Doublers for flush hatch seating

[saad.mech]

I wanted to know how doublers are manufactured in the aerospace industry. I have seen DIY videos where the guy either makes a separate mold for the doubler and bonds it near the hatch cutout or directly does a wet layup near the area of the cut-out with some spacer with a partial cut hatch at that location.

What is the correct way for making a composite doubler?

 

[rb1957]

both are reasonable ways to manufacture a composite dblr. The first makes the doubler as a separate piece, like a metallic dblr ... this has issues in ensuring that the dblr will conform to the primary structure (it should, but often things don't work out as they should). The latter is a wet lay-up. This needs to be done carefully, so that you don't "overcook" the primary structure (under the dblr). This means that the dblr will be a different composite material than the primary structure, which complicates the analysis.

"Hoffen wir mal, dass alles gut geht !"
General Paulus, Nov 1942, outside Stalingrad after the launch of Operation Uranus.

 

[SWComposites]

The correct way is to review your aircraft structural repair manual (SRM) which will provide detailed procedures and locations where such repairs are acceptable.