J-B Weld not setting

[John HinkleyParticipant @johnhinkley26699]

I have made an error while machining the main body of my boring and facing tool after having invested a LOT of time getting it what I thought was right. I've drilled the hole for the idler gear in the wrong place, but only by a gnat's knee-cap. In trying to rectify the situation, all I've managed to do is make it worse. I've read good reports on J-B Weld coming to the rescue of some on here, so I thought I'd at least give it a try. I wanted J-B Steelstik but all I could get was some two-part J-B Kwik from a local motor factors. I mixed it as directed after cleaning the part thoroughly and applied it to the hole. It was supposed to set in 4 minutes and be machinable in 4 hours. That was yesterday, and allowing 24 hours plus, I had a look at it. It had the consistency of half-chewed bubblegum! I've emailed the UK importers for guidance, but don't expect a reply for a while, so I thought I'd ask on here if anyone knows:

a) if this could be old stock, past its sell by date,

b) can the stuff go "off" – i.e. become unusable in the tube and

c) how do I remove the sticky mess I'm left with?

Thanks for any assistance forthcoming,

John

P.S. Ideally I'd use proper metal weld to fill the hole but no longer have welding facilities at home.

 

Edited By John Hinkley on 25/06/2016 20:07:38

[John HinkleyParticipant @johnhinkley26699]

[JasonBModerator @jasonb]

Like quick setting araldite it is probably not as good as the original JBweld in the red & black tubes so have never used the Kwik version. The original has always set for me so can't offer much advise as to what will remove it.

J

[here againParticipant @hereagain]

I used jbweld once and it set but didnt stick well..I wondered as its heat resistant if it needed heating ! Best I ve used is a very dark black/brown and yellow one which I forget the name of!

[John HinkleyParticipant @johnhinkley26699]

JasonB – that seems to be what I've got, at least red and black tubes, that is. Guess I'll have to wait and see what the bods at J-B Weld have to say for themselves, or find a friendly local welder.

John

[Nick_GParticipant @nick_g]

Posted by John Hinkley on 25/06/2016 21:09:59:

JasonB – that seems to be what I've got, at least red and black tubes, that is.

John

.

If it is the 24 hour stuff it will take that length of time to set to set. Although that to a point will be temp dependant.

After 24 hours I have found it to be OK to carv excess away with a sharp knife and file a little bit. However filing at this stage tends to clog the file. This tells me it's not 'properly' cured.

If you intend to machine it I would say it needs a few days to cure to that point where it machines like metal.

 

Nick

Edited By Nick_G on 25/06/2016 21:19:04

[John HinkleyParticipant @johnhinkley26699]

Nick,

Thanks. There's no indication on the packaging that it might take that long! Perhaps I'll give it another go tomorrow and bring it indoors while I wait for a response to my email.

John

[Clive FosterParticipant @clivefoster55965]

My experience with Devcon, RS Components and JB Weld metal loaded fillers / adhesives is that they take a lot longer to go off than the book says. More like a week than a day! Whether its uniquely poor technique on my part or whether the book is optimistic / assumes conditions different to those in the home workshop I know not. But they all seem to have gone off to full strength eventually so whatever was wrong didn't have permanent consequences.

Nicks experience of needing 24 (or more) hours before its hard enough to carve neatly is pretty much in line with mine. I find full hardness takes two or three times as long again after carving. JB Weld is much more a glue than filler. Thicker layers seem to go off disporportionately slowly. Devcon is rather more the opposite with thicker layes going off faster. But it still isn't body filler.

Clive.

[duncan webster 1Participant @duncanwebster1]

warm it up, see thread at **LINK**

[Bill PudneyParticipant @billpudney37759]

Duncan has it. Keep it in a warm place (20degrees +) for as long as it takes. All commercial "normal" epoxies will respond to warmth when curing.

Best of luck.

cheers

Bill

[not done it yetParticipant @notdoneityet]

These materials must comply with what it says on the tin/instructions/advertising.

But, of course, they choose the optimum conditions for their conformance tests. Large bulk at higher temp, not a thin film at reduced temp. They advertise the best result attainable.

Think here of concrete dam building. In these very large structures the cement will generate so much heat during curing that cooling pipes have to be inserted to prevent thermal cracking. One reason why lots of fly ash is included as a cementitious element of the mix. Think of fermentations – start too warm and the yeast produces so much thermal energy that the temperature rises more and the yeast works even faster, often to the detriment of the wine.

There are numerous other examples of 'thermal runaway'. Nuclear reactors, overloaded electrical cables, transistors or integrated circuits 'letting out the smoke', plastering walls cf plaster in a bucket, etc which are detrimental and lots of examples where extra heat is a good thing. You can be sure they test their JB weld in the best conditions!

[John HinkleyParticipant @johnhinkley26699]

So, the consensus seems to be that I've been duped by the hype (again). I'll give it another go indoors and leave it for longer to cure. It could also be an excuse to buy a new welding kit – if I can squeeze it past the treasurer!

Thanks for all your input, chaps.

John

[JasonBModerator @jasonb]

John, you said you had the kwik version and then said you have red and black tubes. Kwikweld comes in black and yellow tubes. They do a syringe of teh Kwik that has a red/black lable but both the kwik ones are weaker and won't take the high temp or original JB Weld

If you have the red/black original then that will need a good 24hrs before it can be worked. Note they quote both a setting time and a cure time are you looking at the setting time when it firms up and expecting it to have reached the hardness of the cured product which is 24hrs plus

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[John HinkleyParticipant @johnhinkley26699]

JasonB,

You're right, of course. Now that I've been out into the garage in the cold light of day, I see the red tube is yellow. The eyes aren't what they used to be – neither, apparently, is my short-term memory! I have removed the plug of J-B from the part and I've decided to get it welded up by a local firm, so that I can reposition the location from scratch, so to speak.

