Jump to content

J B WELD


31 LaSalle
 Share

Recommended Posts

I keep seeing references to a product called J B WELD on this forum

its not something I am familiar with and I was wondering would it be suitable to fill a small crack in an alloy casting

that's not under any stress.

Link to comment
Share on other sites

It’s just two part epoxy. Filling a crack under no stress or exposure to heat usually will hold up ok. It will become unstable over time if exposed to fuel, oil, or heat. Works well in certain applications. Be sure there is no oil in the casting by heating it in an oven for a few hours at 300 degrees. Too many people try and use it as a cure all…….and it isn’t. They make multiple products, go to their web site and figure out which is best for your application. Practice with it on something else before you use it on your part.

  • Like 9
  • Thanks 1
Link to comment
Share on other sites

It is an epoxy type product. Has "fillers" added, very good adhesion, and some strength. Comes in a variety of mixes, fast setting, slow setting, some types for more specific materials. Most J B Weld unlike regular epoxy is gray in color when mixed, although I have seen some other colors (never used them though).

J B Weld is somewhat resistant to oil and gasoline as well as alcohol. It is NOT impervious to them! So some consideration should be used where the fully set product will be exposed to those chemicals.

Most varieties also handle a fair amount of heat. The regular stuff I use if I recall correctly does fairly well up to about 300 degrees Fahrenheit (about 150 Celsius). I have used it for radiator repairs with great success! However I prefer solder whenever practical.

 

It is a love/hate thing. Not a cure-all (as edinmass I see just posted!). Some people love it too much. Other people despise the very idea of it.

I have salvaged pot metal parts that had been broken into twenty small pieces! Light switches, ignition switches, numerous non-critical parts. I also use it to repair Bakelite and other era plastic parts. You should see the Bakelite ignition switch for my 1915 model T Ford. Decades out in the weather and sunlight had shrunk and warped the thing almost beyond recognition! I had to whittle out areas inside because it had shrunk in too small, recreate the mounting positions for the switch contacts, and then build up the exterior back to size and shape! Once painted flat black? It took some effort building it up in stages and filing and sanding to shape. But mounted onto the coil box, it looks like a perfect original!

I sometimes use J B Weld for aesthetic repairs to chassis and engine parts, or surface damage to wooden wheels before painting. It is durable enough to take the vibration and general abuse in those areas.

  • Like 3
  • Thanks 1
Link to comment
Share on other sites

One important thing to note: there are better products than jb weld for the same uses. Belzona 1111 seems to be a popular, although expensive and hard to find option, that I have not yet tried but have a project for it in the wings. 
 

jb weld is very good though. It does degrade over time, but is highly cost effective. We used it on a cracked water jacket of a model A ford block and it lasted ten years, so we took a grinder to it and put new jb weld back in… lasted several years until the car was sold. With the repair cost being half a day and $10.00, I consider that a huge success story over an engine pulling correct repair. 

  • Like 1
  • Thanks 2
Link to comment
Share on other sites

Yes, JB Weld is a Brand name for an epoxy product.

 

There are many Brand names out there; and of course some are better that others.  If used as directed, cleaning the part first; and i mean really cleaning the part' is the first thing.  Use on non-load bearing items.  And keep dry from water, solvents, gas, oil; and you will be surprised what can be done with this stuff.  Certainly not a Cure-All.'

 

Just an example:  An aluminum cover, for the ignition stator on a motorcycle that may have some light damage. No oil on either side of this cover.  Road rash scrapes, on the out side; and really deep into the aluminum. I will mention this cover was originally painted a silver color. Clean it, CLEAN It, and sand or grind the area, to get a good cross hatch pattern, for super adhesion; apply the proper mix of the 2 part epoxy. Let dry and sand; and depending on your abilities to sand and paint; the item is as good as new or better, forever; until the next Road-Rash incident.  

 

intimeold

  • Like 1
  • Thanks 1
Link to comment
Share on other sites

Thanks for the reply's to my post 

  I Intend to use it for a cosmetic repair on a rear light mounting on my 31 LaSalle

which is Mazak [ pot metal ] 

just a thought I wonder if I could have the mounting chromed after repair with J B weld

it would have to have some metallic element to enable chrome plating

has anybody tried this

thank you for you help

john

 

Link to comment
Share on other sites

No doubt there are other epoxy products available locally that will do the same job.

