PCB Stencils – 275 days old

[SimonJA]

I've made a lot of PCB's but never used stencils so thought I would give them a try.

I usually use a syringe to dispense the solder paste but it's very tedious and not very precise.

I never do more than a few boards so a stencil is not really necessary but I just fancied having a go' it may even take longer but probably won't hurt my thumb as much!

One thing that has stopped me in the past is the price of them, when you can pay around £10 for a bundle of boards the price of a stencil seems expensive.

I've just ordered some boards at PCBWay ($14 for 10) and adding a stencil to the order was going to take the price to around $50!

Not wanting to give up I found a couple in the UK:

http://www.hobbytronics.co.uk/pcb-stencil £12 inc shipping

https://www.smtstencil.co.uk/secure/ £15 inc shipping

Does anyone have any recommendations for cheap stencils? Has anyone tried any of the above?

[Henk57]

My thoughts.

I use sometimes also solder paste, if it is drying up a bit bit, if so, then I use a tiny drop of (iso)alcohol and solder flux,
and mix them together with a wooden toothpick
Then I use another toothpick and place solderpaste on the smd-pad(s) accurate, and if you have try it a little bit then you have your own practice.
Then it is doable and cheap.

But there are also Solder Dispencer, I have one, but in test, it was already broken, 2 IC's defect and power Fet's.
I draw a handmade sketch and I see the culprit in the powersupply ciruit (and fix it also).
I could repair the Dispencer, but after all the toothpick method was more handy (for me)!

Henk.

[SimonJA]

Yes my solder paste is pretty old! I use the same method, thin it down usually just with flux.

When I first got the paste I kept it in the fridge sealed in a bag but now just have it on the bench, despite being well past it's sell by date (it's probably over five years old!) it still solders just fine.

I had thought about a dispenser and even started making one once, what is it like to use when it did work?

[Henk57]

Yes my solder paste is pretty old! I use the same method, thin it down usually just with flux.
....what is it like to use when it did work?

Look at youtube to see some vid's while hobbyist working with Dispencer.
I'd like to work with toothpick's, but you know it's me.

Henk.

[Tim]

My 2 cents worth

For SMD that is not just simple SMT and it's a one off eg has legs that stick out then a solder iron is great. If it has hidden legs or is very fine pitch then a solder mask is great. They are simple to use and work well. Combine it with a toaster oven and you can do pretty good work.

PCBway etc will not ship you a little bit of plastic as a solder mask. It's a great big aluminium framed A3 sheet of stainless steel. It's designed for production manufacturing. It's useless for the home user.

I'm not sure on Hobbytronics but have used smtstencils. First order took around a week. I had to threaten a refund from Paypal before they shipped my last order. So I cannot recommend them.

With the plastic sheet using a stencils is easy. Put down 2 pieces of PCB to keep registration then line up the mask and stick with tape down on one side. Flip it up to remove the PCB once paste has been laid down.

[SimonJA]

In the end I decided against trying a stencil, this time.

When I looked at the spec for the stencils I had several components with a finer pitch, I was going to alter the dxf file but it just seemed easier to do things my usual way.

I did however order a paste dispenser on Ali Express which came very quickly, it is not great quality but works reasonably well and is quicker and less painful on my thumb than a syringe. The nice thing is I get a spare hand to move the board around under the microscope as I go which speeds things up and in the end is probably quicker than a stencil for doing a single board at a time.

[SimonJA]