How much flox

BGordon · #1 08-09-2018, 09:35 AM

Good morning everyone,
I am working on the emp fairing between the HS and VS. It is a good fit, however there are a few areas where the fiberglass doesn't sit flush with the aluminum. I want to fill these to get rid of the warped appearance and was wondering...how much flox (if any) should be added to the resin? I am using the West Systems slow hardener.
thanks in advanced
Brandon

rocketman1988 · #2 08-09-2018, 09:43 AM

Realize that adding flox tends to make sanding more difficult. There are some good articles on what each fiberglass filler does and about how much to use at fiberglass.com. I also highly recommend permagrit tools, they go through fiberglass like butter...

Carl Froehlich · #3 08-09-2018, 09:50 AM

Micro balloons are more typical for this application.

Carl

Mike S · #4 08-09-2018, 09:52 AM

Sounds like you are looking to fill under the fairing to fill the gap to the alum below?

Put clear packing tape on the alum, smear on the flox----mixed to peanut butter consistency----mount the fairing and let dry.

Remove the fairing and clean up the flox that has squeezed out.

With the flox being structural, you can sand out any high spots/bumps that appear on the top side of the fairing and not worry about cutting through the glass.

BGordon · #5 08-09-2018, 09:52 AM

so, do you think that just using resin will be strong enough, the gaps aren't more than 1/16
B

crabandy · #6 08-09-2018, 09:53 AM

Probably use Micro instead, mix to get your desired consistency. A little bit will be Soupy like hot cheese dip will drip and run, you?ll probably want more micro until it spreads like warm peanut butter.
I highly suggest mixing up a couple grams to practice with, make 1 soupy-1 like warm peanut butter- 1 like pizza dough. Spread them out on some scrap sand etc.

DanH · #7 08-09-2018, 10:29 AM

Whatever works...micro, flox, or plain epoxy. For the tiny gap you're describing, I'd thicken mixed epoxy with cabosil so it won't run. Remember, cabosil makes epoxy thixotropic, a gel of sorts; it only runs under pressure, like toothpaste.

http://www.vansairforce.com/communit...2&postcount=15

RV-14E · #8 08-09-2018, 10:48 AM

Just did something similar on my empennage fairing which was pillowing out.

Packing tape on aluminum, smeared the flox mixture on, installed the screws (lathered in Boelube to prevent the flox from sticking to them) and smoothed it as desired.

A couple of hours later, the screws came out easy, the fairing came off and the tape was lifted. No mess. Area was filled well enough...

Then later sanded down to get a nice surface profile.

William · #9 08-09-2018, 11:26 AM

Quote:

Originally Posted by BGordon

Good morning everyone,
I am working on the emp fairing between the HS and VS. It is a good fit, however there are a few areas where the fiberglass doesn't sit flush with the aluminum. I want to fill these to get rid of the warped appearance and was wondering...how much flox (if any) should be added to the resin? I am using the West Systems slow hardener.
thanks in advanced
Brandon

Hi Brandon before doing any bonding try this first. Place the fairing in position on the aircraft and heat the area up with a heat gun for about 30 seconds. This will soften the fiberglass to make it formable. Then form the fairing to fit. Must hold it in position as it cools for about 2 minutes. I’ve done this on a few different aircraft with great results!

Good luck
Bill

BillL · #10 08-09-2018, 06:22 PM

I found that on my 7 intersection fairing there were uneven surfaces on the aluminum contact side. Sometimes drips, or extra layers of reinforcement, and I kept fitting and sanding until it fit pretty well. It did not take much irregularity under there to lift the edges.

Assuming this has already been done, resume epoxy work appropriately. FWIW I used microballoon mixture under the remaining gaps and did not find it necessary to sand afterward.