Surf PI Beach test...

[plumabob]

I use polystyrene 12 x 24 sheets. I got them off ebay awhile back 25 sheets of 1/16 for 50 bucks shipped. The guy who sells them has no more. I recently asked. MEK will dissolve styrene. You make a slurry with it. It's what the coil manufacturers use to hold their coils together. I use it to bond plastic pieces to weaker areas inside my shells for strength and to attach the ears which are solid polystrene. Also if you develope any stress cracks the slurry seals it right up permanently. Like I said before I want to make the lightest coils I can and use as little epoxy as possible. Most are well under a pound.

Bob

[dfbowers]

I use polystyrene 12 x 24 sheets. I got them off ebay awhile back 25 sheets of 1/16 for 50 bucks shipped. The guy who sells them has no more. I recently asked. MEK will dissolve styrene. You make a slurry with it. It's what the coil manufacturers use to hold their coils together. I use it to bond plastic pieces to weaker areas inside my shells for strength and to attach the ears which are solid polystrene. Also if you develope any stress cracks the slurry seals it right up permanently. Like I said before I want to make the lightest coils I can and use as little epoxy as possible. Most are well under a pound.

Bob

My coils have been coming out at 13 oz.. all epoxy and fiberglass fill.
I will let you know how my next one comes out with a foam fill.

Thanks!
Don

[plumabob]

I don't use anything smaller then a 13 inch coil for beach hunting. The challenge was to make a large coil light and strong. My 13 x 11 DD weights in at 15-16 ounces. I'm guessing this mono will be a bit lighter.

Bob

[plumabob]

13 x 11 mono is finished. Had problems getting her to run smoothly at the lowest delay settings. I ended up using a 1.5K damping resistor to settle things down. Now she runs as smooth as silk. In house it is a bit deeper then the 9.5 and still very sensitive to small gold jewelry. As soon as I can get down to the beach I will write a follow-up report.

Bob

[dfbowers]

13 x 11 mono is finished. Had problems getting her to run smoothly at the lowest delay settings. I ended up using a 1.5K damping resistor to settle things down. Now she runs as smooth as silk. In house it is a bit deeper then the 9.5 and still very sensitive to small gold jewelry. As soon as I can get down to the beach I will write a follow-up report.

Bob

Wow.. 1.5k seems really high. I would have expected 400 - 600 ohms... but I guess as long as it works!

Can you post a pic of your coil? Also, did you have to make the shell in pieces??

Don

[plumabob]

When making my GoldQuest coils years ago a 1.2 - 1.5 damping resistor was used so this is similar. It was working at 8-9us but it was ringing, the 1.5R calmed everything down. I installed a pot and kept adjusting until she ran smooth. Here is a pic of my Surf PI 13 x 11 coil. This one finished off a little rougher then most but who cares it works great! Coil is formed in 3 pieces the main shell, the ears and then the bottom.

[dfbowers]

When making my GoldQuest coils years ago a 1.2 - 1.5 damping resistor was used so this is similar. It was working at 8-9us but it was ringing, the 1.5R calmed everything down. I installed a pot and kept adjusting until she ran smooth. Here is a pic of my Surf PI 13 x 11 coil. This one finished off a little rougher then most but who cares it works great! Coil is formed in 3 pieces the main shell, the ears and then the bottom.

Well that doesn't look too bad at all!

So, did you make a "clam shell" with matching top and bottoms parts like Hayes does?
Mine show imperfections as well, but like you said, as long as it's functional. After all, we are just home builders in the end.

One thing that helps. When (if) you run out of plastic sheets, get ahold of ABS with a "hair cell" texture. It tends to hide little imperfections as well as scratches that will occur later on. It's the same texture that you can find on White's coils.

[bernte_one]

here my findings of 2 hours beach hunt



Uploaded with ImageShack.us

[Qiaozhi]

When making my GoldQuest coils years ago a 1.2 - 1.5 damping resistor was used so this is similar. It was working at 8-9us but it was ringing, the 1.5R calmed everything down. I installed a pot and kept adjusting until she ran smooth. Here is a pic of my Surf PI 13 x 11 coil. This one finished off a little rougher then most but who cares it works great! Coil is formed in 3 pieces the main shell, the ears and then the bottom.

Is this a metal bolt connecting the coil to the stem?
Also, shouldn't you have used shielded cable?

[dfbowers]

Is this a metal bolt connecting the coil to the stem?
Also, shouldn't you have used shielded cable?

I have been guilty of that.. Stainless steel seems to be OK though. Nautilus detectors come that way!

[plumabob]

Ok boys lets all calm down.... Nylon nut and bolt is used and cable is shielded, no way it would work as good as it does without it.

Bob

[Qiaozhi]

Ok boys lets all calm down.... Nylon nut and bolt is used and cable is shielded, no way it would work as good as it does without it.

Bob

Hi Bob,

We were just concerned that you may not be getting full performance from your detector.

[plumabob]

You worry more about me then my wife does and I thank you for it! She also demands full performance!....LOL

[silverdog]

You worry more about me then my wife does and I thank you for it! She also demands full performance!....LOL

[bernte_one]

i have tested the surf pi with a plastic shaft and also aluminium it makes no differnce
but decided for plastice because i BELIEVE it is better