I'm in the process of building axe-throwing targets using 6x6 pressure-treated wood blocks. We've experimented with different adhesives like Titebond II, Titebond III, and Liquid Nails, but we're having mixed results. Sometimes the blocks bond well, but often they don't adhere at all, especially since the adhesive is applied to the milled ends rather than the end grain.
I suspect the moisture content of the pressure-treated wood might be affecting adhesion, though we actually like the current moisture level for our targets. We're allowing three days for curing with fans circulating air for the first two days, and the blocks are clamped together in a 4x4 frame during assembly.
I'm looking for advice on how to achieve a stronger, more reliable bond for these targets. Any tips would be greatly appreciated! Also, we have around 56 of these 6x6x6 blocks to work with, so we'd like to keep costs reasonable for any adhesive solutions.
4 Answers
Have you tried E6000 adhesive? It's known for its strong hold and versatility. It might be worth giving it a shot!
If you can find some thick slabs of solid oak from a local tree company, that might be your best bet. A natural log would likely hold up better than glued blocks. Just keep in mind that while you want them moist, drying out could cause warping. Alternatively, backing everything with sheet metal or stacking plywood might reinforce the structure while still making sure the wood doesn’t crack under stress.
You might want to think about combining adhesive with some kind of mechanical bond since the impact on the target can be pretty intense. If you can, routing channels in the blocks to use a spline could really boost the adhesion surface area. A half-inch deep, one-inch wide channel with spline could create a stronger bond, especially since the routed surface will be smoother than the rough PT exterior.
Moisture can definitely be a challenge with adhesive and pressure-treated wood. Have you considered using mechanical fasteners, like ledger locks or deck lags? Depending on your design, framing around the blocks to support them might also help—just a thought!
We do frame it out and use shims to apply lateral pressure, which helps keep everything in place, but it’s not a perfect solution. Still, it makes a difference!
That sounds like a solid idea! I was thinking of routing channels in a similar way and possibly using steel pieces to reinforce the structure horizontally. It might add some weight and cost, but if it keeps everything together, it could be worth it!