made a new tiny heatblock for reflow soldering

Flashlight Modding and DIY Parts
1

In this thread sac02 showed how he made his heatblock using these ultra-cheap 3D printer heaters to make a heat block for reflow soldering, after a suggestion of mrheosuper.

So I made my version.

Of course not everything went smooth, i.e. notice the many not so straight angles ;-) , and one heating element was DOA, I'm glad I tested them first before I hammered them (bit of arctic silver) into the 6mm holes that I made in the aluminium block. Come to think of it, tip: drill the 6mm holes through the block to the other side so you can remove an element when it is dead (I did not do that so I just hope they keep working)

And I first had no aluminium shield against the wood. And after the block had been 240 degrees C. for a while, the wood began to blacken where the (free hanging on one bolt) block was bolted into the wood. I should not have gone for one M5, it passes way too much heat, two a bit longer M2 bolds on both sides would have been smarter. And I may had better avoided wood altogether probably. So the heat shield is not so much for radiation shielding, but to spreaden the heat that comes via the bolt. Now at 240 degrees the wood carbonises a lot slower, but I expect it to gain character fast! ;-)

You can see where the wood had burned, therefore I added aluminium on both sides from the bold.

I made the sides of the block black with engine paint so I can measure the temperature with my (cheap but works well) infrared thermometer.

So here the block is 234 degrees steady state, which is a great reflow temperature, it takes 18 minutes to get there. This is at 3.2 A and about 6V at the block (the two elements are parallel, the leads are long and not so thick), so about 19W. When I place a 20mm Noctigon board on the block, the temperature fast drops 10 degrees, the temperature then recovers in about a minute, sounds fine to me.

At the outside of the bolt I attached a bit of black aluminium too to wick away some more heat, and that becomes disturbingly hot too (let's see how long the wood lasts ):

I'm pretty happy with this thingy, it works well for what I want it for (reflowing leds on boards, and reflowing components on driver boards, I may add a video of a reflow later).

I would change a few things here and there next time, and who knows how shortlived these cheap heating elements are, but at least it was fun to make :-)

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edit: a one-handed (thus a bit un-handy) video of a XP-L reflow. I noticed that it is hotter than my usual reflow block, I may lower the temperature a bit next time:

2

woah, drill a hole to fit 16 and 20mm MCPCB
pump the voltage up to 12V for fast heating
i even pump the volt to 24V, 100W, over 500*C(guess, was red hot), and the element still working more than 5 minute

3

Cute. :slight_smile: Nice work :+1:

4

very nice!

5

Great job.

Looks far more elegant than my method of reflow soldering (stick star in wooden clothespin. Stick clothespin in small table vise. Hold soldering iron tip to bottom of star with left hand while using right to manipulate tweezers. Afterwards lap off any solder stuck to the bottom of the star with a file)

6

This is brilliant. Now I have to order some of those heaters :smiley:

7

Very nice

8

Very nice djozz. Only one question this time. Does the girlfriend like it? :slight_smile:

9

Well, I showed it to her and she actually said it was cute :partying_face:

10

Well thats a win. Take them when they come. :slight_smile:
It may have been the incense smell from the charing wood?

11

Charred oak does smell nice :slight_smile:

12

Very cute indeed :slight_smile: . Now I have to make one for myself :smiley: .

13

I did similar last month, here:

https://budgetlightforum.com/t/-/43857

I’ve updated mine from the “wires everywhere, insulated by a oven mitt” version I posted. I’ll take some pics of my updated version tonight.

I made mine wide enough to easily hold 2 two MCPCBs, but not much bigger. That way I can easily do a quick LED swap, but I keep the AL block small to reduce heat loss through surface area. Your block is thicker than mine, which I think is good - the stock I had available on hand was only 0.5inch thick.

I use a laptop power brick supplying one of those CC/CV buck modules, with a PWM module in line for easy adjustability. I like that it has it’s own power supply, so that I don’t have to dedicate any output of my benchtop powersupply (which is under construction) for the reflow block.

