Stainless -aluminum glue ?

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cvairwerks

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Takes a lot of roughing up the glue area on the stainless as well as absolute cleanliness. We used a Hysol two part adhesive, but I don't remember what the Hysol part number is. I remember our spec, but unless you have access to a Hysol rep, or F-16 material specs, it will take some detective work to find it. I do remember that it was good for up to 250F.
 

Pilot-34

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lm building a sluice box I can fly with . I’m dealing with size constraints so it’s going to be modular and foldable.
One member of the group has 60 inch stainless piano hinges and another has 12 inch wide 1/8 thick aluminum. They became the materials of choice.
I’m thinking rivets but the subject of glue came up.
 

Toobuilder

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If you are using the piano hinge to join the sides of a box together (and then throw in a river filled with sand and rocks), then its mechanical fasteners all the way. Just to keep this thread somewhat homebuilt related, this is how I joined the plenum lid to the baffles on my Rocket. The lid is a diaphragm so tries to ballon up with air pressure. This loads the rivets in shear in my application.
 

Jay Kempf

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Look into Methacrylates. I use them quite a bit for dissimilar material bonding with good results. They do well on aluminum. Stainless might be tougher but they respond well to roughing up a surface with 40 grit. They are way less sensitive to prepping surfaces and cleanliness than epoxy based solutions. Ventilate well. Nasty stuff as it is self etching. I've used it to bond 3d printed parts to composites, aluminum to composites, glass and plexiglass to composites, fasteners for hard points, etc... fast and slow cure available. You do your own research and testing on suitability of your application. There are large and small dual tube injection systems available and inexpensive.
 

Fiberglassworker

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Takes a lot of roughing up the glue area on the stainless as well as absolute cleanliness. We used a Hysol two part adhesive, but I don't remember what the Hysol part number is. I remember our spec, but unless you have access to a Hysol rep, or F-16 material specs, it will take some detective work to find it. I do remember that it was good for up to 250F.
I think the part number you are looking for is Hysol EA9309 NA
 

AeroER

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A sluice box? Stick it together with auto trim or contact cement.
 

geraldmorrissey

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EA934NA is what we used in many applications in asrospace for metal and composites. It's 40years old and Hysol is still selling it. Down side, it's expensive and you may have a minimum quantity to buy. Fasteners sound like a better option.
 
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wktaylor

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A few serious factors, not mentioned, come to my enginerd brain, over-thinks at once...

Extruded aluminum alloy hinges [MS20001 style] are either made from 2024-T3511 or 7075-T3511... excellent alloys for flight strength and toughness and ~long hinge-life... with proper coatings and isolation to other aluminum alloy structure. The specified Hinge Pin [MS20253] is strain-hardened CRES and is often oil or grease lubricated on installation... or the pin can have a solid film lubricant applied it's full-length.

However...

Aluminum alloys and stainless steel [SStl, 300-series???] are highly dissimilar. Without substantial coatings for Isolation... fastened together... or on adhesive bondlines... aluminum corrosion in a wet environment is inevitable. This include corrosion between the hinge pin and the ID of the hole quickly since lubricants often 'wash-away' [although a solid film lubricant applied the full-length of the pin might work OK, for awhile]. IF fasteners hole everything together, then they-too are subject to corrosion/rusting in the presence of aluminum, SStl and water.

Aluminum is a poor choice if it can come in direct contact with abrasives [sluice?], fastened or bonded to SStl. It will degrade coatings 'fast'... then corrode fast.

Aluminum and SStl fastened or bonded together will work 'OK' for awhile @ ~100F total temperature variation... but for wide temperature variations the much-higher thermal expansion and contraction rate of aluminum alloys VS SStl may be enough to eventually crack thru holes or disbond the parts... certainly leaks will occur.

Perhaps, SStl 'piano hinge' [MS35824 roll-formed sheet, with a SStl pin] welded to SStl sheet is a better option?
 

wsimpso1

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Stainless and aluminum in contact with each other usually requires that the stainless be passivated. The stainless rods common in aluminum hinges are passivated as are stainless bolts used on aluminum. Thankfully passivation is easy - do your internet homework, then follow the process.

If it were me, I would rivet with epoxy adhesive on the faying surfaces between aluminum plate and stainless hinges. As a sluice box, you gotta know it is still going to be a consumable assembly.

Billski
 

wktaylor

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Billski...

RE your reply to my original discussion[?]... Sorry, Sir, cannot agree... Although, almost any combination can be made last 'just long enough' for quick jobs.🗣yep

Passivated SStl... has limited value in direct contact with aluminum, without corrosion preventative primer on the passivated surface of the SStl [paint adheres better to freshly passivated SStl] … and IF alodine/primer are applied to the aluminum... and sealant is applied in-between... and it's assembled wet with sealants... especially a wet environment... and can be worse within holes for fasteners.

The CRES Pins in extruded aluminum hinges should always be installed [butter-lubed-with] aero-grease or a thickened/persistent oil... and re-lubricated regularly to drive-out gunk/wear and restore corrosion-protective lubricity. Short hinges/pins [~9-inches] are easy lube/install/re-lube... long hinges/pins are tough to lube/install/re-lube... which is why SFL is usually applied.... and spray-lubed.
 

wktaylor

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FYI for passivation of SStl...

Go To USAF T.O. 1-1-691 [Technical Orders].

Passivate [de-oxidize/clean] SStl [CRES] materials per...

5.9.4.2 Chemical Corrosion Removing Materials for Stainless Steel (CRES) and Nickel Based Alloys.
[or]
5.9.4.3 Passivation of Stainless Steel (CRES) Alloy Parts.

Pasa Jell 101 is the easiest for most shops to obtain/use... as noted.

BE CAREFUL... this is not kids' stuff!
 

Fiberglassworker

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Nope, the adhesive is two parts, with one being a dark amber and the other a white, semi-translucent gel. Came in two glass vials, maybe two of three tablespoons worth.
EA9309 is a 2-part epoxy, it is the Mil spec version of EA 9430 high peel strength epoxy the hardener is amber the resin is white or grey. the resin is quite thick, and the hardener is water thin. this results in you having to chase the mix around for quite a while to get it blended in.
 

Jay Kempf

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Epoxy bonds to aluminum have a tendency to age out and peel or moisture corrosion creep and are way sensitive to surface prep. Alex Strojnick years ago built spars out of plywood and aluminum extrusions. The acid etch to make it happen was not for the faint of heart. Almost no one recommends even trying that now.

Like Billski almost always says in these threads. Make a part, like a wing, out of one material. If you then have to bolt it to another material so bit it, but deal with the nobility of materials when you do with liquid or other inert shims or sacrificial lams.
 
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