Epoxy concrete bolts mould release

[fizzy]

Has anyone tried epoxying a bolt into concrete. Then unscrewing it again later? I would have thought a liberal coating of silicone release agent would work?
The usual method is to use threaded rod and cut it off when no longer required but it would be easier to just unscrewing if no longer required. Holding down machines or pallet racking etc.

 

[Ali]

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

 

[ajlelectronics]

Thunderbolts. Marvellous things.

 

[Dcal]

Just oil the threads, they will come out easily.
They will also hold just as well.

 

[Hitch]

Just use Thunderbolts or equivalent.

They're excellent in concrete floors.
Drill, blow out, and screw in with an impact wrench.

 

[ajlelectronics]

screw in with an impact wrench.

If you have one, otherwise a conventional socket ratchet will do the job perfectly well. We used to fit all of our satellite and aerial brackets with them. The only thing they don't work with is some stone, oh and bricks with frogs are not as strong a fixing of course.

 

[Revs1972]

We put up some pretty big structures in film stages using thunderbolts ( M16 normally )
The pullout strength is more than enough for what we need. Most of the time we just drill a bit deeper than we need to embed , so any spoil is left at the bottom . No need to blow out like you do with resin

 

[wyn]

Use the female threaded resin socket things that are made for this sort of job.

 

[Gragson]

Thunderbolts. Marvellous things.

Coincidence, I have some M6 on order to use next week, what size hole do you drill undersize for brickwork. 5mm?

 

[Pete.]

Has anyone tried epoxying a bolt into concrete. Then unscrewing it again later? I would have thought a liberal coating of silicone release agent would work?
The usual method is to use threaded rod and cut it off when no longer required but it would be easier to just unscrewing if no longer required. Holding down machines or pallet racking etc.

For pallet racking use knock-in fasteners for speed and convenience. Position rack, drill hole through the foot, smash the fastener in and nip the nut up. Just drill the hole extra depth so when you no longer need them you just hammer them in below flush and a dab of making good mortar over the top.

 

[ajlelectronics]

Coincidence, I have some M6 on order to use next week, what size hole do you drill undersize for brickwork. 5mm?

6mm fixing, 6mm hole.

 

[fizzy]

For pallet racking use knock-in fasteners for speed and convenience. Position rack, drill hole through the foot, smash the fastener in and nip the nut up. Just drill the hole extra depth so when you no longer need them you just hammer them in below flush and a dab of making good mortar over the top.

View attachment 472268

Thar is what I used before.
I have used tapcons which are similar to those thunderbolts. I just like the idea of drilling a hole. Squirting epoxy in and just poking the bolt down by hand. Will have to experiment.
Not just for racking but IF we do move I quite fancy getting a 2 post lift as well.

 

[ajlelectronics]

Thar is what I used before.
I have used tapcons which are similar to those thunderbolts. I just like the idea of drilling a hole. Squirting epoxy in and just poking the bolt down by hand. Will have to experiment.
Not just for racking but IF we do move I quite fancy getting a 2 post lift as well.

Thunderbolts need no resin, just drill and insert. Job done.

 

[DaveB]

All the mechanical fastener mentioned above - thunderbolts, tapcon, the fischer wedge anchor - push out against the sides of the hole to function.

Just filling the hole with epoxy will not do this.

The resin anchor systems for setting studs all have a hard filler material added to the adhesive, and are more often a polyester chemistry.

 

[ajlelectronics]

All the mechanical fastener mentioned above - thunderbolts, tapcon, the fischer wedge anchor - push out against the sides of the hole to function.

Thunderbolts are in effect Self tapping screws.

 

[Gragson]

6mm fixing, 6mm hole.

Thank you.

 

[Pete.]

All the mechanical fastener mentioned above - thunderbolts, tapcon, the fischer wedge anchor - push out against the sides of the hole to function.

Just filling the hole with epoxy will not do this.

The resin anchor systems for setting studs all have a hard filler material added to the adhesive, and are more often a polyester chemistry.

On the flip side the mechanical fixing types are fit and forget. Resin anchors depend very much on the diligence of the person doing the installation. I've seen plenty of them pulled out looking like a dust lollipop. Also, resin fixings can be cut off short and fixed shallow if the person drilling the hole hits rebar and cant be bothered to diamond drill through it. 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.

 

[awemawson]

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)

 

[fizzy]

Thunderbolts need no resin, just drill and insert. Job done.

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.

 

[Pete.]

Knock-in fixings usually have ratings for cracked and non-cracked concrete.