Correcting Airliner Fuselage Warp?

[POTKC]

In short, I've started building an airliner (Eastern Express 737-300, to be precise). Both fuselage halves are slightly warped, but just enough to not fit together properly. I've tried heating them in hot water, then holding firmly in the 'straight' position, and cooling them in cold water to lock the shape, as was recommended on another site. It seems the plastic is too firm/resilient, as precisely nothing has changed. Any suggestions on how to fix the problem?

[Vesa Jussila]

One way to try to fix this is clue 25% of distance at the time. Let clue cure and proceed then to next part. This can fix issue if wrap is not too much.

[Black Knight]

The only way other way I can think of is to strap/clamp each half to a thick stout plank and leave them where the sun can shine on them, such as a window sill or a car window parcel shelf. Let the sun heat them up. Keep a careful eye on them. It might take a few days.

I know this can work as I used it on a large wing which was twisted and was too big to do by the hot water method.

[Romeo Alpha Yankee]

The only way other way I can think of is to strap/clamp each half to a thick stout plank and leave them where the sun can shine on them, such as a window sill or a car window parcel shelf. Let the sun heat them up. Keep a careful eye on them. It might take a few days.

I know this can work as I used it on a large wing which was twisted and was too big to do by the hot water method.

You don't do that in this part of the woods, especially for a few days in summer when it can hit 50-60 degrees in a parked car in the sun. All it takes is a couple of hours and you have a melted mess.

[Mike]

Tape it to a flat surface and pour hot water over it, then douse it in cold water to set the changes in place. It's more controllable than relying on the sun... especially in the UK or where it's hot

[POTKC]

OK, I'll try taping to a surface and then doing the water method - might be easier than trying to hold it. If that fails, maybe I'll glue it in stages.

Edited July 6, 2016 by POTKC

[Mike]

Good luck! Watch you don't scald yourself too

[richellis]

I always remember the person who was trying to cure a warped resin part, he held it in shape with his hand and poured boiling water over it, and his hand.

Nope, it wasn't me!

[POTKC]

...poured boiling water over it, and his hand.

Nope, it wasn't me!

You sure?

[richellis]

Nope, they where severe burns, he poured directly from the kettle. He passed through ED while I was working one Sunday afternoon.

[Graeme H]

I got a Revell A320 that had fuselages halves so distorted they only touched at front and rear and a few other places along the bottom, biggest gap was about 4mm,

Now normally I might have contacted Revell, but I thought I would take on the challenge.

I started at the parts where they did meet OK, and used MEK, (Tamiya Extra Thin would be just as good), then secured that with superglue on the inside and let set for a day, then pushed another bit together, and did the same, after a week I had it done, that was over 10 years ago and it's still together.

This method takes time, and you do not attempt to do the bottom and top at the same time, just one or the other,

The secret is to use something like superglue to get a really solid join, best is good quality Gap filling types.

I don't have many Eastern Express kits, but I wonder how good the plastic is though, hate to see it develop fractures or distortion elsewhere

[POTKC]

...I don't have many Eastern Express kits, but I wonder how good the plastic is though, hate to see it develop fractures or distortion elsewhere

Well another part did snap at a thin bit ('bout 1mm) when I sanded the edge after cutting it off the sprue, so I'm weary of accidentally snapping it. On the other hand, a rule I've set for myself is "unrepairable damage = upcoming crash diorama"...

[Pin]

While the methods above will work you may want to do cuts inside the fuselage parts to relieve tension

[POTKC]

Well, Alexey, I saw your reply too late. Both taping to a flat surface then doing the water method and taping the two fuselage halves together into the correct shape then hairdryer-ing them failed. Instead, I'm going to glue them together step by step. I've made some aligning tabs on the inside of the fuselage to make that easier. Do you think I would be able to make a thread in the WIP section and then have it transferred over when the airliner GB starts?

[Skodadriver]

Better run that past the GB hosts one of whom has already contributed to this thread!

I've had limited success with using hot water on injection-moluded plastic and I endorse what Graeme says. A similar technique worked for me with a rather warped Revell A330 a few years ago.

[Ologist]

I have exactly the same kit in progress, with exactly the same issue. I used elastic bands to clamp each fuselage half to a 12inch steel ruler, and initially tried dunking in hot water followed by cold. This had remarkably little effect, so a more aggressive approach of pouring boiling water over the clamped halves was tried (obviously keeping hands out of the way!). Left the still warm and clamped pieces for about 2 minutes, then put under cold tap. This got rid of most of the warp, and there doesn't seem to have been any tendency for it to return after a week or so.

One point to watch out for though if using this method is that the bottom of the fuselage behind the main wheel wells wants to curve inwards. There are a couple of prominent sink marks here, so its going to get treated to a layer of filler anyway.

Eastern Express plastic is soft rather than brittle, which doesn't make for much fun when sanding back sprue attachment points, of which there are an excessive number.

[POTKC]

Ologist, I noticed the excessive number of sprue attachments. They've also got massive amounts of excess plastic which has to be removed around the attachments...

What's very strange is the kit doesn't actually have a main gear bay, instead the wing spars (three flat ones) create a sort of 'ceiling' above the gear bay cutouts, which also attach as a separate part (the one that broke for me). Oh and also that part doesn't fit properly. I have a feeling that the wing root of my 737 will be 95% Tamiya filler...

[The 3rd Placer]

I'm entering a EE 737-300 in the upcoming Airliner Group Build and it has the same warping problem.

It will be fun to sort out.

Ryan

[POTKC]

I see the problem is quite common. Unless you have an industrial heat gun, I doubt you'll be able to heat the plastic enough to actually change its shape...I've tried pretty much everything up to, but not including, using a blowtorch...