It is possible to chrome plate plastic and other non metallic items. I used to help my father bronze baby shoes. He would coat them with powdered copper so the electroplating would take. You could do something like that, but I don't know how durable it would be in the weather.

An alternative would be to weld them up with a special low temp aluminum welding rod and gas torch.

Safest course would be to paint them unless you can find good ones to rechrome.

  • Thanks 1
Link to comment
Share on other sites

As a counterpoint to the no contact with solvents, fuel, ETC.  I operated "big rigs" over the road for 40+ years. Owned my own equipment.   On two occasions an aluminum fuel tank was punctured through the bottom.  The first one was punctured large enough to slip four fingers into.  The hole was closed up as best possible, steel wool saturated with J B Weld and then pressed into the hole. Never leaked a drop of diesel fuel.  Second time, a different truck, same results.  That has been my experience. 

 

  Ben

  • Like 5
Link to comment
Share on other sites

6 hours ago, 31 LaSalle said:

I keep seeing references to a product called J B WELD on this forum

its not something I am familiar with and I was wondering would it be suitable to fill a small crack in an alloy casting

that's not under any stress.

If "alloy" is aluminum, have it TIG welded. If it's pot metal, find a plating company that specializes in the repair and replating of pot metal. No epoxy product is capable of being plated in a normal metallic plating process. The metal part needs to be electro-chemically stripped of the old plating first, which will also remove any non-metallic filler. The replating process also will damage any non-metallic filler. Plating is extremely expensive. Trying to cheap out with "bondo" is a really bad idea.

 

And yes, plastic parts can be plated. These are all-plastic parts, not non-metallic filler in a metal part. Also, nearly all plastic "plating" is actually vacuum deposited aluminum. There are vendors who actually apply the traditional copper-nickel-chrome to non-metallic parts, but this usually requires depositing a metallic coating on first, again with vacuum-depositied aluminum.

  • Like 2
  • Thanks 1
Link to comment
Share on other sites

Belzona is indeed the gold standard. In my previous life I was involved in overhauls of large Marine Diesels. Where the cylinder liner O rings seal against the cylinder block, the block becomes corroded over the decades and even new O rings won't seal.  The Co. I worked for had many engines that were 30 - 50 years old, at 3 - 5 Million $ each { even more these days }  you want to get your moneys worth out of them. 

 Big enough engines that you just sit on the crankpin inside the engine to work on this area of the block. Corrosion is wire wheeled down to base metal. And we always used Belzona to repair the area.  A very sucessfull method.

 In truly extreme cases we would have to bore out the area and fit a shrunk in sleeve, but as you can imagine this was a major undertaking and reserved for only the worst cases.

 

 

Edited by 1912Staver (see edit history)
  • Like 4
Link to comment
Share on other sites

What Ed said...

I detest the stuff, mostly because it has fairly limited uses but is advertised as being the be-all-end-all for fixing everything. So far, the only place I've used it was in pattern making and, in one case, to fill a slot in a piece of phenolic. I used it because it's dielectric and will not be subject to much wear. I can't say how many stupid repairs I've seen that used it.

  • Like 1
Link to comment
Share on other sites

I had it in my head to make some additional comments here, and see that ED has also again posted. And again, what he says is very right! Part of that "love/hate" thing is way too many people think of it as a magic "cure-all"! It is a tool. A product that can do some wonderful repairs at an affordable cost. But those "repairs" have limitations.

The Bakelite switch repair for my 1915 model T Ford is likely as permanent as was the original switch over a hundred years ago. Using it on pot metal? Not so much.

Realistically, the light/ignition switch I put nearly twenty pieces back together for might last almost as long as the pot metal did when it was new? Or not. Regardless, when using any such epoxy product to put pot metal together? The pot metal pieces will continue their slow disintegration around the epoxy! My light/ignition switch may actually last longer because it is now more epoxy than it is pot metal. The many little pieces will continue to degrade, with surrounding epoxy holding shape and function. 

The irony is, that a better part, in fewer pieces, will also continue to degrade at a faster rate surrounding the epoxy eventually crumbling away.

Cost sometimes has to be a consideration. Certainly, a new casting of more stable material is a much better way to go! But for some of us, bargaining for another twenty years (maybe) might have to be enough.

