DYI Thermaltronics/Metcal sleep stand mod question

[Jamieson]

I've got a Thermaltronics SHH-4 stand with a microswitch but I'd like to convert this over to the newer style sleep stand with magnets.  Playing around with a rare earth magnet from a hard drive and holding it near the tip doesn't seem to have much effect on tip temperature.  Do the sleep stands use a pair of magnets on either side of the tip?  How strong/close do the magnets need to be to tip to effect the curie-point of the alloy material?

[MosherIV]

Do the sleep stands use a pair of magnets on either side of the tip? 

Yes, that is correct.

How strong/close do the magnets need to be to tip to effect the curie-point of the alloy material?

Do not know how strong the magnets are.
There is a gap of around 30mm between the magnets.

[thm_w]

See the photo below, taken from the back of the handle rest.

They look to be standard older HDD magnet size and strength (about 3mm thick). The actual tip extends about 2-3cm beyond this plate, so presumably the magnetic field flows through the outer cyclinder of the cartridge.

[Jamieson]

Thanks for posting this info!  Those magnets look closer and more powerful than the ones I was experimenting with.  Also the hard drive magnets I was using have a N and S pole on each face -- this probably works well for a moving voice coil actuator, but it not ideal for establishing a uniform magnetic field around the soldering iron tip.

I'm planning on picking up some different magnets and testing a few different configurations, maybe 3D print a bracket that can be dropped into Thermaltronics and Metcal stands.  We've got a bunch of older Metcal stations at work and I'm always finding irons left on, cooking away destroying tips.

[Jamieson]

Here's an update on my sleep stand mod for my Thermaltronics TMT-2000S system.

The stand I've got is the SHH-4 model.  This stand has a microswitch that closes when the handle is placed in the stand. When the CC-1 "connection cable" is installed between the stand and the TMT-2000S/TMT-5000S power units the station will completely power down when the handle is resting in the stand.  (Note that the CC-1 is just a 3.5mm male to male "stereo cable".)  I'd rather not completely power down the system every time the handle is resting. A sleep stand will reduce the tip temperature by about half, according to Metcal: http://blog.okinternational.com/why-use-a-soldering-sleeper-stand

First, the top part of the stand is separated by removing two screws from below. Next, I removed the microswitch assembly and installed a pair of rare earth magnets that were salvaged from a hard drive.  These strong suckers measure 32mm x 20mm x 10mm thick. Unlike most hard drive magnets these are pretty thick and they have only one pole on the largest faces. The magnets were installed in the stand so that they were repelling each other. A bit of RTV helped hold them in place.

I tried smaller less powerful magnets and they weren't very effective on my TMT-2000S station. (These smaller magnets were however effective on the Metcal 13MHz stations though -- maybe the curie-point alloys are different in 13MHz and 470kHz inductive systems?)

I don't have a thermocouple to take a direct temperature reading at the tip, but it's clear that when sleeping the tip temperature drops significantly, just about to the point where 60/40 solder begins to melt, which I'd guess is in the 180C-190C range.  Remove the handle and it's back up to full temp in a couple of seconds. The Kill-a-Watt shows:

Handle idle, off the stand: 10-11W
Handle idle, in the stand: 6W
Soldering big stuff to power planes: 25W

So, anyway, it seems to work fine. It's a cheap way to transform the basic stock Thermaltronics stand into a sleep stand on the TMT-2000S and TMT-5000S systems. (The TMT-9000S comes standard with the sleep stand.)

[the_mihalich]

Ps-900 owner question:
I have a station with ws1-ns which means as I believe a “non sleeper”.
I checked the power consumed by station at rest and it’s always ~20watt (i’m from 240V Russia) and resting tip temperature is ~310°C.
I disassembled the wand stand and found that there are two cavities, one on each side of resting iron tip which can hold 22*18*3mm big magnet (around 7/8”*3/4”*1/8”)
I found such magnets (N38 material, and it has 4,54kg of lifting power ~10lbs)
and installed them into stand cavities in all possible ways:
N-S (tip) S-N same pole towards tip
S-N (tip) N-S same pole towards tip
S-N (tip) S-N different poles toward tip
None of these setups reduced idle temperature of iron or made idle power consumption lower.

So I wanted to ask a ps-800 or ps-900 owners with sleeper stands to do the following:
- measure a sleeping and idle power consumption.
- open a stand and check for magnets. How big are they?
- what is their position? Same pole towards the tip or opposite poles towards the tip?

I see the recommendation of 10mm thick magnets and of course I can buy or salvage such beasts somewhere, but there is no room in original stand for them. So I really want to know how original ps-900 or ps-&00 sleeper stand is made and which magnets are there.

[the_mihalich]

Anybody?

I sourced evil powerful magnets and burned my fingers during attempts to make it sleep - no luck.
I clearly understand the principle of “how it works” but still can’t make it sleep and go for lower temp in cradle.

