Bill Diedrich

Working on the repair and redo of glass-work bonding wood frames to glass fuselage
and re-installing a few reinforcement bulkheads and formers on a Byron 33% RV-4.
From what I can tell the fuselage is a polyester resin product. My question is not
having access to "Cab-O-Sil" ,as there are no fiberglass shops nearby, would micro
ballons do the same thing when mixed with ther ployester resin?

Bill D.

amtpdb

In reinstalling bulkheads you need the strength and usually you only use a mix of micro balloons and resin as a light weight filler. Usually you use flox and resin as a stiff glue.
Just my 2 cents.

speedracerntrixie

My Feedback: (29)

Micro ballons nor cab o sil add any strength to the resin. As the previous post I would add flox or better yet milled fiber to your resin. Any of these can be shipped anywhere in the US in just a matter of days.

Scorpion Racing

Cab-O-Sil or sometimes called Fumed silica is a thickening agent for resins. It is mainly used to keep the resin from flowing to much when you are placing it on a vertical surface. The micro balloons or glass spheres lighten the resin by filling the space with air, but weaken the resins overall joint strength.

To reattach a bulkhead, I would add some milled glass, chopped glass, cotton flock or some other sort of strengthening material. If you don't have any of these available, you can take some fiberglass cloth and cut it up with a roller cutter (like mincing it up) into a "milled glass" and add this to the resin for some additional strength. Make sure you sand and roughen up the area in the fuselage where you intend to attach the bulkhead and clean it with a solvent well so that you get a good adhesion joint.

Bill Diedrich

My intention of using the cab-o-sil was in tight corners to avoid air pockets
when re-attaching the formers that have come lose because of the air cavities
that are present form the original builders not working them out of the resin in the
initial attachment of the fuselage formers. My plan was to have a small amount of
"filler resin" at the ready to avoid this happening, but I do agree that milled fiber is
probably a better "filler" and stronger solution than micro ballons or cab-o-sil.

Thanks for all of your comments, progress continues........

Bill D.

JeffH

My Feedback: (43)

I would just use strips of glass cloth and resin. That is the way Byron's used to tell you in the directions.(at least on the warbirds) I have seen Byron's planes take a great deal of abuse with formers installed this way.

Bill Diedrich

I have 1 1/2" wide tape that will be used in conjunction with the filler.

tschmidt

My Feedback: (1)

Hi Bill

When installing bulkheads in fuses I use a mixture of cabosil and milled fibers in the resin. You can buy both on line from www.fibreglast.com. Cotton flox as stated earlier will work also but it usually is a good idea to mix cabosil also to make it into a thicker paste so it stays put.

Todd

Randy Etken

My Feedback: (10)

I chop up Carbon Fiber and add to the resin. Strongest there is.

dhal22

i chop up cf as i try to cut it. maybe i should save it and add it to epoxy resin.[X(]