Surfacing compounds

[mariner]

hi, i recently finished cpes and my first prime coat. I would appreciate some input on surfacing compounds (not two part) for minor dents and skim coating some areas. thanks, mariner

[Scott Rosen]

Pettit makes a traditional one-part surfacing/glazing compound for your situation--fairing and filling primed or painted surfaces. I used to use the Interlux product, but they stopped making it. I tried the Pettit for the first time this year, and I like it better than Interlux. I used it to fill the grain on some wide portions of my transom, as well as the usual chips and dings on my topsides, and it worked just fine--filled well, didn't shrink much and sanded easily.

[Paul Frederiksen]

There is a product which all the carpenters are using now called Famawood. It is a one part filler with hot solvents which evaporate quickly. It sands easily, and handles well. I have been using it and am happy with the results.

If you choose to try it there are a few things you should know. If you leave the lid off for more than a few seconds it drys out and is useless. I take a spoonful out at a time and otherwise keep the lid on. Also it lasts much longer if it is stored upside down so that the air pocket is not at the top where it gets recharged each time you open the container.

I really like this stuff but since it does not have a picture of a boat on the can I am sure someone will say it is unacceptable for marine applications.

It is up to you.

[Scott Rosen]

Paul,

How has it held up on the water? Would it be suitable for the damp marine environment?

[Paul Frederiksen]

I don't know. I am using it on my drysailed boat. For something which will live in the water it may not be ideal. But then again if the hull below the waterline is covered with antifouling then there is no need for fairing compound anyway, right?

I was discussing this with my dad (a home builder) and told him of the old mantra, "Never use bondo on a boat as it absorbs water." To which he replied, "What, and wood doesn't?" It got me thinking that maybe this fear of a little water absorption is mostly good marketing by 3M so they can sell you the same stuff with a boat on the lable for twice as much.

I did take a bit of Famawood and spread it on a piece of wood which now lives in my dishwasher -- so far so good.

This may be a great place for Chemist to weigh in.

[thechemist]

I am prejudiced towards the two-part epoxy compounds, so take what I say in that light.

Do whatever the supporting literature and the label on the container of your whatever filler says to do, and then, having put it on two pieces of wood and kept two separate pieces of filler, perhaps 1/4 inch thick and two inches in diameter, immerse one each in a jar filled full of water, seal it and set it aside for a month or two. For a more severe test, use hot water. Arrange a cardboard box with a crude heater such as a light bulb or two, to keep it hot in there. All chemical reactions go faster as the temperature rises. They double roughly every ten centigrade degrees (eighteen fahrenheit degrees). 64 days at 20 deg. C =32 days at 30 = 16 days at 40 = 8 days at 50 = 4 days at 60 = 2 days at 70 = 24 hours at 80 = 12 hours at 90 = 6 hours at 100 degrees C which is boiling and so you could do that in an afternoon with a vegetable pressure-cooker/steamer sort of thing.

Examine the aged results, particularly for hardness, by gouging with a small screwdriver. two-component products will soften and fail, if not thoroughly mixed to a state of molecular intimacy. That said, examine the results.

Make observations concerning the products. Best to test several side-by-side.

I can make general statements about ester-based things and other sorts of chemistry but the manufacturer of your whatever filler is unlikely to give us a useful formula. Besides, there is no substitute for direct personal observation.

[mariner]

thanks all. Regarding the petit and famawood. How do their adhesion qualities seems to be, especially over a period of time given the movement that wood can have. This famawood kind of sounds like something called "plastic wood", a mixture of sawdust and adhesives which dry out very quickly.

Petit glazing is best worked with two putty knives, one large one small.Load the little one and wipe onto the edge of the big one. Wipe it on to the hull with the big one then clean off crust and reload with the other. Keep lid on can between loadings. Thins with denatured alcohol, and will likely need some before you get to the bottom of the can.

[Charlie J]

Don't know about for marine use, but Famawood is the only filler I use in my furniture repair shop. It's the only commercial brand I've found that will take a stain at anywhere near the right color. It does dry out quickly, but they sell a reducer for it. I use Acetone instead, which has worked well for 15 years. Have very little adhesion difficulties, and have never had it come out of a properly prepared spot.
It's different from Plastic wood, which I don't use.

[mariner]

I am in southern new england, and i can't seem to find either petit surfacing compound or famawood anywhere? Help!

[Charlie J]

actually it is spelled Famowood. Our Lowes carries it, as does several lumber yards.

[Scott Rosen]

Mariner, the stuff is hard to find. Any good chandler should be able to order it for you. Harry at Harry's Marine Repair in Westbrook, Connecticut, ordered it for me and I had it the next day.

[Dubb]

I would just like to add to this older topic that Famowood is *highly* toxic if inhaled. Whenever I use this stuff, I take the same safety precautions that I do when using epoxy. Call me over-cautious.

[ken mcclure]

I use Famowood alla time (not on boats). Beware. If you need to thin it, it uses acetone as a thinner. Dries quick and hard. Keep the can closed except when you are scooping some out, because it dries out FAST. No idea on water resistance, though.

[bob goeckel]

i've used Formula 75 by Evercoat for a long time with excellent results

[This message has been edited by bob goeckel (edited 11-26-2001).]

[Ian Wright]

International interfill 100 (aka trowel cement) for topsides, P38 car body filler under water. Both are first class on my boat,,,,,,,,

IanW.