Hi Patrick
Just made my payment. I have a couple of questions.
Is the inside surface anodized? It seems like you would get better heat transfer if it was not, but maybe it doesn't matter as the heat will be small.
Also what stops the heat sink from sliding down?
Thanks again for running the GB, and designing the part.
Regards
JimS
Just made my payment. I have a couple of questions.
Is the inside surface anodized? It seems like you would get better heat transfer if it was not, but maybe it doesn't matter as the heat will be small.
Also what stops the heat sink from sliding down?
Thanks again for running the GB, and designing the part.
Regards
JimS
> Is the inside surface anodized?
Yes.
> It seems like you would get better heat transfer if it was not, but maybe it doesn't matter as the heat will be small.
You are correct. It is better in theory. And it can be done by plugging the hole with plastic during anodising. It is just too expensive to do. I am sure you don't want another $5 added to the price per heatsink for making the plastic plug (which you unfortunately cannot wire cut).
> Also what stops the heat sink from sliding down?
You have to place the heatsink and the transistors (legs up) on a piece of wax papaer on a flat table (best glass surface). Smear thermal glue (e.g. arctic silver) on both the top edge of the hole and the bottom edge (non-leg side) of the transistors with the glue, and insert the transistor into the hole. When both done, tip the heatsink carefully 90 deg to sit on the no-fin surface, and carefully wipe off any excess glue. Allow the glue to cure with the transistor legs lying horizontal. After that, you get a perfect assembly.
Practice the procedure first with a bit or contact cement and cheap TO92 bipolar transistors. You can reuse the heatsink afterwards by cleaning off the contact cement with acetone.
Hope this helps,
Patrick
Yes.
> It seems like you would get better heat transfer if it was not, but maybe it doesn't matter as the heat will be small.
You are correct. It is better in theory. And it can be done by plugging the hole with plastic during anodising. It is just too expensive to do. I am sure you don't want another $5 added to the price per heatsink for making the plastic plug (which you unfortunately cannot wire cut).
> Also what stops the heat sink from sliding down?
You have to place the heatsink and the transistors (legs up) on a piece of wax papaer on a flat table (best glass surface). Smear thermal glue (e.g. arctic silver) on both the top edge of the hole and the bottom edge (non-leg side) of the transistors with the glue, and insert the transistor into the hole. When both done, tip the heatsink carefully 90 deg to sit on the no-fin surface, and carefully wipe off any excess glue. Allow the glue to cure with the transistor legs lying horizontal. After that, you get a perfect assembly.
Practice the procedure first with a bit or contact cement and cheap TO92 bipolar transistors. You can reuse the heatsink afterwards by cleaning off the contact cement with acetone.
Hope this helps,
Patrick
Hello Patrick,
Nice initiative. In the course of this year I would consider some projects where your Jfet heatsinks might be usefull. I am not yet prepared to count how much and then I saw this thread. I don’t know if I can manage to scroll partslists before you order as I am in a timesquize now. Hmm, what is your advice? Would you have like probably 10 pieces spare ones when I come back on this in february?
Best, Arjen.
Nice initiative. In the course of this year I would consider some projects where your Jfet heatsinks might be usefull. I am not yet prepared to count how much and then I saw this thread. I don’t know if I can manage to scroll partslists before you order as I am in a timesquize now. Hmm, what is your advice? Would you have like probably 10 pieces spare ones when I come back on this in february?
Best, Arjen.
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