandpaper will do wonders to clean up any left over paint in the tubes..i gave mine a scrubbing before final assembly and they looked great for the short amount of work...
With those long tubes it might pay to acetone the foam away and whatever is left in the tubes will scrub out..small wire brush works very well also...

Above all else those things look good and you can tell you put forth a lot of effort to get them right..excellent craftsmanship..The whole jet!

Grab your build time when you can..I will even take 10 minutes to just go over the build to see where to go next or how I will get "there"...With a 5 year old sometimes 10 minutes is all I get....lol
Take care ...................Chris
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Old Sep 21, 2012, 03:44 PM
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Hampton, VA
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Update time. First the bad. The first duct came out, but didn't. The first layer of glass went on pretty good. But things went sour for the second. AIR BUBBLES are a menace to glassing. I had gathered everything needed, save for a pin. That was my downfall. Some how I had these tremendous air bubbles and could not get rid of all of them. That was the first lesson learned.

The second, make sure glass pieces are cut to size. No more, no less. This may have contributed to the air bubble. Started in the middle, then spread to the ends of the duct, then start in the middle again to wrap the glass. Well, the glass was wide enough in some areas to start a second wrap.

Third lesson. Only had tooth pick stuck in end of duct on one side. Should have done both inlet and fan face sides. Also, use something that can go a good ways up the duct. This became a problem the longer I worked. The tooth pick started to come loose and the duct would spin on it. Not to mention, the over hang on the end of the duct, made holding the tooth pick a pain. Pics do tell a thousand words. The duct came off, but so did everthing else. A lot was learned, so the next duct should be perfect.

At any rate, the fan former is cut and fitted. The H Stab control horn and bearing tubes are set up and glued in. And there's clearance to keep everything inside the fuse. Here are a few pics of the good and bad.
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Old Sep 21, 2012, 04:15 PM
it wasn't me flying that plane
Hover or die's Avatar
United States, NC, Wilmington
Joined Mar 2011
705 Posts
ksqm,
I'm sure yu know where the problems were and have it figured out..don't stop as i know looking at your awesome construction techniques this is just a matter of having it all come together for you...You and i both would benefit from a batch of pva...
Really enjoying the work on your airframe...
Take care.................Chris
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Old Sep 21, 2012, 06:33 PM
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Hampton, VA
Joined Mar 2009
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Don't worry, I'm going to get these ducts done. I know what went wrong and most importantly, why. I was tempted to finish without the ducts. There's a fly in this weekend, Electrics Over Tidewater, I wanted to fly at. But it'll just have to keep. I'll just fly the T-50. More to come.

Ksqm
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Old Sep 28, 2012, 07:27 AM
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D_FAST's Avatar
Denver CO
Joined Apr 2008
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ive used beacon myself, i havent any problems eating foam. Are you guys not wiping it toa thin film with a CC or something hard and flat.

My enitre j-14 build used this glue. Didnt have any problems.But i do use Owens&Cornings brand of foam though.
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