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DavesFlatsBoat
03-30-2003, 10:07 PM
I glassed one of my hulls this weekend - now I need to fill the weave (12oz biaxial) on my verticle & nearly verticle surfaces. See my web site: Bill the Cat (http://www.davesflatcat.com)

Anybody have a technique that works for them?

mmd
03-31-2003, 12:29 AM
You seem to be being ignored, DFB. My hands-on experience is limited in this as I'm the guy who specifies this kind of stuff, but rarely does it. You know, the old "those that can do; those that can't, teach.. er, design". :D However, seeing that I have done this - quite a long time ago, mind you - and I am the sidewalk supervisor for some pretty gifted boatbuilder buddies, this is how I've seen it done:

Mix a batch of epoxy and blend in micro-balloons until the epoxy has the consistancy of stiff cake batter. Use a flexible plastic squeegee normally used for applying body putty on cars at autobody shops to apply the epoxy paste and spread it evenly around, then lightly squeegee the excess off. The thickened epoxy should have enough firmness to stay in the weave of the cloth, and any runs or drips can be easily sanded off with a longboard when you fair the hull for painting.

That's my two cents - I'll look back in, in a bit, to see if anybody with more recent personal experience can teach me a new trick.

Good luck.

David N.
03-31-2003, 01:33 AM
Been helping build two kit planes off and on for a couple of years . The guy's doing the lay up , will first cut and shape all the bracing , to hold the lay-up in place ( wood , foam , whatever is handy ) , and have clamp's if they can use them .

When they make their " slurry " , the will leave a little without mirco spheres , this is used to go over the area first , to get better wet out , then they will put the slurry on and the cloth . All along they will add slurry and dab with a brush till they know there are no air pockets .

Now this a trick that may help , they will take a piece of wax paper and put mold release on it , then put the bracing in . That way you dont have to grind off the bracing .

Some of the cowling's I have been painting are just work's of art , complete with NACA scoops and louvers that really work , all out of glass that is no more than 3/32" thick . This one guy has never worked with glass before ( he is the master ) and my cousin , we tell him go make money stay out of the shop !! .

If you are close to an airport or know anyone building a kit plane they should have video's they might loan you , or the library ?? .

NormMessinger
03-31-2003, 09:05 AM
Mmd's method suits me but tongue.gif there are lots of ways to skin a boat. Mixing the epoxy with glass ballons will fill the weave faster and give you a slightly lighter weight fill. I have not used micro ballons however. I pour the epoxy along the top of the vertical surface and go at it with a foam paint roller. Don't pour so much on that it run off before you can roll it out (duh!). On an overhead surface you'd have to use a roller tray and apply the epoxy just as you would paint.

I'm not sure if my method or mmd's would use less material. The pros he refers to surely have worked that out. The more micro ballons you put in the goop the easier it is to sand but, I would think you would want to roll a layer on last to fill the ballons that are broken when you sand and to harden the surface. If you are using dry micro for fairing you would want to squeegy on raw epoxy to get a bond, as David describes.

Best wishes to you.

--Norm

jlapratt
03-31-2003, 09:35 AM
The first thing you want to do is ensure that the cloth is fully wetted out with unthickened epoxy. You should not see any white or opaque patches of cloth. I did this by dabbing epoxy on the top of the piece and used the squegee to work it into the weave and down the side of the piece. It takes a couple of times to learn to dab just enough epoxy on the top to do the job and not have most of it run off the bottom :eek: . When you are sure all the cloth is wetted out, then you can use epoxy and microballoons for final fill and fairing. When fair, apply a coat of unthickened epoxy to seal the piece as the microballoon fairing compund is not completely waterproof.

Good luck,
Jeff

DavesFlatsBoat
03-31-2003, 09:52 AM
Thanks all - the glass was wetted out well - and since Devlin and others talk about using unthickened epoxy to fill I was wondering how. But their boats are turnable and not so box like.

So now I will create a purple hull with the microballon mix - and be well motivated to fair & paint quickly - that stuff is doubly ugly.

JimConlin
04-01-2003, 12:54 AM
Consider glass microspheres instead of phenolic microballoons. They're white, less expensive and work the same.

jlapratt
04-01-2003, 07:24 AM
Jim is absolutely correct. Glass microspheres is what to use. They sand very easy and work well. Microballoons are much harder to sand.

Jeff

Ian McColgin
04-01-2003, 09:15 AM
I've never tried thickeners. I make sure the cloth is cut right and laid on a rack behind me ready to go. I practice lay the glass on dry wood so I have an idea of time.

I then mix some WEST straight, no thickeners, and unless it's really hot out I use the faster hardener. I put that on the wood and let it get a little kicked, so I can put the glass on the tacky epoxy and it will stick.

After that has cured, I epoxy again really wetting out the fabric. Wetting out too early makes the fabrick heavy and it pulls off.

This works overhead.

G'luck./

Ian McColgin
04-01-2003, 09:17 AM
I've never tried thickeners. I make sure the cloth is cut right and laid on a rack behind me ready to go. I practice lay the glass on dry wood so I have an idea of time.

I then mix some WEST straight, no thickeners, and unless it's really hot out I use the faster hardener. I put that on the wood and let it get a little kicked, so I can put the glass on the tacky epoxy and it will stick.

After that has cured, I epoxy again really wetting out the fabric. Wetting out too early makes the fabrick heavy and it pulls off.

This works overhead.

G'luck.

landlocked sailor
04-01-2003, 06:12 PM
Okay, I give up, where does one get glass microspheres? Is this the same stuff as WEST low density fairing filler? Rick

DavesFlatsBoat
04-01-2003, 09:38 PM
My favorite Fiberglass, Epoxy, & Supply Store is Fiberglass Coating Inc. www.fgci.com (http://www.fgci.com)
They have the microsheres - now if they would only carry biaxial tape

Thanks All - I needed the help

Dave

John Blazy
04-01-2003, 10:18 PM
How 'bout laying a layer of plastic film (LDPE or polyester preferably) into the final wet fill layer and rolling a dry roller over it to get the bubbles out. Then peel the film off after cure. The film will hold the liquid epoxy in the weave not allowing it to 'drain' due to the flow restriction. Works well for me and creates a glass smooth surface that needs light scuffing as opposed to fairing.