| Page 1 of 2 | 1 | 2 |
|
|
exploding MDF
So Im out in the garage today working on a new router table. A few
days ago I took two pieces of 1/2 MDF, glued them together, clamped them tightly and let them sit. Today I need to rip those pieces down into a slimmer shape. I started to slide the mdf into the blade, got about 14 inchs into the cut when the wood seemed to explode! I have no idea what happened, but explode is about as close of a description as I can get. Pieces went flying everywhere, into my gut (lots of blood and bruises from that one, but no trip to the hospital), my wifes truck (that one is gonna cost me a pretty penny) and all over the garage! I was being safe around the saw, push sticks and hold downs and all. Has anyone ever had any trouble with perhaps weak spots in your wood reacting poorly to a blade? Jason |
I'm just guessing, but I would bet on it having some residual tensions
from the glue up that caused it to warp and bind up against the blade. If it had been a more solid peice of wood things might have been worse. Jason wrote: So Im out in the garage today working on a new router table. A few days ago I took two pieces of 1/2 MDF, glued them together, clamped them tightly and let them sit. Today I need to rip those pieces down into a slimmer shape. I started to slide the mdf into the blade, got about 14 inchs into the cut when the wood seemed to explode! I have no idea what happened, but explode is about as close of a description as I can get. Pieces went flying everywhere, into my gut (lots of blood and bruises from that one, but no trip to the hospital), my wifes truck (that one is gonna cost me a pretty penny) and all over the garage! I was being safe around the saw, push sticks and hold downs and all. Has anyone ever had any trouble with perhaps weak spots in your wood reacting poorly to a blade? Jason |
On Sat, 09 Apr 2005 22:55:03 -0500, Australopithecus scobis
wrote: On Sun, 10 Apr 2005 03:07:15 +0000, Jason wrote: I started to slide the mdf into the blade, got about 14 inchs into the cut when the wood seemed to explode! While we wait for answers from people who actually know what they're talking about, I'll wave my hands and say "steam explosion." Water in your glue couldn't get out and saturated nearby areas of mdf, then the sawblade superheated that area. If he'd have grounded it first, that wouldn't have happened. Unless he cleaned it with acetone. -- LRod Master Woodbutcher and seasoned termite Shamelessly whoring my website since 1999 http://www.woodbutcher.net Proud participant of rec.woodworking since February, 1997 |
"Randy" wrote in message ... I'm just guessing, but I would bet on it having some residual tensions from the glue up that caused it to warp and bind up against the blade. If it had been a more solid peice of wood things might have been worse. Solid wood tends to kickback and tosses it at you, but I never heard of it exploding. The fact that the fibers run in one direction and are fairly long would help there. MDF has no fibers like that. You mention tensions from gluing. I wonder if it absorbed the water from the glue and swelled it making that tension? |
On Sun, 10 Apr 2005 03:07:15 +0000, Jason wrote:
I started to slide the mdf into the blade, got about 14 inchs into the cut when the wood seemed to explode! While we wait for answers from people who actually know what they're talking about, I'll wave my hands and say "steam explosion." Water in your glue couldn't get out and saturated nearby areas of mdf, then the sawblade superheated that area. -- "Keep your ass behind you" vladimir a t mad {dot} scientist {dot} com |
I'm only guessing, but: Yes, similar to case hardening in solid woods.
