BenKeith wrote:Angermanagement, if you consider those heavy gauge, suitable for the application being used in that espresso machine, then go for it. When it fails again you can always keep blaming everything else for the failed connections. Not trying to create a conflict, after all, it's not my machine, just trying to give a little advise that might save a repeat of the same problem.

Ben; I was highlighting that spade connectors are available from Auto shops etc and that if you read; these are the places many go to get connectors etc. And the person that had the issue; did just that.

I have been stating that you need the right parts and tools to do the job correctly and that these types are not suitable.

I can only assume you have not read all the posts and or missed one or two.

Things are verging off topic and into personal comments. Let's try to keep this about the issue and not the personalities.

Frenchman

What is the status on your unit as of now ?

Key points.

Good connectors and connected with care to the right gauge wiring.

* If a connector slips on with ease and you can rock it side to side with ease = a pivot point = a potential hot spot.

SSR and many other devices may have a nominated rating; but often that is only part of the specks.

* Rated Current - Continuous (with or with out heat sync) or Surge - Switch on...

SSR are cheep enough these days and can even come with their own heat sync (like a CPU). NOTE: Never part heat sync a device be it a power transistor / CPU / SSR etc as you will cause hot spots and cause problems.

OF note is the fact that load side of SSR's always come with screw terminals to manage and chance of a poor connection; thus your wiring from those terminals should have same or better on the other end.

PS: Where ever possible any wire that carries > 2A I try to make sure it is not a spade type; not always possible or easy. But the largest number of Faults I have seen over 40 years of Electronics and Electrical where heating elements and power is involved has been due to poor connectors.....

And in the medical / aircraft field they are a no no in may situations due to unreliability.

AngerManagement wrote:Frenchman
What is the status on your unit as of now ?

It is still down, but I have somewhat of a plan (I'm getting tired of tea):

- I am getting new spade connectors whose amp rating I will know (and that will be sufficient).
- I am replacing the thermal fuse (easy), also from a reputable source.
- I am getting two new SPDT switches of industrial quality (Arcolectric C3950BA), one to replace the one that has signs of burning, and a spare.
- I am getting a better microswitch than the Amico. One where I can read the spec sheet for example.
- I am getting the 50A industrial SSR I linked to previously (not another Amico one).
- I will get a heat sink.

I have three question re: the heat sinking:

- If I find a heat sink that is slim enough to fit where I mounted the SSR previously, I can just mount it there, right? The heat sink will only be partially in contact with the chassis but the SSR will be fully in contact with it, and the heat sink by definition is the heat dissipator. Right?
- If I don't, I will affix the heat sink to the bottom plate of the machine. I don't really want to drill there, can I just use silicon? I initially was thinking heat transfer adhesive but I cannot find any (or a $200 roll of 3M tape). Ideally I'd use heat transfer adhesive so the machine would help dissipate even more heat than the sink, but the sink should be enough, right?
- Is there a rule for sizing of the sink, or are all SSR heat sinks equally okay?

AngerManagement wrote:PS: Where ever possible any wire that carries > 2A I try to make sure it is not a spade type; not always possible or easy. But the largest number of Faults I have seen over 40 years of Electronics and Electrical where heating elements and power is involved has been due to poor connectors.....

In my espresso machine, every single connection is a spade one. Maybe I'll skip connectors on the SSR, as there is no real need to disconnect those. For other things, like the microswitch, it helps when you need to work on the machine to be able to disconnect the switch and get the water reservoir support out.

I also need a new microswitch. This C&K one seems fine and rated for 75,000 operations or so. I don't know what the one sold by Stefano has that would make it work better?

There is a white cream used to improve the heat transfer between two rigid metal objects. It's usually available at an electronics supply store.perhaps Radio Shack. It's called Heat transfer paste and I'd recommend it in your application of SSR and case.

I have the heat transfer paste, it's what you put between the SSR and sink. I put some on the SSR. It's not an adhesive though so it wouldn't work to hold something.

Thyermal past is just that...It transfers the heat = NO

What it does is fills any spaces / groves so that you get as close to 100% surface to surface contact. Thus a better transfer process due to contact surface area and min hot spots.

Go light on the paste; and give the two pieces a bit of a twist etc when you put them together; to squeeze the excess out.

When it comes to CPU's and heat sinks on video cards etc I always lap the surfaces first with 2000 grit and then a cut and polish.... That way I can use the very least amount of high quality past and get exceptional transfer rates.. Helps when over clocking and pushing clock speeds

As to the following;

"- I am replacing the thermal fuse (easy), also from a reputable source."

You should use heat sync pliers if going to solder, and if a high value fuse; then solder is not a good idea as it can get soft and the joints can fail; if in a high temp area for long periods of time.

That is why; you will find them crimped into the wiring, in most if not, all commercial cct's.

I use special fishing / crimping pliers and prefer the copper / PELAJ CRIMPS (double style) of the right size to ensure a good connection. In many cases the wiring in a system may also be teflon coated and even a single core or some other material etc. The crimps take out all the guess work and provide great strength to the join as well.

PS. Trust these hints are of assistance...

As said, thermal paste needs two perfectly(as humanly possible) flat and smooth surfaces. And less is more. Just enough should be used to cover the entire surface of the component in a very thin layer, but no more. Even, mechanical, clamping is also required.

Another approach is thermal transfer pads. Better for less than ideal smooth/flat surfaces, and where a good mechanical clamp can't or won't be achieved. Some are also self sticking. Often used with components with less thermal sensitivity than CPUs.

AngerManagement and cupofjoe, thanks for the advice on the paste, but that's a part I am good on (assuming I can find my paste somewhere). It's finding an adhesive for the sink to the chassis that I don't have a good solution for.

I'm going to have to admit to using a cheap crimper. But then I'll question critical (welcome) advice on checking the voltage rating of everything, and favoring fishing crimps