JB Weld?

[PaulR]

Whilst trying to encourage the overdrive unit back on to the gearbox mainshaft after a gbox rebuild I have broken off a piece of the overdrive casing that contains one of the studs. I reaLLY DON'T WANT TO HAVE TO REBUILD THE OVERDRIVE AND WHILST LOOKING FOR SOLUTIONS I CAME ACROSS THIS

http://jbweld.net/index.php

HAS ANYONE ANY EXPERIENCE OF IT OR ANY OTHER SOLUTIONS FOR REATTACHING THE BROKEN PIECE.

[trelfin4]

Have used in past to repair aircon, power steering pipe leaks also on alloy rads etc in these situations it works very well.

[pfenlon]

Whilst trying to encourage the overdrive unit back on to the gearbox mainshaft after a gbox rebuild I have broken off a piece of the overdrive casing that contains one of the studs. I reaLLY DON'T WANT TO HAVE TO REBUILD THE OVERDRIVE AND WHILST LOOKING FOR SOLUTIONS I CAME ACROSS THIS

http://jbweld.net/index.php

HAS ANYONE ANY EXPERIENCE OF IT OR ANY OTHER SOLUTIONS FOR REATTACHING THE BROKEN PIECE.

 

 

Can you post a pic of the broken part, it would help you to find the right answer.

[PaulAnderson]

Whilst trying to encourage the overdrive unit back on to the gearbox mainshaft after a gbox rebuild I have broken off a piece of the overdrive casing that contains one of the studs. I reaLLY DON'T WANT TO HAVE TO REBUILD THE OVERDRIVE AND WHILST LOOKING FOR SOLUTIONS I CAME ACROSS THIS

http://jbweld.net/index.php

HAS ANYONE ANY EXPERIENCE OF IT OR ANY OTHER SOLUTIONS FOR REATTACHING THE BROKEN PIECE.

 

 

There is a UK site at http://www.j-bweld.co.uk/

Interesting stuff. I've a spare set of trailing arms for my TR4A which while appearing to be very nice, unfortunately the brackets for the brake pipes have snapped off. This might be able to repair / replace them.

[PaulR]

I've now taken some photos of the broken piece and casing

[randall977]

It looks very good, I used a simular product to repair a cast iron range and it works very well indeed and has withstood temperatures far in excess of what is recommended... I would definitely go down this route again for other applications.

[pfenlon]

I've now taken some photos of the broken piece and casing

 

 

 

I think it is repairable by a proffessional welder, although I would price up a replacement casing, purely because if it does leak when repaired its a sod of a job to get at to correct, good luck and if you go for a "repair" buy a tube of Wellseal for the gasket.

[Guest MikeFe]

I've now taken some photos of the broken piece and casing

 

The literature reads well but cutting though the hyperbole …. Basically this stuff is a filled epoxy adhesive. (the same family as Araldite).

Industrially these types of products are used in a variety of repair and maintenance applications, Belzona in Harrogate www.belzona.co.uk is one of the better known companies, JB is a domestic focussed operation.

The important thing to remember when making adhesive repairs is to choose a suitable type for the application and then the joint/bond design

Type and grade has been done for you by JB Weld

Relatively adhesives bonds are not very strong, [but may still be strong enough]. The bond strength those guys are quoting is goodish for a filled epoxy but about 10x less than a braze for example, also adhesives are not in themselves as strong as metal,

So you need to be a little careful (sceptical) about the product claims. So though Cold weld type products can be used to mend stuff they are not form fit function replacement for metal.

Essentially in this app. the lower strength means you need to make a larger area bond

Also you need to get completely clean, rough (scored) surfaces. This give a good key and max strength bond.

Worst-case scenario is a "butt joint": typically where you simply push things back together with a bit of glue in between.

So looking at your damaged part. It seems as though this has a fixing stud, which would apply tension and leverage to the repair area. On this basis I would suggest you make up a metal patch, Bent to the contour of the box. Reassemble the broken part, apply your weld compound and then stick the patch on. You don't need a huge thickness of material in the sandwich - it will not add strength. You can have the patch on the outside or the inside of the box if there is clearance for moving parts. Or both if you wish. Inside would be best, as this would give best protection against possibility of oil being pushed under pressure into bond-line. Adding adhesive into the fracture line will make the repair proud, and give poor gasketing on re-assembly. You should be able to contour theparch / weld material so that it doesn't really notice.

Sorry for late response, I messed up something on the reply posting so I can't now post as Mike F, I have reregistered to get round the problem.

Hope this helps anyway.

 

 

Mike

Edited December 2, 2010 by MikeFe

[MikeF]

The literature reads well but cutting though the hyperbole …. Basically this stuff is a filled epoxy adhesive. (the same family as Araldite).

