• Fiberglass Release Agent for Vacuum Bagging

    From John Foster@21:1/5 to All on Wed Feb 15 19:40:05 2023
    I'm about to start a project of making new wing cradles for my trailer (a home-made trailer). I plan to vacuum-bag them using the wing as a mould. However, I still haven't finalized what I'm going to use as a release agent on the wing. It is an old
    glider that has damage history, and has been painted. The pain is chipping and peeling up in places, and I hesitate to use packing tape in case it would lift the paint off the wings. I've also considered using a thin piece of construction plastic taped
    over the wing, but question whether this will cause problems with the vacuum, as the vacuum will be applied over top of it. Any other ideas, or feedback on these thoughts?

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  • From Morgan Hall@21:1/5 to John Foster on Wed Feb 15 23:09:10 2023
    I would use vacuum bagging release film. No worries about whether you waxed it enough or had any places where the resin might bond. Additionally you might want to put your felt padding or whatever on the wing and then cover with release film. Then
    your layups and bag it. Most likely you're going to want the cradle oversized enough to accept some type of cushion or pad. You may have to experiment with multiple layers depending on how much it compresses from the vacuum force.

    Morgan

    On Wednesday, February 15, 2023 at 7:40:08 PM UTC-8, John Foster wrote:
    I'm about to start a project of making new wing cradles for my trailer (a home-made trailer). I plan to vacuum-bag them using the wing as a mould. However, I still haven't finalized what I'm going to use as a release agent on the wing. It is an old
    glider that has damage history, and has been painted. The pain is chipping and peeling up in places, and I hesitate to use packing tape in case it would lift the paint off the wings. I've also considered using a thin piece of construction plastic taped
    over the wing, but question whether this will cause problems with the vacuum, as the vacuum will be applied over top of it. Any other ideas, or feedback on these thoughts?

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  • From Martin Gregorie@21:1/5 to John Foster on Thu Feb 16 11:57:09 2023
    On Wed, 15 Feb 2023 19:40:05 -0800 (PST), John Foster wrote:

    I'm about to start a project of making new wing cradles for my trailer
    (a home-made trailer). I plan to vacuum-bag them using the wing as a mould.....
    Any other ideas, or feedback on these thoughts?

    I've not tried this on glider wings, but I used to fly entirely self-built
    F1A free flight models with carbon wing D-boxes which I vacuum formed over hot-wired blue foam male moulds.

    My first thought is to tape whatever felt you'll line the wing cradles
    with round the wing, and cover that with plastic film that's a suitable thickness to wrap closely round the felt and give a smooth outer surface.
    Then vacuum-form the cradles over that, using glass cloth as the inner and outer layers and glass matt layers between them to give the cradles
    whatever thickness and strength you require.

    You could either vac-form the cradle's inner layer using one or two
    glasscloth layers and then add more glass mat layers and a final
    glasscloth layer or two without a using vacuum bag. This would probably be easier than trying to assemble all the layers on the wing and then add a
    vacuum bag over the lot.

    Note that by 'vacuum bag' I mean using a plastic sheet with a vacuum
    connection thats a suitable size to fit over the wetted glasscloth that
    will form the cradle and be taped to the wing all round with something
    like wide masking tape to provide a vacuum seal.


    --

    Martin | martin at
    Gregorie | gregorie dot org

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  • From [email protected]@21:1/5 to All on Thu Feb 16 06:15:11 2023
    Stretch film Is the cheapest. Mylar film Is the pro.

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  • From Hank Nixon@21:1/5 to John Foster on Thu Feb 16 05:37:07 2023
    On Wednesday, February 15, 2023 at 10:40:08 PM UTC-5, John Foster wrote:
    I'm about to start a project of making new wing cradles for my trailer (a home-made trailer). I plan to vacuum-bag them using the wing as a mould. However, I still haven't finalized what I'm going to use as a release agent on the wing. It is an old
    glider that has damage history, and has been painted. The pain is chipping and peeling up in places, and I hesitate to use packing tape in case it would lift the paint off the wings. I've also considered using a thin piece of construction plastic taped
    over the wing, but question whether this will cause problems with the vacuum, as the vacuum will be applied over top of it. Any other ideas, or feedback on these thoughts?

