|Jan 24, 2013, 10:51 AM|
How to make a Fiberglass slip tube
Hi everyone. I am completely inexperianced with fiberglassing and I thought I could start gaining some experiance by making a slip tube for a wing joiner (I will probably need one in the near future).
So, what materials do I need and is there any guide or video link to help me?
|Jan 24, 2013, 11:31 AM|
Alot of these are made with molds that are metal or composite on the outside (perhaps made with a piece of brass tubing and splitter plate) and often times silicone is used to press the inside of the layup.
Search here for "Silicone Press" molding, try the F3X forum looking for "joiner construction" and you'll likely find something. "Bladder molding" will net you alot of hits but many of the joiners are built this way as well.
Here's a brief example of a search output...
|Jan 24, 2013, 12:12 PM|
I just made some using Dr. Drela's instructions. I used either thin painter's polyethylene drop cloth or waxed paper (both about 0.013mm or 0.0005" thick) for the inner release layer, rather than 0.0005" mylar he calls for. Both released fine, and just required some poking to get out of the inside.
The ones I just made had about 7 wraps of the 1.7oz./yd^2 Kevlar and 0.75 oz glass sandwich. I used a strip cut from the polyethylene drop cloth to wind on the outside. I didn't use the cabosil to get it started, just picked up the edge of the glass and got it on the tube as straight as I could.
|Jan 24, 2013, 06:10 PM|
Hi dk31, I'm doing a tiger 60 bash and I made a fiberglass sleeve off the 3/4" aluminum tube for slip on wings. Total cost was about $20, works great and easy to do, includes the tube.
See the build here: www.rcgroups.com/forums/showthread.php?t=1786693
|Jan 25, 2013, 02:14 AM|
I think that you refer to how to make/mold the joiner itself. I am going to use a bought CF tube as joiner and just want to make myself the slip tube (the "nest" for the joiner that will be built in the wing)
So if I got it right, the order of layers from joiner and out are:
-mylar or thin polyethylene drop cloth
-wax (what type of wax? any link would be greag
-7 wraps of Kevlar and glass sandwich (Is Epoxy aplied here? If yes, over the glass surface or both Kevlar and glass? )
-polyethylene drop cloth strip
Is that right?
|Jan 25, 2013, 02:28 AM|
So, if you ignore the first attempt, your method would be:
-Clear packing tape on the joiner
-Wax on the tape
-around 6 wraps of glass soaked in epoxy
Is that correct?
Also, I forgot to ask before, do you need liquid epoxy? I have the common gel-like 30min epoxy, would that do the job?
|Jan 25, 2013, 11:05 AM|
I wet out the Kevlar/glass cloth sandwich with laminating epoxy while it was laying flat on a piece of glass, but a kitchen cutting board would work. You might need something thinner than the common tube-style epoxy to easily wet out the cloth. You could just use just 2 oz. glass on a bias (45 degrees), rather than Kevlar/glass, but Kevlar is much lighter and stronger for this application.
Pick up the 1/2" extra of the thin glass, get the wrap started on your waxed paper wrapped CF tube, and roll it all onto the tube as shown in Dr. Drela's drawings. Wrap with a spiral strip of polyethylene maybe 1" wide, and then another wrap with a stretchy tape like electrician's tape. Let it cure at room temperature.
It slides off pretty easily on the layer of Vaseline, and then you have to poke the waxed paper out from the inside. The resulting tube is about 0.001" over-size on your CF tube, which is nice fit. Packing tape would make a looser fit, and maybe wouldn't slide off as easily as the Vaseline layer does.
|Feb 02, 2013, 10:42 PM|
When I had to make a fiberglass tube I used a similar technique to the one in post #3, but instead of rolling the last plastic layer around the mold and fiberglass I just folded it around and clamped the two ends in between two pieces of wood pressed hard against the mold.
The advantage I see in doing it that way is that it's easier to squeeze the last layer to remove as much excess resin as possible; just clamp it and pull on the ends to tighten the material over the mold.
Of course there's a small ridge along the length of the final shape but it's easy to remove by sanding, or it won't bother at all for the intended use.
|Feb 11, 2013, 03:17 PM|
Material gathering will delay a little as there are only few sellers and they're far from where I live... So I decided to give it a try with what I have in hand, for educational purposes
It went like this:
1.Vaseline on the tube --> not exactly a uniform layer. I spread it with a piece of cloth, trying to keep a thin layer equal around the tube, but it spreads like more here-less there.
2. One wrap (with a little overlap) of Plastic drop cloth. It was a very very thin cloth that resembles food storage film
3. Ten wraps of 0.75oz fiberglass. I mixed some regular epoxy with alcohol and aplied with a paint brush
4. One inch strip of drop cloth-spiral around the tube
5. Electrician's tape
Release of the tube was very easy, inner drop cloth came out easily and the slip tube makes a perfect fit with the alu tube.
What went wrong, is that the outer drop cloth spiral got stuck on the outer of the slip tube, and I had to peel it off bit by bit, like skin under the summer sun. Also the outer surface is wavy.
Next attempt will be with thicker drop cloth, heavier Fiberflass and maybe squezzing the excess epoxy off while rolling the fiberglass...
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