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1/18 Scale Blue Box F4U-1A Corsair Modification


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Hi, Jay


Instead of putty for those massive trenches and divots on the inner wings, I'd use CA glue, either the black rubberized version or just your garden variety CA with some dental acrylic powder, or even baby powder works. Reason being putty has a tendency to shrink, which means you'll need several rounds of applying putty/sanding over a period of at least a few days to get it to somewhere on par with the smoothness of those metal skins. Black CA (or with added filler), on the other hand, does not shrink and if you spray it with some accelerator will harden instantly, which means you can get right into sanding and get the job done with much more expediency, not to mention better results.


Spellbinding work, as always, dude!

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Ok, I’ll bite.

Knowing it’s a) not my model and b) still not my model and I’m not doing the work.  If it was me, I’d do the skinning. I think you have better than even odds knocking something loose while sanding whatever you decide to use to fill those trench-like panel lines. Plus side it’ll match what you’ve done with the rest of the airframe, which is resplendent. 

That being said, I agree with Tag. Cyao with a filler.

And as always, thanks for taking the time to document and share with us. Ranks up there with Peter’s amazing work!

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I would consider JB Weld to fill those panel lines and rivets. You can smooth it with acetone (or nail polish remover with acetone) as it sets up, and it sands and feathers beautifully- plus it is super strong when cured, but easy to scribe and drill, and it won’t crack.


Timmy! Turned me on to it years ago. It is my go-to filler for all the reasons I describe.

outstanding craftsmanship BTW! Love everything you are doing!



Edited by Pete Fleischmann
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Go, Jay, Go!


Nothing to add to your request on filling as you've got some good input already. I'm in with the "skin" it if possible recommendation. Fill/sand or skinning will still be a chore either way as your build has it's gear installed. In the end, I'm sure you'll win either way! 


Best of Luck, whichever route you take. Gorgeous Corsair work, just Gorgeous!



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Brilliant work on the wing fillet panels Jay, especially taking them on for your first attempt!


For the wings, if you can't skin them then I would fill with a nice easy to work filler like P38 (bondo in your parts?) and cover with a nice thick high build automotive primer.  That's the easiest route to a clean finish.  The beauty of it is that the scribing largely happens in the primer  not the substrate...


Try it on a mule with awls for fastener detail etc to see how you fare



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Brilliant work on the panels Jay!


Totally understand your reasoning for not skinning. If it was me I'd do it, but I'm not known for rational decisions..... ;). Might be a bit of work, but would using thin styrene rod or the like and painting glue on them to effectively "melt" them into the panel trenches to fill them be worth a shot? All the above suggestions are equally valid, but I was thinking that might produce a nice homogenous finish?


Peter's suggest is probably the best way forward though to be fair.....


Whatever the route you choose, it'll look a billion times better than the original kit though! 



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So there was a bug when I tried a quote a reply last night.  Peter is spot on with his material suggestions, let’s call it automotive filler and a 2k (meaning 2 part) primer, you can make subtle panel lines just as advertised.  However, my vote, for what it’s worth, is to skin to match the fuse.  Got that application I suggest JB Weld.  JB Weld is not magic, it’s epoxy with a metal powder filler; it’s not too far removed from automotive filler, but there is more epoxy relative to filler in JB Weld.  In a practical sense JB Weld will stick better in smaller areas than a body filler simply because there is more glue than filler.


if you want to sheet the wings and need a solid foundation of filled panel lines, I can’t recommend JB Weld or a similar metal filled epoxy enough, to give you a solid substrate to sheet over. 

Without prejudice and sooper happily following this build…tho admittedly quietly.  


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Thank you fellow modelers for all the comments and suggestions for moving forward on the wing surface treatment.  Still have not decided what to do, but will soon.


Meanwhile - I have some encouraging news on the removable panels over the engine accessories compartment.  The compartment is covered by three panels - a top panel, and a LH and RH panel.  I intended all three panels to be removable - fixed in place by magnets.  Something I have never done before save a Tamiya P-51 a couple years back.  


First the not-so-good news.  It became apparent to me that this plan was just asking too much.  Just too many variables to juggle and expect clean results.  I have noticed in pictures of Corsairs, both modern and period, that it seems rarer that all three panels are removed.  More often, the top panel stays in place, and either the LH or the RH or both side panels are removed.  So I decided to permanently attach the top panel, and stick with the plan on the side panels.  


So, the top panel:




Do you see the little wafer magnets?  Ten of them, meant for the side panels that share that edge.  They are .03 inch thick by .06 inch diameter, bonded with CA.  The hard part was dealing with the magnets.  I would put a small puddle of CA where I wanted it to be, wet my fingertip, pick up the magnet, and attempt to place it on the CA puddle.  At which time the magnet would suddenly, just before successful placement, zip off my fingertip and fly over to an adjacent magnet!  Using tweezers (steel tweezers) was problematic, as the magnet would want to stick to the tweezers rather than the still uncured CA puddle.  But with persistence, I got them on there. 






This panel was quite easy to fabricate.  It is plastic through and through except the magnets.  It got its curvature from taping the .020 skin detail to a bicycle water bottle, dipping in boiling water, and then tossing it into the freezer for a while.  I'll always be thankful to Peter (Airscale) for turning me on to that method.  Later it would be skinned with aluminum, and the access door for the hydraulic reservoir added.  You can see its skin cutout.


