Fiberglass and aluminum?

[Matt.D]

Can anyone tell me if fiberglass (poly or epoxy) will stick to aluminum successfuly? Matt

[Boatbuilder NL]

There is different ways to connect GRP with alu, can you tell more about your need(s)?

[Fanie]

No it won't. But what does work is if you rivit the allu and the fibreglass together. The rivits should be close together ie 50mm to 100mm if you're going to walk on it. The fibreglass should be layered thick enough for proper strength.

[yipster]

Originally Posted by Fanie

No it won't

yes it does

[rwatson]

Thats news to me. Aluminium has a severe difference in expansion rate to GRP - how the heck do your ensure a non mechanical bond with GRP ( not epoxy) ?

[Fanie]

Not the allu and polyester I used, even if the allu is grinded course. A pluck or knock on the allu made it come clean off the fibreglass. Unless you glass all around the allu it won't hold. Riviting it properly does work.

[tuks]

I have bonded some aluminium plates to my hull which have blocks or fairleads attached. The hull is epoxy, and I used an epoxy adhesive. The plates have stuck securely, but I was told that epoxy glues are porus(to air not water) and the surface of the aluminium will oxidise after a few years and the bond will fail. None have failed yet.

I have had some of these plates anodised, I roughened up the back of the plates with a rasp before they were anodised, Does anybody know if anodising the aluminium plates will prevent the bond from failing in a few years?

[yipster]

Originally Posted by Fanie

No it won't

Originally Posted by yipster

yes it does

Originally Posted by Fanie

Not the allu and polyester I used, even if the allu is grinded course. A pluck or knock on the allu made it come clean off the fibreglass. Unless you glass all around the allu it won't hold. Riviting it properly does work.

did not go as far as actually trying monsters but did read-up on it some time back
there were plenty advantages bonding over welding since there is no distortion, stronger etc
primer seem to be important and lotus glues the low cost extruded aluminum elise chassis
carbon reinforcement was a good idea i thought and try to remember more or check again!

Boatbuilder NL can perhaps enlighten us with some knowhow

[Fanie]

I used allu in my previous boat front for seats, The allu was cut, bent and rivited to form the shape I required. It was then glassed, but not encapsulated in the glass. The next day fiddling on the boat I noticed it delaminated on some places and a pluck on it got the whole frame comming out.

The solution was as I said, painfully drill holes all around and blisters I mean rivit the glass and allu together. After that it never budged.

[Matt.D]

I want to make a pod or more like a tub in the shape of the hull , extend the stringers thru and bold them to the tub. The tub will double not only as a outboard mount but a deck extention about 1m long . i want to cut the transom out then and extend to the floor thur to the new transom for added strength i was going to glass it to the sides of the ally tub.
Matt

[Fanie]

If you have an allu hull, have the allu extention welded on professionally. What you're attempting is not something you can just do - not with an outboard ! If you don't do it properly, and with the proper beams for strength, taking the extra weight and twist in consideration you're heading for serious troubles.

If I was you I'd seek some advice from a boatbuider that specialize in allu hulls.

[yipster]

Fanie your right and aluminium bonding is not that easy eighter but is done

a book like this may also make a good read
http://www.amazon.com/Fibre-Metal-La...325235-6214515 and http://www.amazon.com/Advances-Compo...325235-6214515 are looking even better...