Van's Air Force
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yet another fiberglass question
- Thread starter rwshooter
- Start date
David-aviator
Well Known Member
Flox is more difficult to sand and not good for finish work. Definitely do not use it last. I did mine entirely with micro and glass.
alpinelakespilot2000
Well Known Member
I know this is true for structural parts, but I can't imagine any problem with doing this on non-structural parts. There will be times when a little filler between fiberglass layers makes the process go much easier. Also, fiberglass is often used over a filler layer just to hold the filler in place long term without any worry of cracking down the line. Just don't build your wings this way! : )
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Flox being a structural filler, you use it where you have a need to maintain the integrity of the joint, allowing a little room to build up afterwards with micro for the finishing filler. If you needed to build up an area, using flox would be the choice as a thick buildup of micro would tend to crack. For glassing empanage tips, typically it is just a thin layer to fill the seam between the tip and metal and a slight fill (<1/16"). For this situation I would use micro only, there is no need for additional glass or flox. I would say micro could be used even up to 1/8" for fill if not structural and avoid use of the flox. Flox is great for use in composite aircraft where you are joining corners of foam/fiberglass sandwich construction to glue the two pieces together and provide a moldable (when wet) adhesive. It is then glassed over, allowing the glass to be lain in gentle curves instead of sharp angles where it is subject to failure. There is really little use for flox in our aircraft using premolded components, unless you need to make a significant buildup or repair. My previous experience was in building a Dragonfly, which is all composite. Flox had many uses as I described above, but I'd be suprised if I used more than a fraction of a dry cup of flox in my RV.
The main reason I wanted the strength of flox wasnt for the joint itself, that has been hysoled and blind riveted together and is really a strong joint. after a little fill a layer of 1.45oz cloth tape should finish it nicely. the center of my counter weight skin has a slight depression in it right down the center of the rivets, I want to flatten (fill) this area out to match the edges. So I thought that the flox mix for the first or second pass would be stronger than micro. Then I can finish with micro. Right?
Robb -7a
Robb -7a
osxuser
Well Known Member
Yes, make sure you have good adhesion surface for the flox, but that sounds like you have the right idea.
rv9av8tr
Well Known Member
RV7Guy
Well Known Member
No flox needed
1) Sand everything with 80 grit paper. (1" wide on the metal.)
2) Clean with acetone
3) When ready to pop rivet mix thick epoxy/micro blend, spread on joggle
4) Pop rivet in place.
5) Squeegee smooth on seam line.
6) Let cure
7) Sand smooth fill any low spots with micro
8) Block sand for perfect transition of parts, clean w acetone or alcohol
9) Epoxy 1" wide glass cloth on metal/glass seam use minimal epoxy, just enough to the weave.
10) When done sand to remove gloss
11) Fill edges and low spots with epoxy and micro filler
12) Block sand, clean, repeat until satisified
13) Spray work with high build primer, wet sand with 320 when dry
14) Reprime, then mist on a coat of Krylon black or BBQ paint to serve as guide coat.
15) Block sand with 320 wet. The black mist will remain in the low spots.
16) Fill low spots with epoxy and micro or Rage auto body filler. If very small you can use Evercoat 416 glazing compound.
17) Repeat as necessary or until it meets your satisfaction.
This is not the only way but the easiest way for those not intimately familiar with glass work.
The structural end of this was riveting the tips on. You are now doing finish work and therefore don't need flox.
Hope this helps.
1) Sand everything with 80 grit paper. (1" wide on the metal.)
2) Clean with acetone
3) When ready to pop rivet mix thick epoxy/micro blend, spread on joggle
4) Pop rivet in place.
5) Squeegee smooth on seam line.
6) Let cure
7) Sand smooth fill any low spots with micro
8) Block sand for perfect transition of parts, clean w acetone or alcohol
9) Epoxy 1" wide glass cloth on metal/glass seam use minimal epoxy, just enough to the weave.
