How strong is JB Weld?

[atr]

Greg,
I have used JB weld in a number of applications related to motorcycle repair and that epoxy has never failed. The key is to have clean surfaces, hopefully not smooth as glass because you would like the epoxy to bond into the material. Pay attention to the drying time. Also if this is a vaulted ceiling then you might have trouble with the epoxy running out of the hole, due to gravity. In which case you might want to us an expansion type anchor.
Expansion anchors are good if you have the correct thickness of material to expand in to.

I would stay away from Gorilla glues as it expands considerably.

best
atr

[Finster101]

If the stone was easily drilled, he would have already done that. Any type of anchor will require drilling which is exactly what he is trying to avoid because of potentially destabilizing the structure.

[Bloodman14]

The OP's question was about drilling/tapping JB Weld. I don't believe that he intends to use it as an adhesive. He is concerned about drilling into the rock, destabilizing the structural integrity.

[Bloodman14]

The OP's question was about drilling/tapping JB Weld. I don't believe that he intends to use it as an adhesive. He is concerned about drilling into the rock, destabilizing the structural integrity. Greg, need more info; what exactly are you attempting?

[MarkP]

It would be better to attach a threaded part to the rock rather than drilling and tapping the adhesive. JB has a tensile strength of 5,200 psi and shear strength of 3,100 psi. Differences in thermal expansion could get you if there is a large temperature fluctuation. Preparation is key.

I was at a engineering seminar a few years ago where the presentation on was about roofing panels inside of a tunnel that fell onto traffic killing some drivers. IIRC threaded rods were epoxied into drilled holes in the concrete ceiling. I think it was the "Big Dig" in Boston.

[elmacgyver0]

I have a pistol smithing book by George C. Nonte Jr.
He discusses using epoxy in gunsmithing and said, he always at least triples the curing time as he thought the cure times stated on the package is too short for full strength.
If you go the epoxy route, give it plenty of cure time.
Alien tape is awesome! (For some applications).
Not for hanging lights!
I was replacing the florescent lights in my basement.
I removed the fixture in my gun vault room and used Alien tape to hold up the new LED fixture to the drywall ceiling.
The next day the fixture was hanging from the wires.
Conclusion, Alien tape not good on porous surfaces.
That said it is awesome for many other uses.

[gwpercle]

For maximum strength Do Not Use any fast setting or fast curing epoxy ... JB Weld and others make the 10 minute , fast settin and fast curing types ... they are fast but weak in strength .

Use whatever epoxy you want but make sure it sets in hours and fully cures / hardens in days.

Used to be only one J-B Weld ... the good slow cure stuff now there is 40-eleven different J-B Weld adhesives ...the old original is still best .

Gorilla Glue has developed a clear Non-Foamy glue ... look carefully at the package .
The foamy stuff sucks rocks ... why you want glue that goes foamy is beyond me .
The new Clear-NON Foaming stuff is great on ...glass ...!
Our microwave oven has a large thick clear glass plate that turns , food sits on the plate and rollers turn the plate as the food cooks ... we cook / re-heat in the microwave a lot !!!the wife took it out to wash it ... it broke ... right down the freaking middle. The clear non-foaming glue said it was good on glass ...nothing to loose , followed instructions for glueing glass ... it has held that big heavy glass plate together for about a year and a half ... the wife still takes it out and washes it weekly !

I would have bet my life ... that glue would Not have held that big thick plate together 2 weeks maybe three ...
To my utter amazement and wondermont ... that clear non-foaming Gorilla glue has been holding for 18 months and we cook / heat with the microwave every day ...
It's a 1 part Clear Glue , I don't see a product # but on the package top flap it says :

"Gorilla Glue Strength in a
Clear, No Foam Formula "

The package looks a lot like the foamy stuff so watch it ... for any glass or ceramics that gets broken ... this is one of the best adhesives I've found ... I think it may work better on glass / ceramics than clear two part epoxies you have to mix ... it dries clear and I gave my big glass plate a week to fully cure and harden ... and , so far , it's working !
Gary

[megasupermagnum]

I don't really understand where the JB weld will be going, but I'm going to assume it is in a crack between some bricks, stones, or similar. I will say that for drilling and tapping, JB weld is extremely strong. It's definitely stronger than lead, it's right up there with brass and copper as far as real world durability. The problems you will run into is it will not set inside something upside down without some kind of a mold. That would get old really quick unless you are only hanging one light maybe. The putty's like Quicksteel are not as strong as JB weld, but they might be strong enough anyway. They don't bond to surfaces nearly as well as a liquid epoxy.

[country gent]

Depending on the use I have used a waxed thread to "cast" the threads in JB weld when filling the crevice. This normally gives a very snug thread fit. There are tricks to filling a crevice or over head work. a cars board cover taped heavily over the crevice wax one side heavily. A big veterinary syringe is a big help. punch a hole in the card board to fit the stem snug. pull the stem out and mix the epoxy in the barrel install the stem and inject the epoxy up into the crevice when filled remove syringe and cover hole with tape. Let it self level and cure. When cured if you used a thread to form the threads. remove it and then the card board cover.
There are dyes available that will make the job match the rocks or material, If using a dye I add it to the resin and mix first then add the hardener and mix.

Using the above method you need a good tape and complete seal on the edges. The cover needs to be able to hold the weight of any threads and the weight of the epoxy. What might work easier is a small brass or aluminum plate with the hole drilled and tapped in it then glued to the face of the rocks.

