What is this on my cowl and why is it there?

Jamie · #1 11-12-2006, 03:22 PM

Guys:

I just started working on fitting my two cowl halves together and when I turned the top over and looked at it I found this:

It feels like cotton, is only on one side (right inlet) and is bonded into the cowl with epoxy.

It feels and looks like cotton and my only assumption is that it was used as packing material before the epoxy was fully cured. It is firmly in place and I can't pull it out easily. So my question...how can I get this out?

This cowl fitting task is off to a poor start.

Thanks,
Jamie

RV7Guy · #2 11-12-2006, 03:33 PM

It almost looks like cotton flox. If it is cured in epoxy then use your Dremel with sanding drum and smooth it out. Ideally you'd like to have a uniform contour in that area.

GaryK · #3 11-12-2006, 05:45 PM

It looks like Dacron (Peel Ply) to me. They use it during the cowl construction. If you get too much resin/hardener over the peel ply it's tough to get off. Just use some sandpaper 100 grit or so to sand it off.

Gary

Mike S · #4 11-12-2006, 06:15 PM

Bleeder material, used in vacuum bagging. Helps to allow air to escape the layup. In a wet layup, helps to get rid of excess epoxy, in pre-preg as this is, just allows better air removal so the part is forced into the mold better.

Peal ply is used where there is going to be a future joint/layup.

Mike

Guy Prevost · #5 11-12-2006, 08:59 PM

Mike S. has it right. It's used when vacuum bagging in order to prevent bubbles in the bag. Without it, the vacuum will pull the bag closed near the hose, and leave the rest of the layup unclamped. It looks like they got a bit sloppy this time. Just pull, scrape, and sand it out.

G

Jonathan Cude · #6 11-13-2006, 07:33 PM

mine had similar problems as well... i wish they would have taken their time laying everything down... usually the breather ply and vacuum bag gets stuck when you don't cover the entire part with the dacron peel ply. but since dacron peel ply doesn't stretch it takes some time to lay it all down on the curved parts and i guess they just don't take the time!

RV7Guy · #7 11-14-2006, 08:10 AM

I was drawing a blank and then read Mikes post. I went out to my shop and checked my vacuum bagging stuff (do bagging of model airplane parts) and sure enough it looks like bleeder cloth.

Simply Dremel it out and clean thoroughly.

Quote:

Originally Posted by Mike S

Bleeder material, used in vacuum bagging. Helps to allow air to escape the layup. In a wet layup, helps to get rid of excess epoxy, in pre-preg as this is, just allows better air removal so the part is forced into the mold better.

Peal ply is used where there is going to be a future joint/layup.

Mike

Jamie · #8 11-14-2006, 08:20 AM

I did manage to get the bleeder material out last night. I used my angle die grinder with various radii sanding drums. It took quite a while but I finally got it out. I actually managed to get the cowl a little too thin in a couple of places, but I guess that's the advantage of working with fiberglass -- it's easy to add back what you've taken away.

Thanks for the help as always, guys.