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#1
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Fiberglass adhesion to aluminum?
I've got some slight cracking in my aluminum nosebowl and have stop
drilled them twice. I'm considering backing the cracks with fiberglass in hopes to keep the vibration down. How well does fiberglass adhere to aluminum? What system is better. I have easy access to the West system chemicals. Any hints? Alodine first? Thanks Dave |
#2
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Fiberglass adhesion to aluminum?
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#3
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Fiberglass adhesion to aluminum?
If a fiberglass patch on an aluminum backplate stays on for one entire
trip around the pattern, I'd be flat out amazed... |
#4
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Fiberglass adhesion to aluminum?
On Fri, 06 Jan 2006 05:59:37 GMT, Richard Lamb
wrote: If a fiberglass patch on an aluminum backplate stays on for one entire trip around the pattern, I'd be flat out amazed... Properly preped it'll stay on as well as the paint, better in some cases. Without a good degrease and prep I doubt it'd stay on past the run up. :-)) Many of our "plastic" planes have Aluminum to glass/resin bonds. Roger Halstead (K8RI & ARRL life member) (N833R, S# CD-2 Worlds oldest Debonair) www.rogerhalstead.com |
#5
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Fiberglass adhesion to aluminum?
Roger wrote: On Fri, 06 Jan 2006 05:59:37 GMT, Richard Lamb wrote: If a fiberglass patch on an aluminum backplate stays on for one entire trip around the pattern, I'd be flat out amazed... Properly preped it'll stay on as well as the paint, better in some cases. Without a good degrease and prep I doubt it'd stay on past the run up. :-)) Many of our "plastic" planes have Aluminum to glass/resin bonds. Roger Halstead (K8RI & ARRL life member) (N833R, S# CD-2 Worlds oldest Debonair) www.rogerhalstead.com I know, Roger, but.... Someone who is actually building a plastic plane should step up to the microphone and tell how those metal plates are installed. I know of no structural design that has aluminum plates "glued" on to glass. My best guess is that they get "bonded in" by covering them with more layers of glass. - in effect, the metal is burried inside the glass. That's not he case here. Richard (the skeptical cave) Lamb |
#6
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Fiberglass adhesion to aluminum?
On Fri, 06 Jan 2006 18:00:32 GMT, Richard Lamb
wrote: Roger wrote: On Fri, 06 Jan 2006 05:59:37 GMT, Richard Lamb wrote: If a fiberglass patch on an aluminum backplate stays on for one entire trip around the pattern, I'd be flat out amazed... Properly preped it'll stay on as well as the paint, better in some cases. Without a good degrease and prep I doubt it'd stay on past the run up. :-)) Many of our "plastic" planes have Aluminum to glass/resin bonds. Roger Halstead (K8RI & ARRL life member) (N833R, S# CD-2 Worlds oldest Debonair) www.rogerhalstead.com I know, Roger, but.... Someone who is actually building a plastic plane should step up to the microphone and tell how those metal plates are installed. As for the three methods described below you will find photos at http://www.rogerhalstead.com/G3_file.../glasair11.htm along with some description. As you'll note, these are not just "slapped" in. :-)) It depends on which part and where. Typically, you'll find captive nuts like the K2000-4 (If I remember the number correctly) both pop riveted in place and then have the "ears" glassed in with two layers of cloth and resin. The "glass serves as much to keep from losing the captive nuts as it does structurally. Lose one of those suckers and it means cutting a hole in the horizontal stab, glassing in a new K2000-4, and then patching the stab so it looks like you never had to bore a hole in it. The backing plates for the engine mount attach bolts (which are held under considerable compression) are of 0.10" SS. The face and edges are thoroughly sanded and these are bonded on the face and sides to the engine mount attach point reinforcements using a resin and mill fiber mix. For six attach points there are a total of 96 individual lay-ups just for the reinforcements, plus six more two layer lay-ups used for forms. The third method which is *similar* to what he's asking about is the fuel tank filler neck. There the outer ring is set into a tight fitting opening just a tad forward of the windshield. This pieces is held entirely by a resin and mill fiber mix. which is built up around the neck. This is in an area which would receive pretty much the same kind of stresses as the cowl crack and receives a lot of stress from expansion and contraction of the machined Aluminum filler neck and cap. *However* how I've seen a cowl patched, and the only way I've seen it done was to first, "stop drill" the crack. Then a small "doubler" was made out of Aluminum about the same thickness as the cowl. As the crack included the leading edge of the cowl where the edge is rolled back and extended back about 2 inches. ( Of course the thing would never crack where it's easy to fix) (Yah ever try to type with a lap full of a 16# cat? At least he didn't have his claws out when he jumped up.) Slight distraction there. At any rate, The entire area was thoroughly cleaned, sanded, cleaned again, the doubler fitted, then flush riveted in, and finally the whole thing was glassed over on the inside with two layers of glass and resin. The glass was a last resort as the doublers were refusing to hold. Hmmmm... Good thing I'm not writing and this has a back space key. He just knocked over the waste basket. I think I have a cat who wants some attention.:-)) I know of no structural design that has aluminum plates "glued" on to glass. Nor do I, but didn't he ask about patching a cowl crack? It is structural, but only for vibration and a slight wind load. Of course it does depend on where in the cowl as well and I'd still want to use a doubler.. Roger Halstead (K8RI & ARRL life member) (N833R, S# CD-2 Worlds oldest Debonair) www.rogerhalstead.com My best guess is that they get "bonded in" by covering them with more layers of glass. - in effect, the metal is burried inside the glass. That's not he case here. Richard (the skeptical cave) Lamb |
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Fiberglass adhesion to aluminum?
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#9
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Fiberglass adhesion to aluminum?
I had some fretting on my 1948 Bellanca cowling. It was worn clear thru.
Cleaned the area. Built up the area with epoxy and micro-balloons. Still there 15 years later. -- Cy Galley - Bellanca Champion Club Newsletter Editor-in-Chief & EAA TC www.bellanca-championclub.com Actively supporting Bellancas every day wrote in message news Thanks for the info. BTW, this is on the cowling, not the spinner. Dave Dave S wrote: wrote: How well does fiberglass adhere to aluminum? What system is better. I have easy access to the West system chemicals. Any hints? Alodine first? Thanks Dave You have to sand the AL to roughen it up, to provide something for the epoxy to bite into. The hardpoints in the Velocity construction are prepared in this manner. No alodining, no painting. Coarse grit Sandpaper to roughen. I want to say we used Velocipoxy resin and hardner, or alpha Poxy, on our work. I am more concerned about the need to BALANCE the spinner, and if you apply a layup on one side of the bowl, you may need to put another layup on the other side to provide some sort of balancing effect. I am not exactly sure of how much force is involved at only 8-10" from the hub at the RPMS involved. I've never patched a spinner in this manner but intuitively it COULD work. Dave |
#10
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Fiberglass adhesion to aluminum?
wrote in message ... I've got some slight cracking in my aluminum nosebowl and have stop drilled them twice. I'm considering backing the cracks with fiberglass in hopes to keep the vibration down. How about welding it? Just a suggestion (since I haven't seen the part or the cracks). I didn't see that suggested and I can't help but wonder 'why not'. Just glass-bead blast that area and have it TIG'd up. I've seen some folks successfully 'Heli Arc' some very delicate material. A character by the name of Vince Wyatt used to weld little stick figures (about 2" tall) onto the top of his Copenhagen cans at Todd Shipyard in the early 70's. I'd keep an eye on how much bead (mass) is added to one side. Possibly add to the other side to balance. Does that sound feasible? |
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