 

To the plating question. Fifty years ago, when most people took pride in their work? And chrome plating shops took a lot more pride in what they could do than did most people!!!!  I have no doubt that a good plating shop could have chromed over epoxy repairs and made them beautiful! Shops that friends and I used to deal with always bragged about how they could chrome plate anything! And yes, it involved special foundation layers.

Today? I wouldn't have any idea as to where to begin looking for a shop that could, let alone would, actually do it.

 

About use around hostile exposures. It works amazingly well, in a lot of cases. However, it is a matter of trust to be considered. What happens IF that repair fails in that spot? A fuel tank begins leaking diesel in slow drips will likely be noticed quickly during routine (required for professional drivers!) walk around inspections. A slow breakdown inside a carburetor might go unnoticed until it sets the car on fire!

I have myself glued together small items and put them inside a plastic jar filled with gasoline (or other chemicals) and let them sit for months, even years, just so I could test their strength myself. For certain applications, long-term exposure would worry me. Although they may still hold okay? The strength of the hold and the strength of the body of the epoxy does weaken and become more brittle. 

 

I am not actually "proud" of some of the repairs I have done with J B Weld.

But I also like to think of myself as a realist, and mostly honest. 

There are a lot of really good uses for it. And for every one of those really good uses are probably ten really BAD uses!

I do use it. I admit it. I like a lot of the results I get from it.

Many years ago, I was working on one of my cars. The car had been run for many years with a damaged spring and shackle. The spring wore an area on the axle housing. The size and location wasn't sufficient to weaken the housing in any significant amount. But the worn area annoyed me! So I thoroughly mixed steel wool and J B Weld into a heavy on the steel wool mass. Then using pieces of plastic (that the J B Weld will not stick to!) and electrical tape (also won't stick to) stretched to compress the mixed mass into an approximate shape and position, allowed to set. A coarse file did the final shaping, and once painted it looked like a near perfect piece. Purely an aesthetic repair. A lot tougher than most fillers.

  • Like 1
  • Thanks 1
Link to comment
Share on other sites

It has it's place. I've used it a few times but as a filler not as a glue. The color mimics oily cast iron and works great filling dings in machine tool tables. After a bit it's pretty much invisible. Not that I'VE ever run an end mill or drill into a Bridgeport table.............Bob

Edited by Bhigdog (see edit history)
  • Like 1
Link to comment
Share on other sites

A long time ago, I personally tested J. B. Weld, along with other epoxies for use on zinc alloy a.k.a. "pot metal" a.k.a. "white metal carburetor castings.

 

ALL of them, including J. B. Weld, failed in less than 3 months.

 

Don't use it around gasoline.

 

I also tested some of the magical special welding rods to "weld" pot metal. The weld would hold, but the pot metal would fail where the weld was applied, so no cigar.

 

Jon.

  • Like 2
Link to comment
Share on other sites

The other manner (no one has brought up) of fixing, which will be more condusive to plating over is laser welding. I have some experience with a friends's machine but have only done really small parts and not pot metal. You probably need to contact a commercial outfit and they'll probably say there's no guarantee. Steel, brass, bronze, sliver, gold (I suppose 🙄) rod can be used and all plated over. It's a matter of how big a crack and which will stick to the substrate. Then it is ground or filed and polished from the exterior.

  • Thanks 1
Link to comment
Share on other sites

I cast a new seat for a check valve in a power brake unit and machined it very like a valve seat it's been working fine for 15 years. 

If it should fail you just would had to push  harder on the brake pedal I don't drive it hard 

  • Like 1
Link to comment
Share on other sites

3 hours ago, carbking said:

A long time ago, I personally tested J. B. Weld, along with other epoxies for use on zinc alloy a.k.a. "pot metal" a.k.a. "white metal carburetor castings.

 

ALL of them, including J. B. Weld, failed in less than 3 months.

 

Don't use it around gasoline.

 

I also tested some of the magical special welding rods to "weld" pot metal. The weld would hold, but the pot metal would fail where the weld was applied, so no cigar.

 

Jon.


 

Jon……. You mean there isn’t any free lunch? 🫣

  • Like 1
Link to comment
Share on other sites

For part of one year (1917), Ford experimented with a type of plastic mixed with some sort of fibrous material (some historic records say straw?) to make the four coil boxes each car used out of something other than wood. The plastic cases were supposed to be simple plastic castings and require less labor than to cut/shape/fit six pieces of wood.

