# Intro and a stainless tig rod on cromo question



## Evil Con-fecal (Jan 31, 2004)

Hi guys. I am getting prepped to build my first bike frame. I have no intentions of being a professional frame builder. I have fabrication experience with heavier gauge materials with quite a bit of mig and tig experience. I have no real formal training in welding, mainly OTJ and books. Basicaly I can weld pretty well, but I don't claim the distinction of calling myself a weldor. Anyways, I have been lurking awhile deciding what to build and I think I have it nailed down.

The bike is going to be a cromo trials bike with a seatpost. 380mm rear chainstays, + 15mm bb, with a 80mm fox fork (accounting for sag), approximately a 1070mm wheelbase, 13 inch seattube. I've drawn up some plans for the basic double triangles, chainstay with a yoke to clear a Michelin 24 2.5 (huge nod to lunarbikes). I am working on design and drawings for my drop outs. I'll post them up when I get them more refined.

I've also been praticing hand mitering and welding (relatively) thin wall tubes (035). I've brazed a few hole in radiators but I am much more comfortable with a tig torch. 

Here comes my question. I have been looking for a local supplier of Weldmold 880t after reading about it here and on frameforum. I can't find it for love nor money. One supplier recommended a stainless 316 rod as an alternate when I described what I was doing. Anyone using this on cromoly steel? It flowed out really nice and left a clean shiny bead. It was also a little spendy at about $16.50 for a pound of 035. Is this a good choice? How comprable is this to the 880t? Would I be better off with a 312 rod or the standard ER70S-2. I have quite a supply of the 70S-2.

Please help a brother out, Thanks. John.


----------



## Walt (Jan 23, 2004)

*If you can't find any 880t...*

I am happy to sell it in smallish quantities (ie, 1# at a time). I usually have 20# worth in a mix of .035, .045, and 1/16 on hand at any given time.

It's spendy, but a pound of the stuff will last 15 frames, easy. It ends up being about $1/frame extra cost over ER70S or whatever. So not too significant in the long haul, but a little pricey if you just want to do one frame.

I have no experience using the 316 and wouldn't try it unless a real metallurgist/welder tells you it's ok. Just my $.02.

-Walt



Evil Con-fecal said:


> Hi guys. I am getting prepped to build my first bike frame. I have no intentions of being a professional frame builder. I have fabrication experience with heavier gauge materials with quite a bit of mig and tig experience. I have no real formal training in welding, mainly OTJ and books. Basicaly I can weld pretty well, but I don't claim the distinction of calling myself a weldor. Anyways, I have been lurking awhile deciding what to build and I think I have it nailed down.
> 
> The bike is going to be a cromo trials bike with a seatpost. 380mm rear chainstays, + 15mm bb, with a 80mm fox fork (accounting for sag), approximately a 1070mm wheelbase, 13 inch seattube. I've drawn up some plans for the basic double triangles, chainstay with a yoke to clear a Michelin 24 2.5 (huge nod to lunarbikes). I am working on design and drawings for my drop outs. I'll post them up when I get them more refined.
> 
> ...


----------



## Evil Con-fecal (Jan 31, 2004)

Walt said:


> I have no experience using the 316 and wouldn't try it unless a real metallurgist/welder tells you it's ok. Just my $.02.
> 
> -Walt


Cool, thats why I was asking around on this board.  I know there can be a huge difference between a pretty weld and a strong weld. Also, I would be interested in purchasing a pound of the 880t. How would I go about buying some from you?


