JB Weld Alternative

[PVC Arsenal 17]

I was walking though Sears the other day and I came across Loctite Weld.

The box claims that it is stonger than JB Weld, and has a quick set time (5 minutes). I don't know if they were comparing it to JB original or JB Kwik, however.

I'm not sure if it's metal filled like JB, though I would assume so. It was less than $5 so I bought it and thought I'd give it a try. I'll post my results later on. I'm not sure if this is a new product but I know I have never seen it before until I went to Sears. Either way, I think it has potential for us impatient types... though JB Kwik and regular quick epoxy can meet most of our demands.

[spudamine]

In the UK you don't see JB weld around, araldite is the big name but I've used lots of the cheaper unbranded ones without problems. If it's metal filled one of the components is going to be black or grey.
Loctite is a big brand as well, I wouldn't expect it to be too shoddy.
As to whether a 5min epoxy is as strong as a regular one, I have ofter wondered but i doubt it, there has to be a disadvantage somewhere.
You can usually shorten the cure time of any epoxy considerably and sometimes increase the final bond strength by baking it at 40-60C, if you have an oven that goes that low, any higher and you risk shrinkage.
Of course JSR is the epoxy knig and will probably be along shortly to offer his opinion.

[Necrosis]

Use loctite 638!

The bond will be stronger than when you're soldering it. (Also I think the bond will be stronger than the pipe itself. )
takes 5 minuted to set enough for handling, and only 24 hours to be at full strength!

Huzzaa!

[FORE!!!!]

Use loctite 638!

The bond will be stronger than when you're soldering it. (Also I think the bond will be stronger than the pipe itself. )
takes 5 minuted to set enough for handling, and only 24 hours to be at full strength!

Huzzaa!

stronger than solder? i dont think so.... that is if ur using silver solder which i know for a fact is stronger than copper pipe

[spudtyrrant]

Use loctite 638!

The bond will be stronger than when you're soldering it. (Also I think the bond will be stronger than the pipe itself. )
takes 5 minuted to set enough for handling, and only 24 hours to be at full strength!

Huzzaa!

10100 can you guess what that number is, it its the tinsel strength of 95/5 tin antimony solder in psi.
3615 can you guess that number its the tinsel strength for locktite 638 in psi.

[inonickname]

For the sake of discussion, loctite 638 (accordinto the site) demands a .25mm clearance between surfaces. Of course, this is to cover them.

From anyone with experience, what's the upper limit? (considering that we usually won't be using it at extreme pressures).

I think Nev's has 638, I should go check on Monday..

[Gippeto]

There is a link to a short treatise on joint strength and brazing joints in my pump how to.

http://www.thefabricator.com/TubePipeFa ... cfm?ID=575

In a nut shell;

Find the shear strength of the epoxy/solder (sometimes referred to as lap shear strength), find the surface area of the joint (pi*r*r*length)...multiply.

You now have the force required to (instantly) cause a failure. Use the interior diameter of the pipe/tube/etc. to calculate area. Divide the force by the area.

You now have the pressure which will THEORETICALLY cause a failure.

Divide this by a MINIMUM of 3 to get a maximum working pressure.

If heat or other factors (extended service... you leave things pressured up for extended periods of time)are a reality, use a higher number for the safety factor. ie. The joint can "creep", causing a reduction in surface area, and subsequent lower pressure failure.

[Necrosis]

Use loctite 638!

The bond will be stronger than when you're soldering it. (Also I think the bond will be stronger than the pipe itself. )
takes 5 minuted to set enough for handling, and only 24 hours to be at full strength!

Huzzaa!

10100 can you guess what that number is, it its the tinsel strength of 95/5 tin antimony solder in psi.
3615 can you guess that number its the tinsel strength for locktite 638 in psi.

Uhuh. Only soldering tin doesn't bond as well. As far as i know. some soldered connections failed at 20 bars and after loctite it held up to 70 bars. (And the my fridgy started making weird noises)

This can mean 2 things: I suck at soldering, Or: Loctite is stronger than soldering.


Also I can't find the shear strength of solder, I have found the shear strength of loctite though. Its: 3,625 psi

So if anyone can find the shear strength of the 95 percent tin soldering stuff.

[Gippeto]

I suck at soldering, ....

Just remember... you said it first.

Properly done, solder forms a chemical bond (with copper at least) with the surface as well as a mechanical one. It's stronger than any epoxy I've run across be a wide margin.

Clean, flux, and don't over heat.

Spudytyrant... Tinsel is that "foil string" you put on the christmas tree, I think you mean...tensile strength.

Edit: 95/5 mechanical properties

http://www.weldcotemetals.com/dataFiles ... timony.pdf

[Necrosis]

That would be the problem, I was using steel. (haha)

[Northir]

sorry to stray from the current conversation but. . .
ive been using this stuff



i have a few bottles left over from a job, takes 24 hours to fully set not sure how strong it is it seems to be doing well i used it to patch a 1/2'' hole in a sprinkler valve

[Moonbogg]

JB has a tensile of over 3,900. And I don't see how soldering can hold a damn thing together any better than duct tape.

[inonickname]

JB has a tensile of over 3,900

Except that solder has a tensile strength of... OVAAAAAR NINEEE-THOUSANDDD!

I'd suspect the strength of epoxies/JB will drop massively if the parts are insufficiently mixed or dispensed in different amounts, which can be easy.

But jesus, I just looked... They didn't have 638 but they had hydraulic sealants and super high strength retaining compound at..$50 a bottle!!