Problems began showing up soon after sales, as cars in real environments and weather would go from wet to dry and back to wet again. The wood-like fibers inside the plastic would begin swelling and shrinking. Coils would get stuck in the coil box, or lose electrical connection (or both!), resulting in unhappy customers. The plastic without the wood-like fibers wasn't tough enough, so the whole idea was dropped after several months. Ford dealers replaced the coils for customers (Ford actually did want to keep his customers happy!)

Those 1917 plastic case coils are somewhat rare (an overused word that relatively speaking in this case is appropriate!). In over fifty years of looking, I have only seen maybe a dozen of those coils! And I have spoken to only maybe another dozen people that told me they have one! (There are of course many more out there.) I did run into one fellow that owned a beautifully restored 1917 T that told me it had four fully restored plastic case coils in the coil box! (And people think I am crazy?) Unfortunately for me, he was driving a different T on that tour, so I didn't get to see them.

Somewhere along the line, I got one along with a bunch of other model t stuff I bought. It was in terrible condition, and missing the one side piece that was originally tarred into place. The other side however, looks the same, with a pattern and the "Ford" script cast in it. So, I don't recall now what I used to make the mold, but something that peeled off the side carefully. Then laid flat, and paddled a mass of mixed J B Weld onto the mold. After changing the capacitor and testing the coil to know that it functioned okay, I trimmed to fit and glued the new side piece into place! Not perfect. But it looks fine to me. And I have a functioning 1917 plastic coil to show and tell.

 

There are a lot of things for which J B Weld is perfect! No major special equipment or tools required. And there are a million horrible patch jobs out there that should have never been attempted!

Maybe I should tell you about the little pickup my younger son bought twenty some years ago?

  • Like 1
Link to comment
Share on other sites

JB Weld- It works until it doesn't. 

 

I have a couple of packages around, worth a try for the cost. I wouldn't use it as an adhesive but more of a patch.

 

I keep some KwikWeld tubes in my "mobile toolbox" that I throw in my trunk for car tours for emergency repairs.

 

  • Like 1
Link to comment
Share on other sites

11 hours ago, edinmass said:

Like I said in my original post……too many people try and use it as a fix all……….make a new casting in bronze. Or buy one. Gluing bad pot metal together is a waste of time. Old cars are work, and cost money. You can’t restore and drive cars held together  with plastic putty.

Thank you for the advice I have now made the decision to fill the crack then sand it down to enable it to be cast in bronze

I will then send it for chrome   I hate pot metal why manufacturers used it I dont no I suspect it was easy to manufacture and cheaper

 

  • Like 1
Link to comment
Share on other sites

Sounds like the best way to go!

Sand cast, or lost wax? Full mold compensating for thermal shrinkage?

Just curious.

A close friend years ago used to do some excellent sand mold casting in aluminum and/or brass. I have a radiator cap for which I would like to try lost wax.

  • Thanks 1
Link to comment
Share on other sites

5 hours ago, wayne sheldon said:

Sounds like the best way to go!

Sand cast, or lost wax? Full mold compensating for thermal shrinkage?

Just curious.

A close friend years ago used to do some excellent sand mold casting in aluminum and/or brass. I have a radiator cap for which I would like to try lost wax.

There is a small company local to me here in the uk who does sand casting I will use him 

I will have it done in brass as I had a part done by him a few years ago in aluminium and had trouble with pin holes before chroming

hoping for better results in brass

  • Like 1
Link to comment
Share on other sites

There are several variations of JB Weld now including one they say is for patching gas tanks, I haven't used it but it may be worth trying for gas applications.

  • Like 1
Link to comment
Share on other sites

15 hours ago, wayne sheldon said:

Aluminum is generally cheaper, both material and labour. However, the general consensus is that for parts to be plated? Brass is better by far! 

100% yes

Link to comment
Share on other sites

Back in the early ‘80s I was moving a sailboat with an old 4 cylinder Atomic gas engine from Trinidad to Newport, RI. Half way there, about 800 miles off shore the engine overheated and cracked the water jacket on the head. After letting it cool down, I filed the crack with triangle file, doused and scrubbed it with alcohol then filled it with JB Weld. It got us to Newport and the owner used it that way for several more years. As always, it’s all in the prep work!

