West 403 Microfibers are a fine fiber blend used as a thickening additive with resin and hardener to create a multi-purpose adhesive especially suited for bonding wood. Epoxy thickened with microfibers has good gap-filling qualities while retaining excellent wetting/penetrating capability. Color: off-white.
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I want to fill the depressed areas in a fiberglass raised panel door to create a level surface to bond a new laminate color sheet. Depth of depressions is 1/4" x 1 1/2" wide. Will the West epoxy with high strength filler be suitable for placement in full depth at once?
Yes, you can fill with thickened epoxy with 403 filler.
JD Tech Team
Which has a smaller grain size 403 or 406? Which gives stronger bond 403 or 406?
Not owning a microscope I can't literally answer about grain size. Colloidal Silica (406) has a finer texture out of the container and blends easily to form a smooth adhesive whose thickness is easily controlled. 403 seems easier to sand once hardened. The West System chart shows 403 better for laminating and 406 better for fillet bonds. It also shows 406 as higher strength. While I have both, I have primarily used 406 for years for bonding.
Just saw this query today, so you probably have already had a lot of responses... Bottom line:406 is super-fine and is valued for it's smoothing and thixotropic qualities. Used extensively in producing smooth fillets under epoxy-glass construction. Will sand smooth without much fuss. 403 is stronger in face-to-face bonding, where I much prefer to use it, but that is the only place I use it over 406 because it is much, much more difficulty to sand smooth than the 406.
I bought the WEST 105 and 206 hardener. Need to make a "Peanut Butter" sauce to bond my new plywood floor to the side hull. What third agent should I buy? So many to choose from WEST! Please help!
I have used both 403 and 406 fillers and personally prefer the 406 colloidal silica for making smooth peanut butter. It is easy to mix and work. The only qualifier is that the finished surface is harder to sand than micofibers, but this may not be an issue in your case. Without knowing whether the joint is exposed and what potential flexing there might be it is hard to advise on the detail. 406 and west epoxy will likely be stronger than whatever they are connecting to. Good luck!
I used 403 filler for general thickening. If The epoxy was going to show like on an edge and a didn't w abt to sand (i don't like sanding) and wanted a very "fine" rdge, I used 404 filler.
I actually prefer 406 for this purpose. 403 will work, but tends not to give as smooth a fillet as 403. You really need to use a lot of either additive, especially 406, to prevent sag. The other option, although much more expensive, is to use West's Six10. This is premixed, and because you are using a caulk gun, it lays on a fillet very smoothly and evenly. The price is much, much more than mixing your own, however.
406 colidial silica and 403 micro fibers mixed together. It will be strong and spread smooth. 403 by itself clumps.
The 403 filler is good for that. Essentially hardened resin is very brittle. Adding a fiber acts to stop if cracking. So a microfiber filler is used when strength is needed. Microbaloons are used when no strength is needed, such a fairing or fillers. Reading Gougeons Bros book on the subject would be well worth it if this a large project.
I would buy this product again!
Like all West products, it's easy to use, it cures well, and it makes a smooth finish.