Hello everyone,
I am putting up a fence soon and as usual I have to overcome an unusual situation. Most of the fence posts will be 6x6s 42″ in the ground but some of the posts will have to be set on a standard cast in place concrete curb. My plan is to drill a hole and epoxy 5/8″ threaded rod in the curb, but I’m not sure what the best type of epoxy would be for fastening the rod into the posts. The “epoxy” for the concrete is actually an acrylic adhesive, specifically Epcon A7, which is made for concrete to steel applications. Where the fence is on the curb I will be adding a shed so the structure will be square in plan which will help resist wind loading to avoid a blow-over, but I would like the rod/wood connection to be at least as strong as the tensile strength of the wood. I don’t have any experience with structure epoxies for wood and am open to any other ideas anyone may have.
Thanks for any help,
Chris
Replies
In my experience with epoxy, mostly with boatbuilding, you will get a bond way stronger than any wood. A few types of lumber, the oily ones like teak, are a little harder to bond. A wash of acetone fixes these.
I've never glued pressure treated wood with epoxy but I doubt it's a problem, specially in a core as you've described. You should thicken the glue, wood flour is fine. This can be saved from your sander or purchased from any purveyor of epoxy. To do an absolutely bang-up job, coat the hole for your rod with unthickened epoxy first so the wood doesn't absorb the epoxy from your mix.
N.B. mix the two-part epoxy very well BEFORE adding the thickener.
System Three brand has a great little handbook on epoxy use, free with their 10 buck sample kit. That kit's a great deal. Gougeon Bros. of the West brand, are generous with their information as well.
Good luck
p.s. If you are going to use teak, mail me your address! <g>
6x6 42" in the ground. Hmmm. That's quite some fence. What are you trying to keep out/in.
I would be tempted to use a HD commercial post base. Simpson is one manufacturer, I'm sure there are others. The one I'm familiar with has a sturdy base and two stout braces that come up about 18" on opposite sides. Drill 4- 1/2" holes for redheads in the concrete bury the exposed studs in silicone, mount the base and attach the post to the base with screws shot through the braces. This would also keep the wood slightly above the concrete where it is most likely to rot.
I have seen similar jobs done this way. I would think it would be sturdy enough. Assuming your not fencing rhinos or elephants. Just my 2 cents worth.
42" is the frost line around here, but I also live in an urban area with a lot of foot traffic and I really wouldn't be surprised if some day I see someone hop over the fence just so they don't have to walk around the building next to me.
Your idea is similar to what I initially designed, but the fasteners alone were going to cost 20$ a post. The fence is 6' high and faces west so I'm worried that the post bases are not strong enough for the compound forces. Are the ones you have seen used on freestanding fences?
I'd love to use teak, maybe we should get together and try it out, you can supply the wood and I will do the work. I will look into the epoxies you mentioned, Thanks.