So anyone figured an easy way to cut a hinge at an angle across corro flutes?

Easy enough to slit a flute for a hinge in-line with flutes, but not so easy when doing a hinge angled to flutes!

Stripping the 45 looks real crappy!

Solder iron maybe?? But it will most likely leave a hard melted crust that may cause cracking?

"draftman3" on youtube, tips and tricks, rout out a groove

Do it all the time. Not only for hinges, but also to get sharp trailing edges and sharp chines on wing strakes etc.

I don't find it 'crappy' at all, but it does require a little more care than the 'along the flute' hinge.

The trick is to use the table edge or a metal straight edge to prevent the knife from cutting the hinge part. These are the steps I use:
1) Cut the hinge line across the flutes, making sure to not cut the underside skin (same technique as for cutting a 90 degree bend)
2) Fold this cut back on itself. If it is difficult to fold, carefully cut those flutes that are not yet cut.
3) Lay the piece about 3mm from the edge of the table/ workboard. If you run your knife at 45 degrees along the table edge, it should start cutting just above the folded skin....thereby removing the flutes, but not cutting the hinge skin itself.
4) Now cut carefully. A sharp knife is key, and I find that changing the angle of the knife relative to the flutes can make the cutting much easier. Make sure you press the correx flat on the table...if it lifts up, you will cut the hinge skin. You can hold the workpiece down with a metal ruler, or even clamp it in place (probably the best option).

You can also mark a cut line 2mm in from the edge of the hinge line...if you follow this line with the one end of the knife, your piece is the right distance from the table edge and it does not lift, you should end up with a neat groove and not cut the hinge skin.

With practice it becomes very simple and routine. I have tried using a soldering iron and heated paint scraper, but this works less well. The melted correx makes a mess, and it is actually harder to avoid damaging the hinge-skin itself.

Occasionally I slip up and nick the hinge skin, but so what - there is still way more 'hinge material' than if I was hinging a balsa airplane with 2 x plastic hinges per control surface.

Hope this makes sense - quite hard to put in words, but very simple in practice. Also very hard to take pictures as I would need 2 sets of hands!

I hope this question implies that you are graduating from profiles to more challenging correx projects

Thanx ES.. it does make sence. The main reason for asking is that i'm not getting 3mm straight flute. Can only get the wavey stuff.

At the moment having too much fun with the profiles.. sooo many planes, so little time! I,ve got it down to an art.. built 2 F22's in 4 hours the other night.

Will eventually get to something i want to build that will require the "higher" levels of corro art!

OK, that clarifies. Hinging across the flutes is easiest when the hinge line runs close to 90 degrees to the flute, and is hardest when it runs close to, but not quite parallel with the flutes...which will be the case if you are using S-flute correx with the flutes running spanwise (as I guess you would on a profile).

You could try cutting a 'box' rather than a 'V' hinge....in other words, cut a second line parallel to the hinge line and then clear out all the flute material between the two cuts. As long as the crease is on only the desired hinge line, you will probably find that this is easier....especially with 3mm correx.

Got it pretty good with your "steel ruler on the edge" plan.

Thanx ES