I found that one element running at 9.3V is just right for mine. Using the PWM module, 1.6A (~15W) is enough to melt solder, though I usually turn mine up a bit to ~17.5 or 18W and it works a little quicker without overheating anything.

I turned it up to 30W and was able to heat a solid copper P60 pill enought to melt solder a T-Pad quad MCPCB to the pill (though it did take a while to get the pill up to temp).

I also added a set screw underneath to make really tight contact on the heater element, to imporove heat transfer even though the hole was very snug around the elemnt. I noticed after adding the set screw that I got similar temperatures with about 0.5W less power - not sure if it was really necessary, but it only took about 5min to drill and tap an M4 hole.

I sunk my AL block into the wood, so I just can slide the MCPCB off the AL and onto the wood to cool when the reflow is done. Mine just barely chars the wood, very lightly. With the AL block sunk into the wood, I don’t have to try and pick up / lift the MCPCB with still-molten solder LED on it. (I have previously dropped one as I was picking it up after reflow, and the LED went skittering across the floor - this new design prevents that potential issue.)

So far I’ve been quite pleased with it.

14

Ah, there’s where I stole the idea, thanks sac02 for the crosspost. So mine is the third version, next to yours and mrheosuper’s . I corrected the OP.

I’m looking forward to seeing your finished hotplate. :slight_smile:

I think that oak chars relatively fast and on top of that I found that the temperature that I measured as 240 degrees (but may be measured a bit low by the infrared thermometer) is a bit too high for a normal reflow, I will try 20 degrees less next time to see if that works better, it will also damage the wood less.

15

Inspiring.

16

Wouldn’t it have been easier to just take an extra soldering iron tip, insert it into the block, then whenever you need to heat up something just connect your iron to the embedded tip?
A 60W soldering iron would have more accurate temp regulation and heat up faster too.

17

Well I got the idea from mrherosuper in this thread, haha. So as far as I’m aware, he owns the patent on this idea. :slight_smile:

And mine is still beta version 2, so don’t expect too much, lol.

I run mine around 385*F (196C) and that works well for most MCPCB reflowing with the common 60/40 or 63/37 solders. Little-to-no charring on my pine block at that temp. When I turn it up above 400F for more difficult jobs I start to smell a little bit of wood char, but it’s still pretty minor.

18

It is handy to have your reflow block independent of your solder iron (my old reflow block btw is a converted 40W solder iron). And nothing beats these $0.76 heating elements in price !
About regulation of these things: the temperature is a pretty accurate product of the current, so I make a simple current/temperature table that gives me all the accuracy I need.

A solder iron can be a bit quicker though, heating faster, but I’m curious how the temperature regulation is affected by the chunk of added heat capacity.

19

Enderman, my thoughts on the “soldering iron extension” concept. A couple people in the previously linked threads had “hot plates” done with old soldering irons, so it is definitely reasonable. Reasons I chose to go with the ceramic heater elements were:

  • Size - a soldering iron sticking out the side takes up more room on the limited space of my work bench.
  • Temp control, unless you had a spare temp control soldering iron which I don’t.
  • I like to have tools that are dedicated and specialized to a task, at least when it makes functional and financial sense. They often make work easier. To me, it made sense, and IMO it has made things easier.
  • I could make this out of things I already had on hand so my only cost was a $1 heater element (although I bought 10 for $10) so the barrier to entry was not high.

So far for me it is working as I intended, and I’m pretty pleased with it. As I mentioned, I am considering to spending about $10 on a temp control unit for it in the future. But as djozz said, controling the amperage is pretty accurate by itself. I did the same as he did with a K-type thermocouple and made notes: 15W=363*F, 16W=372*F, 17W=381*F, etc. (I just made up those numbers, but you get the idea.)

20

Thks, but i dont own any idea since i said it to everyone
Feel free