Is there a specific reason you're using rivets instead of screws?
Will you actually be riveting them with a press or a hammer of some sort?
Many of the holes that you see that are empty at the moment are for stainless M2 screws to hold things solidly in place when reflowing ... especially the bottom copper of course.
But the rivets are in certain places where I need to move heavy current from one side of the board to the other. Instead of a normal plated through hole in those spots, I've sized them for 3/32" solid copper rivets. I'm not cinching the rivets at all, just soldering them in place. They are only there for conductivity, not any type of retention. Two 3/32" rivets have about the same copper cross section as #8 AWG wire. The four places where the rivets are inserted are all in pairs.
I've added a couple of pics showing an M2 securing a piece of top copper bus and then showing how it secures the bottom piece during soldering. The rivets are a snug fit and stayed in place when I flipped the board.
You can also see where I mistakenly left some of the outline silkscreen in white for the hardware parts. I'll remove those in the future.
Last edited by Master Chicken; 07-31-2020 at 11:43 AM.
Hey MC I'm happy to see your well and back at it again mate.
Your progress is very encouraging and the boards look sweet in Black and Gold!
Thanks. More progress this weekend.
Below I've done a very mediocre job of sqeegee-ing solder paste onto the board. Then I installed all of the copper bus parts top and bottom and all of the surface mount parts. I can just about promise you that I will be tossing this board in the trash because I'll probably have to re-flow it several times to get the profile right due to the added mass of copper on the thing. Once I figure that out, I'll be able to build a few to test properly.
I think the heatsinks are just too much for the reflow. I'll leave them off of the next one and then add them after reflow with some solder paste and a small torch. Probably a better way to go with the localized heat at the heat sink tops.
Yeah, I've removed the heat sinks for the reflow process. I still want to solder them for the best heat transfer versus thermal epoxy so it will be a small torch or hot air pencil ... small torch is pretty fast though.
I suppose I was just looking to remove a step from the process and make things a bit easier. Torching them in place shouldn't be too difficult ... he says looking at the 18 heat sinks.
Last edited by Master Chicken; 08-03-2020 at 02:24 PM.
Regardless of the solder struggles, I have to give you some serious props man. This thing looks gorgeous.
Thanks. It's been a struggle at times.
I think I'm going to solder the next one up with just the SMT parts, then I'll butter the bottom of the copper bus parts with solder paste, mount them with their screws, then torch them into place. Then the heat sinks after that. I was just hoping to save time with a single oven pass. Apparently, that's not in the cards. I guess I have an excuse to get one of those Smith Little Torches now.
You can see in the picture where the solder paste under the heat sinks failed to liquify. I still needed a small torch to get them off.
Last edited by Master Chicken; 08-04-2020 at 12:15 PM.