so i am winding down on my fourth boat build and just now beggining to think about epoxy fillers. for better or worse i have developed a love for bondo as a filler. many people hiss when the word bondo comes up but it has worked well for me in and out of the water. i am sure it sounds funney but i don't know a thing about most kinds of epoxy fillers. i have used wood flower but don't care for the difficulty in sanding it. i have been browsing many builder sites lately because it is dang cold outside, i am board and can't afford to go skiing. i have run across several refrences to fillers that are supposed to be easyer to sand and feather. this has left me asking this question: zu? am i missing out on a better and more practicle material?
please illuminate yacht brothers
I'm not sure but I do feel your pain. I too use wood flour and just recently found out how hard it is to sand, I have some tight spots and can only use a block sander powered by me in them, and can barely lift my coffie cup this morning
So thanks for posting this Aaron as I could use an alternative as well.
I think I remember someone refering to fumed sillica at some point but do not recall it's use.
Brian.
In decending order of being hard to sand out with the most difficult first.
Silica Essentially fine grained sand. STructurally extremely strong for fillets and filling holes, gaps, etc.
Wood flour Again a strong filler and in a really fine flour good for fairing. Not as strong as silica but a lot easier to work with after it cures.
Micro ballons Small glass spheres, that sand out quite easily, makes a wonderful fairing compound with epoxy, can be spread out quite thin and sands out smooth for finishing. Good for filling the weave on fiberglass.
There are others, like chopped glass fiber and various ground stone dust or talc. The talc is mixed with polyester resin or vinylester resin to make up a bondo type body filler that is so easy to sand. The downside if it with Bondo is that the polyester resin combination works well on metals but not so well in the long run on wood or fiberglass. Eventually there can be some delamaination issues and moisture incursion issues. Not so with vinylester resin combinations or with epoxy when properly mixed and applied.
The "Bondo" type of resin that the Stevensons use is really a vinylester resin combination with talc. Not Bondo perse'. It is available in Auto Body Supply shops under the name of Microlite or similar names. It holds up very well, is compatable with glass and wood and bonds very well.
Go to the West Systems information sheets and it will give you good data on which to use and how much to mix for any given use.
I have used all 3 of the products mentioned in the post above. The wood flour is good for making fillets in stitch and glue construction. The silica is very good for structural bonding like when you have two pieces of wood that you never want to come apart. The microballoons are great for fairing. Do not use them for structural bonding even if it just happens to be all you have. I found that out the hard way during the gails of '06 at Nickajack, didn't I Keith. :oops:
Yes you did Brian, you also found out that your tent leaked. There were other lessons learned that weekend.
1. Don't trust the thermometer on a smoker.
2. Always use chains on your trailer, even if your just going to the ramp to pull Craig's boat out of the water.
3. If the air pump on your truck is squeaking replace it before you leave.
3a. If you don't fix it before you leave make sure you have a good bottle of rum for the sailor who comes by and lends you a hand.
4. Use the hood on your rain jacket, gallons of water can decide to empty from an awning the moment you are at the edge of it and pour down your back, ain't that right Scott.
I'm sure there were other lessons learned that weekend, some we should probably never speak of.
Keith