melicent

I've been wanting to get a long haul trucker frame and build the bike up myself. A friend has a frame that he's willing to sell me, but it was damaged in a shop fire. I want to make sure before i buy it that the steel won't be weakened by the exposure to fire. Any chemists out there who can help me out?

Carpe Diabolus

If the fire got anywhere close to 1000 degrees Fahrenheit, I'd be worried. If I'm not mistaken that's the temp that chromoly starts to become negatively affected by heat.

Nigeyy

Not a metallurgist and perhaps some others here can have more informed advice, but usually I assume "fire damaged" usually refers to just smoke damage. If I saw any kind of flame/heat damage rather than smoke damage I'd have second thoughts and seek advice from someone who knows. Then again, is it possible to have heat damage and not see the powder coating affected?

If it looks like it's just smoke, I'd assume it would be OK, but again, I'm not a metallurgist....

Carpe Diabolus

At 1000 deg. F, the paint/powdercoat should be non-existent or at a at least severly damaged. A cheap heat gun will melt most finishes, the output doesn't even get close to 1000 deg.

I'm not a metallurgist either, so I'd seek the advice of a one before committing your safety to this frame.

Bacciagalupe

An LHT frame costs what, $400? $450? It's one of the most affordable new frames on the market.

I don't think it's worth the cost savings. Just get a new frame, with no worries and a good paint job.

Rowan

Or go to the framebuilders' forum on BFs and ask there.

Frankly, after the bushfires here in 2009 and what I saw they did to metal of all sorts, I wouldn't contemplate using anything that has been actually subjected to flame. The temper in the metal disappears pretty quick smart. If the brakes and wheels are blobs, or are misshapen, there might be a clue to the heat's intensity.

But as Nigeyy says, if it's just smoke damage, it might be something to play with.

sstorkel

+1 Trying to save a buck on one of the cheapest frames in the business isn't worth it, IMHO.

If you can't afford a new LHT, consider the Soma Saga. During end-of-season sales I've seen the Saga going for as much as $100 less than the LHT. Or buy Nashbar's $100 aluminum touring frame and $50 touring fork; with 700x35 tires on, it rides like a dream. If you wait for one of their frequent 20% off sales, you can grab the Nashabr frame and fork for $120. I've been super-happy with mine and still wonder why people spend 3-4X more for the LHT...

Booger1

1000*-1100* is used to temper CroMO tubing.Normalizing is in the 700*-800* range.

Tempering will subject the complete frame to heat.Depending on the type of CroMo,the dwell time will vary depending on the yield strenght they want.It can vary greatly! This will eliminate the HAZ zone.

Normalizing will subject only the weld to the heat,in order to anneal the weld.This will broaden the HAZ zone,speading the load over a bigger area.

Tempering is done when you give a rats ass,normalizing is done when the part will not be subjected to localized stresses or they want to be cheap.

Is that frame any good? A quick Rockwell test will tell you if the fire has tempered it.Do you know any bike shops with one....NO.If I had it in front of me,I could tell you in 5 min if the fire damaged it.

That's the only way you will know,FOR SURE,if it's ok.If there are melted aluminum parts on it(1200*-1300*),chances are it's toast.If not,chances are it's good.

Would I take a chance on it,if I got it dirt cheap,I would.But I have the ability to test it before I put my butt on the line.

fietsbob

You buying it back from the insurance company?

[one of my dad's friends who owned a welding shop did that after the write off..
as totaled, It was with a Jeep, not a bicycle]