Heating up an aluminum block

[musiclover2000]

In the video the man is heating an aluminum thermostat housing with a can of mapp gas to remove a broken bolt. It worked for him but isn’t this risky. I’ve always heard the aluminum will warp or crack if heated like this?

Thank you

Topic

[Lorrin Barth]

I’ve never done that. It is true that aluminum expands more that steel so the idea is correct. Steel fasteners always lock in aluminum and come loose with a snap so it is important to use a quality fastener. Dropping a bolt and replacing it with one from the junk drawer is not a good idea unless the same quality. If the manufacturer has designed the part correctly and the original fasteners are used you shouldn’t find yourself in this pickle.

[musiclover2000]

Thanks for the info

[Mike]

I’ve never had a problem heating aluminum for that purpose, which I’ve done it many times. I’m normally using Oxy-Acetylene which is hot enough that you can cause damage, but it would take forever to hurt anything with the torch in that video. There’s really no reason to be heating up the broken bolt directly like he was doing, I’ve never done that. Ideally you want to put the least possible amount of heat into the bolt that needs to come out. You need the base metal with the female threads to expand size, to that’s where you want the heat. In difficult cases I will quickly cool the broken bolt immediately before beginning extraction, in an effort to shrink it slightly so it’s not so tight.

[Author]

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