G10 Bonding... Whats enough?

[jraice]

Whats enough sanding for G10 bonding to epoxy and to fiberglass reinforcements?

I am sanding my centering rings, motor tube and fins for internal fillets and glass reinforcements but sanding just doesnt seem to do a hole lot... 60 grit removed the shine but the parts still feel pretty smooth (not glass smooth but not rough)... I also used a saw to scratch it a bit deeper but I want the entire surface a bit better...

Tomorrow I am going to try some 40 grit or 36 grit but what is enough?

Thanks

 

[cjl]

I take some 60 grit, and it doesn't take long. Don't sand for too long, but press pretty hard when you sand. It should gain a fairly rough texture. That's always been enough for me...

 

[jraice]

So hard but short sanding? Ill try that with 40 and just call it good enough...

I got the shine off so it should bond pretty well and with the surface area of glass vs.'s just a fillet it should be real solid... The rings are a bit harder to prep but there is not a huge amount of force on them so it should be fine.

So what would you compare the finished surface to? I'd say mine feels something like a platic mouse pad, just a few very small bumps but otherwise pretty clear... I just sanded until it went from the shiney greenish color to a less shiney and more white transparent color...

 

[ben]

you could always drill some 1/8" holes along the root so it holds epoxy.

Ben

 

[cjl]

Usually, the finished surface when ready for bonding is fairly well scratched - it feels pretty rough. Try it with the 40 grit and see how it goes.

 

[jraice]

Thanks I got some 50 grit, feels rough... Ill give that a try and then just go for it...

I may drill holes Ben but JB weld is pretty thick so I doubt it would penetrate to deep... Maybe Ill drill like semi holes (not all the way threw) just to give little pockets for it to grab to though...

 

[cjl]

I'd go with that - if it feels pretty rough, you should be good.

As for the drilled holes - I've done that before - it can work pretty well (though I've usually done it with expanding foam)

 

[edwardw]

I use a hand sander/grinder with some alligator back on it. Alligator back is what I call the 16 grit I have. Works great.

Edward