  • Like 1
Link to comment
Share on other sites

On 7/20/2022 at 4:56 AM, 31 LaSalle said:

Thanks for the reply's to my post 

  I Intend to use it for a cosmetic repair on a rear light mounting on my 31 LaSalle

which is Mazak [ pot metal ] 

just a thought I wonder if I could have the mounting chromed after repair with J B weld

it would have to have some metallic element to enable chrome plating

has anybody tried this

thank you for you help

john

 

There is a material called Alum-o-lead which is an epoxy with lead and aluminum filings in it. It is a strong patching material. I know that aluminum can be chromed, so maybe it can be chromed. Call a chromer and see what he’s had experience with. 
 If all else fails, I may have a replacement rear bracket.

 

Wayne

  • Like 1
Link to comment
Share on other sites

2 minutes ago, yachtflame said:

There is a material called Alum-o-lead which is an epoxy with lead and aluminum filings in it. It is a strong patching material. I know that aluminum can be chromed, so maybe it can be chromed. Call a chromer and see what he’s had experience with. 
 If all else fails, I may have a replacement rear bracket.

 

Wayne

thank you wayne for the information on alum-o-lead 

but  I have filled the damaged light bracket and sanded it down it is now at the casting shop

it would have been interesting to know if alum-o-lead could be chromed over

 

Link to comment
Share on other sites

I punched a hole through a differential housing when a ring gear bolt worked it's way out and clipped the housing from the inside.  It was December and I didn't have a shop.  Cleaned up the hole and applied JB Weld, used a halogen work light under it to keep it warm over night.  Held without leaking for about 10 years when I broke an axle and replaced the whole thing.    I also fixed a pinhole in the bottom of a gas tank about 5 years ago, so far so good.  

 

Never had any luck using it on aluminum.  The JB Weld for plastic is good stuff for the intended use, it's the only thing that holds up when I break the chassis on my radio controlled cars.  

  • Like 2
  • Thanks 1
Link to comment
Share on other sites

  • 2 weeks later...
On 7/20/2022 at 2:25 AM, 31 LaSalle said:

I keep seeing references to a product called J B WELD on this forum

its not something I am familiar with and I was wondering would it be suitable to fill a small crack in an alloy casting

that's not under any stress.

My fun car is a 1927 Willys Knight 70A two door sedan. It is 100% stock other than the materials used to restore a badly rusty body and missing/rotten wood. The standard six cylinder engine is a sleeve valve, has all original accessories, and runs perfectly. Here in Washington State we have fast and famine of rain, and when the famine ends in August or September, it’s rain feast until the snow comes in January or February. Neither the brakes or the 4” wide tires on my Willys likes rain slick pavement, and the vacuum windshield wipers works better when the car is stationary. Regarding your JB Weld question. I have said all the aforementioned to make clear that I have a limited window of time to (enjoyably) drive my Willys, and most heavy maintenance tasks are put off until bad weather sets in. That maintenance is more often than not associated with the cooling or brake system since most other parts of the car are pretty bullet proof. In this instance it was the “water cover”, or for a non-sleeve valver, the pan which sits atop the engine where one would normally expect a cylinder head. But, a sleeve valve engine has no cylinder head, and instead uses a (OEM) steel, or a more recently available aluminum water cover. Replacement of either, as a necessity, or just for fun, would not normally be a problem, but anytime you turn a 94 year old bolt, problems seem to avalanche once one breaks. So, when the steel water cover of my Willys cracked around the bottom perimeter, and began weeping coolant from the radiator, I could see the usable portion of my summer driving time wasted while waiting for a replacement water cover, and, unavoidably, disassembling the engine to drill and tap the bolts, normally in a inaccessible place. Note here that this car uses some bolts no longer available, and fabricating them also takes time. Anyway, enter JB Weld, and a quick repair to the cracks in the water cover. THIS IS NOT A ENGINE BLOCK, AND THE COOLING SYSTEM OF THE WILLYS IS A UNPRESSURIZED, OPEN TO THE AIR, SYSTEM! The patch was placed in February, I will order a new aluminum water cover as a self Christmas present, and need to go for a drive in the Willys since the patch still keeps my old cooling system working like a new one.

  • Like 3
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...