What is the best product to use when dealing with wood rot in areas that the wood is very difficult to remove such as exterior window sills?
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Abatron makes some excellent products for just that situation.
Its best to replace, or cut out and fill wih a wood repair and west system with one of their powder fillers mixed in. The higher the number the easier the sand with the 405 being just about as much as I want to sand. It seems like 405 and below are harder than the wood making it difficult to get a good finish. I am not a west system expert but they have a good website I also have been using PC Woody petrifier and their 2 part epoxy paste where situations warrant.
Edited 6/12/2005 2:57 pm ET by quicksilver
-------DITTO------.." He who makes a beast out of one's self, get's rid of the pain of being a man"
I have done some beautiful repairs with West Systems, only to have them seperate from the wood due to thermal contraction of the epoxy in cold temperatures. The plastic reacts more to temperature than the wood and the wood reacts to moisture while the plastic does not.
Ray,Please tell us more about those failed patches. All the details you can stand to write down.Thanks, Bill
As far as I know, that's why Abatron products are usually specced in restoration projects....formulated to expand and contract at the same rate as wood, or as close as you can get. I have used lots of West System, and love it, but I use Abatron in wood repair situations.cabinetmaker/college woodworking instructor. Cape Breton, N.S
I have used both West and Abatron. Both have worked well.
West has the advantage of being very 'customizable' for various circumstances and applications. The disadvantage is this flexibility adds complexity to the process.
The most important thing about any wood epoxy repair is DRYNESS. A wet repair will always fail.
Remove as much rotten wood as possible. A die grinder or dremel tool with a carbide bit works well. If there are cracks, open them up with the grinder. Drill a lot of small holes through to sound material to encourage drying (and absorbtion). Cover the area, and let it dry for several days if possible. Then hit the area with a heat gun or hair dryer just prior to repair (well close, let it cool first).
Slow hardening formulas are better for wood, since they have time to absorb more deeply. If you get impatient, you can always add heat to speed things up.
Due to a long story I was invited to tour Lincoln's home (restoration) in '88 when it was "under the bubble" where I saw what I thought was a familiar sight at the bottoms of the fluted outside window trim - Bondo. I ask the guy giving us the tour and he confirmed it - over a mil $ job. If it's good enough for Lincoln it's been good enough for me (ever since).
Just today I did a fill on a piece of furniture mixing a little "raw umber" "burnt seinna" and "black" in the Bondo paste (and a touch on top Bob Ross style- "don't over-mix") to do my impression of a knot(complete with small fisure). One thing I tried different this time was to rub a smudge of hardener around where the fill had to bond (good? bad?). They liked it. Outside we mask for it,chink deep fills with wood, stay with it and cheese grate/sand then Kilz it. It's worked good.
Fonzie,
I haven't researched it but the general advice of my material suppliers is that polyester resins are not well suited to applications involving moisture. (I believe Bondo is polyester resin based). I have used a lot of epoxy to glue stone with no known failures but I have had numerous failures with polyester resin.In the right application I am sure bondo/polyester is fine, just not as foolproof as epoxy.Karl
Bondo might be ok as a wood filler (similar formulas are marketed for wood), but an epoxy rot repair involves 'wetting out' the area with thin epoxy first. The thin epoxy is absorbed into the wood, and consolidates the fibers. Before it sets up completely, a thickened epoxy is applied to fill the voids.
The 'wet out' part is why epoxy works so well on porous materials like wood. The absorbed epoxy displaces potential sites of future water absorbtion.
I used the "Rot Doctor" injectable epoxy with good results. I assume Abatron makes a similar product as I have seen it recommended several times. While West Systems Epoxy makes excellent products, the last time I checked, they did not make an injectable epoxy formulation, although West Marine Products did have an injectable formulation in their boating store (as far as I know the two "Wests" are not related).
If you have a "punky" type of wood that is fairly porous, then you can use the injectable epoxy to consolidate the area and create considerable strength. Still, the injectable formulation is made by diluting regular epoxy with solvents and the resulting formulation has less strength than regular epoxy.
If you have an area where the wood has deteriorated to the point that it is better than small sections of it be removed, then the regular epoxy with a filler should be used as the injectable epoxy would be too fluid for this application. Bondo makes a two part epoxy that can be used as do many other epoxy suppliers. Regular Bondo can be used to enhance cosmetic appearance, although my Bondo application usually requires considerable sanding before it could be considered esthetically pleasing. For additional strength, fiberglass cloth can be used with the epoxy on the areas that are in tension.
You might want to look over the information on the Rot Doctor website even if you aren't interested in purchasing their products:
http://www.rotdoctor.com/L/HouseL/Hqa.html
I just finish using some Abatron to repair some rotted wood, and I loved the stuff... you need a whole box of latex gloves though! I cleaned scraped and vacuumed out most of the bad stuff, and then filled it in like playdoh... my son would have had fun doing it, but, I did not want to glue a three year old to something!
Around here (Coastal CT) you can get a product called Smith's Water Thin Epoxy. I have used just about all the epoxy and polyester products on the market (this is the 300+ yr old house), & Smith's is by far the fastest, deepest penetrating. Then you use their related thickeners for the putty part of the repair. I have some window sills & windows that have been through 3-4 years of coastal climate, & they look great.
A couple of weeks ago somebody in another thread mentioned a product for concrete called Evercrete (http://WWW.evercrete.com ) & they also make everwood, a single component wood hardener. Does anybody know anything about that? I know you people know everything about everthing, given the collective experience of the forum...
Let me add a little to my above post. For wood that is mostly "punky", the recommended procedure is to use a syringe with a fairly course needle to inject the thin epoxy into various parts of the damaged wood. The wood I was aworking with managed to absorb a surprising amount of the epoxy. I would guess that the finished repair was stronger than the original wood (spruce) but given the cost of the epoxy and volume that the wood absorbed, it was not an inexpensive solution. Where ever possible, I would recommend doing a "dutchman" (i.e. cutting out an area and gluing in a similar sized piece of wood) to keep the cost down.
This Old House has an article on fixing rot with epoxy. I haven't read it, but it might be of interest to you:
http://www.thisoldhouse.com/toh/knowhow/_repair/article/0,16417,680938-1,00.html
Edited 6/15/2005 12:19 am ET by CaseyR