    For what you are doing there is no need for vacuum bagging.
    Wrap the entire surface, with extra margin, with corrogated cardboard , with pleats spanwise . This adds allowance for felt. Then tightly wrap in plastic and lay glass directly on that. Masking tape can be used for all taping. It will be accurate enough
    for a wing saddle.
    Good luck
    UH

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  • From [email protected]@21:1/5 to All on Thu Feb 16 12:27:55 2023
    I have used a method similar to what Hank suggests except I use the felt as the spacer instead of cardboard. Polyethylene sheet works well for a release film. Lay up what you want over the plastic film, cover that with more film and squeegee the the
    result. Most excess resin can be removed this way. Not the same as bagging but works well. I have used this method to make wing cradles, wing wheel cuffs and tail dolly cuffs.
    TR

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  • From John Sinclair@21:1/5 to All on Thu Feb 16 13:53:26 2023
    I’d start by securing the wing with leading edge up and then mask off the area beyond your wing saddle, ie mask off everything except your saddle. Otherwise, the squeegee’d excess resin will end up all over your wing around the saddle. Your saddle
    needs to be wider than the wing to allow room for the cushion material ( about 1/4” if using carpeting). Lay up saddle until it’s about 1/8” thick, which will take something like 6 to 8 layers of 8 oz. cloth. Boat resin is fine for this application
    and it cures much faster, too! Add your wooden base plate set in thickened resin (cotton flow) and several layers of cloth to secure it. Trim your new saddle back to desired shape and paint it red, if desired.
    Hope this helps,
    JJ

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  • From Charlie M. (UH, Pi & 002 owner/pilo@21:1/5 to Steve Leonard on Thu Feb 16 14:03:04 2023
    On Thursday, February 16, 2023 at 4:41:10 PM UTC-5, Steve Leonard wrote:
    On Thursday, February 16, 2023 at 2:27:57 PM UTC-6, [email protected] wrote:
    I have used a method similar to what Hank suggests except I use the felt as the spacer instead of cardboard. Polyethylene sheet works well for a release film. Lay up what you want over the plastic film, cover that with more film and squeegee the the
    result. Most excess resin can be removed this way. Not the same as bagging but works well. I have used this method to make wing cradles, wing wheel cuffs and tail dolly cuffs.
    TR
    Curious as to why you go to the extra effort to "remove excess resin" from a non flying part? Unless it is just force of habit from working on flying parts, and you don't want to lose your touch. Peel ply, at the most, on the outer surface as a first
    step for paint prep.

    Just my two cents,
    Steve Leonard
    Removing excess resin also helps to push out air bubbles/pockets, thus a stronger part when done.
    We do peel ply on flying bits, but also squeegee that as well for the same reasons.
    Yes, it's a tiny bit lighter as well.

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  • From Steve Leonard@21:1/5 to [email protected] on Thu Feb 16 13:41:08 2023
    On Thursday, February 16, 2023 at 2:27:57 PM UTC-6, [email protected] wrote:
    I have used a method similar to what Hank suggests except I use the felt as the spacer instead of cardboard. Polyethylene sheet works well for a release film. Lay up what you want over the plastic film, cover that with more film and squeegee the the
    result. Most excess resin can be removed this way. Not the same as bagging but works well. I have used this method to make wing cradles, wing wheel cuffs and tail dolly cuffs.
    TR

    Curious as to why you go to the extra effort to "remove excess resin" from a non flying part? Unless it is just force of habit from working on flying parts, and you don't want to lose your touch. Peel ply, at the most, on the outer surface as a first
    step for paint prep.

    Just my two cents,
    Steve Leonard

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  • From Mark Mocho@21:1/5 to All on Thu Feb 16 16:09:41 2023
    Excess epoxy in globs can also crack under stress. Its best strength is when it provides a minimum volume matrix with the glass fibers. Squeegee out as much excess as possible and cover with a peel-ply polyester fabric which will soak up some even more
    of the excess and then pull the peel ply off when everything is cured.

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  • From Papa3@21:1/5 to John Foster on Fri Feb 17 08:00:03 2023
    On Wednesday, February 15, 2023 at 10:40:08 PM UTC-5, John Foster wrote:
    I'm about to start a project of making new wing cradles for my trailer (a home-made trailer). I plan to vacuum-bag them using the wing as a mould. However, I still haven't finalized what I'm going to use as a release agent on the wing. It is an old
    glider that has damage history, and has been painted. The pain is chipping and peeling up in places, and I hesitate to use packing tape in case it would lift the paint off the wings. I've also considered using a thin piece of construction plastic taped
    over the wing, but question whether this will cause problems with the vacuum, as the vacuum will be applied over top of it. Any other ideas, or feedback on these thoughts?

    Not what you asked for, but... A club member has designed a very simple but effective and sturdy wing saddle using aluminum sheet. It's much less bulky than fiberglass, easier to make, and lighter. The secret is the closure mechanism, which
    is elegantly simple. If you're interested I can try to get some pictures when I'm in the shop on Sunday.

    P3

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  • From Mark Mocho@21:1/5 to All on Fri Feb 17 08:11:33 2023
    . A club member has designed a very simple but effective and sturdy wing saddle using aluminum sheet. It's much less bulky than fiberglass, easier to make, and lighter.

