REFLECTOR: Epoxy question

[Reiff Lorenz]

Ron,

I agree with your (and Larry's) assumption that a 90-degree weave won't provide the same strength along a seam as a 45-degree weave because there will be half as many fibers crossing the joint line.

I just completed some joints along the wing root where I used 2 layers of the 45-degree BID for strength, then created a large fillet of micro-balloons and covered it with 2 layers of the 90-degree BID to prevent cracking. My experience confirms the comments that Bob Wood made in another post: the 90-degree fine bid has a bit of an edge to it. It's nice that it won't unravel at the edges during wet-out, but I'll end up needing to sand it down to make everything smooth.


Reiff Lorenz, Dayton, OH
Velocity XL-RG, 36% complete
Currently working on: Fitting the left aileron bellcrank to the wing root.


The Velocity Builders' Virtual Hangar<https://liveconferencepro.com/guest/loginguest.php?id=d3a73e710c719626dd353d3b101be90f>. Available 24/7 for builders and owners:
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From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On Behalf Of Ron N VelocityXLFG
Sent: Monday, October 08, 2012 5:01 PM
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: Epoxy question

Thanks I believe you would not want to use the 90 bid as tapes. It  would give only 1/2 the strength on a seam
that the 45 degree cut tapes do. Correct me if I am wrong.

Ron
On 10/8/2012 3:22 PM, Reiff Lorenz wrote:

Here's a photo of the thin 90-degree bid from Aircraft Spruce and the thick 45-degree BID from West Marine.

[cid:image001.jpg at 01CDA623.C56E0380]



From: reflector-bounces at tvbf.org<mailto:reflector-bounces at tvbf.org> [mailto:reflector-bounces at tvbf.org] On Behalf Of Reiff Lorenz
Sent: Saturday, October 06, 2012 10:08 AM
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: Epoxy question


Do you have any pictures of the bid tape?


Ron,

It is: West Marine #727 (Episize Biaxial Tape, 4" x 20 yard roll.)  Here is the link to the part on West Marine's site.

http://www.westmarine.com/webapp/wcs/stores/servlet/ProductDisplay?productId=14880&catalogId=10001&langId=-1&storeId=11151&storeNum=50218&subdeptNum=50219&classNum=50226

(If the above link is broken, try:    http://goo.gl/iHedd   )

It is 50% heavier than the stock Velocity BID, so where the plans call for 5 layers of (woven 8.9oz) BID, I've been using 3 (straight 15oz) plies of this. It doesn't stretch or contort as much as standard BID (due to the non-structural, in-line stitching that holds it together), which is great when trying to place a long strip in position, but be aware that it won't conform to tight corners very well.

West has free shipping on orders of $99 or more.

For cosmetic applications, I've been using the Aircraft Spruce fiberglass tape. It's lighter that Velocity BID and it's laid out at 90-degrees, so it's not as strong. Good for keeping seams from cracking or as a smooth layer of glass on top of a structural layup.

http://www.aircraftspruce.com/catalog/cmpages/etapes.php

While you're there, get some peel-ply tape, too. So much easier than trying to cut 4-inch strips from a long roll. I got this from another builder and have used it almost exclusively.

http://www.aircraftspruce.com/catalog/cmpages/peelply.php

DISCLAIMER: I'm not a fiberglass expert. Most of my fiberglass work at this stage consists of fairings and flanges. I have no qualms about using the West fiberglass for things like holding on canard tips or making cowl flanges. I'd check with Velocity HQ or an engineer, though, before I used it in load-supporting applications like bulkhead reinforcements.

Hope this helps!


Reiff Lorenz, Dayton, OH
Velocity XL-RG, 37% complete
Currently working on: Creating a large-radius wing root fairing on the engine cowl.


The Velocity Builders' Virtual Hangar is available 24/7 at:
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