I too wonder, why not weld this? Consider that if there were 100 adhesives and 100 gases to which they might be exposed, it would require 10,000 tests to find out which was compatible with which. I doubt that sufficient research exists to answer the question.

Anything short of welding would be tough as stated above to meet all your requirements. How about press fit?

you can use silicone sealant to hold them together

In plasma environment? I am not too sure.

Or it is other type of plasma- the biological and not the physical?

I agree with Guest #1. If you go with epoxy, not only should the faying surfaces be clean, but use an abrasive to grind the first coat of thin epoxy into the metal. This will prevent the almost instantaneous oxidization of the surfaces. Follow with a light wipe off and a thixotropic such as colloidal silica mixed into fresh epoxy, and fillet the edges. This will not be good for high temperatures. Go with welding if you can.

For a special application like this it would be a good idea to talk directly with major adhesives manufacturers to see what they would suggest (if you have not already done so). They are the experts and may have a suitable product in their range.

I would however strongly suggest welding (or even bolting) as a preferred alternative to adhesives, especially given the requirements you list.

We routinely use welding, brazing and soldering alloys from L&T. Please contact the welding devices division of your local L&T office.

http://www.larsentoubro.com/lntcorporate/LnT_Offerings/Solution_Template1.aspx?res=P_WIP_COFF_SBU_SOLU&slid=418&sbu=115

I fully endorse Bioramani's advice.

I have experimented with the use of L&T's EutecRod® 190 for helicopter Pitot system 6061 tubes both for pressure and vacuum with excellent results.

What you describe sounds like you want to put a cap on the end of a tube. First, I would rule out organic adhesives because they will be attacked by the plasma environment. That leaves you with welding or brazing. A press fit will not give a leaktight joint. I would tig weld the assembly. Just remember that aluminum doesn't perform well at high vacuum. You will likely need to heat it to remove the adsorbed gasses.

Hi Specialists ,

Thanks a lot for all your inputs.

We have already thought of doing an E-beam Weld / Friction welding between the 2 parts.

I am working on inventing something. Just to elaborate more about the inputs given in the past. The 2 Aluminium parts i.e. Plate & tube are finished to dimensions & there is a requirement for me to join these 2 parts together only after final machining. In this constraint if i choose a TIG welding there will be lot of distortion Hence we have studied different welding techniques & thought E-Beam welding is the best one since it produces less distortion, But unfortunately the parts which i want to join are unable to accept that minute level of distortion / Heat affected zone. This made me to think how about using an adhesive which could be compatible to our requirement as explained in the past.

In this perspective i am in search of an adhesive could anybody suggest it Or could anybody suggest if there is any other better cost effective way of welding which could produce distortions less than E-beam welding.

Dear Mr.Varadharaju,

There are quite a few structural adhesives which will meet your requirements depending on the mechanical strength of the joint.

There are plenty of high strength structural adhesive for aluminum.

· Least demanding and easy to apply Eutectic series gas brazing may do your job. Advantage is the local availability of expertise as suggested in #8 and lower heat requirement for the process. Molten filler material enters joint due to capillary action and least possibility of heat affecting the component being joined.

· Alternative is to go for high strength structural adhesive film like 3M Scotch-Weld Structural Adhesive Films AF 6, AF 10, AF 13 (http://multimedia.3m.com/mws/mediawebserver?66666UuZjcFSLXTt4xTt4XM6EVuQEcuZgVs6EVs6E666666--)

· Hexcel Redux structural films (http://www.hexcel.com/Products/Selector+Guides/ReduxSelGuide.htm?sg=Redux+Adhesives)

· Hysol adhesives from Henkal-Locktite (http://www.henkelna.com/cps/rde/xchg/SID-0AC83309-88AE9768/henkel_us/hs.xsl/full-product-list-7932.htm?iname=Hysol%C2%AE+EA+9394&countryCode=us&BU=industrial&parentredDotUID=productfinder&redDotUID=0000000ISD)

· Number of epoxy adhesives from Ciba-BASF (http://cibasc.com/)

Opting for structural adhesives it will involve excellent pre-cleaning, cold storage facilities, autoclaves for heat- pressure cycles, short shelf life of adhesives, air conditioned work place etc.

Good luck

Electron beam and laser welding will provide minimal distortion. For even less distortion, consider friction stir welding.

Mr.Varadharaju, if you decide to use an adhesive, consider a Ciba-Geigy adhesive formerly called CG-1303 or the CG 1302 (another version). It looks like it has probably been renamed, as Ciba is now part of BASF (Ciba-BASF. These epoxy adhesives I developed in the late 1970s are for aluminum bonding. potting (aerospace fly-away adhesives), specifically for AL6061-T6. Are/were used on fighter craft. Plasma is a tall order; don't expect these to hold up for long to plasma. For best results, the Al needs to be prepared with a sulfuric/chromic acid etch, before applying the adhesive. Read the product bulletins for details. Joe M.

But will this CIBA adhesive able to withstand temperatures upto 500 degrees.

500 deg C or F?

Loctite 3050 which as per Loctite company document is a "Structural Adhesive Paint Process Compatible. A weld-through capable, high temperature, acid resistant, two-component acrylic adhesive designed for weld/rivet reduction. Cures rapidly to form tough, durable bonds. Exhibits high resistance to phosphate and autophoretic metal pretreatment processes"

Seems offer exactly the solution you have been looking for.

It is available at Loctite Bangalore.

http://www.gluemytruck.com/HENKELstructuralbonding.pdf will give more details.