What did you use to seal the foam on the rudder tip?

[southwind32]

Instructions say to bond the foam to the top of the vertical and rudder then mix another batch and brush it on the foam to seal. Are they referring to Hysol? How do you brush Hysol, it seems to thick to brush.
What did you use to seal the foam.
Thanks
Brian

[jiott]

I believe they are referring to Hysol and that is what I used, but you are right, it is not easy to brush smoothly, and then it is hard to sand. I ended up using some SuperFill to get a final smooth finish. Probably this was overkill since that foam gets covered with about 3 layers of fabric and some underlying roughness will never show thru.

[southwind32]

What about fiber glassing it?

[jiott]

I don't think it is worth the trouble to glass it. A good layer of Hysol will make it quite strong.

[efwd]

Brian, I will try to describe what I did and it worked very well.
Sorry, I can't get my photos up yet.
once you have your foam glued down let it dry.
I smeared Hysol all over the foam. I then used a piece of paper, held between both hands like you would see a shoe shine guy hold his rag. then I squeegeed the hysol off. The paper will assume the contour of your foam as it floats over it. It may not leave enough hysol. you may see the foam fibers. I mixed up some more after that first pass set up. Did it again. it comes out so smooth there may not be any need to sand whatsoever. I did the same on the tips of the horizontal stabilizer. When my horizontal dried it was shiny smooth.
Eddie

[southwind32]

Brian, I will try to describe what I did and it worked very well.
Sorry, I can't get my photos up yet.
once you have your foam glued down let it dry.
I smeared Hysol all over the foam. I then used a piece of paper, held between both hands like you would see a shoe shine guy hold his rag. then I squeegeed the hysol off. The paper will assume the contour of your foam as it floats over it. It may not leave enough hysol. you may see the foam fibers. I mixed up some more after that first pass set up. Did it again. it comes out so smooth there may not be any need to sand whatsoever. I did the same on the tips of the horizontal stabilizer. When my horizontal dried it was shiny smooth.
Eddie

I'll give it a try, I assume you didn't add any flox to the Hysol.

[efwd]

Correct. It doesn't really run. the layers are thin. I used Oratex fabric and If that was something someone reading is going to do, make the layer of Hysol fairly substantial. The hot air gun used to form the fabric will soften the hysol and I believe I may have melted some foam underneath. when the HYsol cooled all was well.

[David47]

I essentially did what Eddie did, except I used my finger wetted with IPA and just smoothed the surface. I then used a rotary sander to smooth off the surface (the Hysol is tough stuff) and then did a final fill and seal with an auto body filler. Worked well.

[southwind32]

I essentially did what Eddie did, except I used my finger wetted with IPA and just smoothed the surface. I then used a rotary sander to smooth off the surface (the Hysol is tough stuff) and then did a final fill and seal with an auto body filler. Worked well.

I looked up IPA and this is what I found ..... India pale ale http://www.hopandwine.com/what-does-ipa-stand-for/

Is it best to wet your finger and drink the leftover ?? :D

So..............what is IPA??

[jtpitkin06]

I looked up IPA and this is what I found http://www.hopandwine.com/what-does-ipa-stand-for/

Is it best to wet your finger and drink the leftover ?? :D

So..............what is IPA??

Isopropyl alchohol.

[jtpitkin06]

At first I did the Hysol over bare foam. When the horizontal tip got hit with a light tap of hangar rash it shattered a golf ball size area and required surgery. Reasoning the horizontal tip will probably see more unintentional contact in the future I went for a little more protection.

The new tips consist of balsa wood covered with two layers of 4 oz. Fiberglas cloth saturated with West System epoxy. A little body filler and some sanding completed the job. The tip can now withstand a much harder blow if someone says "oops!... Sorry"

The West System epoxy can withstand more heat than any fabric and will not soften when covering the tips.

John P

[efwd]

Good move John. My next one will be Balsa as well. The foam is not the best. That is why I have used Balsa on anything else that the manual has mentioned foam on i.e. lift strut fairing trailing edge.
Eddie

[southwind32]

At first I did the Hysol over bare foam. When the horizontal tip got hit with a light tap of hangar rash it shattered a golf ball size area and required surgery. Reasoning the horizontal tip will probably see more unintentional contact in the future I went for a little more protection.

The new tips consist of balsa wood covered with two layers of 4 oz. Fiberglas cloth saturated with West System epoxy. A little body filler and some sanding completed the job. The tip can now withstand a much harder blow if someone says "oops!... Sorry"

The West System epoxy can withstand more heat than any fabric and will not soften when covering the tips.

John P

I've never done any fiberglass work, but I've seen a couple of You Tube Videos, and doesn't look to bad.
I take it, you used a solid block of balsa and trimmed and sanded it to the shape you wanted? I assume a little under size since it will be built up a little with fiberglass and resign?
Where do you get a block of balsa wood that size?

If you glassed over the foam, wouldn't the fiberglass make a fairly strong shield over the foam to protect against minor bumps? or is balsa better then foam?
Any help you can throw my way is appreciated. Thanks
Brian

[jiott]

I also used balsa on the tips of the horizontal and elevator for the same hangar rash reasons. Any hobby shop has balsa blocks and if you cannot get one thick enough just glue two blocks together. I just epoxy varnished mine, but I like the fiberglass idea. The only place I used that foam was the top of the rudder and vertical; out of harms way.

[jtpitkin06]

2 in x 3 in x 36 inch balsa boards
available from Aircraft Spruce

They sell 2 in boards up to 6 inches wide

John P