View Full Version : Fairing compound
07-27-2008, 03:02 PM
Can not bring myself to pay $40.00 plus dollars a quart for fairing compound. how does epoxy and microballons work? how about bondo?
07-27-2008, 03:15 PM
Bondo = poor choice. Absorbs moisture and loses it's grip. Darned shame, since it sands well, but it won't last. Even on cars, where it it totally sealed from all sides it does not last forever.
For marine use you need something which is specific against absorption.
Expoy with microballoons is very good, as is epoxy with sawdust (if you can collect it without it having absorbed oils or dirt, etc).
use about 1/3 cabosil, 1/3 talc, and 1/3 woodflour... this works fine.. the more talc, the easier the sanding is... I usually use 50 to 75% talc, and the rest cabosil... it sands fine.. The quickest way to get talc is to just buy Johnsons Baby Powder... just make sure its talc, not corn starch... it smells nice but the fragrance does not hurt the epoxy mix...
Micro-baloons work great too, check the cost of a tub of MB from System III, a quart tub of cabosil is only about $15... a quart tub of wood flour is only $4.50 and its very nice stuff. I have not bought micro-baloons from them.
07-27-2008, 05:02 PM
and to think that 3 cubic feet of microballoons was about $2 in the late 60's.....
Ray Frechette Jr
07-27-2008, 06:25 PM
In defense of the expensive proprietary fairing compounds....
Myself and a few other pro builders I know rave about System 3's quickfair.
Yep, horribly expensive stuff, I know. Hurts every time I write the check, and same comments from other pro builders I know who use it.
But in the long rum it saves enough time in labor to more than pay for it over mix your own thickeners in.
The compound holds it's form and sands incredibly easily when cured. Microballoons tend to sag and deform as it sets. Add enough cabosil to hold form and it is tough to sand.
And quick fair cures hard enough to longboard in 3 hrs, not an insubstantial benefit in a paid shop. Time is money you know.
I still mix up cabosil and epoxy for first coat or two and rough shape it down with a surform shaper, then switch to the quickfair.
07-27-2008, 06:37 PM
There are boats with micro balloons and epoxy on their bottoms and topsides that I faired over thirty years ago that are still hangin in there. There are other suppliers of micros than West System. Crystal Liner in Newport Beach CA is one place if they are still there.
07-27-2008, 07:22 PM
I used west system fairing compound which you mix with west system. If you are invested in "the system" I highly recommend it, it sanded easily and its epoxy...
Never Bondo and water, trust me...
Not sure what microballoons are but if its glass microspheres, I would not use it as it will take forever to sand. I use them to thicken epoxy for serious bonding - minimal sanding.
07-27-2008, 11:34 PM
Microballoons are hollow phenolic resin spheres. They sand pretty easily.
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