Hi all -

I'm slowly making progress on my Classic Airframes SBC-4 and have been pondering what to do about the fuselage aleves that are about 3/16 in. warped.

In the past I've always relied on the strength of the cement bond to hold, but this is way too great a gap for that.

I was thinking about laying the fuselage half on a sheet of glass and putting it into the oven at about 200 degrees until it relaxes. I've tried hot water but that didn't work.

Any suggestions?

Hi Steve

When you say "hot water", how hot? Boiling? That's usually worked for me, and it's half the temperature you're suggesting for the oven. I've never tried putting parts in an oven, so I'll be interested to find out if it's successful. I'd try it with an old kit you don't want first though...

All the best

Rowan

I'm assuming that's 200F
Hot water's sater for the plastic. There are prob hot spots a mostly empty oven.

Hi JP

My oven won't actually go that low - it starts at 225F (110C)...

200C is what's described as "moderately hot", but I'd be very wary of putting a kit in it for more than a few moments...

All the best

Rowan

To borrow from Wikipedia:

"Polystyrene is a thermoplastic substance, which is in solid (glassy) state at room temperature, but flows if heated above its glass transition temperature (for moulding or extrusion), and becomes solid again when it cools off."

The glass transition temperature is 95C and the melting point 240C. So if your part is in the oven at 200C for more than a few seconds (remember, even a Classic Airframes kit will be pretty thin), I reckon you'll be taking it out with a spoon.

If hot water won't do it, and you've taken the temperature up as high as you can bear it, have you tried:

1 the plate-warming setting on your oven? If you have one, it's usually about 100C; or
2 a hairdryer?

When you guys talk about "hot" water, do you mean boiling water from a jug, or 55-65 degree hot water from the tap?

I have an ancient 1/48 Monogram Phantom that needs a bit of warping taken out of the fuselage.....

Hi Ivan

I use boiling water (maybe let it cool a few moments for thin or delicate parts). You can either clamp a part straight, immerse it and then let it cool off, or hold small parts in the water with a wooden clothes peg and then remove them and straighten them whle they're still hot.

All the best

Rowan

Genuinely boiling water is enough to shrivel up some plastic kit parts. I won't go into the gruesome details of how I discovered this!
Use water which is off the boil, I use freshly boiled with about 10% cold water to take the edge off. Experiment with sprue from the same kit to find the highest temperature it can handle, before risking the irreplaceable part. Don't assume the plastic from different kits will behave in the same way, there are far too many variables.

Equally, a hair dryer produces some very high local temperatures, bring the part too close and it will collapse into a gooey lump. It's a useful technique, but be very, very careful,

Cheers,
Bill.

Thanks for the comments. I was speaking of 200 degrees F which is slightly below boiling, so I was apparantly in the ballpark as far as temperature. I think I'll attack it from the bottom up; I'll clamp the fuselage to a sheet of glass and start by using warm water from the tap (it's uncomfortably hot) and if necessary use the oven later.