rydabent

On forks and rear stays there are welding vents. They are small holes the prevent closed tubes from building up pressure when they are welded. This prevents holes and blow outs in the welds.

So the question is ----- is it ok to tape these vent holes to prevent water from getting into the tubes? I have been. I put black plastic electrical tape around the tube.

Airburst

Seeing as some framebuilders fill them with brass when they're done welding/brazing the frame, it must be.

FBinNY 

+1
First spray some Boeshield, WD-40, or similar thin oil coating in, rotate the frame to circulate then drain as much as you can.

Then cover with a small spot of electrical tape, or plug with a dab of clear silicone caulk.

Open and inspect every 25 years or so.

fietsbob

Wiegel frame saver a similar idea.. a coating, thicker, when dry.
tube nozzle squirts in those holes... seatstay its how it has to get in-there

plus bb shell has access to the chain-stays,seat and down-tubes..

note: to rotate the frame well to get stuff to coat, inside ..
bare frame is easier.. than built up bike..

bobn

Can you use the appropriate sized sheetmetal screw with a fine rubber O ring as a gasket? This would eliminate burning the paint and can be easily removed if the need arises. The screwhead can be touched up with the correct color paint.

FBinNY 

Serious overkill. A little dab of Clear Ge silicone bathtub caulk does the job nicely. Or you can go to a fine glassware shop, and buy little sticky dabs of PVC or silicone (Bumpons) that are used as feet so the glass won't hurt furniture, or vice versa. I used electrical tape and punched out little dabs using a standard hole punch.

davidad

Don't worry about it. The frame will out last your interest before it becomes a problem. That should take decades.

duckracer

It's actually called "Gas Porting", and yes you can plug them. When I was building drag cars I would place my gas ports at the tube joints so the expanding gas ported to the adjacent tube and you never see the holes.

FBinNY 

The OP lives in Lincoln, Nebraska. If he rides their salted roads in the winter spray will carry salt into the tubes and the internal rust process will be much faster than it would be for a fair weather rider in Nevada. Covering the vents makes sense, going to great lengths to make a simple job more complicated doesn't.

FBinNY 

Most frame builders do the same thing. The only place you should see vents in the seat stays and fork blades which are closed boxes with no adjacent tube. There are ways builders can close these too, and some do but most don't.