    I built neatly 350 wing wheels from 2001 to 2019, when I stopped production due to other commitments. (As well as getting bored with them and not being able to charge enough to warrant the 15 hours of hand fabrication in each one.) All were made with a
    steel chassis and an aluminum cradle (cuff). Each could be shaped exactly to the wing profile from a cardboard template without having to have a mold or the actual wing to use for a fiberglass layup. Aluminum is a viable choice for a wing wheel, but it
    has to be of sufficient strength to avoid deformation and possible damage to the wing if it flexes excessively. I am considering resuming production on a limited basis, but only if I can charge enough to afford the "better beer" as opposed to the cheap
    swill I used to consume.

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  • From Dan Marotta@21:1/5 to Steve Leonard on Fri Feb 17 08:38:19 2023
    When I made a wing wheel cuff for my LS-6 back in the early 90s, I
    didn't even bother with peel ply. I wrapped a strip of carpet (the
    padding) around the wing, then plastic film, then wet layup glass and
    epoxy. When it was cured, I spray painted it with a rattle can.

    It wasn't beautiful but it worked great.

    Dan
    5J

    On 2/16/23 14:41, Steve Leonard wrote:
    On Thursday, February 16, 2023 at 2:27:57 PM UTC-6, [email protected] wrote:
    I have used a method similar to what Hank suggests except I use the felt as the spacer instead of cardboard. Polyethylene sheet works well for a release film. Lay up what you want over the plastic film, cover that with more film and squeegee the the
    result. Most excess resin can be removed this way. Not the same as bagging but works well. I have used this method to make wing cradles, wing wheel cuffs and tail dolly cuffs.
    TR

    Curious as to why you go to the extra effort to "remove excess resin" from a non flying part? Unless it is just force of habit from working on flying parts, and you don't want to lose your touch. Peel ply, at the most, on the outer surface as a first
    step for paint prep.

    Just my two cents,
    Steve Leonard

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  • From jfitch@21:1/5 to All on Fri Feb 17 08:29:45 2023
    On Friday, February 17, 2023 at 8:00:05 AM UTC-8, Papa3 wrote:
    On Wednesday, February 15, 2023 at 10:40:08 PM UTC-5, John Foster wrote:
    I'm about to start a project of making new wing cradles for my trailer (a home-made trailer). I plan to vacuum-bag them using the wing as a mould. However, I still haven't finalized what I'm going to use as a release agent on the wing. It is an old
    glider that has damage history, and has been painted. The pain is chipping and peeling up in places, and I hesitate to use packing tape in case it would lift the paint off the wings. I've also considered using a thin piece of construction plastic taped
    over the wing, but question whether this will cause problems with the vacuum, as the vacuum will be applied over top of it. Any other ideas, or feedback on these thoughts?
    Not what you asked for, but... A club member has designed a very simple but effective and sturdy wing saddle using aluminum sheet. It's much less bulky than fiberglass, easier to make, and lighter. The secret is the closure mechanism, which is
    elegantly simple. If you're interested I can try to get some pictures when I'm in the shop on Sunday.

    P3
    I'd be very interested in seeing photos of the closure mechanism. This is the Achilles heel of all wing saddles.

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  • From Dan Marotta@21:1/5 to jfitch on Fri Feb 17 17:28:16 2023
    Mine was closed with nuts and bolts at the trailing edge, but the LS-6
    did not have winglets and the cuff was simply slipped on at the tip

    Dan
    5J

    On 2/17/23 09:29, jfitch wrote:
    On Friday, February 17, 2023 at 8:00:05 AM UTC-8, Papa3 wrote:
    On Wednesday, February 15, 2023 at 10:40:08 PM UTC-5, John Foster wrote:
    I'm about to start a project of making new wing cradles for my trailer (a home-made trailer). I plan to vacuum-bag them using the wing as a mould. However, I still haven't finalized what I'm going to use as a release agent on the wing. It is an old
    glider that has damage history, and has been painted. The pain is chipping and peeling up in places, and I hesitate to use packing tape in case it would lift the paint off the wings. I've also considered using a thin piece of construction plastic taped
    over the wing, but question whether this will cause problems with the vacuum, as the vacuum will be applied over top of it. Any other ideas, or feedback on these thoughts?
    Not what you asked for, but... A club member has designed a very simple but effective and sturdy wing saddle using aluminum sheet. It's much less bulky than fiberglass, easier to make, and lighter. The secret is the closure mechanism, which is
    elegantly simple. If you're interested I can try to get some pictures when I'm in the shop on Sunday.

    P3
    I'd be very interested in seeing photos of the closure mechanism. This is the Achilles heel of all wing saddles.

