I thought I would
pass along a little information about welding 4000 series steel. I am not
sure what material the Lancair engine mounts are made from but if it is a 4000
series steel then the material must be preheated before welding and then post
heated for 1/2 hour after welding to prevent cracking. 4340 steel is much
more prone to cracking than 4130 but they both will crack if not processed
correctly. If I was going to repair a cracked engine mount, I would have
it magna-fluxed after weld repair to check for cracks. Very small cracks
may show up, but if they can be removed with a little de-burr, then the welds
are OK. That is, they are OK, if processed correctly.
Craig Berland
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