Heat sink diy

[VertigoCycles]

hi all,
im planing of making a set of heat sink and I'm looking around at the different design one could go with, and that raised the following questions.

first of, is the idea to have as much contact area as possible and as much brass in there, as in brass absorbs the heat and as such the more brass the more heat it can absorb ?
in that case i would go with two round halfs of brass like in the photo below:Attachment 84550

or should i put a bitt more effort in and go with a design that has a few more cuts in its design and as such looks like it can radiate the heat better ?like the one's in this photo ?Attachment 84551

what ever design i will go with it will have to be able to purge as well.

i don't quite know the nitty gritty about how these puppies do there job and i hope perhaps someone here can explain it to me, i have used the search function on heat sink but no price (-:

thanks, mick van aar

I realize that I haven't actually contributed anything to this thread before losing my patience with Mark.

Either one of the designs you posted (the bottom photo is mine) will work great. My photo only shows the actual heatsink portion and not the rest of the tool that makes it work. I would hope that was obvious but wanted to state it in case it's not.

From a fabrication standpoint, it would be much easier NOT to build them they way I have, and to just slit them into thirds or quarters and use a spring clip. This goes double if you're using the internally relieved Paragon head tubes. I'll add that make sure to leave a generous ID on the brass (or bronze) portion to allow the tool to contract enough to easily remove it after welding. The 510 bronze that Paragon uses is much springier than the 660 bronze (and lends itself better to making the spring type heatsink) that I usually use BUT it's very hard to machine with the machine tools most framebuilders have access to. If you go with the 510, make sure you have some serious power at your disposal and get your speeds and feeds dialed. 660 is much easier to machine but makes a huge mess since it essentially turns into powder. When I made mine years ago, I used a very clean mini shop-vac to suck up the chips as they were coming off the lathe tool.

You should be able to make exactly what you need using Alistairs link. IMO, he did a fantastic job putting his tools together as well as documenting the process.

[VertigoCycles]

Mick, if you want to work with stainless and titanium, you might be ok without heatsinks if your heat control is perfect and you use thick wall thickness, but you can't go without purge at all. Heatsinks are not too expensive if you consider the much better quality you'll get on your welds, avoiding overheat, distortion, etc, and if you make them your purge fitting points, you have two functions in one tool, win-win. Paragon's BB shell heatsink/purgue is perfectly made at a very fair price. For headset and seat tube you can make your own or make someone made them for you (I had a super great job made by this Vsalon member Sebaudet ,thanks Seb!)

To me, it's always useful to watch what the experienced people are doing so to learn their process (wich is usually based in long years of experience), there're no shortcuts, sure you'll be able to find your own way on the process, but they're the best living lessons to start with (mixed with your own workbench hours). Watching any of the workshop process pictures from Tig masters like Tyler, Drew, Rody, Sean, Kris, Mike, etc will help you understand what goes where and why, and see what you might need to do the best possible work.
I could never thank them enough for all the information they openly share for anyone to see how does hell's oven get fired. No microwaves here

Cheers

Well put, Aimar.

I'll add that while the Paragon purge plugs are cheap and can get the job done, if you want to skip the heatsink altogether and go the purge plug route, you'd be better off making your own HT rods from some all thread or acme threaded rod and using end caps to cap off the HT. From my time at UBI, I've seen LOTS of students attempt to use the press-in plugs only to have them fall out while welding because they've ovalized the tubes.

If you wanted to save yourself the time of spinning nuts down a length of threaded rod, you could use drill rod and then some caps with set screws to plug the HT up.

[Amaro Bikes]

Just in case it's helpful, here is a picture of some of the nice ones made by Sebaudet, I'm pretty happy with them, thanks again Seb

They're cut in thirds as Sean said, have the purge fitting for plug easily with the argon tube (dedicated back purge bottle) and have some generous mm travel margin so you can make presure without risk of getting blocked after welding. Here are the BSA BB and 44mm HT ones, then there's another one for ST

Cheers

[Alistair]

You should be able to make exactly what you need using Alistairs link. IMO, he did a fantastic job putting his tools together as well as documenting the process.

Thanks Sean. For the sake of completeness, and because I'm fascinated when it comes to bike fabrication to know the history of who invented what, or came up with a particular method, I should say that I made those heat sinks after consulting with you via email on how you made yours. You made me aware of a couple of issues that I hadn't considered at the time (three years or so ago?), so thanks again for that info.

I also got some good insight from Kris Henry's Flickr page (44 Bikes), by looking at the process pic's he had posted of how he made his heatsinks.

Anyway, just wanted to mention that.


Alistair.

[Mark Kelly]

HUH!? I'll get right on that,

Yes, I let my annoyance with Aimar get away. Scrub that comment.

To set things straight, please note that both the heatsink designs shown by the OP have argon distribution incorporated, he specifically said it was a sine qua non and then asked about surface area and material effects, which I answered.

Please don't interpret what I subsequently wrote as saying that these effects are more important than purging, that was not my intention.

In general there's a lot of how on this forum and not much why.

[Amaro Bikes]

Yes, I let my annoyance with Aimar get away.

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