I typically use t-nuts to hold the drivers in to my cabinets. I have had issues with them spinning or falling out, especially in MDF. So I tried a bit of epoxy. No good as the compliance of the MDF would break the bond.
My thought, a compliant glue like 3M automotive weatherstrip glue, what we used to call' black death" for it's ability to stick anything together forever.
Thoughts?
My thought, a compliant glue like 3M automotive weatherstrip glue, what we used to call' black death" for it's ability to stick anything together forever.
Thoughts?
If epoxy is failing due to lack of mechanical strength of MDF, it’s unlikely that any sort of adhesive will solve the problem.
I’d consider adding a small block of something such as poplar or maple, about 5/8” -3/4” thick, behind the MDF, and drilling the screw hole through both the MDF and the block, placing the T-Nut in the block. Good wood glue should hold the block in place as the clamping pressure of the screw/T-Nut will pull the two together. You could use the screw to clamp the block in place for glue drying, before the speaker is installed. Of course the edge of the block will need to be contoured to match the speaker opening.
I’d consider adding a small block of something such as poplar or maple, about 5/8” -3/4” thick, behind the MDF, and drilling the screw hole through both the MDF and the block, placing the T-Nut in the block. Good wood glue should hold the block in place as the clamping pressure of the screw/T-Nut will pull the two together. You could use the screw to clamp the block in place for glue drying, before the speaker is installed. Of course the edge of the block will need to be contoured to match the speaker opening.
On commercial guitar amps and PA speakers, sometimes they drive a small wood/sheetmetal screw into the wood right beside the Tnut. The screwhead prevents the Tnut from backing out. I have also seen them use a couple heavy staples across the edge of the Tnut - the kind of staples they use in construction of the cabinetry.
As to glue, there is tensile strength and then there is shear strength. Tensile is pulling straight apart. Like the superglue ad with the big burly workman hanging from his hard hat by a drop of glue. That is tensile strength, superglue has that, can't pull it straight apart. Shear strength is against crosswise force. That same hat, which you can;t pull free, will come off if you twist it. Superglue has poor shear strength.
SO some wonderful bonds anything glue might hold onto most things, but that doesn't mean it won;t stretch when you turn the nut.
As to glue, there is tensile strength and then there is shear strength. Tensile is pulling straight apart. Like the superglue ad with the big burly workman hanging from his hard hat by a drop of glue. That is tensile strength, superglue has that, can't pull it straight apart. Shear strength is against crosswise force. That same hat, which you can;t pull free, will come off if you twist it. Superglue has poor shear strength.
SO some wonderful bonds anything glue might hold onto most things, but that doesn't mean it won;t stretch when you turn the nut.
Somewhere on the West System site are the instructions:
WEST SYSTEM | Project for Epoxy
Or maybe it's in their 400 page online book, I'll look later.
WEST SYSTEM | Project for Epoxy
Or maybe it's in their 400 page online book, I'll look later.
#10-32 Hurricane Nuts 50 Pcs. 081-1082
Part of the problem with "standard" T-nuts is the wedge shaped stamped spikes destroy the material all around the hole on the way in to begin with. After everything is good and crumbly you may as well forget it.
DAP Products - Construction Adhesives - DAP® Beats the Nail® All-Purpose Construction Adhesive
Don't let this stuff's uncured physical similarity to latex based window sealant fool you. If you do get it in the threads it will wipe out with water, but it cures like a rock.
You don't need epoxy.
Part of the problem with "standard" T-nuts is the wedge shaped stamped spikes destroy the material all around the hole on the way in to begin with. After everything is good and crumbly you may as well forget it.
DAP Products - Construction Adhesives - DAP® Beats the Nail® All-Purpose Construction Adhesive
Don't let this stuff's uncured physical similarity to latex based window sealant fool you. If you do get it in the threads it will wipe out with water, but it cures like a rock.
You don't need epoxy.
+1 on the Hurricane Nuts, or even better threaded inserts - although some types of the latter are a bit more of a pain to install by hand, any of these are much more reliable than T-Nuts
https://hachol02.hafeleonline.com/O...11CEC2CA60CB015724525C025459BD1DBA53DEEF5280D
Beware those threaded inserts are cast zinc. All the weight and half the strength of iron. They can wear or strip more easily than steel.
The construction adhesives are designed to have higher bulk strength than "glue" which is meant to bond surfaces with minimum gap. If you manage to fill the area between the the hurricane nut and box material with the construction adhesive the area will be stronger than the unmodified box material. Most of the hurricane nuts I've seen have a relief stamped in front of them that traps a small volume of adhesive.
The PL9000 and other "brown" solvent based adhesives will work but even the "low volatiles" content types stink, beat on your brain, and are way harder to deal with if it comes in contact with something you're not trying to fasten... than the DAP product I mention. The DAP product does take a few weeks to reach full bulk strength (same with the other stuff, actually), but if your speakers fail and have to come back out that soon you have other troubles. Also the PL9000 etc. tends to foam a little (a side effect of "fast curing") in large volumes, which makes it weaker.
The construction adhesives are designed to have higher bulk strength than "glue" which is meant to bond surfaces with minimum gap. If you manage to fill the area between the the hurricane nut and box material with the construction adhesive the area will be stronger than the unmodified box material. Most of the hurricane nuts I've seen have a relief stamped in front of them that traps a small volume of adhesive.
The PL9000 and other "brown" solvent based adhesives will work but even the "low volatiles" content types stink, beat on your brain, and are way harder to deal with if it comes in contact with something you're not trying to fasten... than the DAP product I mention. The DAP product does take a few weeks to reach full bulk strength (same with the other stuff, actually), but if your speakers fail and have to come back out that soon you have other troubles. Also the PL9000 etc. tends to foam a little (a side effect of "fast curing") in large volumes, which makes it weaker.
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