How are these welds?

[schpud]

I just picked up a project bike, with a tcbros hardtail. The welds don't look particularly good to me however. They don't look horrible either. Could it be they just weren't grinded or smoothed out much? This will be my learning as I go build, and want to start off with a strong frame.

 

[jd750ace]

Looks like a MIG weld. Frame tubing can be done by seasoned professionals and look great with a MIG, but TIG is the way to go for nice consistient welds in thin wall tubing.
Those look blobby, but I done worse learning. That being said, if I had done the ones in the upper photo, I would have done them over. The lower one, that intersection is pretty tough to do with a standard shielded nozzle, unless you get a lot of wire in front of the shield. I'd live with that one.
The other thing is, and this is probably just me, those butt-welds in the upper picture would never be a stand-alone for me. I would have to go with a sleeve over that joint, even if it was short. A straight butt joint is too stressed.

 

[schpud]

Looks like a MIG weld. Frame tubing can be done by seasoned professionals and look great with a MIG, but TIG is the way to go for nice consistient welds in thin wall tubing.
Those look blobby, but I done worse learning. That being said, if I had done the ones in the upper photo, I would have done them over. The lower one, that intersection is pretty tough to do with a standard shielded nozzle, unless you get a lot of wire in front of the shield. I'd live with that one.
The other thing is, and this is probably just me, those butt-welds in the upper picture would never be a stand-alone for me. I would have to go with a sleeve over that joint, even if it was short. A straight butt joint is too stressed.

I dont think it's a butt joint, the tc bros hardtails come with slugs for the bottom rails.

 

[jd750ace]

If it is slugged, meaning an internal splice, that's better, but normally you would cross drill each side in the area of the splice and get at least 4 tacks thru the tubing wall and into the slug so the loads don'tget transferred to the butt weld without any help.

 

[schpud]

Should I get this fixed at a shop or is it safe as is?

 

[jd750ace]

Can you weld? If so, fix it up yourself. If you trust it as it is, put it together. Coming from an aircraft tube structure background, I work all tubing Per Advisory Circular 43.13, standard practices for inspection and repair of aircraft. Good Section on welded tubing repairs due to trellis structure in older fabric covered aircraft. Good luck with it, and hold out for some suggestions from those here that have done hard tail conversions. This is just my $0.02. I'll send you a sketch of what I'm talking about if you want.

http://www.everyspec.com/specifications-standards-search.php

Download AC43.13 for free here. Chapter 4, section 5 covers welding. If it is good enough to fly, it ought to be good enough to roll down the road.

Hope this helps anyone interested.

 

[OakBehringer]

Unfortunately, we cannot tell if the welds have proper penetration.

 

[jd750ace]

That's a big part of the reason for the rosette welds. they are more inspectable at the fusion point, and take full advantage of the splicing member. If you are doing a radial weld around a tube that you intend to grind down, you should bevel both parts at a 45 degree angle or so so the bead has a furrow to lie in and fill. That way, your heat is fusing both tubes and the slug all together in the bottom of the weld, and you are not reducing strength so much by grinding down, as this technique assures the weld goes all the way to the slug. Once ground to profile, your weld bead will fill, as if the tube were solid, and the joint will be stronger than the tubing that is unsupported on either end of it.

 

[TampaSVT]

Pud:

If you're not confident in your welds, take it to a professional shop and have them run a bead and reinforce what you've already tacked together.

I did the same on an earlier frame. Shop cost $100.00+- and I slept much better knowing I'd have somebody else (other than myself) to bitch at if it came apart after all that work...


Rich

 

[swbill]

I've seen and done worse. If it was me I might grind them somewhat smooth and run another bead over them but just judging from the pics I would say there are probably OK.

 

[54inches]

Where are you located? If in Houston, I can reweld for you....

 

[Phyberoptic]

Pud:

I slept much better knowing I'd have somebody else (other than myself) to bitch at if it came apart after all that work...


Rich

I'd be more worried about being alive to bitch than the investment in time.


That being said, visually they don't look any worse than what Yamaha did to the frame originally.

-=PO

 

[schpud]

Unfortunately I didn't do the welds so I can say how they were done. Got the bike from a guy who got the frame from someone else.

And I suppose it's true, they don't look any worse than the stock welds on my 80 frame and I'm not exactly gentle with it.