Another question then: does anybody have a ws2cb cradle part from metcal ws2 stand? If yes can you show the magnets there? How they are arranged?

[Everbrave]

Any update on the placement of the magnets in WS2?

[thm_w]

Any update on the placement of the magnets in WS2?

I would guess they are in the walls pointing inward, I think you can see a split in the mold in the images. Anyway, the best thing to do, IMO, is grab a watt meter and some magnets and play around. You'll understand it better that way.

With the normal iron you can get away with just a few small magnets. I think the ones in the OEM stand are probably a bit overkill, though easy to source from old hard drives.

I have notes on the tweezer here: https://www.eevblog.com/forum/reviews/hakko-rf-soldering-tweezers-fx-1003-$240/msg4215136/#msg4215136

Attached is what I use on my 3D printed holder.

[Everbrave]

Any update on the placement of the magnets in WS2?

I would guess they are in the walls pointing inward, I think you can see a split in the mold in the images. Anyway, the best thing to do, IMO, is grab a watt meter and some magnets and play around. You'll understand it better that way.

With the normal iron you can get away with just a few small magnets. I think the ones in the OEM stand are probably a bit overkill, though easy to source from old hard drives.

I have notes on the tweezer here: https://www.eevblog.com/forum/reviews/hakko-rf-soldering-tweezers-fx-1003-$240/msg4215136/#msg4215136

Attached is what I use on my 3D printed holder.

this is what im trying to do with two strong magnets from a 3.5" HD; still no luck

[thm_w]

this is what im trying to do with two strong magnets from a 3.5" HD; still no luck

Even with one HDD magnet it should be easy to saturate the tip. Set the iron down on a safe surface, hold it with something heavy maybe, just bring the HDD magnet up beside it and the power will drop.

In this case 23W -> 16W.
If you want to compare to the idle power of just the station, unplug the tip and measure.

[Everbrave]

this is what im trying to do with two strong magnets from a 3.5" HD; still no luck

Even with one HDD magnet it should be easy to saturate the tip. Set the iron down on a safe surface, hold it with something heavy maybe, just bring the HDD magnet up beside it and the power will drop.

In this case 23W -> 16W.
If you want to compare to the idle power of just the station, unplug the tip and measure.

Thank you for Kindly responding as always
Since I don’t have a wattmeter, I measured the current (rms) at nominal 240V (232rms to be exact), as follows:
1) SP-200 heating up at 212mA then settles at 90mA
2) SP-200 in the Workstand of the WS1 of MFR-1110, 83mA … knowing that WS1 is not optimized for the SSC cartridge.
3) MFR-1110 heating up at 420mA and settles at 150mA
4) MFR-1110 in its WS1 Workstand, 124mA

Now, bringing the SSC cartridge of SP-200 as close as possible, approx. 0.5-1mm, to one HDD from the 3.5” disc drive, the current sinks to 83mA which is approximately the same as in the WS1.

My conclusion is two fold:
- the power saving isn’t much, certainly not 50%, after the first phase of heating up has finished.
- the DIY magnet should be very close to the cartridge to the cartridge (to achieve a high field strength), which poses a construction challenge. The wisdom is, should I need an auto sleep Workstand for the SP-200, it’s probably better to spend CHF 40.- and buy the WS2 from Farnell

Thanks

[thm_w]

Yeah correct its not a huge power savings compared to conventional systems that shut off, its more that temperature of the tip drops, so the tip lasts longer.

1mm distance is not necessary though, I can get full power savings from maybe 8-10mm away with HDD magnet, go to the edge not the middle.

But now you made me realize you might have better luck with something other than a HDD magnet, as they are not optimal: https://www.reuk.co.uk/wordpress/wind/hard-disk-drive-magnets-for-wind-turbines/
Get some normal axially magnetized (top/bottom) flat magnets and those should work better.

[Everbrave]

Yeah correct its not a huge power savings compared to conventional systems that shut off, its more that temperature of the tip drops, so the tip lasts longer.

1mm distance is not necessary though, I can get full power savings from maybe 8-10mm away with HDD magnet, go to the edge not the middle.

But now you made me realize you might have better luck with something other than a HDD magnet, as they are not optimal: https://www.reuk.co.uk/wordpress/wind/hard-disk-drive-magnets-for-wind-turbines/
Get some normal axially magnetized (top/bottom) flat magnets and those should work better.

Thanks for the additional information.
I separated the magnets from their steel guards, tried tens of placements for hours, burnt fingers, performed a rain dance in vain 😀
I’m done with playing. BTW, the effect with the steel guards is better than without.
My advice to other readers who own the SP-200, buy the WS2 or just keep the -no-sleep- stand; not worth the effort.
My personal decision is the later; will keep the SP-200 to be able to use the SSC cartridges or , just may, sell it since I’m very happy with MFR-1110.