Defluxing

[Andrew R Stewart]

I've noticed that some folks drill the top vent through the fork crown after brazing (using the bottom one to let out pressure then both to let water in/out), and some drill it in the blade underneath that. Is there a specific reason you don't go through the crown?

Before placing vent holes in unseen locations talk with your painter. Andy.

[veryredbike]

Before placing vent holes in unseen locations talk with your painter. Andy.

I'll just tell my friends that the sand marks running out of the holes are the kind of beautiful spontaneous happenings that make my bikes artistinal. It's Berkeley, they should buy it. ;-)

In seriousness, I was thinking more about a hole through the tang than any kind of really hidden stuff. It's recommended in Paterek that you drill there after brazing (the first vent before, of course), to reduce stress on the blade itself, but it seems like that's unnecessary from the number of frames I've seen with both vents in the blade. Just curious if anyone had strong feelings about it.

[Andrew R Stewart]

IMG_0410.jpgIMG_0411.jpgIMG_0412.jpgIMG_0413.jpgJust thought I'd share what i did today involving soaking. I wanted to remove the surface rust that develops on a frame's interior after flux removal soaking. I had heard of the product Evapo-Rust, a liquid that when the rusty item is dipped into will removal rust. So i ordered a couple of gallons (Orison Marketing safe, effective environmental rust, antifreeze, odor and more products) and tried it out on a small bit of scrap tube. It worked far better then i thought it would. Next was treating the frame.

When i soak off flux I've used buckets, sinks, wet rags, running water. What all these have in common is the plentiful amount of hot water from the tap. But I only had two gallons of Evapo-Rust so i had to somehow have the frame sit in a bath of the stuff that only contained the two gallons. So I came up with this idea. I bought a cheap planter trough that measured about 30"x7"x7" and a sheet of 4mil plastic. I placed the planter'removablele base tray inside the trough, it fit quite well and reduced the depth by almost an inch. Then the plastic was doubled over and tucked inside the trough, the excess folded oner the lip and held snug with a few bungee cords.

The Evapo-Rust works best when warm. My basement is cool/cold. So i warmed up the stuff by first heating up a large pot of water then placed esch jug in the hot water. This warmed up the stuff without open flame or fear of melting the jugs. Poured it into the trough and placed the frame in. Let each "side" of the frame (TT, DT, CS then SS) sit in the bath for 10-15 minuted and rotated the frame a few times. Over about 2 hours the whole frame got about 30 minuted each in the bath. For the ST i used a turkey baster to suck up the liquid and squirted it inside the TT periodicly. Three gallons would have filled the trough better but you work with what you have.

I did a hot water rinse off then dried the frame with paper towels. There was still some moisture about so i baked the frame in the oven set on warm for about 30 minutes. It's having S&S couplers helped to fit it mostly all in.

Soon we go to the paint shop to check out the chip charts for the color. Andy.

[Craig Ryan]

That's interesting Andy, are you planning on doing your own paint? If one's not painting, my recommendation is to just soak the thing during production like normal then let your painter worry about the rest. Painters have ways of cleaning the frame before paint that meet their needs to get it done right. I wouldn't worry about vent holes plugged or unplugged, media dust from blasting, or anything else, they expect it.

[Andrew R Stewart]

Craig- I have a very good relationship with "my" painter. Last i counted I've dealt with 10 different painters (including me as the first 35 years ago). Very few did much, if any, pre delivery discussion as to how they wanted the bike to be prepped. Very few described their process to clean and prep the frames. This lack of communication has led to some issues in the past. But the current relationship and my prior experience has made me very aware to how I present the ready to paint frame.

Point in particular, that i already mentioned in post #21, is the location and number of vent holes. Untilll I started to work with Doug Fattic, no painter made a point of discussing where vent holes shouldn't be. Or that if you vent once only and your painter uses a soak tank he better be able to FULLY seal that vent before the frame goes under. A second vent is pretty much a NEEDED feature to allow complete draining out of the solutions.

So i now prep the frame as close to what i want it to be if the painter does no extra work or does no special precautions. And I need to add this is not because Doug does sub standard work or can't deal with what comes his way. But I want my painter to have the easiest job possible. He's the one that will make my frame look great as opposed to merely just good. Andy.

[MrkiMedo]

How about fluxes that do not dissolve in water? Is it possible to use acetic acid (white vinegar)?