Industrially these types of products are used in a variety of repair and maintenance applications, Belzona in Harrogate www.belzona.co.uk is one of the better known companies, JB is a domestic focussed operation.

The important thing to remember when making adhesive repairs is to choose a suitable type for the application and then the joint/bond design

Type and grade has been done for you by JB Weld

Relatively adhesives bonds are not very strong, [but may still be strong enough]. The bond strength those guys are quoting is goodish for a filled epoxy but about 10x less than a braze for example, also adhesives are not in themselves as strong as metal,

So you need to be a little careful (sceptical) about the product claims. So though Cold weld type products can be used to mend stuff they are not form fit function replacement for metal.

Essentially in this app. the lower strength means you need to make a larger area bond

Also you need to get completely clean, rough (scored) surfaces. This give a good key and max strength bond.

Worst-case scenario is a "butt joint": typically where you simply push things back together with a bit of glue in between.

So looking at your damaged part. It seems as though this has a fixing stud, which would apply tension and leverage to the repair area. On this basis I would suggest you make up a metal patch, Bent to the contour of the box. Reassemble the broken part, apply your weld compound and then stick the patch on. You don't need a huge thickness of material in the sandwich - it will not add strength. You can have the patch on the outside or the inside of the box if there is clearance for moving parts. Or both if you wish. Inside would be best, as this would give best protection against possibility of oil being pushed under pressure into bond-line. Adding adhesive into the fracture line will make the repair proud, and give poor gasketing on re-assembly. You should be able to contour theparch / weld material so that it doesn't really notice.

Sorry for late response, I messed up something on the reply posting so I can't now post as Mike F, I have reregistered to get round the problem.

Hope this helps anyway.

 

 

Mike

 

[BrianC]

...I would suggest you make up a metal patch, Bent to the contour of the box. Reassemble the broken part, apply your weld compound and then stick the patch on. You don't need a huge thickness of material in the sandwich - it will not add strength. You can have the patch on the outside or the inside of the box if there is clearance for moving parts. Or both if you wish. Inside would be best, as this would give best protection against possibility of oil being pushed under pressure into bond-line.

 

 

In the case (no pun intended) of a gearbox, I'd rather have a patch come unstuck on the outside!

[MikeF]

That's a fair point I was too busy pontificating and not thinking thorugh the actuals.

 

Of course it shouldn't happen, but Sod's Law says it will and that it when it does it will be at the worst possible time. On balance of hazards, stick it on out side, or mechanicallt fix with pop rivets or ...

 

 

 

Mike

[RogerH]

Paul,

you have all the bits, get it welded - dead easy for a pro. JBweld is a bodge.

 

Roger

[Ashley James]

Paul,

you have all the bits, get it welded - dead easy for a pro. JBweld is a bodge.

 

Roger

 

 

Absolutely! There's only one way to do a job: PROPERLY

 

Ash

[Paul JB]

Out of interest, is this the same as 'Chemical Metal' that I've seen in motor factors?

[MikeF]

 

Absolutely! There's only one way to do a job: PROPERLY

 

Ash

 

 

Well that's a value judgement, Perhaps another way to look at it is that the adhesive repair can be done without dismantling so the loss of use is small. In addition the car can now be used until a planned/permanent mend can be done, perhaps when other servicing is scheduled.

 

Out of interest, is this the same as 'Chemical Metal' that I've seen in motor factors?

 

 

Yes the same type of generic material, [you have to distinguish between these epoxy type materials and cosmetic fillers.]

 

 

 

Mike

 

 

[RogerH]

Hi Mike,

I didn't mean in any way to rubbish your posts at all.

The product is excellent for many applications but I feel this is not one of them.

I agree that a quick repair can get the car back on the road but at this time of year is it being used as a daily driver or at all.

 

These materials need to be bonded to very clean surfaces that often can't be acheived at home.

Should the filler degrade/fall out/unbond then the consequences could be rather expensive.

 

Having worked in aerospace for many years I have grown up with adhesives of many types being used in more and more applications.

From Fokker's first attempts at bonded structures to the latest Boeing & AirBus offerings. Adhesives and synthetic structures are the future.

 

Anyway back to topic - get it welded.

 

Roger

[MikeF]

Hi Mike,

I didn't mean in any way to rubbish your posts at all.

The product is excellent for many applications but I feel this is not one of them.

I agree that a quick repair can get the car back on the road but at this time of year is it being used as a daily driver or at all.

 

These materials need to be bonded to very clean surfaces that often can't be acheived at home.

Should the filler degrade/fall out/unbond then the consequences could be rather expensive.

 

Having worked in aerospace for many years I have grown up with adhesives of many types being used in more and more applications.

