bonding 2 pieces of ali?
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bonding 2 pieces of ali?
Hi everyone
I’m looking for a ultra strong glue for bonding 2 pieces of aluminium approx 32` thick together. There are glues on the market for bonding in the rotary maintenance, does anyone know of any names etc? MUST BE ROCK HARD
I’m looking for a ultra strong glue for bonding 2 pieces of aluminium approx 32` thick together. There are glues on the market for bonding in the rotary maintenance, does anyone know of any names etc? MUST BE ROCK HARD
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What 'Ali' do you mean? If for aircraft use your maintence and structural repair manual will advise on authorised adhesives for particular applications
Unless it is not for aircraft use?
Unless it is not for aircraft use?
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araldite holds the wings of the Sukhoi 27 on... gee I wonder if anyone has told the Sukhoi Design Bureau...
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This stuff has a very good reputation. I've used other products from them over the years and was impressed.
System Three: Products: SilverTip MetlWeld
JB Weld might be easier to source where you are though - sets hard enough to mill and thread tap.
Rob
System Three: Products: SilverTip MetlWeld
JB Weld might be easier to source where you are though - sets hard enough to mill and thread tap.
Rob
If you use Araldite clean with a degreaser then abrade with emery loaded with Araldite then if possible vacuum the joint during cure ( use the 24 hour not the fast cure Aroldite) have used this method for numerous projects on boats works well, carry out all operations as quickly as possible, also use minimum amount of glue.
Last edited by 500e; 2nd May 2009 at 21:51.
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Adhesive bonding
Dear me. The level of knowledge about adhesive bonding within the rotorheads community is really low. I suggest that you try reading DOT/FAA/AR – TN06/07, Apr 2007 BEST PRACTICE IN ADHESIVE BONDED STRUCTURES AND REPAIRS. You can get this document by emailing the FAA Tech Center. If you want a soft copy send me a private message.
Firstly, the selection of the adhesive is almost a trivial aspect of the technology. Most adhesive bonds do not fail through the adhesive, they fail through the interface between the adhesive and the metal. That form of failure is driven by the surface preparation prior to bonding. Can I assure you that if you "clean with a degreaser then abraid (abrade?) with emery" you will have a weak bond. Here is why:
Adhesive bonding depends on the development of chemical bonds between the adhesive and the metal. (It has very little to do with surface roughness.) To achive a good bond, the surface must be clean (so that the chemical reactions can occur), but it also must be chemically active, which is why the surface must be etched or abraded. If you do clean with a degreaser then abrade with emery you will get what appears initially to be a good bond. However, the interface between the adhesive and the metal will be susceptible to degradation over time and eventually the bond will fail. The mechanism is that the aluminium oxides formed immediately after abrasion will have an affinity for water and will form a hydrated oxide (bohemite). The chemical bonds formed initially dissociate so that the hydrated oxide can be formed, and this leads to disbonding. Hence it is essential that you treat the surface to produce chemical bonds that are resistant to hydration. Be careful though. There are many adhesive bond primers out there which are virtually useless. I suggest that you contact me or visit my web site Adhesion Associates
If you follow this advice, then virtually any adhesive you select should provide a strong, durable bond. If you don't follow the advice, then it will not make any difference which adhesive you use. The only difference will be the colour of the disbond. Obviously, the amount of effort you wish to expend depends on the importance of the bond to structural integrity and the consequences of failure. If the joint is required to provide ongoing strength in a structure that is critical, then you must do everything you can to assure integrity of the bond. If the bond is nothing more than cosmetic and failure is inconsequential, then use a sealant. That will keep the material together probably better than an adhesive at least for a short period of time.
Regards
Blakmax
Firstly, the selection of the adhesive is almost a trivial aspect of the technology. Most adhesive bonds do not fail through the adhesive, they fail through the interface between the adhesive and the metal. That form of failure is driven by the surface preparation prior to bonding. Can I assure you that if you "clean with a degreaser then abraid (abrade?) with emery" you will have a weak bond. Here is why:
Adhesive bonding depends on the development of chemical bonds between the adhesive and the metal. (It has very little to do with surface roughness.) To achive a good bond, the surface must be clean (so that the chemical reactions can occur), but it also must be chemically active, which is why the surface must be etched or abraded. If you do clean with a degreaser then abrade with emery you will get what appears initially to be a good bond. However, the interface between the adhesive and the metal will be susceptible to degradation over time and eventually the bond will fail. The mechanism is that the aluminium oxides formed immediately after abrasion will have an affinity for water and will form a hydrated oxide (bohemite). The chemical bonds formed initially dissociate so that the hydrated oxide can be formed, and this leads to disbonding. Hence it is essential that you treat the surface to produce chemical bonds that are resistant to hydration. Be careful though. There are many adhesive bond primers out there which are virtually useless. I suggest that you contact me or visit my web site Adhesion Associates
If you follow this advice, then virtually any adhesive you select should provide a strong, durable bond. If you don't follow the advice, then it will not make any difference which adhesive you use. The only difference will be the colour of the disbond. Obviously, the amount of effort you wish to expend depends on the importance of the bond to structural integrity and the consequences of failure. If the joint is required to provide ongoing strength in a structure that is critical, then you must do everything you can to assure integrity of the bond. If the bond is nothing more than cosmetic and failure is inconsequential, then use a sealant. That will keep the material together probably better than an adhesive at least for a short period of time.