----------



## Iridethedirt (Jan 20, 2008)

Hi, I saw your question about what kind of filler rod to use on cro-mo. I'm a TIG/MIG welder, I've never built a bike frame (but am starting to want to!) I went to school to learn to weld, and i hold a few certifications in both TIG and MIG processes. Here's the skinny:
Do not mix-n-match fillers to the metal being welded. You absolutly, for a STRONG high performance weld, need to match the alloy of filler you are using to the base metal being welded. otherwise you are essentially mixing alloys together, and as was previously mentioned, unless a metalurgist tells you to go ahead with it, you're dabbling in some dangerous territory. different metals have different properties, especially when heated to welding temperatures. some metals become brittle and weak, others become stretchy and will bend and deform fairly easily. If you need some help sourcing the correct filler rod material send me a PM and I'll see what i can turn up through my employer and the suppliers we use. i can also look into finding out weather or not you should be purging those tubes while you weld. it certainly can't hurt, but I dont think its required on cro-mo. 
Now i dont know if anybody else who actually HAS made some bike frames has used such a method, but being that you guys are riding these frames, i can only assume, pretty hard, a dye penatrant weld inspection kit might not be a bad idea to invest in as well. this will turn up any cracks, porosity, or other weld flaws that could lead to potential weld failure in the future. 
So yea, use the same metal in your filler as your tubes are made out of. 
good luck and post some pics of your progress, I'd love to see it!
also, If you guys have any other frame building/TIG welding questions, I'll try to keep my eyes out for them, i have a family member who used to TIG weld Ti frames for a pretty well known CA based company, and can probably answer about any frame building question you'd have.
good luck!


----------



## Evil Con-fecal (Jan 31, 2004)

*Thanks for the information*



Iridethedirt said:


> Hi, I saw your question about what kind of filler rod to use on cro-mo. I'm a TIG/MIG welder, I've never built a bike frame (but am starting to want to!) I went to school to learn to weld, and i hold a few certifications in both TIG and MIG processes. Here's the skinny:
> Do not mix-n-match fillers to the metal being welded. You absolutly, for a STRONG high performance weld, need to match the alloy of filler you are using to the base metal being welded. otherwise you are essentially mixing alloys together, and as was previously mentioned, unless a metalurgist tells you to go ahead with it, you're dabbling in some dangerous territory. different metals have different properties, especially when heated to welding temperatures. some metals become brittle and weak, others become stretchy and will bend and deform fairly easily. If you need some help sourcing the correct filler rod material send me a PM and I'll see what i can turn up through my employer and the suppliers we use. i can also look into finding out weather or not you should be purging those tubes while you weld. it certainly can't hurt, but I dont think its required on cro-mo.
> Now i dont know if anybody else who actually HAS made some bike frames has used such a method, but being that you guys are riding these frames, i can only assume, pretty hard, a dye penatrant weld inspection kit might not be a bad idea to invest in as well. this will turn up any cracks, porosity, or other weld flaws that could lead to potential weld failure in the future.
> So yea, use the same metal in your filler as your tubes are made out of.
> ...


I appreciate the information. I know a lot of guys like to use Weldmold 880T for tig welding 4130 cro-moly. I was trying to find a local source for the 880T and one supplier recommended 316 as an alternative. I have also seen here and on Lincoln's site that 312 is acceptable. http://www.lincolnelectric.com/knowledge/articles/content/chrome-moly.asp So I thought I would give it a try. It flowed out nice, but I am no metalurgist so thats why I threw the question out before putting down a bead on something I would actually ride.

For the most part I have been using ER70S-2 for mild steel, some 304 for 304 stainless, and a little 309 for mild to stainless welding. I think I will go with ER80S-D2 for the 4130 cro-moly. Unless I can find some Weldmold 880T.


----------



## BeatAFool (Jan 14, 2008)

I've been looking for the 880 also with no luck. LWS said they might be able to special order it for me but I had to get 10+ pounds. Thanks but no thanks.

So.... is Walt the online supplier for Weld Mold?? 

I've been using the copper coated er70 and ain't happy. How's the ER80s-D2?


----------



## Walt (Jan 23, 2004)

*Dudes*

If you need small quantities of the 880t, just email me. I have tons of it in pretty much every size you'd want for bike building. waltworks at gmail dot com.

If you're planning to build a lot of bikes, just suck it up and get 10# from your LWS. You'll blow through it surprisingly quickly.

-Walt


----------

