Bonding Aluminium to Fibreglass

[ChrisL]

Has anyone had any experience in bonding a flat aluminium surface to a flat fibreglass surface? Although I don't need it for a structural application, I would like it to be a rigid and enduring bond.

PS.
My appologies to the US guys for the non-US spelling of these items

 

[Paul Bearman]

I have used a thin bead of SurFlex or SikoFlex to bond the Aluminium panels to the inner tub of my '40. It has reasonable sheer properties and has the added advantage of giving a good water seal.I know it comes in black & grey but there may be other colours available.You can purchase this from any good auto paint supplier or marine shop.

The bond should be strong enough so long as you don't intend hanging an Elephant from it!!


You can use industrial adhesives such as Loctite, but you have to ensure all surfaces are clean & free from grease & oil. An applicator agent is usually used to cure the surface before applying the adhesive. The only problem you may have is that adhesives normally require a reasonably thin air gap to cure properly & fibreglass tends to have an uneven surface. SikoFlex/Surflex will compensate for this.

Hope this is of some help.

 

If want to hang an elephant from it..... use 3M 5200. The only problem with this stuff is it takes seven day to cure.

 

[Guest]

If you must bond alloy sheet to fibreglass make sure you coarsely rough up the surface very well and if possible drill as many "bonding holes as feasable through the metal.If, however, you just wish to put "show" panels onto fibreglass rough up the area only you want to bond, clean with thinners and use SIKAFLEX. There are two types available, 221 being the most widely used and will support a baby elephant. If, however you do want to bond a adult elephant onto the fibreglass then use the structural grade which will quite happily take 10 tons in sheer. You will break the car before you break a Sikaflex bond!!!!!!
Regards,
GTA Racing.

 

Sikaflex and 3M 5200 are both good. 5200 works just as well as Sikaflex without the nasty smell. You can get 5200 in the red container which is the fast cure stuff. That will only take 12 hrs. to cure including the stuff you leave in the container.

Marine epoxy is another option.

 

[Jim Rosenthal]

Either sikaflex or 5200 will work. 5200 is available in a fast cure as mentioned. Essentially to debond 5200 you have to saw the two pieces apart; it is very strong and also elastic enough that it will tolerate vibration where rigid bonds such as epoxy will not. It is also available in a slightly less ferocious form called 4200; I use this for marine hardware bedding and most bonding as there is virtually no installation above the waterline that requires 5200. Get all these by mailorder or in marine stores. They can also be painted which is an advantage; two part paints stay on them very well.

 

There is a solvent for 3M 5200 but it is fairly expensive and time consuming to use (as demo on Shipshape TV). Just be sure you don't want to ever have to break the bond. from experience! cb

 

[Julian West]

FWIW I asked about Sikaflex in my local motor factors & they told me of an equivalent product called 'texflex'. They rekon it has the same bonding power but has a longer shelf life than Sikaflex.

I'm not sure if this is true, but I know Sikaflex definatley has a shelf life & you should check the sell=by date before buying it!