10) When done sand to remove gloss
11) Fill edges and low spots with epoxy and micro filler
12) Block sand, clean, repeat until satisified
13) Spray work with high build primer, wet sand with 320 when dry
14) Reprime, then mist on a coat of Krylon black or BBQ paint to serve as guide coat.
15) Block sand with 320 wet. The black mist will remain in the low spots.
16) Fill low spots with epoxy and micro or Rage auto body filler. If very small you can use Evercoat 416 glazing compound.
17) Repeat as necessary or until it meets your satisfaction.
This is not the only way but the easiest way for those not intimately familiar with glass work.
The structural end of this was riveting the tips on. You are now doing finish work and therefore don't need flox.
Hope this helps.
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RV7Factory
Chief Obfuscation Officer
Darwin, you are the man!
I've done all the steps up to #7 exactly like you put it with the exception of micro mix in joggle. I used hysol 9430, I have no worries with that stuff. Today when I sanded the glass to metal joints, basically lowering the glass to meet the metal edge, chunks of glass fell out, I think they were air pockets in the factory product. But everything looks great as far as mating in line and on the same plane. I will follow the rest of your instruction from here, OR, you can come to VEGAS, do all my glass work for me and my family and I will show you a great time! Would that be legal?
.......really appreciate the help from all
Robb -7a
I've done all the steps up to #7 exactly like you put it with the exception of micro mix in joggle. I used hysol 9430, I have no worries with that stuff. Today when I sanded the glass to metal joints, basically lowering the glass to meet the metal edge, chunks of glass fell out, I think they were air pockets in the factory product. But everything looks great as far as mating in line and on the same plane. I will follow the rest of your instruction from here, OR, you can come to VEGAS, do all my glass work for me and my family and I will show you a great time! Would that be legal?
.......really appreciate the help from allRobb -7a
RV7Guy
Well Known Member
Forgot an important note
The glass parts from Van's that are gel coated are not very good.
These include the wing tips and tail glass. These should be prepped first as follows:
1) Clean the parts with acetone or alcohol
2) Sand the gel coat to take the gloss off, even to the point of removing the gel coat. This will expose voids in the glass.
3) When done clean again
4) Use a flashlight and shine from the inside. This will allow you to see any big voids in the gel coat.
5) If large voids fill with micro and epoxy.
6) Sand and proceed
The glass parts from Van's that are gel coated are not very good.
These include the wing tips and tail glass. These should be prepped first as follows:
1) Clean the parts with acetone or alcohol
2) Sand the gel coat to take the gloss off, even to the point of removing the gel coat. This will expose voids in the glass.
3) When done clean again
4) Use a flashlight and shine from the inside. This will allow you to see any big voids in the gel coat.
5) If large voids fill with micro and epoxy.
6) Sand and proceed
ok, everything is looking great after glass and filler. 2 questions. If I glass in the inboard side of the counter weight skins now, how do you balance the elevators after paint if you cant get to the lead? also which high build primer do I use?...I'm using jeffco epoxy if this helps. Honestly guy's, this fiberglass stuff aint that hard if you follow the direction givin here. One neat thing is you can screw up, sand it off and do it again ask me how I know. It's also cool to watch your pieces take shape with each stroke of the sanding block while becoming super slick and smooth.
Robb
. It's also cool to watch your pieces take shape with each stroke of the sanding block while becoming super slick and smooth.Robb
Help
anyone have an idea how to clamp the rudder (in tow) to the VS so that the two can be fit together(sanded together) at the fiberglass tips? My make shift ones dont work very well and I have an absolutely horrible fit between the two parts and this seems to be the best way to get through the final shaping of the glass. IE, sand em both together while in tow. Sound right?
anyone have an idea how to clamp the rudder (in tow) to the VS so that the two can be fit together(sanded together) at the fiberglass tips? My make shift ones dont work very well and I have an absolutely horrible fit between the two parts and this seems to be the best way to get through the final shaping of the glass. IE, sand em both together while in tow. Sound right?
1/2 oz fiberglass cloth
An experienced builder turned me on to the kind of fiberglass cloth the R/C guys use. It comes in a few different weights but I think I have used 1/2 oz the most. It will make you life easier, easy to use, conforms to any compound curve, easy to fill the weave.
