How to build Silverdogs Surf Pi 1.2 detector

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Paul van Heerden

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Luuk kindly helped me out with my surf pi, and fortunately there wasn't too much wrong with it. He helped me with my coil by shielding it, and also sent me some more coax, RG58. Mine was RG59 and was just not working

I now have to make my coil housing and shaft for the detector. I have drawn a pattern on wood for the coil, and I am going to cut it out and then glue the outline onto a piece of hardboard. I will then use epoxy and polystyrene beads to encase the coil into the mold. The epoxy I bought is just the same as Epidermics 372, but just R150 cheaper  :). I will take pictures as I go. I thought that I might use cling wrap in the form so that the epoxy doesn't stick to the wood.

The form that I cut out of the wood will then be used to make a mold for future coil housings. You can buy a compound that dries like rubber. You put your form into a pan making sure that it is flush with the bottom so that you don't get the liquid rubber underneath. You pour the stuff in, let it set, and then pull the coil form out. You now have a rubber mold which you can use to pour epoxy in for future housings.

The detector casing is going to be a lunchbox with foam in to keep the circuit and wires snug.
« Last Edit: May 27, 2014, 11:06 AM by landuse »
Paul

Paul van Heerden

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Last night I cut the coil shape out that I had drawn on the board. I thought tha what I am going to do is buy that rubber compound to make a mold of the form that I have cut out. I will go buy the stuff today. What you do is put the form in a dish so that it is flush with the bottom, and then you pour the stuff over it and leave it to set. You can then take the form out and you are then left with a mold that can be reused to make coils.

The white stuff you see on the form is pollyfilla. I put it around the cut edges and will sand it today. This is just to get a smoother surface than what the wood had, so that the rubber compound doesn't stick in the wood and make it hard to remove

I will post pics of the progress tonight
Paul

Paul van Heerden

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So yesterday I got the rubber compound to make my mold. When I got home I realised that I had no dish big enough to fit the coil in to pour the rubber around. I was going to have to make something. I got some hardboard and duct tape and eventually made a container that was the right size to hold my wooden form.

Mixing the hardener into the rubber glue stuff was a bit of a nightmare. It is messy and sticky, and you can be sure that you are going to throw anything away that you used to do the mixing. I eventually got it done, poured the stuff, and then realised that I might not have enough to cover the form. Jonty, my son in law, came up with the idea of sticking stuff into the rubber to try and displace some of it, making the lever rise. We had toilet roll inners, so we covered the one end with tape and stuck them in.

This morning everything was hard, so we took it all apart. The mold came out great!! I just have to trim and clean it slightly, but otherwise it looks good. Now all I have to do is actually make my coil using the epoxy. I might coat the mold with a bit of vaseline before I pour it, just to make sure nothing sticks too tight and I can get the coil out of the mold.
Paul

Tony Curnick

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Nice work Landuse,just one small issue....you should have cast a hole through the silicone mould for the cable that attaches to the coil. You may have to cast a hollow  bottom tube into the resin and feed your cable through the mounting tube....you just won't be able to adjust the angle on the coil.
Where is that five Shilling???

Paul van Heerden

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Nice work Landuse,just one small issue....you should have cast a hole through the silicone mould for the cable that attaches to the coil. You may have to cast a hollow  bottom tube into the resin and feed your cable through the mounting tube....you just won't be able to adjust the angle on the coil.

Thanks Tony. What you are looking at though is the top of the coil. The cable will be coming out of the top of the mold. I will put a layer of epoxy on the bottom of the mold, place my coil on that, and then cover it with the rest of the epoxy. The cable will come out the top. I will just have to peg it into place somewhere above the mold while it is hardening so that it comes out straight.

It will probably be clearer when I do it and post some pictures though. I am not the best at explaining :)
Paul

Tony Curnick

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Got it!!,good luck with your casting and post a pic when your done..
Where is that five Shilling???

Paul van Heerden

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So last night I got a chance to encase the coil in my mold. I am still not too sure if I like it, but I have to do some work still to get it looking nice. It is still a bit rough. The coil is completely encased in epoxy and beads, even though you can sort of see the darker shade of the coil on the underside

Just a word of caution for people doing this. Epoxy is messy and sticky and not too easy to work with. Once the coil is looking good I will start on the shaft for the detector
« Last Edit: June 02, 2014, 08:46 AM by landuse »
Paul

Paul van Heerden

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Last night I had a couple of free minutes to start on the control box. I had bought some foam from a place in town and cut it to the exact size of my lunchbox, making sure it fitted real snugly. I then had to try and decide where all the components would go. After a trying a few combinations, I thought the one I came up with would be the best.

I placed the PCB on the foam and drew around it with a marker. I then got a craft knofe and started cutting away at the foam until I had a nice pocket for it to fit snugly in. I then did the same for the battery pack. I then cut away the rest of the foam, and theis is where I think I am going to mount the dials and have all the wiring. I still have to decide if I want to mount the dials inside the box or have them poking outside. Ifthey are inside, I will have to open up each time I turn it on, but if they are on the outside, there is more chance of water getting in there. This things is not going to be waterproof, but I want it as splash proof as possible

I will post more pics as I go along
Paul

Paul van Heerden

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Last night I started mouning all the pots to the lunchbox. The volume pot had a wire that was just too short to mount next to the other one, so I just mounted it on the side of the box.
Paul

Paul van Heerden

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I managed to do some more work on the detector. I got some stiff PVC pipe for the bottom part of the shaft. I then bent the aluminium. I cut some gutter pipe for the arm rest as well.

What did take me an he to find was the plastic bolt to hold the could to the shaft. I eventually found some. They were toilet seat connection bolts. They connect the seat to the bowl.

I painted everything a nice gloss black. The bottom of the coil I covered in some marine silicone sealant, just to give it some durability. I need to hot glue the hinge onto the coil for the connection of the shaft.

Tomorrow I will put everything together. Hopefully everything lines up and is straight.

Here are some pic for you guys to look at
« Last Edit: June 14, 2014, 07:50 PM by landuse »
Paul

Paul van Heerden

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She's alive!!!!!

I am finally done, except for some final cosmetic touches. I hot glued the bracket I made onto the coil, connected the two shafts, connected the control box to the shaft, and then connected everything together.

I had a bit of a heart stopper when I put the batteries in and nothing worked, but it turned out to be a flat battery.

It works really well. I am going to have to get used to the tones, but that will come.

Thanks to Luuk and everyone else that helped with this build. If anyone wants to know how I did anything, please let me know
Paul

Louis Kriedemann

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Good for you Paul. hope you find many goodies with it

Paul van Heerden

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Good for you Paul. hope you find many goodies with it

I might be at the beach this coming weekend, so hopefully I will be able to post some finds after that
Paul

Tony Curnick

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That was a long wait and some hard slog!!....welldone for hanging in there...good luck with it!
Where is that five Shilling???

jasoncpt

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So I ordered a kit and other parts , haven't heard back from the guy as yet , how long did you guys wait for your kits and did you order them off the silverdog site ?

Metal Detecting Forums South Africa

Re: How to build Silverdogs Surf Pi 1.2 detector
« Reply #104 on: June 18, 2014, 08:20 PM »