TESORO GOLDEN SABRE

[simonbaker]

Some formers.. I need to start making them out of a plywood as pine tends to warp when heat is applied to one side. Also, they tend to crack easily.

Don

I would be interested in seeing the whole process of making the coil housing that you use, maybe in a separate thread. The wooden forms look like they were crafted with much care.

Regards,

-SB

[mikebg]

Some formers.. I need to start making them out of a plywood as pine tends to warp when heat is applied to one side. Also, they tend to crack easily.

Don

Don, it is wery dificult to make formes of plywood. Better impregnate wooden formers with epoxy resin, but you should warm the wood about 100 deg. C in advance to absorb the resin.
Mike-BG

[dfbowers]

Thanks for the advice on making formers. I will try covering them with resin first to see if I can prevent warping. I will put together my process making coils and post in the "mechanical" section near the bottom of the forum.. I think that it would be more appropriate to post the whole thing there.

[sajkel]

http://analog.chipfind.ru/search.htm?s=LM308 Who tasted

[Mullihaka]

Phase shift vs residual voltage?

I have a request for all members who have a TGSL which has detection distance of 30cm or more for a (1 eur) coin in the air.

Would you be so kind and measure:
- the phase shift between TX signal and RX signal (at pin 7 of the LF353)
- residual voltage at the preamp output (pin 7 of LF353)

I'm trying to figure out what kind of combination of the abovementioned I should try on my TGSL to get it beyond 20cm.

I can get the phase shift of 20 degrees or residual voltage of 450mV, but only one at time. Having either of them "as it should", the other jumps far away.

All results appreciated,

Andy

[Carl-NC]

Some formers.. I need to start making them out of a plywood as pine tends to warp when heat is applied to one side. Also, they tend to crack easily.

This is due to moisture differential. Apply a couple of coats of polyurethane, or fiberglass resin or (as Mike suggests) epoxy. Make sure whatever you put on it can withstand the heat.

- Carl

[mikebg]

DRYING with MICROVAWES

This is due to moisture differential. Apply a couple of coats of polyurethane, or fiberglass resin or (as Mike suggests) epoxy. Make sure whatever you put on it can withstand the heat.

- Carl

There is an ideal instrument to remove moisture from the wood and warming the wooden formers before you put on epoxy resin. This is the microwave oven. For better results do not put oven at full power. Warming thus wood greedily absorbed the epoxy resin. We have not tried to put coated with epoxy wood again in the microwave with the purpose of the resin to solidify rapidly, but microwave heating of ferrite cores is used for quick stick with epoxy of coils and transformers. Perhaps heating of such devices with ferrite cores in a microwave oven is the only method of ripping off successful and use their components again.

[0cool]

Please help

On my TGSL I accidentally weld the GND and -6, 25V. Now detector works, but with reduced sensitivity. Voltages are okay -6.25 V and 7.99 V, what should I check first? I have no oscilloscope.

[simonbaker]

On my TGSL I accidentally weld the GND and -6, 25V. Now detector works, but with reduced sensitivity. Voltages are okay -6.25 V and 7.99 V, what should I check first? I have no oscilloscope.

Please give a complete description of your project; what schematic; what pcb; photos of your PCB (both sides) and your coil; how you built coil; coil parameters (size, resistances, inductances); how you nulled the coil; any parts substitutions?

What air distance can you detect at? What do you use for target (1 Euro coin is best)?

A video with sound of your air tests with 1 euro coin might be helpful.

Regards,

-SB

[0cool]

Please give a complete description of your project; what schematic; what pcb; photos of your PCB (both sides) and your coil; how you built coil; coil parameters (size, resistances, inductances); how you nulled the coil; any parts substitutions?

What air distance can you detect at? What do you use for target (1 Euro coin is best)?

A video with sound of your air tests with 1 euro coin might be helpful.

Regards,

-SB

It is the basicschematic TGS without notch part. The values of the components respected the original unit except TIS75, it's a 2n4393. The PCB is modified ivconic's 1265 pcb to match the original scheme. Coil by "TGSL - complete details". Coil nulled on pin 7 LF353 with DMM. On 1 € in air 36-38cm. Now, after my mistake about 28cm. I mistakenly merged pin3 and pin4 on the lower LM308. Currently I am not in a position to make some photos or video clips. Perhaps in these days later. Before the problem occurred there was very little instability when the pot of the sensitivity set to max, now it's all quiet and sensitivity is much weaker.

[simonbaker]

It is the basicschematic TGS without notch part. The values of the components respected the original unit except TIS75, it's a 2n4393. The PCB is modified ivconic's 1265 pcb to match the original scheme. Coil by "TGSL - complete details". Coil nulled on pin 7 LF353 with DMM. On 1 € in air 36-38cm. Now, after my mistake about 28cm. I mistakenly merged pin3 and pin4 on the lower LM308. Currently I am not in a position to make some photos or video clips. Perhaps in these days later. Before the problem occurred there was very little instability when the pot of the sensitivity set to max, now it's all quiet and sensitivity is much weaker.