[36g]

How about drilling the hole, taking a bolt of the same size/thread, coating the bolt with a thin coat of paste floor wax as a release agent, then filling the drilled hole with DEVCON steel filled epoxy paste, adding a coat of the DEVCON to the bolt, and then pushing the coated bolt into the hole and let things cure. Remove the bolt after curing and you are good to go.

[john.k]

Even apparently thick epoxies will run out ....so the OP needs a specialized adhesive .....and drilling into a stone arch may be problematic.........not so much the arch,but the vault in between arches is often just a collection of pieces sitting there,held only by the download on the material..........one vault i looked at was only 4 " thick of placed stone,then an infill of loose rock.........and it was 100ft above the floor.......knock out one stone ,and the whole lot could come down.

[samari46]

Regarding the "blue screws" I've used them for fastening brackets for shelves into bricks. Here in the States they are usually sold under the brand name "Tap con". Usually come with a carbide masonary drill bit as part of a pack of 50. But you can get them as a separate item. FWIW. Frank

[Sasquatch-1]

Post one:

I don’t want to use an impact hammer to drill a hole, in fear of loosening the stones that are only held in place by the effect of the pressure in an arch.

Post two:

Masonry bits won’t put a dent in these stones unless the drill uses a hammer function.

Apparently, he cannot drill the stone easily.

To GregLaROCHE, any chance of some pictures of the area?

[gwpercle]

Using both Direct - Indirect wall lights and / or Direct - Indirect concealed lighting ...
You can have the lighis mounted on the wall but they can illuminate the walls and/or ceilings .
The fixtures can be visable (i.e. wall sconces) or hidden from view (concealed lighting ) and can be designed to light up both walls and arched ceiling or just the ceiling ...but the mounting is high on the wall not in the ceiling .
A good lighting designer could fix up what you need ... Lighting stores will help with this and usually there is no charge .
Gary

[MaryB]

It would be better to attach a threaded part to the rock rather than drilling and tapping the adhesive. JB has a tensile strength of 5,200 psi and shear strength of 3,100 psi. Differences in thermal expansion could get you if there is a large temperature fluctuation. Preparation is key.

I was at a engineering seminar a few years ago where the presentation on was about roofing panels inside of a tunnel that fell onto traffic killing some drivers. IIRC threaded rods were epoxied into drilled holes in the concrete ceiling. I think it was the "Big Dig" in Boston.

Some of those construction epoxies are insanely strong. The ham radio tower next to the house is sitting on 4 threaded rods epoxied 8" deep into an existing concrete pad. Tower is also bracketed to the house so they don't see the full force of the wind but there is still plenty! I used an epoxy they use for bridge construction... designed for setting bolts. I tested it in a hole in a concrete slab form when they tore up the sidewalk to see how strong it is and the concrete broke before the epoxy... I also tried filling a hole then drilling it... I would rather drill stone! Stuff is HARD.

[gwpercle]

Greg,
I have used JB weld in a number of applications related to motorcycle repair and that epoxy has never failed. The key is to have clean surfaces, hopefully not smooth as glass because you would like the epoxy to bond into the material. Pay attention to the drying time. Also if this is a vaulted ceiling then you might have trouble with the epoxy running out of the hole, due to gravity. In which case you might want to us an expansion type anchor.
Expansion anchors are good if you have the correct thickness of material to expand in to.

I would stay away from Gorilla glues as it expands considerably.

best
atr

J-B Weld also makes an epoxy putty ... two parts , knead together and press into place .
I use it in places where I don't want a liquid to epoxy run or drip ...
the putty cures hard but I'm not sure how strong it is .
Check strength of putty against strength of regular J-B weld ... it may not be as strong .
Gary

[Soundguy]

I was wondering if I drilled and tapped into JB Weld, how strong would it be? Stronger than lead maybe, but not as strong as brass?
I want to attach some lights to a vaulted stone ceiling. I don’t want to use an impact hammer to drill a hole, in fear of loosening the stones that are only held in place by the effect of the pressure in an arch. I was wondering if JB Weld might be the answer.

Surface area is your friend with epoxy. Make up a mount for the light... Brazen or weld it to a plate.. Then epoxy that plate to the stone. Rough the stone and metal..or drill holes in the metal..

[Electrod47]

When you build your own hot rod you can make some departures from sanity as required. Buddy and me built a T-Bucket in 1993. Frame and body had already been painted with some high dollar metal flake. We had several bolt holes ( Not primary load bearing ) that did not align on the body to frame and even on one of the mounting brackets for the Jaguar rear-end we installed. Our fix was to drill out larger
holes, pack with JB Weld, then drill and tap. Buddy, still had the roadster in 2009 and everything was still together.
In fact, everytime we got together with that rig over the years, all we talked about was the JB Weld job!

[GregLaROCHE]

Hello everyone,
I’ve had a lot going on recently and haven’t been able to visit the forum.
I made a mistake. I’ve used a lot of epoxy in the past and it’s amazing what you can do with it. We used the West System and had several ingredients we could add to increase its viscosity to a paste. When recalling the epoxy I used years ago, I mistakenly thought it was JB Weld. I just received some in the mail today. In my mind it was a paste. Now I realize what I was thinking about what was called PC7. I think it is still made today. I thought I could make a golf ball size and push it in between two stones. Now I realize that JBWeld is too liquid to be used overhead. Maybe the best thing is to use the JBWeld I now have, to glue in some pieces of wood and then screw into it.
Sorry I wasn’t able to provide any photos. Ever since I changed to an IPad , I haven’t been able to figure out how to upload pictures.
Thanks to everyone for your comments and advice.

[jonp]