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Main Forums => The Roundtable => Topic started by: Hawkmoon on September 11, 2020, 02:49:19 AM

Title: JB Weld question
Post by: Hawkmoon on September 11, 2020, 02:49:19 AM
How thick can JB Weld be built up in one lift/pass?

I have a cylindrical thingie that I need to fill with something metallic(ish). Length about 1-1/4", diameter -- well, okay it's not exactly a cylinder -- about 1/2" x 3/4". Can I just mix up the goop and ladle it in, or does JB Weld need thin layers to cure properly? The instructions don't seem to address that.
Title: Re: JB Weld question
Post by: griz on September 11, 2020, 07:14:01 AM
I've used it to fill gaps maybe a 1/4 inch or so and had no problems.  3/4 seems reasonable to me, but I don't know what they recommend.  Any strength required or is it just fill?
Title: Re: JB Weld question
Post by: HankB on September 11, 2020, 07:52:53 AM
I contacted the JB Weld company with a question about my own epoxy application a few months back, and they got back to me within a few hours. I suggest you contact them.
Title: Re: JB Weld question
Post by: Hawkmoon on September 11, 2020, 12:35:00 PM
I've used it to fill gaps maybe a 1/4 inch or so and had no problems.  3/4 seems reasonable to me, but I don't know what they recommend.  Any strength required or is it just fill?

Just volume fill.
Title: Re: JB Weld question
Post by: 230RN on September 11, 2020, 02:12:51 PM


I would think the catalyst you mix it with will cure it under a thick layer regardless of exposure to air.

Sort of like concrete curing at the bottom of a deep pour, no?  "Curing" does not necessarily mean "drying."
Title: Re: JB Weld question
Post by: K Frame on September 11, 2020, 02:25:51 PM
^^^ What he said.

The only thing you'd have to worry about would be the heat generated by the curing process*, and I doubt that would be an issue because the area you're talking about really isn't that big at all.



*The Hoover Dam was done in a series of hundreds of interlocking block pours because of the heat generated by the curing process. Had it been attempted as one continuous pour it would have taken several hundred years to actually finish curing/cooling (it likely would have failed first due to the intense heat generated by the curing process).  

Ah, here's an article that talks about what they did do with the Hoover Dam to dissapate the heat generated by the curing process.

http://concretecontractor.com/concrete-construction-projects/hoover-dam/#:~:text=In%20this%20way%2C%20the%20dam%20was%20poured%20into,begin%20channeling%20the%20Colorado%20River%20towards%20the%20dam.
Title: Re: JB Weld question
Post by: Hawkmoon on September 11, 2020, 10:02:02 PM
I contacted the JB Weld company with a question about my own epoxy application a few months back, and they got back to me within a few hours. I suggest you contact them.

I submitted an inquiry, and they responded much faster than I expected. The answer is that I can fill it in one pass, but it will take longer to cure. That's not a problem in this case.
Title: Re: JB Weld question
Post by: French G. on September 11, 2020, 10:39:09 PM
^^^ What he said.

The only thing you'd have to worry about would be the heat generated by the curing process*, and I doubt that would be an issue because the area you're talking about really isn't that big at all.



*The Hoover Dam was done in a series of hundreds of interlocking block pours because of the heat generated by the curing process. Had it been attempted as one continuous pour it would have taken several hundred years to actually finish curing/cooling (it likely would have failed first due to the intense heat generated by the curing process).  

Ah, here's an article that talks about what they did do with the Hoover Dam to dissapate the heat generated by the curing process.

http://concretecontractor.com/concrete-construction-projects/hoover-dam/#:~:text=In%20this%20way%2C%20the%20dam%20was%20poured%20into,begin%20channeling%20the%20Colorado%20River%20towards%20the%20dam.

Yes, heat would be my only concern. The damn dam link is interesting.