Thread: I nearly burnt my shed down!
31st Mar 2021, 05:28 PM #1
I nearly burnt my shed down!
I got hold of a load of old New Guinea Rosewood and have been making a bench out of it.
I have been cutting some of the rosewood on my bandsaw with a new 3/4" resaw blade. The bandsaw is a Laguna 14-12 with ceramic blade guide blocks. I had noticed some burning smells while cutting, and at one stage a minute or so after I had turned the BS off, I smelt burning and noticed a bit of smoke coming from the machine. Upon inspection, it appeared that fine sawdust had accumulated in the lower blade guide and was smouldering. I removed the guide block and extinguished it. Why did it catch fire, I asked myself, unlike any other wood? I switched to blackwood, there was also a burning smell and fine charred black fragments were being scattered over the table. I often get a few sparks off the ceramic guides with a new blade, but had never seen anything like this smouldering happen. FYI, the BS is also connected to my dust extractor.
Then I noticed that there was a build-up of sticky fine rosewood sawdust on each and every tooth of the saw blade. There was my answer - dust rubbing against dust, friction heating and causing ignition. I immediately replaced the blade, tried cutting the blackwood again with no issue, and vowed never to cut NG rosewood on a bandsaw ever again.
I thought that was worth sharing with you - today's Safety Share, if you will. Has anyone else had this problem with NG Rosewood? See pictures below also.
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31st Mar 2021, 08:15 PM #2
Get a spray bottle and mix up a squirt of dishwasher detergent and water and spray the blade when youíre cutting oily or resinous Timber, itíll help to stop it sticking or baking itself to the bandCheers
31st Mar 2021, 09:51 PM #3
See, if that had be me I'd have conducted some SCIENCE!
Create ignition! ... force the issue, see just where those limits lay...
Then again, I am a pyro with an 8 y.o mentality.
Looks like that blade needs a good soak in the turps.
31st Mar 2021, 11:24 PM #4
I think your problem is more the tpi of your re-saw blade. Going to a more aggressive 1 tpi blade and slowing down your feed will allow the saw blade gullets to actually clear the waste from the blade kerf. NGR can be problematic. Is your saw a two speed bandsaw?
It also looks like the back of your blade has been getting a fair work over by the rear thrust guide block / roller?
Very fortunate that you observed the smell and then had the sense to investigate the source. Smart move on your part.Mobyturns
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31st Mar 2021, 11:31 PM #5Member
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- Jan 2019
Wow, a sense of smell is invaluable... lucky you decided to investigate!
I've watched my friend use his Laguna bandsaw a few times and seeing those sparks around the guides was not encouraging! I guess it's more a set of freak circumstances though.
Thanks for sharing your experience...always appreciate a good safety share!
2nd Apr 2021, 07:40 AM #6GOLD MEMBER
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Iíve never had that happen in 40 years, and never with Rosewood. It looks like either the timber is wet, or the blade doesnít have enough set. Having that build up in the gullets wouldnít be doing the tyres any good either.
2nd Apr 2021, 09:52 PM #7
I have had blades gunk up like that twice but never had a burning smell. First time was green wood. Second time was very old recycled pine but it still contained resin. Both times happened in seconds. I have cut a fair bit of NG rosewood and not had any problems with it. I guess most timbers have the odd rogue board. My close encounter with fire was the belt sander so sparks and wood dust again.
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