Regards
Blakmax
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For what its worth - I glued the flywheel onto the crankshaft of a Morris 1100 car engine with 24hour Araldite Epoxy and it held forever.
The metal key had worn away causing the flywheel to freewheel and glue was a quick fix designed to get us home and it lasted till the normal demise of the car.
OOW
The metal key had worn away causing the flywheel to freewheel and glue was a quick fix designed to get us home and it lasted till the normal demise of the car.
OOW
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Bonding Morris 1100!
Crikey OOW! My experiences with a Morris 1100 meant that your bond had to last the life of the vehicle.... about six months! 
Seriously, a different application. You weren't really relying on the bond, you were relying on the bulk properties of the adhesive material, and that is a different requirement to transferring load through an interface. The consequences of failure would also have been less stringent than for a structural bond on an aircraft. But then, a broken down 1100 near Walgett at midnight can be pretty risky too!
Blakmax
Seriously, a different application. You weren't really relying on the bond, you were relying on the bulk properties of the adhesive material, and that is a different requirement to transferring load through an interface. The consequences of failure would also have been less stringent than for a structural bond on an aircraft. But then, a broken down 1100 near Walgett at midnight can be pretty risky too!
Blakmax
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its aircraft aluminium and is not for aircraft use.
Depending on what you want to achieve,
HYSOL
Metalset
Magnabond
Proseal/Flame master tank sealant
Araldite
Cyanoacrylate
The list goes on.
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SIKAFLEX....it's an isocyanate-curing polyurethane, iirc.
use to stick alloy car panels together and alloy to steel also to fit bonded -in glass.
Yhe stuff is rubbery when set and you can get high and low -modulus types. As with Epoxy (or soldering/brazing ) a relatively thin film is stronger. metal sheet will tear before the bond breaks.
Prep and priming are the key to a successful long-term bond.
use to stick alloy car panels together and alloy to steel also to fit bonded -in glass.
Yhe stuff is rubbery when set and you can get high and low -modulus types. As with Epoxy (or soldering/brazing ) a relatively thin film is stronger. metal sheet will tear before the bond breaks.
Prep and priming are the key to a successful long-term bond.
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Araldite and Metalset have always been excellent performers, working without failure when applied to correctly prepared materials, during my time using them in workshops.
When asked it they were good, I'd reply that they were so good, they'd stick air to water!
When asked it they were good, I'd reply that they were so good, they'd stick air to water!
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Metalset seems to work well but the Hysol products win for my money. Many manufacturers seem to agree and you can get them in the small squeeze tubes. McMasters has good prices. Check on the RC forums 
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I had a similar problem a while ago, Finally achieved a durable (so far) bond using a dental silane as a pre-treatment before epoxy. Dental silanes are hugely expensive though. I wonder if Max or anyone knows of an industrial version at a more reasonable cost?
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You are on the money gaseous
Hi Gaseous
You are absolutely correct. We have been using a silane (gamma glycidoxy propyl trimethoxy silane) since 1992 and we have reduced our repeat repair rate from 43% to
near zero out of about 3500 repairs. Silane is a component in "Bojel" a sol-gel product developed by Boeing in kit form. The best results are achieved by sovent degreasing followed by a grit blast and IMMEDIATE application of the silane. Boeing recommend the use of a primer but our experience is that the silane IS a primer and is effective in corrosion prevention. If you can't find Bojel then try Dow Corning Z6040.
The difference between grit blast and hand abrade is significant. Grit blast where possible, but NOT in fuel tanks.
God it is good to find someone who knows that it is not just a process of selecting different "glues".
By the way, in the past I conducted a course in which I told the students that they needed to spell the name of the coupling agent gamma glycidoxy propyl trimethoxy silane before they could pass the course. I then set a question stating "Spell the name of the coupling agent gamma glycidoxy propyl trimethoxy silane". Would you believe that out of about fifty students who actually did attempt the question, only four got it right and it was written in front of them!!!
You are absolutely correct. We have been using a silane (gamma glycidoxy propyl trimethoxy silane) since 1992 and we have reduced our repeat repair rate from 43% to
near zero out of about 3500 repairs. Silane is a component in "Bojel" a sol-gel product developed by Boeing in kit form. The best results are achieved by sovent degreasing followed by a grit blast and IMMEDIATE application of the silane. Boeing recommend the use of a primer but our experience is that the silane IS a primer and is effective in corrosion prevention. If you can't find Bojel then try Dow Corning Z6040. The difference between grit blast and hand abrade is significant. Grit blast where possible, but NOT in fuel tanks.
God it is good to find someone who knows that it is not just a process of selecting different "glues".
By the way, in the past I conducted a course in which I told the students that they needed to spell the name of the coupling agent gamma glycidoxy propyl trimethoxy silane before they could pass the course. I then set a question stating "Spell the name of the coupling agent gamma glycidoxy propyl trimethoxy silane". Would you believe that out of about fifty students who actually did attempt the question, only four got it right and it was written in front of them!!!