Repair of broken mounting tangs on 11" coil?

[bklein]

I will be receiving an 11" coil with the shaft mount tangs broken off. Any idea on the best way to fix it? Is there a special type of plastic to use and/or glue?
I won't be getting the broken off pieces.

 

[trojdor]

Read this thread through to the end...

Be sure to follow the safety suggestions.

edit .....


mike

 

[IDXMonster]

Kind of the same idea as welding metals,which I have much experience with as an auto mechanic...you have to find a way to get both parts into a liquid state so they bond on a molecular level,not just an adhesive bond. Starting with plastics that are alike is key....and should yield the best results. Don't use any kind of bonding agent with metal particles in it of course,as it may upset the coils null. And be careful not to get that nasty ass MEK on your skin or elsewhere!
Please be sure to post a pic of your repair as others can use the info as to what worked in that situation. Congrats on your future Pro coil!

 

[bklein]

I don't know plastics well - what kind of plastic are the coil tangs on a CTX coil?
So I just grind down the existing base and then apply the MEK/same plastic goop while holding 2 squares of same type of plastic (or a channel cutoff) in place?

 

[jas415]

I did a Google search "repair broken detector coil mounts' and got maybe a zillion hits. In looking at a few I thought the simplest, maybe a tad longer to do, was to locate some thick 90 degree plastic, carefully grind off the broken ear down flush,and mount the 90 degree plastic using some of the 'glues' mentioned. I dont know if I would drill the hole first or last. Several of the 'fixes' in the search did that. There was one hit that showed a complete new ear mount base, that after carefully ginding off the entire mount area a 'new' 2 ear mount ws attached with a larger base and thicker ears. Seems to me the 'ear' would be more likely to fail if repaired at the original break. Putting a new 90 degree thick plastic there may make it last forever. Doing that may not require a new bolt either, but that shouldnt be an issue anyway.

Edit.No links to other forums allowed

 

[bklein]

I have been attempting to glue plastic to plastic for years and usually fail at it. All the super glues, epoxies, jbwelds, etc. for the most part fail on stress areas - because of the reason it failed in the first place - too much stress or the plastic is degrading. That fixit doodad in your middle link gave me a good idea though - I'm going to have my friend do a 3D print of one for this coil. Still I need to understand which type of plastic would be best for this and what to glue the two together with. I've never used MEK but it seems very useful and succesful for joining coil housings. I'm going to experiment with it after reading more.

 

[cjc]

MEK definately the way to go.
cjc

 

[bklein]

MEK is illegal to sell and probably have in Orange and LA counties here in CA.
San Diego may be ok though.

 

[utahshovelhead]

I've used the JB weld to recreate a loop bolt hole before. In fact i actually made the bump or tang completely out of the goop, molded it close to what I wanted then used a grinder and drill to make it fit. I did not use a third piece of materiel, just made my part out of JB weld. It took a little time, did not look great but worked reasonable well. Yes I over did the areas that were not in the way so that i had lots of area traction to attach to.

It never broke and I used it on and off for probably a year. Sold the loop later.

Lets see what you come up with.

good lluck.

 

[Foiled]

I used JB Weld on my pinpointer to glue a chair leg cap on where a hole wore through the tip, it says it has metal in it and I tested it and my detector, neither found any trace of metal, it didn't seem to affect it at all. That stuff is strong.

 

[robinb]

here you go

https://youtu.be/SKHt31WrJBA

 

[brother steve]

I have had really good success welding plastic with acetone. Not as toxic as others. May take a few coats. You can get it at lowes .

 

[Jim Koski]

Look on youtube superglue and baking powder!
Amazing chemical reaction where you can actually mold a
new portion of a damaged part and drill it or whatever!

 

[robinb]

Yes, seen that, just not sure its upto the job.

 

[bigelow]

I 3d printed some for my spare coil but have yet to affix them

I may be able to print you one and send it to you if you want to try still experimenting with different plastics but ABS should be strong enough.

 

[sgoss66]

VERY cool stuff, bigelow!

I will add one thing here that may be of help...

IF you know the two materials you are bonding, I suggest a call to the Henkel corporation, business division. They are the makers of Loctite products. During my research for producing my CTX rods, I had several very long, detailed conversations with their technical/engineering group, and they were immensely helpful in educating me, and helping me to find the proper, ideal Loctite adhesive for the materials I am bonding, and the application for which I'm using the materials. If you know the material that the exterior of the coil is made of (I'm sure someone does), and if you know the material you will be using to make your "coil tangs/coil ears" with, then the guys at Loctite/Henkel will help you choose the proper adhesive for that application.

Just a thought...

Steve

 

[robinb]

I 3d printed some for my spare coil but have yet to affix them http://md-hunter.com/wp-content/uploads/2017/02/coil-repair-with-3d-printer-new-ears-01.jpg I may be able to print you one and send it to you if you want to try still experimenting with different plastics but ABS should be strong enough.

Could you email the file, I have a 3D printer.

Great ideas

 

[bklein]

I bought a black pvc pipe and cut a section off it, made a cut in it, and then heated it up with a heat gun to form a part just like in that photo.
I then glued it to the coil housing - but I don’t remember what glue. I described it on another forum, but it won’t come off. If it does I just try a different glue...
I think I used JBWeld and then either painted it or covered it with pvc glue. edit

 

[bigelow]

sent you a pm

I 3d printed some for my spare coil but have yet to affix them http://md-hunter.com/wp-content/uploads/2017/02/coil-repair-with-3d-printer-new-ears-01.jpg I may be able to print you one and send it to you if you want to try still experimenting with different plastics but ABS should be strong enough.

Could you email the file, I have a 3D printer.

Great ideas

 

[robinb]