Interfacing -- iron-on or sew-in?

[Mule]

I'm making a tutorial for the bonnet project I posted about in the May thread. I'm trying to keep things as simple as possible since other people with varying sewing skills will be making them.

The bonnet brim needs a very stiff interfacing. I used a sew-in type when I made my sample, but it was difficult to machine baste on due to the curve. It didn't want to lay flat so I ended up having to hand baste. I'm worried others may see hand basting as "too fussy." It might be simpler to use an iron-on interfacing, but the concern I have is it needs to be trimmed out of the seam allowances before turning due to being so stiff. I'm thinking iron-on interfacing would be difficult at best to trim out, and might not even be possible.

Any thoughts?

[Mule]

If using iron-on, I thought of trimming it down a bit before applying. I'm worried it would need to be trimmed precisely though, and not sure others will do that.

[sewingrandma]

I would recommend the iron on and have them cut the seam allowance off and mark the seam allowance on the brim so that when they ironed it on they would have lines to follow. This is what I do when I have to apply interfacing that is trimmed to size first. It is easy enough to mark a seam allowance. It can be done with the sewing machine stitching the line on each piece and then trimming the interfacing to size or use a ruler and pencil. I've also laid my tape measure and used it as a 5/8 to mark seam allowances. I won't tell you how long I had been sewing when I found out the width of most tape measures is 5/8!!

[Mule]

Thanks Brockie! I made another bonnet using the fusible, and it was much easier. I can make it foolproof by cutting out all the interfacing pieces and ironing them on when the fabric is cut, before they are distributed to the sewers. That way we can be sure the edges are aligned with the stitching lines. It just has to line up exactly since the interfacing is so stiff! Any discrepancy would be obvious.