Removing JB Weld?

Hi. Last month I made a Mag85. I had all of the parts (including bi-pin 1185 lamps) but no socket. My host is over 20 years old and it looked like the easiest thing to do was go potted. Not wanting to wait, and not wanting to buy yet MORE lamps, I smashed up the old stock PR and did my own potting job with one of the 1185's and JB Weld. It worked okay but for a permanent solution I ended up buying a Northern Lights PR to bi-pin socket adapter (I highly recommend these!).

Well now I have the poor homemade lamp to deal with. The heat caused some shifting (probably because I just couldn't wait a full day to try it!!) so I tried to take it apart to salvage the virtually new lamp but that JB Weld doesn't want to let go!

I know it's only five bucks but I hate just throwing it away. Is there an easy way to clean that stuff off of it? Or maybe someone needs a bench test lamp? You can still get to the pins and the lamp still works!

If it's anything like their Stik-Weld steel putty, you can hack, scrape, squeeze, and gouge at it. It's stiff, but not hard.

JB Weld is hard and pretty strong but can be removed in some cases. The most controlled removal method would be to use a Dremel tool, file, sandpaper, etc. to grind off the JBW. It is somewhat brittle so if you can remove the PR base you may be able to chip it off the pins of the bulb. It is also flammable when exposed to an open flame for quite a bit. I have set it on fire when messing around, but I don't know how well it burns or how good of a removal method it is since I put it out immediately.

I have used this for some time when potting the old Dorcy AAA circuits and it sets up very hard. I once tried to remove the stuff in order to salvage some resistors and the coil form the potted circuit and after about an hour just gave up. Believe me it is really not worth the effort or at least for me it was not. I tried simply cutting it away with an exacto knife then went on to the Dremel tool. I believe it could have been done but again after many sore fingers and scraped knuckles I gave up.....good luck if you do try it.

JB Weld is just a filled epoxy. Use a heat gun to soften the epoxy then remove the parts. While the epoxy is soft you can scrape most of it off. Clean it up with a dremel and sandpaper etc. Epoxy is not a good adhesive to use on high temp parts. Dow Corning makes some silicone based adhesives that work up to 500-550°F. Furnace cement available at your local hardware store can be used also. The following company also has a wide range of high temp materials:
http://www.cotronics.com/vo/cotr/newprod.htm

NMP at 165°F can also be used to clean epoxy off. The fumes are deadly tho, -so don't try it!

Torque1st said:

JB Weld is just a filled epoxy. Use a heat gun to soften the epoxy then remove the parts. While the epoxy is soft you can scrape most of it off. Clean it up with a dremel and sandpaper etc. Epoxy is not a good adhesive to use on high temp parts. Dow Corning makes some silicone based adhesives that work up to 500-550°F. Furnace cement available at your local hardware store can be used also. The following company also has a wide range of high temp materials:
http://www.cotronics.com/vo/cotr/newprod.htm

NMP at 165°F can also be used to clean epoxy off. The fumes are deadly tho, -so don't try it!

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I think you underestimate jb weld. Check out the properties for yourself. Resistant up to 500 F
http://jbweld.net/products/jbweld.php

Heat gun is not gonna work. You just have to chip it away.

A heat gun works fine. I have used it a time or two when it has failed in much lower temp applications. There is nothing magic about JB Weld. It is just epoxy with a filler, -probably talc, or cabosil, and some pigment. It is a good epoxy adhesive tho.

I would also take that advertised 500° figure with a big grain of salt... What does it actually mean?

You can try acetone but I haven't done it myself and don't know if it will work.

Quote from the FAQ of J.B. Weld site:

" Q: How can I remove J-B Weld after it is fully cured?

"When fully cured, J-B Weld can only be removed by grinding or filing it off, or by directly heating the product above the 600 degree maximum temperature threshold. "

Without researching, but based on experience,there are several types of JB Weld with seemingly different compositions. I've also experienced differing results based on the proportion of mix.

I've tried really, really hard to avoid saying this, but --- Wattnot, looks like you're stuck with it.

I have been using JBWeld to hold a custom board that i made to my heatsinks and this stuff hold really well. its really hard to get the board off then afterwards i need to grind down the JB weld to get rid of it. Its some really hard stuff

BIGIRON said:

--- Wattnot, looks like you're stuck with it.

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This has been my experience, too. :sigh:

Thanks for the replies. Again, if there is a tinkerer who wants a new 1185 as a test bench lamp, this would be a good candidate!

No matter what the company "claims" on their website I have had good luck with a heat gun even with properly mixed material. I worked with epoxies for years in aerospace applications and labs. Again, there is nothing "magic" about JB Weld. The company would like people to think so tho. Similar to other companies and their "advertising claims".