You can find it at better hobby stores, any that sell R/C boats and planes should have it.
Fiberglass Cloth, 1/2 oz. 1 sq yd
An experienced builder turned me on to the kind of fiberglass cloth the R/C guys use. It comes in a few different weights but I think I have used 1/2 oz the most. It will make you life easier, easy to use, conforms to any compound curve, easy to fill the weave.
You can find it at better hobby stores, any that sell R/C boats and planes should have it.
Fiberglass Cloth, 1/2 oz. 1 sq yd
ok, everything is looking great after glass and filler. 2 questions. If I glass in the inboard side of the counter weight skins now, how do you balance the elevators after paint if you cant get to the lead? also which high build primer do I use?...I'm using jeffco epoxy if this helps. Honestly guy's, this fiberglass stuff aint that hard if you follow the direction givin here. One neat thing is you can screw up, sand it off and do it again ask me how I know
Robb
everything should set you up for the lead counterweight being a little on the heavy side. I think you wait till painting is done, then you can drill out some lead if the counterweight is to heavy. on composite planes this is no problem at all, you drill right through the fiber. On an RV, i'm not sure if there is a spot you can drill through. I haven't done this part yet on an RV, just lancairs.
VS tip done
Finally got a piece done to be proud of. This was by far the worst fit ever so I stayed with it to learn the process better. 2 things I learned...Follow Darwins instructions. And Dan H. said "learn to do it right" and " fill it once and sand it once" Amen brother! I read a great way to fill pinholes and it works awesome. When you think you are ready to apply high build primer, do a seal coat instead using straight epoxy and your tool of choice to spread and force the epoxy into every nook and cranny while scraping it all off in the process. 2 coats one right after the other and no more pinholes. WOW! Then your ready for primer.
Thanks for the help guy's.
Robb -7A
Back in fiberglass bliss
Finally got a piece done to be proud of. This was by far the worst fit ever so I stayed with it to learn the process better. 2 things I learned...Follow Darwins instructions. And Dan H. said "learn to do it right" and " fill it once and sand it once" Amen brother! I read a great way to fill pinholes and it works awesome. When you think you are ready to apply high build primer, do a seal coat instead using straight epoxy and your tool of choice to spread and force the epoxy into every nook and cranny while scraping it all off in the process. 2 coats one right after the other and no more pinholes. WOW! Then your ready for primer.
Thanks for the help guy's.
Robb -7A
Back in fiberglass bliss
Not sure if it's been mentioned yet, however, here is a good technique for putting the light cloth on.
Cut a piece of lightweight (1.45 oz) cloth about 24" x 12". Get a medium weight clear polythene bag the size of the glass and cut into 2 pieces. Tape one layer of polythene down to a cutting board or piece of ply, tape the glass on, mix 1 pump of West or whatever system you are using - i.e. not much ! Pour out onto the glass in thin lines. Tape the other piece of polythene on top and using a roller, wet out the cloth.
Using a rotary cutter, cut 2" strips through the whole pile - carefully peel one piece of the polythene away then lay the strip onto the joint. Peel the other layer of polythene off - voila, the glass is on, no wrinkles, no stippling, no fuss.
We thought we would have to mess around to get the technique - the whole empennage was done from start to finish in under an hour - that simple !
Cut a piece of lightweight (1.45 oz) cloth about 24" x 12". Get a medium weight clear polythene bag the size of the glass and cut into 2 pieces. Tape one layer of polythene down to a cutting board or piece of ply, tape the glass on, mix 1 pump of West or whatever system you are using - i.e. not much ! Pour out onto the glass in thin lines. Tape the other piece of polythene on top and using a roller, wet out the cloth.
Using a rotary cutter, cut 2" strips through the whole pile - carefully peel one piece of the polythene away then lay the strip onto the joint. Peel the other layer of polythene off - voila, the glass is on, no wrinkles, no stippling, no fuss.
We thought we would have to mess around to get the technique - the whole empennage was done from start to finish in under an hour - that simple !