The glue up resulted in some form of internal stresses, and when it was sawn, the peice twisted, and bound up on the blade. If it was a peice of solid wood there would have been a nasty case of kick back. Another possibility is that the glue wasn't all the way dry, and bound up on the front of the blade, resulting in the peice being driven down into the table, and things did the "rapid spontaneous disassembly" thing. Edwin Pawlowski wrote: "Randy" wrote in message ... I'm just guessing, but I would bet on it having some residual tensions from the glue up that caused it to warp and bind up against the blade. If it had been a more solid peice of wood things might have been worse. Solid wood tends to kickback and tosses it at you, but I never heard of it exploding. The fact that the fibers run in one direction and are fairly long would help there. MDF has no fibers like that. You mention tensions from gluing. I wonder if it absorbed the water from the glue and swelled it making that tension? |
Australopithecus scobis wrote in
e: On Sun, 10 Apr 2005 03:07:15 +0000, Jason wrote: I started to slide the mdf into the blade, got about 14 inchs into the cut when the wood seemed to explode! While we wait for answers from people who actually know what they're talking about, I'll wave my hands and say "steam explosion." Water in your glue couldn't get out and saturated nearby areas of mdf, then the sawblade superheated that area. And it wouldn't have happened with hand tools, right? When was the last time the dozuki kicked back? Patriarch, also in smartass mode... |
LRod wrote:
On Sat, 09 Apr 2005 22:55:03 -0500, Australopithecus scobis wrote: On Sun, 10 Apr 2005 03:07:15 +0000, Jason wrote: I started to slide the mdf into the blade, got about 14 inchs into the cut when the wood seemed to explode! While we wait for answers from people who actually know what they're talking about, I'll wave my hands and say "steam explosion." Water in your glue couldn't get out and saturated nearby areas of mdf, then the sawblade superheated that area. If he'd have grounded it first, that wouldn't have happened. Unless he cleaned it with acetone. How many times does it have to be said? The circuit breaker protects the wiring NOT the MDF? Any damage to the saw blade? I'm wondering about a "freak" occurrence where you might have had a piece of metal in the MDF mix. |
In article , Unquestionably Confused wrote:
Any damage to the saw blade? I'm wondering about a "freak" occurrence where you might have had a piece of metal in the MDF mix. Yeah, I wonder about that too. Seems more likely than anything resulting from residual moistu the OP said he glued it up "a few days ago" which should be plenty of time for moisture to disperse and dissipate. I've cut MDF glue-ups within a couple hours of gluing, and never experienced anything similar. -- Regards, Doug Miller (alphageek at milmac dot com) Nobody ever left footprints in the sands of time by sitting on his butt. And who wants to leave buttprints in the sands of time? |
Doug Miller wrote: In article , Unquestionably Confused wrote: Any damage to the saw blade? I'm wondering about a "freak" occurrence where you might have had a piece of metal in the MDF mix. Yeah, I wonder about that too. Seems more likely than anything resulting from residual moistu the OP said he glued it up "a few days ago" which should be plenty of time for moisture to disperse and dissipate. I've cut MDF glue-ups within a couple hours of gluing, and never experienced anything similar. Maybe. Some years ago, I had a piece of OSB disintegrate as I was crosscutting it on an RAS. Tore up my right hand a bit and a chunk large enough to matter hit me in the groin so hard it was 10 minutes before I realized my hand was pumping blood all over the place. What happen? My guess: lack of glue at the point I was cutting allow wood chips to catch, ride the blade and catch again in the kerf, ripping the kerf apart, and flinging wood all over the place. I don't know if MDF fibers can do the same, but I'd guess it's possible. Even a small chunk of metal that rides a tooth instead of getting flung would something similar, I'd guess. A larger metal piece might just tear the hell out of things more immediately (as if 1/1000th of a second is going to make a lot of difference). |
On Sun, 10 Apr 2005 02:24:02 -0500, the inscrutable Patriarch
spake: Australopithecus scobis wrote in ie: On Sun, 10 Apr 2005 03:07:15 +0000, Jason wrote: I started to slide the mdf into the blade, got about 14 inchs into the cut when the wood seemed to explode! While we wait for answers from people who actually know what they're talking about, I'll wave my hands and say "steam explosion." Water in your glue couldn't get out and saturated nearby areas of mdf, then the sawblade superheated that area. And it wouldn't have happened with hand tools, right? When was the last time the dozuki kicked back? The little red button on the end of my ryoba puts it in automatic kickback-free mode. I leave it engaged. -- STOP LIVING LIKE VEAL ----------------------- http://diversify.com Veal-free Websites |
Charlie Self says...
Maybe. Some years ago, I had a piece of OSB disintegrate as I was crosscutting it on an RAS. Tore up my right hand a bit and a chunk large enough to matter hit me in the groin so hard it was 10 minutes before I realized my hand was pumping blood all over the place. What happen? My guess: lack of glue at the point I was cutting allow wood chips to catch, ride the blade and catch again in the kerf, ripping the kerf apart, and flinging wood all over the place. I don't know if MDF fibers can do the same, but I'd guess it's possible. Even a small chunk of metal that rides a tooth instead of getting flung would something similar, I'd guess. A larger metal piece might just tear the hell out of things more immediately (as if 1/1000th of a second is going to make a lot of difference). Ouch. I feel your pain. I could see that happening more easily if there was a ripping blade in the RAS where a crosscut or laminate blade would have been much better. The manager of one of the Indy BORG said that OSHA is so strict on RAS's that there's is caged to the extent that it is almost worthless. |
Jason wrote:
the saw, push sticks and hold downs and all. Has anyone ever had any trouble with perhaps weak spots in your wood reacting poorly to a blade? I have had some interesting things happen with *wood*, but MDF ain't wood and is remarkably well-behaved, cutting wise. This is a very bizaare story. |
Hax Planks wrote: Ouch. I feel your pain. I could see that happening more easily if there was a ripping blade in the RAS where a crosscut or laminate blade would have been much better. The manager of one of the Indy BORG said that OSHA is so strict on RAS's that there's is caged to the extent that it is almost worthless. Combination blade, IIRC. No matter how bizarre an accident is, there is always that chance for error, or for simple chance crappy luck, that creates the hassle. Though it wasn't the saw's fault, I got rid of it the next week, and have seldom used an RAS since. Kind of silly, because it was almost certainly a combination of operator error--did I have the wood all the way against the back fence--or poor wood storage. Or both. |
Charlie Self says...
