2-4-2 Powered Unit repairs to shell corners

3D model of replacement corner material.

The plan is to shape it to fit and super glue in place.

Are you planning to butt join the new pieces to the original shell?
If so, I have to wonder whether the joint would be strong enough.

yes. from the underside.  Maybe a bevel to the pieces would help.  The hope was superglue kicked with baking soda in layers would create a strong bond and fill at the same time.  It would probably be wise to experiment first

I also think regular Superglue is rather brittle. Might not be the best choice for glue.
There is a flexible formulation, but I am not certain how flexible it really is.

Keep us posted.

The 3D printed pieces from Shapeways.com

Traced the cutout line

Test fit. A lot of back and forth with files and dremel

Stuck the piece on with some glue.  Then soaked the gap and sprinkled baking soda until covered

Same top side

Needs a little more fine tuning, but overall very happy with the results.  The 3d Printed material is a little grainy, but smooths out with filing.

Test fit of the larged piece. I goofed on the placement of the hole. Luckily it was cut out of the material anyway. I Will drill a new one later.

Piece tacked in place with tape and drop of glue.

After soaking gap and adding baking soda to add bulk.

Top side.

After some filing and a new hole drilled.  Overall very happy with the way this turned out.  I've experimented with mixing some testors paints and have come up with a combo of white, yellow and wood that comes very close to the yellowed plastic.

Looks like a pretty good job.  I hope it holds up for you.

Looks good, the proof will be in the longevity.

I think my approach would probably be JB-Weld with a thin backer for strength.  I'd probably use some of the .020" fiberglass sheet I have for the backer and JB-Weld to build it up to the shell thickness.

Thanks. I'll report back if it ever fails.  The JB and fiberglass sounds solid.  I'll look into getting those materials on hand.

I don't have a 3D printer, so I have to do it the old fashioned way.

I don't either. I use an online service for the printing.  One day I will, but for now getting prints off a $100K machine for dollars is the way to go.  I do use CAD all day, so it's easy to turn my day dreams into models ;-)

seems like a nice repair...like to see the finished product after the touch up work....do you plan on just touching up the repaired area? or are you going to attempt a blend out and coat the entire model with some sort of satin clear to help hide your repair? if you get the color real close, an airbrush and a blend out and then a final top coat over  the entire piece may yield you a better re-finish for all your hard work in making the repair parts.....great job on the parts!

StrapHanger posted:

I don't either. I use an online service for the printing.  One day I will, but for now getting prints off a $100K machine for dollars is the way to go.  I do use CAD all day, so it's easy to turn my day dreams into models ;-)

You have just nailed why I don't have a 3D printer!  While I can muddle through very basic CAD stuff, designing anything meaningful with CAD just isn't in my wheelhouse.  That is the major sticking point for general use of 3D printing, at least for me.

JBW is interesting to mold with and likely would have been my filler on the backside. I prefer the quick set for most molding to avoid droops. Plastic wrap leaves a smooth glossy surface once removed but pinches in corners and folds you leave. It can be worked as it sets, using water to keep it from sticking to fingers and tools.

But it looks pretty good. I'd think about some rubber washers or O rings under the shell, screw heads or both. Nylon screws are another possibility to stop it. 

Folks use um on FMTMs 

harmonyards posted:

seems like a nice repair...like to see the finished product after the touch up work....do you plan on just touching up the repaired area? or are you going to attempt a blend out and coat the entire model with some sort of satin clear to help hide your repair? if you get the color real close, an airbrush and a blend out and then a final top coat over  the entire piece may yield you a better re-finish for all your hard work in making the repair parts.....great job on the parts!

For now just Testors enamel model paint and a brush feathered to the edge of existing plastic.  I would like to get an airbrush setup, but its just not  something I have time for now.  The 3D printed material is a little grainy so might need some primer filler and sanding first.

what does the baking soda do in the repair process ??  thanks

StrapHanger posted:

harmonyards posted:

seems like a nice repair...like to see the finished product after the touch up work....do you plan on just touching up the repaired area? or are you going to attempt a blend out and coat the entire model with some sort of satin clear to help hide your repair? if you get the color real close, an airbrush and a blend out and then a final top coat over  the entire piece may yield you a better re-finish for all your hard work in making the repair parts.....great job on the parts!

For now just Testors enamel model paint and a brush feathered to the edge of existing plastic.  I would like to get an airbrush setup, but its just not  something I have time for now.  The 3D printed material is a little grainy so might need some primer filler and sanding first.

use the JBW quick set as a body filler over the grainy surface of the 3d repair material....then fashion a small block to use as a small block sander and block the filler down to level with 600 or finer, if its as grainy as you say, rattle can primers, even the filler type are lacking in their ability to "fill". That kinda primer will barely fill in 600 grit scratches, let alone a grainy surface....still, you've done a superb job!

f cashwell posted:

what does the baking soda do in the repair process ??  thanks

I was curious about that myself.

gunrunnerjohn posted:

f cashwell posted:

what does the baking soda do in the repair process ??  thanks

I was curious about that myself.

I googled that while I was eating dinner....evidently it acts like a super accelerant and makes CA bond stronger......I never knew this either....my luck it'd make a bomb and the feds would come snatch my a** up!

I have seen it suggested to use as a gap filler along with the CA.

Gap filler.

The topside looks close. For topside finish filler, I'd use plain modeling putty for ease of sanding and best feathering as the JBW will likely be harder than the host plastic making feathering harder on the host. The bottom was a better JBW candidate.

Interesting, it's never too early to learn something new, never knew about the baking soda trick.

Adriatic posted:

Gap filler.

The topside looks close. For topside finish filler, I'd use plain modeling putty for ease of sanding and best feathering as the JBW will likely be harder than the host plastic making feathering harder on the host. The bottom was a better JBW candidate.

 Actually, JB-Weld sands very easy, especially the Quik stuff.  I've had no issues shaping it when repairing plastic with it.  I prefer the Quik for repairs that don't require maximum strength as it sets up pretty quickly and isn't as liquid as the standard mix.

f cashwell posted:

what does the baking soda do in the repair process ??  thanks

It sets the glue instantly and adds bulk to the glue that would otherwise dry down to a thin layer. Even when applied thick.  It can be shaped, drilled and sanded.  Best method is to add it in layers of glue and sprinkled in baking soda.

Puddy sounds like the way to go.  There is a automotive finishing version that i might try out.  Its used over sanded bondo for final blocking

I'll be the first to point out that I did not 100% nail the color match.  I'm still happy with the results though. The camera and lighting adds more shine and yellow then appears in person.  From a foot away it blends well with the rest of the shell that has a yellow to tan marbled look to it. I just did two coats with a fine sanding in between to smooth out the finish.

I'd say you did a very nice job, good save!

I agree with John.  Nice job indeed.