They never told me

[ZG4Me]

I slurry and squeege the seatback bulkhead with slightly stiff slurry per plans, proceed to do the glass layups.

Squeege, stipple, add more epoxy, ... Some of the micro bubbles migrate to the fiberglass layer(s), and are squeeged to the edge as a semi-white transparent foam. I hear this is normal, and expected.

Other option (a heavy part?) would be to lay the glass on, pour the epoxy on and wait for it to self level (dripping all over the place).

So are a 'few' micro baloons acceptable in a layup (per above). And if so, how many. Or should I "hard shell" and avoid this problem?

Rick

[kjashton]

Originally Posted by ZG4Me

So are a 'few' micro baloons acceptable in a layup (per above). And if so, how many. Or should I "hard shell" and avoid this problem?

I mix the micro to a pancake-batter consistency or sometimes a little stiffer. When squegeeing you will always cause a bit of micro to migrate into the glass but when finished you won't see obvious micro in the weave, but some is OK.

If the finished layup looks too cloudy perhaps you're leaving too much micro on the foam. A jeweler's loop (eyeglass) is useful to refine your technique.

Jeesh, forget hard-shelling.
-Kent
Cozy IV N13AM - flying
Long-EZ - 60%

[ZG4Me]

Originally Posted by kjashton

I mix the micro to a pancake-batter consistency or sometimes a little stiffer. When squegeeing you will always cause a bit of micro to migrate into the glass but when finished you won't see obvious micro in the weave, but some is OK.

Pancake batter is the consistency I use. About 1::1 epoxy/balloons.
I squeegee this off to the point I'm getting some blue foam flakes in the dross.
I think the issue is, I'm squeegeing/stippling too much on the first ply, but I'm getting real light layups in a relatively cool work area. No bubbles, per say, in the layups, but they just don't "look right".

I'm using a roller (bubble buster) on most all my layups at the git go. It's a 1" x 3" roller, made of bristles designed mostly for inter-laminar bubbles in UNI fabrics. A 1" paintbrush on steroids if you will. Perhaps I'm too aggressive with it.

Hmmm, maybe I should lightly squeege a thin coat of epoxy down after the slurry, that way I'm not trying to force the epoxy down through the first ply. Me thinks a test is in order.

Jeesh, forget hard-shelling.

I can see the advantage Same for vacuum bagging and/or lo-vac. I wanna build a plane and fly it before I croak. The next one (if there is one) will be 'mo better.

Rick

[argoldman]

Originally Posted by ZG4Me

Hmmm, maybe I should lightly squeege a thin coat of epoxy down after the slurry, that way I'm not trying to force the epoxy down through the first ply. Me thinks a test is in order.


I can see the advantage Same for vacuum bagging and/or lo-vac. I wanna build a plane and fly it before I croak. The next one (if there is one) will be 'mo better.

Rick

Hold-it,

Don't put more epoxy over the slurry. All you will do is to further dilute the slurry and make your problem (if it exists) worse.

The thickness of the slurry should be determined by the type of foam you are squeegeeing over. porous substrate requires a thicker slurry, relatively smooth a much looser one is required. The purpose of this is to fill the voids (cut cells) in the foam so that the glass has no bubbles under it. Remove as much slurry as possible, without injuring the underlying substrate. For flat surfaces, I prefer a drywall type putty knife.

Lay your glass on top of this squeegee for tack and then ad epoxy on top and continue.

Don't hard shell as you must get all of it dull or you will have some non-bonded areas (depending on how long it was before you glassed). This is a pain, and actually increases the time necessary by almost a quantum number. There is little, if any upside.

[ZG4Me]

Originally Posted by argoldman

The thickness of the slurry should be determined by the type of foam you are squeegeeing over.

Ah-ha! The seatback was my first time for H-45, possibly I should be using a stiffer slurry. The other bulkheads turned out OK (in my eyes anyway); the seatback is blue, bigger pores, and large, ...

I dump on the slurry, squeegee, wait a few minutes. The re-slurry and squeegee, I've found the first coat seeps in a bit. The surface is pretty dry when I'm done, the first ply of fiberglass doesn't really stick much, if at all.

Am sure I'm doing OK, it just don't seem rite. When Curt (Strider) is ready for me to help lay up his fuse sides, I'll know more... twice what I know now!

Rick

[Kraig]

Rick,

Get all the education you can doing the ch. 4 bulkheads. When you start doing the sides is when you will use all that you have learned. This is where the education pays off, especially the inside areas of the fuselage sides. Big layups, at an angle, going around curves and across depressions, all while keeping the fibers straight and the bubbles out.

Man do I remember it well now. And I did it all by myself. Sure is rewarding when it is finished. After chapter 6 you will feel quite confident in finishing the rest of the plane.

One piece at a time, my friend!

Kraig

[ZG4Me]

Originally Posted by Kraig

Get all the education you can doing the ch. 4 bulkheads.

Several builders in/around KLMO, but they sure are quiet. Probably wouldn't hurt if I asked either

When you start doing the sides is when you will use all that you have learned.

I did the top longerons two days ago, glued the shorter pieces on this AM. I spent hours just looking at the curves from the end... It looks like a plane

Rick

[Dust]

the finer the foam the thinner the slurry and the opposite, the seat back is a coarse foam and can accept thicker micro.