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Hobart G-213 Coils Shorted Out

bugle

New member
The porcelain insulators on my old Wisconsin TJD driven Hobart G-213 welder have been falling out in pieces over the years and have finally gotten to the point where the coils shorted out on the frame. The part number for the porcelain insulators is AAW-2628 and I can't find them anywhere. Does anyone know a fix for this? The old welder is otherwise in pretty good shape.
 

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Tracy T

Subscriber
i would imagine this coil is no different than the ones we reworked in the transformer shop and we got some old ones to rebuild! we replace the porcelain with fiberglass. you may research electrical insulation and come up with the material to make your own. we got fiberglass in 4x8 sheets and in stock maybe a half inch thick by two inches wide 12 ft long. be sure to clearcoat the fiberglass when finished to keep moisture out.
 

s100

New member
I find this post very timely since I also have a G213 that has broken insulators. And like the OP I was hoping to find a source for them. But Hobart, while once a prominent name in welding machines, has really fallen by the wayside and I gather it is not much more than a marketing name any more, owned by Miller. I was told at one time by Miller that parts for these machines are no longer available nor have they been for many years, since the last store of parts was used to build out a few more machines at the end of the product's life cycle. So I think the odds of finding new parts is all but nonexistent. And since we are now two owners who share the same problem, it seems these parts may be a weak point.

The idea of making new insulators is a great one. But fiberglas? I'm not so sure. Hobart made these things out of porcelain for some reason. And the coils' placement, right next to a screened opening in the housing, implies that they get hot. If that is the case then fiberglas is a very risky material to use, should it get hot and maybe start to burn.

When I get back around to it, I will try one of several ideas:

1. I think I have all the pieces so maybe I can find some high-temp glue to repair the insulators. This is a poor option as it is highly unlikely that the glued parts will be even remotely as strong as the old ones, which are proving to be inadequate to the task.

2. Make new insulators out of plate glass. Cut some heavy plate glass into pieces similar to the overall size of the insulator. Make a mask that has the exact form of the insulator from sheet rubber and glue to the blank. Sandblast away the exposed glass to form the new insulator. This sounds like a lot of bother.

3. Make new porcelain insulators. Thousands of years ago one of my sisters took a craft class where they made ceramic figurines and the like. Might be able to take a craft class and make new insulators. This idea has the most possibilities, I think. The new insulators can be made to exactly copy the originals or they can be strengthened, maybe with a steel core or a steel spine running up the inside. All that is needed, I think, is to make a mold that corresponds to what you want the insulator to look like. Classes like this, if they are available in your area, are inexpensive,probably cheaper than buying the parts. And if you are even cheaper than me (unlikely) then maybe you can research the process, buy the materials and make the parts at home.

There may be other options, such as finding a heat resistant material that can be bought in sheets and making the insulators out of that. Unless someone here knows of a stash of old Hobart parts though, I see making new ones as the only option. I have to do something, as mine is a very low hour machine I bought when it was six months old, and it is still in excellent shape, far too nice to give up on. But mine will have to wait its turn as I am swamped with other issues right now.
 

bugle

New member
I don't have enough pieces of the porcelain to glue together. I suspect that they failed because the steel frame they were attached to swelled from rust. Mine is trailer mounted and in a region where roads are salted.

I do hope that if someone takes the initiative to actually make new insulators, that they make a few dozen of them and sell them on ebay or the like so the rest of us would have an easy solution.

I was thinking that a candidate for heat resistant material might be fiberglass cloth, using only enough resin to prevent it from unraveling.

---------- Post added at 09:45:24 AM ---------- Previous post was at 09:29:20 AM ----------

But fiberglas? I'm not so sure. Hobart made these things out of porcelain for some reason. And the coils' placement, right next to a screened opening in the housing, implies that they get hot. If that is the case then fiberglas is a very risky material to use, should it get hot and maybe start to burn.
Thinking about your concerns, I looked around the net

https://www.engineeringtoolbox.com/fiberglass-pipes-temperature-limits-d_787.html

300 degrees f for epoxy fiberglass.... polyester resin only good to 200 degrees...do you think those coils get hotter than 300?
 

Troll

Subscriber
I have hundreds of welding hours on my G-213 I've owned since 1974. Those inductor coils do get hot to a dull red which can be seen at night. I recast my porcelain spacers from a high temperature ceramic material and fired it in a friends kiln. I used one of my originals as the pattern. The replacements are much better than the originals, and look almost an exact copy. I did thins back in 1996 so they've held up quite a spell.

IMG_0443.JPG
 

Power

Active member
As a temporary repair, can you adapt oil burner igniter porcelain insulators?
I have cut them to size using a carbide wheel.
They are exposed to very high temperatures.
 

I like oldstuff

Subscriber
Search out Glastic in your area. It's a easily worked fibreglass and will work well for you. Unless the coils get over 400F glastic is the go to material.
 

Troll

Subscriber
I have a loader bucket to build up and hard face next week. I'll shoot the inductor when it's hot and think you will be surprised at their operating temperature. I did this work for years at the mines and am very confident 650 degrees is conservative.
 

Tracy T

Subscriber
i am not sure just how much heat was generated in our transformers, but they did have on average 6 fans per unit for cooling. we used fiberglass insulators on both the high voltage and the low voltage side. its been years ago but some of the units we tested we had to make our own electricity to produce the needed voltage. its a weird feeling being around that kind of voltage when the hair on your arms stand up!
 

