View Full Version : Timber filler

03-29-2013, 04:37 AM
I'm rebuilding a 21ft trailer sailer & almost finished .I'm refinishing the deck & cabin & need a filler for the old screw holes & minor dents & scratches.What product would you suggest for this application.I have used Timbermate in the past but not on a boat as it is water based.Is this an issue ??? I was thinking if i painted over it with acrylic paint it could bubble under the paint .Any thoughts ????

03-29-2013, 06:22 AM
Epoxy with microballoons--light weight fairing filler.

03-29-2013, 06:45 AM

wizbang 13
03-29-2013, 07:53 AM
epoxy and probably WEST 407.

03-29-2013, 09:55 AM
Question: Would epoxy with just Aerosil/Caobosil be a good fairing bog?

wizbang 13
03-29-2013, 10:14 AM
cabosil is a structural / hard filler, and thus, is difficult to sand. The wood around the stuff is usually softer, and will be / show lower than the cabosil .The cabosil will be "proud" and you may not notice it until the shiny paint goes on.
For fairing , 407 , and for very fine fairing 410, are easy to sand.
Filling screw holes or big deep dings and scratches? sure cabosil and microfibers are fine . But for fine fairing, the top eighth of an inch, the red stuff ,407 phenolic microspheres ,is best.
Fairing fillers are not strong, they should NOT be used for gluing.
Different fillers make a HUGE difference in the end product.

03-29-2013, 10:41 AM
cabosil is a structural / hard filler .... Fairing fillers are not strong, they should NOT be used for gluing.
Different fillers make a HUGE difference in the end product.

Now I remember! Cabosil or Aerosil give you a nice stiff fillet you can use in vertical joints. For structural stuff, I've been using Aerosil, milled FG, and wood flour.
Is there a fairing filler that is relatively opaque or even white? I don't fancy the purple or red.

David G
03-29-2013, 10:44 AM
capefox - All that information is readily available to you at West System. Their big 'bible' on boatbuilding w/epoxy is even available now as a free download. Have a gander:


wizbang 13
03-29-2013, 11:33 AM
410 is whitish, but read the fine print. being VERY light ( in weight) it is VERY weak, not correct for application over a sixteenth of an inch thick.
Read the book , (i never did).

03-29-2013, 01:23 PM
I use quartz microspheres, essentally glass bubbles, as a fairing filler.
They're white and are relatively easy to sand.
In realistic quantity, it's an inexpensive material.
One vendor: http://www.mertons.com/Additives/bubbles.html

03-29-2013, 02:20 PM
capefox - All that information is readily available to you at West System.

By Grabthar's Hammer, that is a truly informative library. I really like it!

03-29-2013, 07:03 PM
I have used bucket full of epoxy on the restoration project but was seeking something simpler & easier to work with for the cabin top.Something like Polyfilla or timbermate but wasn't sure of the lifespan of these products.I'll go to the local hardware & troll the filler section.

03-29-2013, 09:25 PM
What if you made a fillet from titebond 2 or 3 and wood flour or talc? Satisfactory for above the water line. I've used this for furniture and it sands down nicely.

MN Dave
03-30-2013, 12:03 AM
13 replies, all good advice and no arguments. The powdered garden variety (literally) limestone is also a very good inexpensive white filler. It's hard to sand, but glass bubbles are easy to sand, and a mixture of both will be somewhere in between.

A small titebond fillet can be color matched by putting the glue in the defect and sanding over it while it is wet. The sanding dust will mix with it and hide the divot.

Polyfilla Woodflex says it is for exterior wood, so it should be OK above the waterline. It will be painted. The only timbermate I found says it it is for interior use, which is not so good.

Here is some more descriptive information on fillers from a UK & Australian source:
--and mixing fillers for tailoring the properties: http://www.pondussnickeri.se/PDF/LEFG5.PDF
--and more fillers:

03-30-2013, 12:22 AM
Thanks for all that responded .I went to the local hardware & was convinced that Agnews Powder would do the trick (the hardware man had patched concrete externally with it .Time will tell.I have used it and have sanded some of it and it seems very hard .will apply sealer tomorrow & see how it goes.

03-30-2013, 08:12 AM
That's a plaster-based putty. I'd doubt that it will do well in wet places.

03-30-2013, 10:46 AM
The hardware man is always a sage source of boat building advice - said nobody ever..

MN Dave
03-30-2013, 03:05 PM
Agnews sounds risky. It could work, but...

Agnew's Water Putty is an excellent filler for patching and levelling wood, plasterboard, cement sheet, concrete, etc. Particularly suitable if you need a hardwearing surface. Agnew's Water Putty sets hard, adheres permanently and fills to any depth without shrinking or cracking. It can be sawn, drilled and sanded. Agnew's Water Putty is also ideal for Architectural and Hobby Moulding.

Agnew's Water Putty is not a flexible compound. Use only in an exterior situation if you have ensured that the substrate has a low propensity to expand and contract as the ambient temperature changes and have ensured that the Water Putty is dry and then sealed.