BATC Forum

I am looking for advice on hand soldering SMDs onto a thin Rogers PCB. My problem is that I can't get enough heat into the joints as the heat is being conducted away rapidly through the thin substrate into the ground plane layer underneath. A large soldering bit is impractical. I have become quite competent with FR4 boards and components down to 0402 size but this Rogers material is proving difficult. I have considered the idea of working with the PCB on top of a hot plate at 100 degrees or so but that might prove painful! Ideas will be gratefully received.
Russ, G4SAQ

Interesting....never really thought about it as an issue.
I've just built a pair of G4DDK preamps which are on normal FR4.
I did buy fine bits for sma but found I could solder everything better with my usual 2.3mm chisel bit. That's on my Weller TCP so it's got 50 watts if needed. Temp 7. For bigger stuff I've got a large 9 which is very capable.
What are you building?
Gareth

Hi Gareth,
Like you, I've built a DDK VLNA without issue but this job is proving awkward. It's a 600W SSPA - W6PQL design. Some of the components have been ok to solder but resistors on the wide input lands are difficult. I'm using a 50W temp controlled iron and a 3mm bit will not put enough heat down. I have a larger bit but it will make a mess. My 80W iron is the size of a poker!
Russ

Hi Russ - the trick is to heat the board up on a hotplate first. Less heat needed then.

Mike

Thanks Mike. I asked CHAT Gpt the question an hour ago and that also suggested a hotplate or coffee warmer. Luckily I bought a hotplate and aluminium billet for soldering the LDMOS device to the copper heat spreader (it worked a treat). I'll try the hotplate at 60 C initially and see how that works.
73
Russ.