Much harder are the side panels - I am in the midst of fabricating the LH panel:




Note the stiffening elements - .03 x .04 (or .03 x .03) plastic strip.  The skin detail also got the hot water / freeze treatment.  It is holding its shape magnificently especially with the stiffeners.  The hard part here was getting the periphery trims right.  It involved draping masking tape over the fuselage where it's supposed to go, without any surface to tape to except the surrounding edges, marking the edges with pencil, removing the tape and applying it to .020 inch thick plastic sheet, and hoping for the best.  I actually got it on the first try, but it took a couple of hours of careful trimming and filing and sanding. 


Here it is placed on the fuselage:




Folks - this is a major victory.  What a thrill.  I am not totally happy with the surface mismatch - the aluminum skinning is going to be a bit proud of contour here and there.  But except for that, the edges match pretty well with the other panels, the magnets are working wonderfully (MOF it's kind of hard to remove!).  And it's contour is spot on.  Next you see it, it will be skinned - just a giant victory.  All this time - years really - I did not know if the magnet plan was going to work well.  Am very relieved.  






I intend to close up the gaps at the edges when it gets skinned.  Still, the plastic panel fits pretty darned good.  


Then I skinned the top panel, an easy job but care had to be taken not to put too much pressure on the panel while burnishing the aluminum down.   Mustn't buckle it!








Next post I will have the LH panel skinned, and maybe the RH panel finished too.


See ya soon.  



Edited by JayW
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Last post, I declared victory on the engine accessories bay removable panels.  Well, the battle was not over it turns out.  The RH panel (not started at the time I declared victory) was much more complicated than the LH panel, and more importantly, neither panel had been skinned yet. 


The last two plus days have been spent trying desperately to convince these two panels to behave and lie down on contour, befitting of good highly visible parts on a big Corsair:




Turns out the multiple access doors on the RH panel were eventually non-problems.  But to get there I had to provide some extensive framework around the holes, and add an inside web to help with the stiffening and shaping. 




Labor intensive and stressful, but ultimate successful after a fashion.  No, the problem was the aluminum skins - which have a mind of their own when bonding to a somewhat flexible removable panel.  To date, all my skinning efforts have taken place on a hard stiff surface.  So even if they don't want to, they can ultimately be burnished down to match contour.   Not so much on the removable panels.  If the aluminum skin doesn't want to conform to a contour, it tries to take the underlying panel with it!  So it was a two day battle to get the panel shapes as close as possible to contour.  What you will see here is the best I could do.  I could have doubled the amount of magnets and got some improvement, but not much.  Besides - too late for that.  Woulda coulda shoulda.  I was also subjected to the variation of the original model skin gage, which varies from about .075 to .085 inch.  This also adversely affected surface mismatch. 


Here are the finished removable panels installed:






And panels removed:




Note also that I have attached the 3D printed "shoulders" that are underneath the cowl flaps (once they show up). 


That RH panel is pretty busy - let me further describe:




I am going to show you the worst of the contour mismatch:






A couple more hours of fiddle-farting around might improve some, but I am at a point of diminishing returns, for sure.  I wish I could have detected the variations in the original model's thick skin gage earlier - perhaps I could have done a couple things different.  That was the biggest culprit.  Anyway - these pictures make it look worse than it is.  I am mindful that what I have here is removable panels that uncover a full blown engine accessories compartment!  Huzzah!  


With those big panels done, the way was cleared to install the 3D printed shoulders.  This was straight forward, but I got an unpleasant (but not entirely unexpected) surprise.  I have excessive gaps between the shoulder details and the 3D printed exhaust stack cover plates:




"Not entirely unexpected" because the aluminum skins are .005 inch thick, and do not lie down perfectly.  This increases the circumference of the cowl a few hundredths, something I didn't design for - so there you have it....   The other side is the same way.  That gap is a bit too much to deal with easily.  Plus - the longer free standing tab on it doesn't match the fuselage cutout very well.  I am going to design revision "A" of the exhaust covers, with one end extended about 0.05 inch, and include them in my next 3D print order coming up soon.   Replacement of 3D print parts is happening a bit too often here!  :(


The way was also cleared to install the long awaited forward external tank hook.  The F4U-1A, if you will recall, had provisions for a large centerline fuel tank (or bomb).  It lacked the twin mounting provisions that we see on the "D" models.  The drawing:





About three months back you may recall the aft hook was installed under the spar:




The forward hook was a simpler fabrication yet still a PITA.  Here it is finally installed onto the engine mount ring:








So now my centerline aux tanks provisions are in place.  Yay!


This project is taking forever.  Here are a couple of pictures, just to remind all of us the end game - to show off that big radial (and not hide it):






That's that for now.  Next I will try to convince myself to begin wing skinning.  A quote from a recent post:  "Here is what I am NOT going to do - skin the wings."  And then I got a chorus of complaints.  Along with some very good suggestions.  So yes - I have decided to give it a go even though I don't feel very good about it.  I am not sure the gear doors can survive more handling - I try and try to be careful but they get nudged alot, and I have broken the gooseneck hinges on both already.  They can be repaired but its a bit messy.  I wish there were an easy way to just remove them, but there isn't.  Hope they survive this intense work....


Stay tuned - there is great adventure coming. 





Edited by JayW
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