Working with Aluminium Honeycomb Panel

[greenpower dude reloaded]

As some of you know I build Electric race cars and I have recently come into a few panels of 10mm Aluminium Honeycomb sandwich panel. Problem is I have only ever used Fibreglass/ali sandwich and so basically I just want to know the best way of joining it and as I understand it to be so widely used in motorsport chassis construction, I thought this would be the best place to ask.

In the past I used Carbon fibre tape and Epoxy resin to stick the fibreglass skin ali core panels.

Thanks,

[humble sabot]

As i understand it that is the preferred method.
Epoxy and tape.

[greenpower dude reloaded]

ahh excellent, I'll get to work on that soon. I've seen people use Ali angle and rivets but I don't like that idea much.

I just wasnt sure whether epoxy/tape would work as well on ali skin but i'll give it a go.

Thanks!

[Carlos]

A very interesting subject, many possibilities and something debated for years
Research solvents to clean surfaces. The West epoxy system is the standard for ahhesive/tape aluminum sheet and honeycomb application. Welding, including high tech friction welding are also alternatives.

[AeroGT3]

Aluminum does not bond welt. I'd use brackets or welds.

[greenpower dude reloaded]

Does anybody know what is used to bond the Lotus Elise chassis together as I understand that to be aluminium.

So what is the general consensus? does ali bond well or not?

[tomislavp4]

The elise chassis is indeed aluminium, it´s glued together with some kind of a glue and rivets

[Carlos]

See my post above.It was accurate yesterday and still is today.


West Epoxy System & CF tape are the standard materials used to bond aluminum rolled sheet and honeycomb sheet by most fabricators. Details readily available by internet search using any search engine.


Researched the Lotus Elise last year. Epoxy, specialized solvents to clean aluminum castings, construction in clean room conditions. The only personnel that know the specifications of the epoxy are the supplier and Lotus employees. It is not surprising Lotus regards the materials and exact methods as proprietary.

[greenpower dude reloaded]

I had read your post carlos it was just Aero GT3's comment that made me wonder thats all. I use West System Epoxy and CF tape normally on fibreglass tape after following the Clean Abraid Clean preperation method in as clean an environment as I can find.

I usually use Cellulose thinners as the cleaning solvent and then rough it up abit with some corse sandpaper or a DA.

My reason for this topic was just that I was worried that I might use the wrong type of method because not only does this stuff not come cheap (although I did manage to acquire mine from the scrap bins at work) I am really making a big push this season and so it's vital I have the strength in the chassis.

So all of your tips and advice is all greatly appriciated

[Carlos]

AeroGT is right in that the historical problem with bonding aluminum with epoxy is 'peel' under load. Over the last few years progress has been made. It's a difficult subject. You might want to contact West for specific advice.

West makes a product for aluminum surface preparation:
860-8 Aluminum Etch Kit
A two-part treatment for preparation of aluminum surfaces for bonding with epoxy. Research shows adhesion to aluminum is significantly improved with this process. Also improves paint adhesion. Comes as 2 1/4 pint bottles, enough to condition 40>50 square feet.


Here are some backround links for research; articles, forums, abstracts:
http://www.eng-tips.com/viewthread.cfm? ... 018&page=1
http://stinet.dtic.mil/oai/oai?verb=get ... =AD0262716
http://home.earthlink.net/~jimlux/hv/epoxprep.htm
http://stinet.dtic.mil/oai/oai?verb=get ... =ADA199533
http://www.finishing.com/0800-0999/871.shtml

Books on the subject. Expensive but may be worth the money or library available:
http://www.amazon.com/Adhesive-Bonding- ... 0824774051
http://www.amazon.com/Handbook-Aluminum ... _rech_dp_8

[scarbs]

Hexcel have quite a lot of info on their website regarding honeycomb panels, if its not on there, try mailing them they seem to be a helpful co.

http://www.hexcel.com

[riff_raff]

Use a good structural grade of epoxy, Hysol or 3M Scotch-Weld. You should also rivet through the aluminum face sheets. The epoxy adhesive bond joint is very good in tension or shear, but will quickly fail in peel. The rivets provide a margin of safety in case the bond joint begins to fail in peel.

Proper surface preparation, application and curing of the adhesive are very critical to achieving a good, sound bond joint. Follow the manufacturer's instructions to the letter.

[justinbell]

if you have tried many times to fix it, then final is to make contact its technical from company they must guide you the way to do this proper.

[polarboy]

Depends what your going with it really,if your doing cut and fold put a strucual adhesive in the join before you fold,clean the excess an then tape join.
really rough the area where you are going to tape,3m an hysol are good an you can also use them to do the fold join ,3m9323 is a structual adhesive an stronger than all the epoxy resins you get but its really thick so unless you have carbon tape ? wet out a large carbon patch then cut your strips from it,also apply a brush of the 3m glue before you put the carbon on to ensure a really good bond
You really have to work the 3m to get it into the cloth (large firm squeege can be good to remove the excess glue)but its worth it.
peel ply the joints once your finnished to avoid all those nasty carbon splinters
Some parts can almost be like woodwork and have bridle joints or cross halfing joints etc an then glue and tape
worth talking to Technical Resin bonders at cambridge as al they do is make sheets an really know their stuff

[greenpower dude reloaded]

I've no problem with this being an informative thread but if you look at the date this was 2007 I've built about 5 cars since then using composite panel.