I shall, nevertheless be interested to hear what J-B have to say.

John

[Clive FosterParticipant @clivefoster55965]

Problem with heating is that JB Weld, like all such things, thins out when warm so if the joint layout is unfavourable most of it runs out and sets in the wrong place! When designing something for adhesive fixing its usually possible to arrange things to avoid uncontrolled flow but with repair work you have to take the jopint line the break gives you.

Clive.

[RICHARD GREEN 2Participant @richardgreen2]

John,

If you've only got a hole in the wrong place, why not thread it and plug it with a threaded steel plug, loctited in and then re-drill the hole in the right place ?

Richard.

[John McNamaraParticipant @johnmcnamara74883]

This weekend I made a drilling jig for drilling linear ball rails from scrap steel that was at hand, there were a couple of 9mm holes that while not in the way spoiled the look of the jig which I intend to keep.

They were old and a bit rusted so first I drilled them out to a slightly larger size (they were through holes in 5/8 bright plate). Two lathe turned plugs were made about a thou oversize and about 5mm long from mild steel, these were driven into the holes until projecting both sides by 2.5mm.

Next I peened the plugs until they flared around the edge of the hole slightly this reduced the height to about 1.5mm. this forces the mouth of the hole out forming a taper and making the join line close to invisible when finished.

Then I machined off the projecting plug with leaving the thickness of a piece of paper about 3 thou to go, I did not want to mar the surface of the 5/8 steel plate.

Lastly I stoned off the remaining projection.

These plugs would have to be driven out with considerable force they will never work loose and are almost invisible.

The trouble with glueing in plugs is there will be a fine grey line around them. The same applies to threaded holes. I prefer to drill out the thread, fit a tight driven in plug then finish as above.

Regards
John

[RICHARD GREEN 2Participant @richardgreen2]

Hello John,

Yes, I totally agree, but I would rather plug the hole with steel than use filler.

Richard.

[John HinkleyParticipant @johnhinkley26699]

Richard/John,

Much as I appreciate your helpful suggestions, if you look at the photo below, you will see that the hole is (was) very close to an edge. My attempts to rectify the situation have made things considerably worse, leaving me the only option as I see it, which is to find someone to weld it up for me. Unfortunately, I left my welding kit in France last year when we came back to the UK, along with a load more stuff I now find I could do with!

As you can see, the hole – originally 4mm diameter and since increased to 5mm, has broken through the side of the main body. I'll get it welded, clean it up and re-drill (in the right place) to 3mm and use a stepped shaft. That's the plan.

Thanks to everyone for your contributions, I'm sorted, now, I hope.

John

Edited By John Hinkley on 26/06/2016 16:03:36

[Nick_GParticipant @nick_g]

.

That must be so frustrating for you John after all that time consuming not to mention seemingly nice work.

I wish you the best in a satisfactory conclusion.

Nick

[Michael GilliganParticipant @michaelgilligan61133]

John,

Just a thought [feel free to ignore it] … You could, carefully, run an M6 tap down that broken-out hole.

Insert a length of M6 screw, with something like Loctite 601 retainer, and then trim it to shape.

MichaelG.

[Nick_GParticipant @nick_g]

Posted by Michael Gilligan on 26/06/2016 17:11:01:

John,

Just a thought [feel free to ignore it] … You could, carefully, run an M6 tap down that broken-out hole.

Insert a length of M6 screw, with something like Loctite 601 retainer, and then trim it to shape.

MichaelG.

.

I agree with Michael.

I would (if it was me) prefer to try that option rather than have welding splatter to deal with. If it should fail it could always be milled out with a slot and that then welded.

Nick

[John HinkleyParticipant @johnhinkley26699]

Michael,

You know, I will give your suggestion a try. After all, I've nothing to lose by it. Will report back if and when.

Nick. You may well be right. Weld splatter is not very pretty.

John

[Clive FosterParticipant @clivefoster55965]

Although running a tap down partially broken out hole can, and does, work its tricky operation at the best of times as the tap will not only try to run out sideways through the broken bit but also attempt to jam up in it. How great the problem is depends on the depth of the broken out bit relative to the thread. If the broken out part is deeper than the thread its likely to be a battle. For a similar issue I was advised to clamp a piece of light alloy over the break and run the tap down. Theory was that the alloy would keep the tap sufficiently straight. Probably used a second cut tap. It seemed to work adequately but on reflection I wasn't over happy so welded it up for a do-over. At least I didn't have worries about body distortion affecting precise dovetails. Re-drilling the hard weld posed its own problems. Milling out a clean slot so all the re-work is in weld sounds to be a good approach.

i'm pretty sure that given a bit of practice I could have nailed the technique for straight tapping partially broken out holes to give more than acceptable results. But for something I never expected to do again the effort seemed disproportionate especially as by the time I needed to do it again I'd have lost the technique. Currently running at less than once a decade on that particular problem. Possibly because having discovered what right pain in the posterior fixing it is I tend to take a bit of extra care.

Clive.

[not done it yetParticipant @notdoneityet]

Using a spiral tap might make threading such a hole easier. That is the way I would go, if I had gotten that far with the project. I would avoid welding because of the distortion and redrilling problems. I might even clean it out as a slot or dovetail and simply replace the area with an insert (grub screws at the edges would hold the new piece in).

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