B-17 Flying Fortress/44-83735 ~ the Duxford resto thread

[The Tarheel Lemon]

not exactly
This trap is under the wing after the engine, the compressor outlet
I see a picture included on page 4 with a small label that exceeds

[8674planes]

How long does it take for the paint to dry on an aircraft as big as a B-17?

[bomberflight]

Welcome to the early evening news here on Primer Time TV ......



And today's main news item is ~ PRIMER !



And more PRIMER !



We go now to the paint area in Hangar 5 at the Imperial War Museum ~ Duxford for this special Primer Time TV photo report ......



























Another update soon

[Fouga23]

Why do they paint it in sections?

[RAMC181]

not exactly
This trap is under the wing after the engine, the compressor outlet
I see a picture included on page 4 with a small label that exceeds

Peter, the access panel in question is from here, in the left wing trailing edge section underside behind the spar:



Wrong wing in this drawing, but you get the idea:



And the original panel from Tarheel Lemon itself:



Hope that helps a bit,
Paul

[bomberflight]

We better answer the outstanding questions before I post some pix from today .....

Thanks for you're input Paul with the photos / diagram !

8674 planes wrote

How long does it take for the paint to dry on an aircraft as big as a B-17?

It depends on a lot of factors ~ which include :-
the weather outside / ambient temperature and humidity inside the heated hangar / how much hardener is mixed with the paint

That's why you'll see the reddish glow of the infra red lamps in some shots ~ these are being used to heat sections of the airframe
if the skin needs additional warmth to paint or for the paint to dry.

This answer also applies to the question from Fouga 23 as to why it's being painted in sections.

Although additionally ~ just prior to the primer being applied ~ the section is cleaned down one final time with "tack rags" to wipe off
any dust or debris that will spoil the primer / final paint finish.

As many of you will have noted from the pictures being posted ~ the primer / paint process is taking a number of days to complete ~
so the fuselage needs some type of masking off to prevent over spray effecting the rest of the fuselage ......

And this might be the right moment to share some pixs from today when the underside of the fuselage was being painted





There's very little wriggle room underneath the bomb bay and radio room ~ so we'll move down the fuselage and watch the next section
to be painted .....







Are we having fun yet ?



One more from this side .....



And a quick whiz around to see the other side of the rear section being painted





The grey paint has been applied high enough up the fuselage side to that there's a good overlap for when the olive drab is applied



First coat done !



I'll finish this post with just a couple of pix of the second coat being applied ......





To be continued .....

[Ken]

I have to assume that the new nose art has been chosen ... therefore you must share!!

Keeping the secret sounds like a good idea, until you realize all the valuable time you're losing by not having the WIX crew turn up details and history that will enhance the final product ... don't make us wait until the last minute

[ZRX61]

A 'hole finder' works too, ....
Then it's easy to drill and cleco and be 99.999% sure of picking the existing hole up dead on, it's old timey production tooling that always travels the world with Boeing's AOG teams.

I can't believe no one at Dx has a set of these tools. That buggering about with bits of lexan just wastes time....

On another note, I notice the new paint on the left side of the cockpit section is 2 different shades...& then they didn't throw a sheet of plastic over that section while the got busy with the primer. That small section of masking paper isn't going to stop the overspray from going further forward no matter what the airflow in the hangar is. It seems they do outstanding work one day & foul it up the next.

[The Inspector]

More tricks and tips. Another trick to locate holes in a new skin is one used by Boeing AOG and anyone doing skins @ an MRO. You line up a known true edge of the existing part on top of the new blank skin and drill and CLECO like a maniac, we got to the point where a crew of 6 to 8 structures folks could remove, back drill, deburr, apply sealant and start installing lower aft fuselage body skins on 737's inside two 8 hour shifts.

For TARHEEL LEMON.
Your access door is from 42-97338 B-17G-45-BO, l/n 7811 attached to 398th B.G. 601st B.S. side code 3O*C, then to 600th B.S. side code changed to N8*C named according to Baughers site as 'Ugly Duckling' but the 398th site says it was indeed 'Tarheel Lemon' and had at least three different crews, one of those 'who ya gonna believe, me or your lyin' eyes?' deals. It appears to have survived combat, but then where it went is a mystery. Fin ID was a white W inside black triangle, same as the markings of the EAA's B-17.

Last edited by The Inspector on Thu Jan 19, 2012 8:11 pm, edited 1 time in total.

[ZRX61]

More tricks and tips. Another trick to locate holes in a new skin is one used by Boeing AOG and anyone doing skins @ an MRO. You line up a known true edge of the existing part on top of the new blank skin and drill and CLECO like a maniac..

Yup, replaced a lot of Spitfire skins using that method

[bomberflight]

Let's see if I can respond to some of the comments posted this week with some pix I took today ......

This is part of the new trailing edge skin that's now in place. Essentially it's a "V" section piece that slides under the edges of the existing skins on both sides .....



That's one of the reasons why a hole finder wasn't being used ~ it cannot slide under the new skin panel.

The other reason it was being done this way is that the reskinning operation was being done by volunteers supervised by a
full time member of staff. This skinning process is one that can be performed accurately by the volunteers. ( 4 full time staff and 70 volunteers work on the aircraft )

Paint colors ! You'd be amazed how many questions we answer every day about the paint that's been applied .....

Take a look at the following images ~ there's only 1 green applied to these air frame sections and yet depending on the angle ~ the amount of daylight ~
shadows cast from outside and inside ........



I've made an attempt to draw your eye to the ends of the red lines I've daubed on the pictures ~ here we can see 3 shades of the same grey paint





Lastly ~ I've highlighted in red one of the air inlet filter panels in the spraying area. There's another one around the other side of the nose.
The fuselage is aligned so the extractor fans stream the airflow straight down the sides of the fuselage.



This is why there's only a single width of brown paper over the Olive Drab on the nose ~ which is close to the air inlets as any over spray should
be carried back away from the nose. I took this close up to try and illustrate how effective this has been.



I'll close this update by saying that all of the activities I try and illustrate and share on this forum are discussed and carefully planned by the full time
staff in the IWM Conservation Hangar. If there's any failure on this thread ~ it's my ability to explain everything fully on occasions

Ohhhh ! I nearly forgot Ken's question about the nose art ......

Ken ~ we're BOTH going to have to be patient for just a little while longer !

Another update soon

[The Inspector]

I just realized what I haven't seen done during the re -paint, and can only assume it's because the airframe will be inside under climate controlled conditons. No ALODINE 1200 application prior to priming to treat the skins against filiform corrosion ( the 'worm trails' you sometimes see under the paint in an older paint job)and gives the primer/paint more 'tooth' for adherance.

[cooper9411]

Peter, from my vantage point, the work is awesome and I understand the color contrast because of lighting. Thanks again for the update and keep them coming.

[ZRX61]

This is the pic that shows 2 shades of green I was refering to, the line where the color changes is pretty much straight down from the windshield support. It's subtle, but it's there.

They might not be using alodine because they are using white acid etch or epoxy primer? I imagine they can't get away with using Yellow Death (VariPrime) in that booth set up? Another thing is that the primer they are using isn't suitable for application over alodine?

[CAPFlyer]

I'm looking at the photo over and over and I see only a change in lighting, not a change in actual color. Looking at other photos of the area supports that it's a lighting change, not a paint color inconsistency.