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  • From weemacgregor@21:1/5 to All on Thu Mar 9 11:29:06 2023
    On Friday, 17 February 2023 at 11:00:05 UTC-5, Papa3 wrote:
    On Wednesday, February 15, 2023 at 10:40:08 PM UTC-5, John Foster wrote:
    I'm about to start a project of making new wing cradles for my trailer (a home-made trailer). I plan to vacuum-bag them using the wing as a mould. However, I still haven't finalized what I'm going to use as a release agent on the wing. It is an old
    glider that has damage history, and has been painted. The pain is chipping and peeling up in places, and I hesitate to use packing tape in case it would lift the paint off the wings. I've also considered using a thin piece of construction plastic taped
    over the wing, but question whether this will cause problems with the vacuum, as the vacuum will be applied over top of it. Any other ideas, or feedback on these thoughts?
    Not what you asked for, but... A club member has designed a very simple but effective and sturdy wing saddle using aluminum sheet. It's much less bulky than fiberglass, easier to make, and lighter. The secret is the closure mechanism, which is
    elegantly simple. If you're interested I can try to get some pictures when I'm in the shop on Sunday.

    P3
    Greetings P3:

    I was wondering if you were able to get pictures of the aluminum sheet wing saddle that one of your club members had designed? I would be very interested in seeing this.

    Thanks,

    rob p.

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  • From Papa3@21:1/5 to weemacgregor on Thu Mar 9 18:57:47 2023
    On Thursday, March 9, 2023 at 2:29:08 PM UTC-5, weemacgregor wrote:
    On Friday, 17 February 2023 at 11:00:05 UTC-5, Papa3 wrote:
    On Wednesday, February 15, 2023 at 10:40:08 PM UTC-5, John Foster wrote:
    I'm about to start a project of making new wing cradles for my trailer (a home-made trailer). I plan to vacuum-bag them using the wing as a mould. However, I still haven't finalized what I'm going to use as a release agent on the wing. It is an old
    glider that has damage history, and has been painted. The pain is chipping and peeling up in places, and I hesitate to use packing tape in case it would lift the paint off the wings. I've also considered using a thin piece of construction plastic taped
    over the wing, but question whether this will cause problems with the vacuum, as the vacuum will be applied over top of it. Any other ideas, or feedback on these thoughts?
    Not what you asked for, but... A club member has designed a very simple but effective and sturdy wing saddle using aluminum sheet. It's much less bulky than fiberglass, easier to make, and lighter. The secret is the closure mechanism, which is
    elegantly simple. If you're interested I can try to get some pictures when I'm in the shop on Sunday.

    P3
    Greetings P3:

    I was wondering if you were able to get pictures of the aluminum sheet wing saddle that one of your club members had designed? I would be very interested in seeing this.

    Thanks,

    rob p.

    Sorry - forgot to do this when I was in the shop last week. Will try this weekend.

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  • From Papa3@21:1/5 to All on Sat Mar 11 05:53:22 2023
    Greetings P3:

    I was wondering if you were able to get pictures of the aluminum sheet wing saddle that one of your club members had designed? I would be very interested in seeing this.

    Thanks,

    rob p.
    Sorry - forgot to do this when I was in the shop last week. Will try this weekend.

    Here are pics one of the club members took. https://share.icloud.com/photos/0e4Dsb8L_hzDX4woT4PJxvHCw

    Things to note:

    - Saddle is bent aluminum made from a single sheet.
    - Closure uses PVC pipe with a slot cut in it to capture two robust pieces of aluminum bar stock.
    - Foam is a medium density material that works very nicely.
    - Mounting plates for the truss are riveted into the bent sheet.
    - The truss could probably be made a little more robust (this one had a shock absorber/damper but it suffered from neglect and abuse in a club setting)

    P3

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  • From weemacgregor@21:1/5 to All on Tue Mar 21 07:25:58 2023
    Great design, pictures, and explanation.

    Thank you for your trouble P3.

    rob p.

    On Saturday, 11 March 2023 at 08:53:25 UTC-5, Papa3 wrote:
    Greetings P3:

    I was wondering if you were able to get pictures of the aluminum sheet wing saddle that one of your club members had designed? I would be very interested in seeing this.

    Thanks,

    rob p.
    Sorry - forgot to do this when I was in the shop last week. Will try this weekend.
    Here are pics one of the club members took. https://share.icloud.com/photos/0e4Dsb8L_hzDX4woT4PJxvHCw

    Things to note:

    - Saddle is bent aluminum made from a single sheet.
    - Closure uses PVC pipe with a slot cut in it to capture two robust pieces of aluminum bar stock.
    - Foam is a medium density material that works very nicely.
    - Mounting plates for the truss are riveted into the bent sheet.
    - The truss could probably be made a little more robust (this one had a shock absorber/damper but it suffered from neglect and abuse in a club setting)

    P3

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