From Fokker's first attempts at bonded structures to the latest Boeing & AirBus offerings. Adhesives and synthetic structures are the future.

 

Anyway back to topic - get it welded.

 

Roger

 

No offence taken, I was answering the original question.

Do these thigns work? Answer yes if used correctly.

 

There are more general follow up questions: Are they a permanent repair? well could be. Would I (as a former low temperature joining specialist) consider permanent on this occasion? maybe, it depends. The correct product well mixed on properly prepared surfaces would be OK.

Am I confident taht this would be the case? Don't know the user, only seen a picture of app. Not familiar with JB Weld or prodcuts, but they are probably just reseller, I would likely be doing a little more supplier research were I to be in this situation. eg is the product a genuine 2 part material, would like to see data sheets and so on.

certainly I would say the stuff would work till a proper repair can be scheduled.

 

Mike

[PaulR]

Hi Guys

Thanks very much for your responses

Roger, if I was to get it welded would I have to dismantle the o/d in case the heat generated damages any seals etc?

[Ian Vincent]

Hi Guys

Thanks very much for your responses

Roger, if I was to get it welded would I have to dismantle the o/d in case the heat generated damages any seals etc?

 

 

I know you directed this query at Roger but I thought I would chuck in my five bob's worth anyway. I would have thought that a good welder with a TIG set would be able to weld it without necessitating complete dismantling.

 

I would make sure that the unit is sitting surrounded by something to take the heat away - ice? - do the work in small steps without putting too much heat into the joint and rely on the conductive abilities of aluminium.

 

I am sure someone will tell me if I am talking rubbish.

 

Rgds Ian

[RogerH]

Hi Ian,

you are not talking rubbish but they use better stuff than ice.

You may need to support the broken flange in order to keep the shape and the flange sealing surface.

 

Roger

[Peter Cobbold]

Hmmm, epoxy glue and a stud? not sure about that..

 

A proper DIY fix could be to use Technoweld. Its a bit like soldering aluminium - but with a propane blowtorch. An early version was called Lumiweld.

I use it on blower manifolds Technowelded together from bits of of 5mm thick ali- a backfire once bent the ali between two studs 3 inches apart, but the T'weld joints held up.

[PaulR]

Final update

Following Rogers advice I found a nice man who has successfully welded the pieces together and has made a fine job.

Thanks for everyones input

Paul

[MikeF]

Hmmm, epoxy glue and a stud? not sure about that..

 

A proper DIY fix could be to use Technoweld. Its a bit like soldering aluminium - but with a propane blowtorch. An early version was called Lumiweld.

I use it on blower manifolds Technowelded together from bits of of 5mm thick ali- a backfire once bent the ali between two studs 3 inches apart, but the T'weld joints held up.

 

 

I visited their website, that’s a neat idea metallurgically. There could be some concerns about long-term stability of the Al/Zn intermetallic formed. I will look into that with them, no doubt they have answers ready. Probably the minor additions they mention are to fix that as well as to promote bonding.

 

In practical terms I am not sure how effective/easy it would be to remove the aluminium oxide layer as described, and Zinc oxidises very readily when heated also. Looks as though this is a little bit of a skill job, but once the technique has been mastered it would be effective and anyway stronger than a polymer-bonded repair. (Although the polymer bond could be strong enough - which was the original question).

Peter: are you able to indicate how easy/difficult it is to get to good looking effective joints?

 

 

 

MIke

 

 

[Peter Cobbold]

I visited their website, that’s a neat idea metallurgically. There could be some concerns about long-term stability of the Al/Zn intermetallic formed. I will look into that with them, no doubt they have answers ready. Probably the minor additions they mention are to fix that as well as to promote bonding.

 

In practical terms I am not sure how effective/easy it would be to remove the aluminium oxide layer as described, and Zinc oxidises very readily when heated also. Looks as though this is a little bit of a skill job, but once the technique has been mastered it would be effective and anyway stronger than a polymer-bonded repair. (Although the polymer bond could be strong enough - which was the original question).

Peter: are you able to indicate how easy/difficult it is to get to good looking effective joints?

 

 

 

MIke

 

 

Mike,

The 'technowelds' were not pretty -thin,yes, but rough and ragged and awkward to grind down being in a 90 deg angle between two plates ( so I just left it- no point in prettying a trial set-up). I would not use it for stressed safety critical joins. But TIG welding distorted the first blower manifold horribly - the ali sheet warping so much that it needed fly cutting. No such problems with technoweld, which works at much lower temp. Clamping the parts together gave me the most grief,the clamps gettinmg in way of the technweld rod and prodder. So the next time I am going to try to tag the ali plates together with a brief burst of the MIG- we'll see.....