Epoxy concrete bolts mould release

[Gareth J]

Thunderbolts are excellent in the right situation - I've used many BUT they don't like vibration. I tried bolting down a large commercial (ex-launderette) washing machine in my workshop, but it kept shaking itself loose. In the end I used epoxy and studs which has lasted probably five years now.

(Launderette washing machines are rigid mounted with no springing or dampers - usually bolted to a length of RSJ to give enough height for gravity draining though a large dump valve to speed up the cycle time)

Seconded. Different situation but yea, they're not good with vibration.

 

[ajlelectronics]

Yes I know. A self tapper. But obviously not so good in crumbley concrete. Also need a fair bit of force to insert.
The resin thread inserts sound handy but probably need a larger hole.
I thought to just drill a hole. Fill it with metal filled epoxy. Then poke an oily bolt down. When the epoxy sets you have a nice threaded hole with a large ish surface area.

I think you need to try a few before making such assumptions. They will amaze you, honestly. I was full of the same doubts until the rep gave me some samples 20 years ago. Never since looked back.

 

[Erie Fred]

The best (that I have seen) are DECO anchors.

 

[Shedendman]

These unscrew pretty readily with no epoxy involved, and you can usually re-use the hole unless the concrete is really poor

https://www.screwfix.com/p/easyfix-bright-zinc-plated-carbon-steel-concrete-bolts-m10-x-80mm-10-pack/7513P?tc=BT2&gad_source=1&gbraid=0AAAAAD8IdPwQc4UhE2QmorJ5Bl7-raVtc&gclid=EAIaIQobChMI3pH85s3RiQMVuIlQBh0wYg9sEAQYASABEgIeo_D_BwE&gclsrc=aw.ds

Those are brilliant trust me

 

[sako243]

I think you need to try a few before making such assumptions. They will amaze you, honestly. I was full of the same doubts until the rep gave me some samples 20 years ago. Never since looked back.

I've only found them usable in decent concrete. Tried them in all other sorts of material such as stone, mortar etc and can pretty much pull them out by hand.

 

[Onoff]

Epoxy a knurled insert in first. Stud screws into that.

 

[Bobupndown]

oh and bricks with frogs are not as strong a fixing of course.

I'd imagine not.

 

[Onoff]

Cant be done with the knock-ins as they will poke out too much and you can't cut them off to hide the fact as the ends will look wrong.

I've seen the expandy end cut off before now.

 

[Keith 66]

For the odd high strength fastener into concrete i have drilled the hole, blown it out clean, dip or wipe threads with blue PVA release agent (not pva glue) or wax polish. Mix west epoxy with some micro fibres & silica, paint threads pour some into the hole install bolt. It wont come out.
If you do want it out heat up the head with blowtorch & the epoxy will release easier.
I use west cos i always have a gallon of the stuff kicking around.

 

[Onoff]

Turn up a knurled/stud type socket? Drill the substrate & resin that in. Screw whatever into that.

 

[RichardM]

I've known the through bolts to come loose in the concrete on pallet racking. Sometimes they will nip up, sometimes not.