Troll

Subscriber
This is the silica based material I used casting replacement inductor coil insulators in my G-213: https://www.mcmaster.com/#casting-compounds/=1cpov22 . I made both the molds, and actual insulators from the same material using mold parting wax for fiberglass molds. I only made one set of molds so cast each insulator separately. I then fired the completed parts, (insulators) in a kiln but don't remember the temperature or duration as was not present when this actually took place. The kiln firing wasn't really required but I wanted to see if the material would take the temperature without fracture, or shrink precluding fitment. Both were very acceptable and they are still in place today. My original insulators were breaking up from vibration of being set into and out of a truck, plus many, many hours of operation.

The price on that compound is considerably more than it was back in the 1990's.....
 

s100

New member
Based on how this thing is made I have no trouble believing Troll's assessment of the temperatures attained. Plus Hobart made these things out of porcelain for a reason and that reason is most likely heat. And if the coils do get red hot as Troll says then I think 600 degrees may be overly optimistic, if anything.

The fact that Troll has years of firsthand experience with this, and has found a lasting solution, makes his the go-to approach. The only change I might make to his solution is to look at how the insulators are made, try to determine their weakness that leads to their failure and improve on the design in some way. But that may be overkill. The fact that his solution has stood the test of time and what sounds like a lot of use is good enough for me. Thank you Troll!
 

Troll

Subscriber
No problem and glad to help. It really is easy and the cold casting materials available today can be done easily. One could use a castable resin of a silicone nature if they had original insulators much the same as I did with the silicate material. Silicone molding compound will duplicate anything if it's done right. I made my molds in two pieces meaning a top, and a bottom separately. The material readily sanded to a clean parting line for the top and bottom sections and measured very close to the original size when completed. I did try to add about 1% for shrinkage of the cured casting compound. Fiberglass mold release wax was very easy to apply via a spray can so the molds parted from the casting very easily.

Those insulators break from both the hot/cold cycles they take and a LOT of vibration from the TJD Wisconsin engine they are married to. Good engine don't get me wrong but not the smoothest one out there. Built for the long haul for sure. I'm been through mine once when it started missing on one cylinder from valve wear but I know it's got over 3K hours on that rebuild since. I need to replace the oil pan on mine as I broke one of the mounting feet loose on the right side of the engine really pissing me off good. I have another pan, just haven't got to the task yet. Used to run that machine at least six hours per day for both days of a weekend rebuilding and hardfacing ground engaging tools on equipment so it's done me right.
 

wasillashack

New member
An appliance repair shop should be able to supply something that will work. Any appliance with an electric heating element utilizes ceramic insulators to mount the elements. Electric furnaces and dryers would likely be a good source. If you can't find what you need, I have ceramic insulators from heated horse waterers that are about an inch in diameter, 3/16" thick, and have an 1/8" hole in the center,(all dimensions approximate) If you think these might work for you, how many do you need? shack@twinviewfarm.com
 

bugle

New member
Since the insulators have not only the job of separating the coils and keeping them from touching the frame, but supporting their weight so they don't slide down, I think they have to be nearly a perfect fit.
 

AngrySailor

Subscriber
Interesting... I have the same machine. Last time I moved it a small piece of the porcelain fell out. Through the screen I can see the rest spear to be in place still. It will get some attention before use. I think/hope I’m early enough to clean things up and glue the piece back in.
 

f100

New member
HMMM! So that is what those ceramic pieces were on the driveway in front of my truck a couple of weeks ago. I thought might be some resistor in my truck but couldn't imagine what or where they would have come from on it.
I had run the newly acquired g213 and test welded with it in about that spot the week before. g213 welds great but like many others can't get the AC to work.
 

bugle

New member
I pieced mine back together with JB weld and it works fine but I don't expect it to last forever.
I traced out the problem of no AC power, it seems the transformer is corroded and shorted out.
 

samstu

New member
New to forum. My g-213 had broken insulators too. Looked them over, poor design with 90 degree corner inside. I made some models in fusion360 and subsequently molds. Cast a sample last night using product listed above (Rescor-750). Claims to be stable without firing - not really. Cracked in three places during removal attempt. Very weak when green.

I used PLA for molds and any 3d printer user will immediately say this is wrong. But I used this to my advantage and burned the mold off two of the pieces with good result. Baked pieces in BBQ grill at 275 for 2 hours. Still weak and always break at that corner. Turned grill up to 500 which improved things probably to acceptable level. Subsequently tried propane weed burner - meh. Then MAP gas - yee haw. That got the pieces glowing red in a couple minutes. Took glowing piece and dropped straight into water without it fracturing - I think that'll do.

I will post models in Thingiverse (user samstu) (www.thingiverse.com/samstu/designs )so anyone can download.

Disclaimers: use at own risk, don't try using plastic model as insulator - it will melt and may cause injury. This is a substitute part made on my measurements of what my welder needed and not based on measurements of factory part - as such it's similar and not a drop in replacement. For example these are 4+ inches long and you will need two per bar for a total of 6.

I would recommend a kiln and not cowboy engineering....
 

samstu

New member
Mold mix volume: For Ceramic resin

Each piece is 30 cc

Mixture ratio for powder to liquid is 100 to 28 parts by weight.

Each insulator needs 52 grams powder and 15 grams liquid (includes a 20 percent surplus).
 
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