Fairing compound?

[SMHolmans]

Does anyone have a recommendation for a good fairing compound for use below the waterline?
Thanks!

[slash2]

I used MAS Phenolic Micro Balloons added to the epoxy. I don't see any precautions against using it below the waterline. Hope it's ok! I don't see why it wouldn't be. Also, you need to cover it with something for UV protection anyway (well unless it's on the centerboard). In any case it worked really well. I'm embarrassed at how much I used....

[Bflat]

Total Boat's "Total Fair" from Jamestown Distributors is good and very easy to use.
Bob

[Creekboater]

Microballoons, yes. They are fine below the waterline. Only reasons I know not to use it (them?) is in fillets (because they don’t offer strength) or when leaving bright (because they are usually purple).

[SMHolmans]

Thanks guys!

[dbeck]

Our supply shop recommends microspheres (white stuff, made of glass) for use below the waterline.

They also sell microballoons (brown stuff, made of phenolic substance); they do not recommend it below the waterline unless sealed with an additional coat(s) of epoxy.

However, when asking google it seems that the terms microballoons and microspheres are sometimes used as synonyms for the same stuff.

Very confusing.

What we did: We treated the rough spots with a normal fairing (white microspheres) mixture, then sanded. Then, our final 'epoxy coat' has been epoxy only slightly thickened with some white microspheres. We applied it with a roller over the entire lower hull. This was sanded with 120 grid paper. Then we coated the entire lower hull with epoxy primer. This was sanded with 120, then 240 grid paper and finally had satin-like look. I believe the epoxy primer helped in getting a smooth surface for painting.

Cheers,

Dietrich