Coil ressurection

[Peter Jones]

I recently purchased a used White's 6000/Di (older blue box model) which I think is great , it came with 8" & 10" coils , but the 8" is slightly the worse for wear , with a few cracks , no longer waterproof but still working well.
To get more life from it i could glass fibre the outside but it would look a mess . I want to repair it from the inside . Has anyone any tips on glues to use/not use ? also I do not want to disturb the coils themselves are they secure ?
The coils I have are the older white ones , are they the same as the "Blue Max" ones or are they worth considering as replacements ? If they are different internally is there any noticable performance difference?
Sorry for the long post and all the questions , need a bit of re-assurance before opening the coil.

[Carl]

Re: Coil ressurection

You can probably find a new old-stock 8" coil for very little money from a dealer who has one stuck in the back on a dusty shelf, or a good used one from ebay or the classifieds. You might post a wanted ad on some of the treasure classifieds, can probably get one for $15 or so.

If it's just the bottom that's worn out, you can slap on a coil cover. If the joint around the perimeter is cracked, I recall that you can dissolve plastic utensils in some kind of solvent (maybe PVC cement, I don't remember) and make a nice white glue out of it that does a good job.

I'm not entirely sure, but I think the older coils (6B types) will work on newer machines, but the newer coils won't work on older machines. Or maybe I have that backwards...

- Carl

P.S. - I actually have a spare 8", but I've already split it open to look at the innards. You won't damage the windings by splitting the seam and pulling the bottom shell off.

[Reg Sniff]

Re: Coil ressurection

Hi Peter,

I have not looked inside the type of coil you are referring to, but many of the manufacturers use a conductive paint on the inside for shielding.

So, to repair it from the inside you would probably have to remove the paint and then replace it. Care has to be taken to maintain the same resistive value across the surface as the original.

As for the technique to repair them from the outside or inside, most of the coil housings are made out of ABS plastic. One of the techniques of sealing the upper and lower half together is to disolve some ABS plastic in MEK (methyl ethyl keytone)until it is a slurry. Then you can paint or dab it on the cracks.

A friend of mine who makes coils on a regular basis uses a cheap syringe to force the slurry into the seam of the coil halves. I know that some of the major manufacturers do or did use this process. This is what Tesoro commonly did with there older white coils.

Once it is dried it is basically as strong as the surrounding plastic. Once done, it probably won't be pretty, but this should seal most of the cracks.

You can use acetone also to dissolve the plastic, but it takes longer to dissolve and to dry. MEK seems to work the fastest and the best.

As Carl mentioned, some people have used certain plastic forks instead of ABS plastic and had success. Personally, I prefer to use another small piece of ABS plastic. Just cut it into slivers before adding it to a small quantity of MEK and wait a few hours. I normally let it dissolve overnight before I use it.

Reg

[Peter Jones]

Re: Coil ressurection

Thanks for the info. Carl and Reg .
It is the top part of the housing that has started to crack around the "glued" join.
I'll probably go for an external repair as it seems easiest, it'll probably look a bit ugly but as long as it works and keeps the water out then I'll be happy with it.
I had a suspicion that the widescan coil won't work with my old 6000 (series 3) but will the blue max coils not work with it? I was thinking that any coil that worked for Classic 1/2/3 would also work with these?

[Carl]

Re: Coil ressurection

OK, I have a Blue Max 600 (6") coil for my XLT, so I tried it on a 6000/di Series 3. It works, but the VDI numbers are off, everything reads low. So a quarter reads as a penny, a nickel goes into the iron range. I also tried the std XLT 9.5" coil on the 6000s3, same results. So I tried the old 6B 8" coil on the XLT, and everything read high. Thus, the coils are interchangeable, but VDI's will not read correctly.

In looking around, I have the 8" coil off my 6000di/s3 that I would be willing to sell you, but I prefer that you first try to fix yours. If the repair does not work then email me. It is fairly well used but no cracks or holes. I would eventually have to replace it, but no hurry and I occasionally run across deals on coils.

- Carl

[Peter Jones]

Re: Coil ressurection

Thanks for the offer Carl , but I'm just going to do an external repair - the cracks aren't too big so I'm sure I can make it waterproof without making it excessively heavy. A suitable replacement will surely come along in due course but no rush, I recently missed out on an older 6" (5.3"?) coil on e-bay ; they do turn up now and again.
Some people may be wondering why I am bothering with a machine over 10 yrs old , but I think its brilliant and get on with how it works. I find no difference in balance or IDing with 8" or 10" coil fitted and I am getting used to the fast swing in GEB Disc mode , I hope to keep this detector for a long time and keep it in a reliable condition.(any tips on getting the best out of it will be much appreciated)

Thanks once again ,
Peter

[Carl]

Re: Coil ressurection

I would suggest an extended arm rest as these old-style detectors were hard on the wrists. In fact, if you can work metal you might look at making up a new aluminum stem like that used on the newer 6000/ProXL machines. Would make fast swinging MUCH easier, especially with the box near your elbow.

- Carl

[Carl]

Re: Coil ressurection

Thanks, Reg... couldn't remember the details. What do you use for MEK? I believe PVC solvent and PVC cement are mostly MEK, probably the solvent is the better choice.

I also need to repair a coil, a Tesoro 8x15 DD "surfboard". The seam split open.

- Carl

[Peter Jones]

Arm rest

This one already has an arm rest fitted , looks like an official option , but the coil seems "light" , I have to push down on the handle to "keep the coil to the soil". It's not too bad but a full day of furious swinging would probably see me re-styling the stem along the lines of the 6000 PRO for better balance.
I have developed a "lazy swing" which is fast enough without too much effort (my other motion machine needs just a tremble by comparison for the same in-air depth but disc. is not as good and it has no ID)

[Reg Sniff]

Re: Coil ressurection

Hi Carl,

MEK can be purchased at most large hardware stores. I even bought some at a WalMart in a quart container about 2 years ago. Don't know if they carry it now. It goes by the name of MEK.

I have used PVC solvent also when bonding two pieces of ABS together. I did that a few days ago when I changed connectors on one of my PI's to a style I can readily find. The connector I used was smaller so I had to add a piece of plastic with a smaller hole to the back of the detector. Worked fine.

Make sure you disolve the plastic using a glass container. Best to have a jar that seals so it will keep for a while.

Reg