Need clearer explanation...

Did you get 36-38 cm (seriously?!) before, or after soldering (merging) pin3 and pin4 together? Which way is better?

And can't you just unsolder the pins?

Regards,

-SB

[Cyclonite]

Wonderful work @dfbowers !

Here you have an eBook written by Vinvent J. Ginger about a DIY Plastic Vacuum Forming Machine, which may be of interest to those who would want to build there own Coil Housing.

Also, thank you very much to all who have participated in Designing and Refining the Tesoro Golden Sabre Metal Detector.

Excellent Job!

The Refined and Working Finished Project by @Ivconic can be found here:

TGSL - Complete Details, posted by @Qiaozhi's and Designed by @Ivconic:
http://www.geotech1.com/forums/showthread.php?t=15710

And here you have the eBook:

Secrets of Building a Plastic Vacuum Forming Machine - By Vincent R. Gingery (1999)



* Author: Vincent R. Gingery
* Publisher: D.J. Gingery
* Number Of Pages: 106
* Publication Date: 1999-07
* ISBN / ASIN: 1878087223
* EAN: 9781878087225
* Binding: Paperback
* Manufacturer: D.J. Gingery
* Format: PDF (OCRed)
* Size: 4.13 MB

Description by Vince Gingery:

Geez... you should see the samples of vacuum forming Vince sent me! I can show you a photo but until you hold the formed sheet in your hand you don't know how powerful this thing is. It's professional quality. And you can build it for far less than you can buy a machine. And since Vince will reveal his experiences, you should be able to adapt the design and scale it up or down. The best way to describe the machine is to let Vince do the talking:



"The machine is built almost entirely of angle iron and flat bar. Construction is simple, with some welding being required. Being built on wheels makes the machine easy to move from place to place. It has a unique clamp frame that works very well and the adjustable work surface (platen) is a real asset. The machine has a 12" x 15" forming area, and I have formed ABS plastic up to 3/16" thick with it. I believe the machine would form 1/4" as well. Of course, thicker plastic takes longer to reach forming temperature.

The machine operates on a 20 amp 120 volt circuit using a 1500 watt, 120 volt heating element. Temperature is controlled by an infinite range switch mounted in the control panel. Everything required to build the machine is easy to find except for the 120 volt heating element. It's an oven replacement element, and ... will sell for around $30.00 plus shipping...



The vacuum for the machine can be supplied by either an air venturi pump or electric vacuum pump in conjunction with two storage tanks. I am mentioning the air venturi pump as one alternative because it's so cheap. Only $12.99 through Harbor Freight and it pulls 4.2 cfm per minute taking about 4 minutes to pull a 25 kg vacuum on my two 11 gallon tanks. Not too shabby for the price. In order to use it though, you need to have an air compressor capable of maintaining 90 psi.. The other and better alternative is an electric vacuum pump. The electric pump I have pulls 6 cfm taking about 2 minutes to pull a 25 kg vacuum. Although twice as fast, the electric pump costs close to $300.00."

You oughta have a copy of this... for your reference library if nothing else!

Note by @Cyclonite:

You can also use an old Refrigerator Motor as Vacuum Pump, connected to a Buffer Cylinder for fast release of Vacuum Pressure. These Refrigerator Motor Pumps work slow, so you will have to suck a Buffer Cylinder vacuum (empty CO2 Fire Extinguisher etc.) for use with large cavity suction products. The faster you can suck a vacuum, the less heat you will have to expose your plastic forming material to.

Download (RARed 3.80 MB):

Secrets of Building a Plastic Vacuum Forming Machine - By Vincent R. Gingery (David J. Gingery Publishing LLC - 1999) 56s (d).pdf

iFile.it Download Link:
http://ifile.it/td75bo4

or (optional)

MegaUpload Download Link:
http://www.megaupload.com/?d=JP2EVEO7

No Password Required !

Enjoy !

Robert

[dfbowers]

Cyclonite,

Thank you for the information! I have a Harbour Freight about 2 miles away.

Don

[Cyclonite]

Cyclonite,

Thank you for the information! I have a Harbour Freight about 2 miles away.

Don

@dfbowers,

You are welcome!

And how about a Scrapyard!

Or you may become a Dumpster Diver like me It's rewarding, fun, and an excellent source in finding the right equipment and materials really cheep.

Cheers!

Robert

[Cyclonite]

Edited Placement OC

For those of You who would like to Print the Components on the TGSL PCB, You may now also chose for the slightly Edited Version in which the Outer Lines have been Erased.

The Original Working TGSL Project can be found here:

TGSL - Complete Details, posted by @Qiaozhi's and Designed by @Ivconic:
http://www.geotech1.com/forums/showthread.php?t=15710

Originally in PDF-Format, and now in JPG-Format !

Original Placement OC by @Ivconic



Edited Placement OC




With kind regards,

Robert

Placement OC in JPG-Format.zip