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Discussion Starter · #1 ·
Don't laugh.

I'm curious. Can JB Weld be used as a filler, say in a one inch diameter hole, 1/8 to 1/4 deep. There's good metal to back it.
 
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good question, i would like to know too. never used the stuff. :stupido2:
 

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I filled a hole in a Gas tank with it. If you warm it up it flows out nice. while it was wet I stuck some of that fine screen abrasive in it. After it dried, Itop coated it,5 years later no leaks.
 

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Don't laugh.

I'm curious. Can JB Weld be used as a filler, say in a one inch diameter hole, 1/8 to 1/4 deep. There's good metal to back it.
I used it to fill two about 1/2 to 3/4 holes on my '33 Vicky at both rear C pillars, God only knows what they were for...worked good, I just made a temp backing plate of thin aluminum, slightly dimpled in the metal of the body, ductaped the aluminum plate to the backside of the holes greased the aluminum plate, then applied the JB working it into the hole...it was a bit tough to sand down...then I used filler to finish off. Worked pretty good and when I sold the car a couple years ago they were still fine.... it was about 8 years since the car was built when I sold.
 

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Discussion Starter · #5 ·
I filled a hole in a Gas tank with it. If you warm it up it flows out nice. while it was wet I stuck some of that fine screen abrasive in it. After it dried, Itop coated it,5 years later no leaks.
What is fine screen abrasive and what did you top coat it with?
 

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What is fine screen abrasive and what did you top coat it with?
I top coated it with another layer JB, I dont know the name of the stuff but its an abrasive that looks like screen door screen. In fact you could probabaly use it instead.
 

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Discussion Starter · #8 ·
I top coated it with another layer JB, I dont know the name of the stuff but its an abrasive that looks like screen door screen. In fact you could probabaly use it instead.
Gotcha. I have some screen laying around. I used JB to fix a tranny "ear", seems to be fine but hasn't been on road yet, so we'll see. Thought it might work as a filler-certainly hard enough. Main concern is whether it will chemically 'bond/seal' or will moisture be able to find its way in between the layers. It's a support on the inside bottom corner, door side, of front fender where bolt goes up into firewall/body. The outer skin is solid. I'm only guessing but it looks like a welder made the hole-it's not a rustout. There was a little surface rust which I scraped with small xacto blade and slopped on rust nuetralizer. That's when I thought JB would fill it nicely.
 

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My welds use to really suck! They looked good after I coated them with JB weld tho. That was 7 yrs ago and all is well.

I also went to welding school so now I don't have to cover the welds up anymore.
 

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Good Stuff!

My welds use to really suck! They looked good after I coated them with JB weld tho. That was 7 yrs ago and all is well.

I also went to welding school so now I don't have to cover the welds up anymore.
JB-weld and Duct Tape--don't leave home without it. :)JIM.
 

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I have to say I use the JB weld for minor filling under powder coating & it works great. For those who don't know fillers and powder coating don't work well together. There is a hi-temp filler called lab-metal but I consider it worthless & stick with the JB weld. Good stuff in my book.
BB
 

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I have to say I use the JB weld for minor filling under powder coating & it works great. For those who don't know fillers and powder coating don't work well together. There is a hi-temp filler called lab-metal but I consider it worthless & stick with the JB weld. Good stuff in my book....BB
Thanks BB....Good to know....I was going to try that on some valve covers that I'm having powder coated.
 

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Thanks BB....Good to know....I was going to try that on some valve covers that I'm having powder coated.
Please keep in mind that you want to bake the jb weld out hotter than what the powder will be cured at. 2 reasons for this 1 to prevent what we call outgasing of any air that might get trapped in the jb weld. When the part gets baked & its not outgased any air that was trapped in the filler will rise & create pin holes in the coating, not good. 2 the jb weld will shrink after its baked. What we do is fill the area needed & then bake letting the jb shrink, after curing it we will then sand & or shape as desired.
Should work really well on your valve covers just keep in mind what I said above.
Good Luck, BB
Side note: Most powders are baked @ 400 for 10 mins. The jb weld should be cured @ 425 for 30 mins. This is substrate temps not oven temps.
 

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YEARS ago I had a Plymouth Saparro that a carb inlet piece broke on--Only way to get the piece was from the dealer for over $300.00!!! I put the piece on with JB Weld, put the piece in the oven and baked it for about an hour== no leaks--drove the car for couple of years--SWEAR by it!!
 

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Discussion Starter · #16 ·
Main concern is whether it will chemically 'bond/seal' or will moisture be able to find its way in between the layers....

and slopped on rust nuetralizer
Do we have an answer or opinion on the chemical bonding? Actually it has to bond with the rust nuetralizer.

This is an area prone to moisture and I can just picture the typical rust spot coming thru the outside skin on the edges of the inside repair. I'm thinking if it "seals" or bonds completely there's no worry of moisture getting between the JB or 'bondo glass'. Then again the factory made this support hollow and probably for a reason. needs some drain holes.
 

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Do we have an answer or opinion on the chemical bonding? Actually it has to bond with the rust nuetralizer.

This is an area prone to moisture and I can just picture the typical rust spot coming thru the outside skin on the edges of the inside repair. I'm thinking if it "seals" or bonds completely there's no worry of moisture getting between the JB or 'bondo glass'. Then again the factory made this support hollow and probably for a reason. needs some drain holes.
Good question, Not really sure. As far as moisture goes the jb weld is recommended for plumbing repairs so should be fine. As far as applying over a rust neutralizer, I would test it on a separate piece of comparable material to see if it will bond. Of course this will only give you a short term test answer, Don't know how long it will hold up over a period of time on top of the neutralizer.
 
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