On Sun, 5 Apr 2015 09:12:09 -0400, "dadiOH"
wrote:
"Sonny" wrote in message
...
We have two large exterior exposed cypress beams/posts, that are part of the
structural wall and roof support of a breakfast nook area (back patio area)
that have developed rotted bottoms. I've been putting off this repair
because I'm not sure, exactly, what might be the best/proper repair.
Obviously, moisture has wicked up the posts for some time, and the bottoms
are rotten.
Left and right side posts, scroll left:
https://www.flickr.com/photos/43836144@N04/16411478004/
We've started demolition of part of the back patio, for the construction of
a pergola, spanning this breakfast nook wall area. I need to repair these
posts, soon. I'm not sure how far/deep, into the wall, the rot goes, but I
suspect maybe half way through the cross section of the post. I'll probe
it, later. Before I probe (gouge out, cut into) the post, I would like to
know what possibly might be best for the repair..... I wouldn't want to have
removed something, if it could be part & party to the repair.
It would be very difficult to remove and replace the beam, since they are
part of the support structure, but if need be, that will be done. I'd
prefer to repair at least the bottom, for now, unless sunsequent discovery
of very extensive damaged is found. There is no plinth under these beams.
I had thought of epoxy, since I more recently learned some of the virtues of
epoxy use; I've thought of bondo; THought of patch-replacing parts of the
beam.
I've thought of the wood hardening products, for rotted wood, like this one:
http://www.pcepoxy.com/our-products/...terminator.php
Home depot, Lowes and other outlets have similar wood hardening products,
but I don't know anything about these products and I'm not sure which
brand/product is the best for this kind of structural support, weight
bearing use.
I'd appreciate any and all input, for this repair.
We have other posts on an side porch, that are supported on plinths, that
have bottom rot, also. These posts can be easily replaced, but I'd prefer,
for now, to repair the bottoms. They are stained with a paint-like stain,
so bondo may be an option for repairing/filling voids, if need be. The
porch roofing is cantelevered, but the posts do supply some support for the
porch, because of heavy tiles (1500 lbs/square) on the roof. Any advice
would be appreciated for this repair, also. Scroll left for another pic.
https://www.flickr.com/photos/438361...n/photostream/
Do you want a structural of cosmetic repair?
If structural, replacement or reinforcement, in whole or in part, is the
cat's meow 
------------------------------
If cosmetic, I have used Bondo, filled epoxy and wood hardening (very thin
epoxy) like Git Rot.
The latter isn't intended to replace missing wood, just to soak into what is
there and encapsulate it. Generally, you need to drill numerous holes,
sloping down and in, a bit above the top of the bad area to act as
conveyors for the epoxy.
With either Bondo or filled epoxy, you need to dig out bad wood so the
filling material has a sound surface to which it can adhere. Although both
are a fairly stiff putty, they will sag considerably; sometimes you can
construct dams of thin card board and/or packaging tape to contain it, other
times you just have to do multiple fills, starting at the bottom.
Lew doesn't like Bondo, thinks it doesn't stick; clare@snyder says it sucks
up water. I don't know how long I have used Bondo but it has been several
decades and I have never found either of those negatives to be true.
I have a couple of bottom rotted, exterior door jambs that were repaired
with Bondo at least ten years ago. Still good. As Lew said, Bondo is
polyester resin filled with (mostly) talc. To my knowledge, cured polyester
doesn't "suck up water" and talc is about the least liquid absorbing mineral
around which is why it - in rock form - is/was the choice for chemlab work
table tops.
There is no doubt in my mind that filled epoxy is better than Bondo.
Nevertheless, for just a cosmetic repair, I would use Bondo...it can be set
up and sandable in minutes vs the hours for epoxy.
Just going from years of experience with body work and my late
brother who was a bodyman half his life. A hole was always filled with
either a brazed/welded/soldered metal patch or an epoxy/fiberglass
patch before filling with polyester body filler if you wanted it to
stay firmly attached long term. That's why Lew says it doesn't stick
well. Also, it will not stick well to a perfectly smooth surface - you
always rough up the patch area with 80 or 40 grit sand paper before
applying bondo if you want it to stay stuck.It needs a mechanical
"tooth" to stick well. (which is also why a "hack" bodyman will punch
a dent full of holes to extrude the "bondo" into to give it a fighting
chance of staying in.
The newer "light" fillers that use glass microbeads instead of talc
stand up better to moisture, and epoxy or UV Cure fillers are even
better.
When I hear "bondo" I think cheap polyester body filler - and I make
sure it is well protected from moisture in use..