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Apr 18, 2017, 12:32 AM
Registered Airplane Offender
greenseaships's Avatar
Yippee!

72-inch JU-88 from 3 Views alone


Ah! I feel alive again!! I'm finally building a new aircraft. A cool one (I think) that will have nice ramp appeal at the local clubs and funflys.

A 72-inch wingpan Junkers JU-88 "Schnellbomber".

I used to be very prolific with my builds but this is only my second new aircraft of the year and it feels good to have some enthusiasm again, so I'm starting a new build log/thread. As with all my aircraft, this one is being built from 3 view drawings alone. Basically, build a box from 1-inch thick blue foam and belt sand the bejesus out of it until you end up with a roughly oval cross section.

I guess the belt sander (with 120 grit belt) is the end all to this construction. No fancy bulkheads or fuselage formers. But it will be interesting to see how scale-like and accurate it comes out to be.

I only had 2 hours to work tonight, so I didn't get as far as I wished, but it is a major start and once she's sanded into shape, the hardest part of this build will be over!

The bottom panel of the fuselage 'box' is a paper covered foam board that we use in picture framing, but I think you folks know it as Dollar Tree foam. So there will be an imperceptible flatness to the bottom of the fuselage in the final product.
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Apr 18, 2017, 09:05 AM
I Look, Listen, and Learn
Timbo383's Avatar
Glad to see you getting back into building again, it's been awhile.
Apr 18, 2017, 10:32 AM
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greenseaships's Avatar
Thanks, this one's gonna be fun!
Apr 19, 2017, 10:27 AM
Allways the hard way!
georgy's Avatar
Nice subject! Me likey! Will be following...

But: What glue do you use to join the sections that allow sanding across the joint line with-out making booboo?
Apr 20, 2017, 12:43 AM
Registered Airplane Offender
greenseaships's Avatar
Thanks, G! As for your question, it is a very fine line I walk. I use a special tape gun called an ATG gun.

http://www.dickblick.com/products/sc...700-dispenser/

This stuff sticks pretty well to foam. I run a line along the edge of the foam where it will join the other panel. This line must give about 1/2 inch border from the outside of the joint, to minimize the risk of gorilla glue oozing through to the outside of the fuselage!

Then along the INSIDE of the seam, I run a thin bead of gorilla glue. So close to the edge of the foam panel, this gorilla glue is SUPPOSED to ooze out a bit,a nd create a sort of 'shoring up seam' along the inside edge of the panels.

It is important to mask off the area that will be ATG'ed if you are going to spray the gorilla glue (to activate the glue). The ATG will not want to stick to a wet surface. Then run the ATG along the area that was masked off during the 'wettening'

Maybe this illustration can demonstrate.
Apr 20, 2017, 12:50 AM
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greenseaships's Avatar
Belt sanded the fuselage yesterday and I love the way it looks (at least the fuselage behind the cockpit )

Also closed up the cockpit area and got it ready for sanding. Still working on a detailed plan to make the cockpit windows clear. I'm definitely less than a pro at making canopies but I have some experience.
Apr 20, 2017, 07:06 AM
I Look, Listen, and Learn
Timbo383's Avatar
Watching and learning different ways of doing things. I hate carving the hard gg off the outside of the foam after sanding.
Apr 20, 2017, 09:03 AM
Registered User
Zipman's Avatar
Greenseaships,
I have been following many of your builds. Learning a lot. Great idea to use the double sided tape.
What glue did you use to attach the bottom white foam board?
Thanks
Apr 20, 2017, 10:26 AM
Registered Airplane Offender
greenseaships's Avatar
Timbo- yeah, me too, although the belt sander just sorta eats that stuff up. Running the gg seam along the inside is (mostly) successful in keeping the gg on the correct side of the panel.

Zipman- I used a thin bead of gg along the bottom white foam as well. I tried as much as possible to keep the glue to the inside of the foam but inevitably some comes out. So while the glue is slowly foaming up and hardening over the course of a half hour or so, I keep tending to the area, scraping off overflow as it oozes out with scraps of foam.
Apr 20, 2017, 04:28 PM
Vacuum Tubes Forever BCT2/BCR3
A question on the double sided tape and sanding. When you are sanding an rounding the edges, do you sand into the tape?

Thank

JohnB
Apr 20, 2017, 10:30 PM
Registered Airplane Offender
greenseaships's Avatar
Quote:
Originally Posted by jiberk
A question on the double sided tape and sanding. When you are sanding an rounding the edges, do you sand into the tape?

Thank

JohnB
No, I try not to. I try to leave a buffer zone of about 1/2 inch where I can sand the corners of the 'box' without reaching the area where the tape is. Between the buffer area, the tape strip (itself about 1/2 inch wide) and the gorilla glue, it's a lot to squeeze into a thickness of only 1 inch! Sometimes I wind up sanding into the taped zone, sometimes gorilla glue ends up oozing through to the outside of the seam. It's just a thing you get better at with practice.
Apr 20, 2017, 11:40 PM
Registered Airplane Offender
greenseaships's Avatar
Still the only decent doc I can find on the JU-88

Wings of the Luftwaffe: Ju-88 "Schnellbomber" (44 min 10 sec)
Apr 21, 2017, 01:17 AM
Allways the hard way!
georgy's Avatar
Quote:
Originally Posted by greenseaships
Thanks, G! As for your question, it is a very fine line I walk. I use a special tape gun called an ATG gun.

http://www.dickblick.com/products/sc...700-dispenser/

This stuff sticks pretty well to foam. I run a line along the edge of the foam where it will join the other panel. This line must give about 1/2 inch border from the outside of the joint, to minimize the risk of gorilla glue oozing through to the outside of the fuselage!

Then along the INSIDE of the seam, I run a thin bead of gorilla glue. So close to the edge of the foam panel, this gorilla glue is SUPPOSED to ooze out a bit,a nd create a sort of 'shoring up seam' along the inside edge of the panels.

It is important to mask off the area that will be ATG'ed if you are going to spray the gorilla glue (to activate the glue). The ATG will not want to stick to a wet surface. Then run the ATG along the area that was masked off during the 'wettening'

Maybe this illustration can demonstrate.
Thank you kind sir.. whodduf thunk to "not" glue the sanding area!

I like the carve and sand method... but hate the sanding through glue process so I normally just used solid chunks and cored it with heated thin-wall stainless tubing. Nowhere near as strong as a box section.
Apr 21, 2017, 05:55 AM
Registered User
Quote:
Originally Posted by greenseaships
Timbo- yeah, me too, although the belt sander just sorta eats that stuff up. Running the gg seam along the inside is (mostly) successful in keeping the gg on the correct side of the panel.

Zipman- I used a thin bead of gg along the bottom white foam as well. I tried as much as possible to keep the glue to the inside of the foam but inevitably some comes out. So while the glue is slowly foaming up and hardening over the course of a half hour or so, I keep tending to the area, scraping off overflow as it oozes out with scraps of foam.
Green
Here is how I take care of foaming glue. As it starts foaming, I wipe the glue with the bathroom tissue which I soaked with Methyl Hydrate purchased in the Home Depot store. You will have to do the wiping two or three times. Tri it, you will like it.
Apr 21, 2017, 07:31 AM
I Look, Listen, and Learn
Timbo383's Avatar
Quote:
Originally Posted by LADDIE
Green
Here is how I take care of foaming glue. As it starts foaming, I wipe the glue with the bathroom tissue which I soaked with Methyl Hydrate purchased in the Home Depot store. You will have to do the wiping two or three times. Tri it, you will like it.
I'm heading out to home depot.


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