Bicycle Mechanics - Who's good at metal work?

I'm in the process of converting an old mountain bike frame into a fixed gear. I have Dremeled the canty mounts off of the steel fork and I'm in the process of filing down the welds. There are vent holes about 2mm diameter in the fork blades. Since I don't have easy access to welding equipment, what's the easiest way of adequately filling in the holes. Will Bondo stay put in such a small hole that has no backing?

Braze them shut

I would try bondo, its worked for me many times.

Bondo would stay put, five minute epoxy will probabbly work to and be easier to mix in such a small quantity. Epoxy might need two apps tho.

If you have enough heat(mapp or maybe propane?) for silver solder, you can stick a small nail(snug fit) in the hole and silver it in then lop it off and file it down. Be sure to get everything spotless clean first.

Lead solder and a propane torch. They used lead for auto body filler before Bondo was invented. The metal must be clean and shiney and you need to use flux.

http://www.hotworldcustoms.com/images/page%20pictures/Glazing%20Putty.jpg

This is what I use for stuff like this, you can get it at most hobby stores.

Thanks. I think that I will use a two part auto body filler. I have some file marks and low places that have to be filled anyway. I was just concerned about the filler staying put in the holes.

The fast-cure JB Weld works great for filling small holes. Doesn't shrink when curing, sets up hard, looks like metal, can be filed & painted.

If those are jig holes used when making the frame, I would leave them open. The vents will let condensation and water out. If you seal them, you will inevitably get condensation in there which could lead to rust problems. Just spray some WD40 in there once in a while to prevent rust.

spray some Weigel's frame saver in there first then bondo it shut on a hot and arid day.

Then your question should have been…

"What is the quick and dirty way… for someone who doesn’t really care about good metal work"

Then your question should have been…

"What is the quick and dirty way… for someone who doesn’t really care about good metal work"

I asked about "adequate methods" and got pretty much the same answer from everybody but you. I've got to tell you that I've read a lot of advice that the Rev has given to other posters, and I have a lot of trust in him.

I wish that you would have taken the time to provide a little more detail in your answers because I'm interested in hearing your thoughts about why anything less than brazing shut the holes won't be adequate. Giving me hit and run answers to do something that I indicated I don't have the tools to do, and then to say that I must not care about doing a good job might even be the right answer, but how am I to know?

chewing gum.

I do appreciate it when you guys point out when I’m being too sarcastic. I meant the post in an ironic vain, good at metal work and all.

Actually their is nothing wrong with the glazing putty idea and making sure their are weep holes is also valid, although I don’t think I would want them near the location of the old brake mounts.

Brazing is the old school frame builders’ art of course and it can be accomplished with a small map gas rig, But any one that can call them selves a metal worker has a torch, and rod and all that stuff.

There is a lot of flexing going on in a good rigid fork. (That sounds like a contradiction doesn’t it.) A plug of epoxy or bondo or whatever could pop free at some point.

Another option would be to partially tap the hole and screw in a brass screw and cut it off flush. By partial I mean don’t cut all the way to the dies full diameter, so that when you thread in the screw it is tight in the hole and binds. Your first few coats of primer will show the seam but you will sand it smooth before the final coats.

Actually their is nothing wrong with the glazing putty idea and making sure their are weep holes is also valid, although I don’t think I would want them near the location of the old brake mounts.

Another option would be to partially tap the hole and screw in a brass screw and cut it off flush.

The weep hole thing is a non-issue. The fork also has holes in the crown area and near both dropouts.

I thought of inserting a screw and grinding off the head too, but the holes are only about 2mm. - smaller than any tap that I have. The body filler idea is looking better all of the time, especially now that you have confirned what the Rev. suggested.

Keep in mind that the frame that I'm reworking would be dumpster fodder otherwise so one of my objectives is to hold the cost down. It's an old Raleigh Technium. The main frame, even with aluminum main tubes, weighs about 5 pounds and the fork adds a couple more. My projected budget for the entire bike is $150.00. We'll see how it goes.

A #4-40 tap can't cost more than 4 0r 5 bucks but I know what you mean about keeping the cost down. How much is the cost of the compound and the wet dry sandpaper in comparison to the tap and a piece of emery cloth?

What ever you end up doing keep us informed, as their are lots of old frames that need to be converted and returned to use.

This is perhaps outside the scope of this thread but What If… each and every one of us with some extra parts and some time put together a bike or two and gave it to our local community outreach program for a kid or an adult that needs one.

A #4-40 tap can't cost more than 4 0r 5 bucks but I know what you mean about keeping the cost down. How much is the cost of the compound and the wet dry sandpaper in comparison to the tap and a piece of emery cloth?

I've got some low spaces and file marks that need to be filled anyway so I'd still need the compound. My next step is to use a chemical stripper to remove all of the old paint. I wouldn't be looking for a picture of a finished bike from me until maybe the middle of June. Might take even longer because I've got a couple of other old bikes to rework for the grandkids. The wife is going to want me to do make them operational first.

JB Weld

I'm surprised no one else suggested it.