JB weld

[Roger Flaherty 1Participant @rogerflaherty1]

I'm new to this forum and have been reading through several posts. A few times I've come across JB weld, can someone explain why it is used instead ofother similar products. Many thanks

[Roger Flaherty 1Participant @rogerflaherty1]

[Anonymous]

Simply because it works, it;s been around for donkeys years so has built up a following, it hasn't been messed with/neutered yet by 'elf and safety or the EU yet so carries on being used, unlike Nitromors, Hammerite etc. No doubt there are better modern epoxies but if it does the job you want why change?

[Brian JohnParticipant @brianjohn93961]

It also has a much higher temperature rating than the others. I am in Australia and perhaps you have other products available to you in the UK but down here I have found that JB WELD is the best.

[Neil WyattModerator @neilwyatt]

From MEW 231:

J-B Weld

The original ‘J-B Weld’ is a steel reinforced two-part epoxy with a tensile strength of 3960 PSI. It is slow setting (around 25 minutes) and taking about a day to fully cure as you might expect from their highest strength epoxy. It can withstand temperatures of up to 550 Fahrenheit (287 Celcius) making it suitable for repairs subject to very demanding conditions. It can be drilled and tapped, and one well-known use of it is repairing cracked castings, even cylinder blocks.

J-B Weld is often mentioned on the http://www.model-engineer.co.uk forum because of its high-strength and high temperature performance, but it seems many of us are less familiar with other products under the JB weld umbrella. Here are some of their other adhesives:

KwikWeld is the fast-setting version of the original steel-loaded epoxy. Still with a strength quoted as 2424 PSI, it sets in six minutes and cures in 4-6 hours. It can handle boiling temperatures, but not superheated steam. Kwik Weld is also available in a dual-barrel syringe for convenience in use.

ClearWeld is another dual syringe epoxy that sets in just five minutes but needs an overnight cure. Its strength is between the other two epoxies, but use the steel-loaded types if you want temperature resistance.`

Perma-Lock is a thread locking compound, available in high-strength and medium strength formulations. The medium strength type can be dis-assembled with hand tools but the high-strength version requires the application of heat as well.

J-B Weld Clear Silicone sealant and adhesive and Ultimate Black gasket maker and sealant are high performance 100% silicone room-temperature vulcanising sealants.

[Andy from WorkshopshedParticipant @andyfromworkshopshed]

I repaired some garden ornaments with the steel-stik variant.

http://workshopshed.com/2015/05/garden-bird-repair-steelstik/

They were doing a money back for a review offer a few months back but I've not checked if they still do that.

Edited By Andy from Workshopshed on 12/10/2015 09:42:23

[AjohnwParticipant @ajohnw51620]

There is another "untouched" one that can be useful. Milliput. They don't give any physical characteristics.

**LINK**

I've found it can be moulded to a smooth shiny finish by using cling film as a "release agent". I used it to replace a toothed belt sector drive by moulding the teeth with the belt with cling film in between. Repairing stripped threads in plastic parts and all sorts of bits and pieces.

The epoxy putties sold in the £ shops also seems to work well.

John

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[MuzzerParticipant @muzzer]

It seems that epoxy adhesives are exothermic and they go off quicker when you heat them. Once they start to cure, they can then go quickly, depending on the heat path or lack thereof. You can get the glob of mobile adhesive to smooth off nicely by using a heat gun or hair drier but you need to be aware that doing so will speed up the cure and reduce the working time.

[Roger Flaherty 1Participant @rogerflaherty1]

As I mentioned in an earlier post I'm building a James Coombs engine from a set of parts started by someone else. On the main cylinder there are holes tapped 7BA, however one of the holes had a broken off tap down inside, which Imanaged to bbreak up and remove with a 3mm masonry drill. This has left a larger hole than 7BA tapping so am thinking of using JB weld to fill it and then recap Does this sound oOK?

[JasonBModerator @jasonb]

The JB weld will be softer that the surrounding iron so the drill and tap will want to wander into the softer material. If possible open out the hole to say 4mm (5/32" ) and JBWeld in a small piece of iron turned to size. Once set you can drill and tap the plug.

[duncan webster 1Participant @duncanwebster1]

Depends on how much it has wandered off centre but you could consider making a drilling jig to centralise over where hole should be, drill it out say 4 ba tapping, make a stud threaded 4 ba one end, 7 ba the other and face off the 4 ba end so that it dissappears down the hole leaving the step just underflush

[Neil WyattModerator @neilwyatt]

Just out of interest, I fixed a broken camera tripod 'shoe' using JB 'waterweld' – the white putty. I feel a bit nervous about allowing the shoe to be clamped using the repair, just in case, but it seems to have adhered to the plastic (nylon?) extremely securely which was a bit of a surprise.

If the new hole is centred on the old one, I would just drill and tap normally as you will only be going into the JB weld. I would then use a stud retainer to make sure the stud doesn't slip and fret away the JB Weld

Neil

[Roger Flaherty 1Participant @rogerflaherty1]

Many thanks for your ideas, I'll let you know which way I go.

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