Combination blade, IIRC. No matter how bizarre an accident is, there is always that chance for error, or for simple chance crappy luck, that creates the hassle. Though it wasn't the saw's fault, I got rid of it the next week, and have seldom used an RAS since. Kind of silly, because it was almost certainly a combination of operator error--did I have the wood all the way against the back fence--or poor wood storage. Or both. I've never had a problem using a RAS, though I never used one frequently enough to lose the required healthy fear of it. They seem to be increasingly rare these days. One would have to fall into my lap for cheap before I would think about buying one, since the table saw can be made to do the same tricks with some fixtures. |
I checked out the saw and the remaining mdf pieces that I could find
today. The blade and saw are in great shape, no signs of any mishap at all. I found a couple of pieces of shrapnel mdf, it does look like I may have had a small, eraser head size dry spot between the two boards where glue didn't make it. It's possible though that the glue just absorbed into that section. Or the glue could have been an additional projectile. As of this morning, my stomach looks like I got into a sumo wrestle with one of the blue man group. The cuts look like they may leave a cool scar, which I guess is a bonus since I will be able to make up cool knife fighting stories instead of telling ones about lame compressed wood bombs. I have a nice leather aparon on order, so hopefully I'll be back in the shop this weekend. How many times does it have to be said? The circuit breaker protects the wiring NOT the MDF? Any damage to the saw blade? I'm wondering about a "freak" occurrence where you might have had a piece of metal in the MDF mix. |
Jason wrote:
fighting stories instead of telling ones about lame compressed wood bombs. I have a nice leather aparon on order, so hopefully I'll be back in the shop this weekend. Since you raise the safety apparel issue, I'll ask: Were you wearing eye protection? If not, will you be doing so in the future? |
Oh yeah, I have always been fairly safe around the tools. We recently had
our first baby and I have been extra careful since then. At the time, I had on my glasses, ear protection and was actually wearing a mask since I dont have the greatest dust collection in the world and mdf dust leaves me hacking for days. Since you raise the safety apparel issue, I'll ask: Were you wearing eye protection? If not, will you be doing so in the future? |
In article , Unquestionably Confused wrote:
Jason wrote: fighting stories instead of telling ones about lame compressed wood bombs. I have a nice leather aparon on order, so hopefully I'll be back in the shop this weekend. Since you raise the safety apparel issue, I'll ask: Were you wearing eye protection? If not, will you be doing so in the future? Eye protection, hell! I've said it before, many times, and I'll say it again: there are *other* things on your face that are worth protecting *too*, not just your eyes. I wouldn't fancy catching one of these MDF bombs in the teeth. Face shield, face shield, face shield! -- Regards, Doug Miller (alphageek at milmac dot com) Nobody ever left footprints in the sands of time by sitting on his butt. And who wants to leave buttprints in the sands of time? |
"Doug Miller" wrote in message . .. In article , Unquestionably Confused wrote: Jason wrote: fighting stories instead of telling ones about lame compressed wood bombs. I have a nice leather aparon on order, so hopefully I'll be back in the shop this weekend. Since you raise the safety apparel issue, I'll ask: Were you wearing eye protection? If not, will you be doing so in the future? Eye protection, hell! I've said it before, many times, and I'll say it again: there are *other* things on your face that are worth protecting *too*, not just your eyes. I wouldn't fancy catching one of these MDF bombs in the teeth. Face shield, face shield, face shield! I concur. I have seen enough accidents to make sure I got a good one., I went to an industrial safety supply house. I got the kind that fits onto a hard hat. And I got the toughest, thickest polycarbonate face shields they have. A bunch of them. Just to make sure I have plenty around. I have had several smacks in the face shield with various objects. It makes a big noise, but I was well protected. Best investment in safety equipment I ever made. And I am, by nature, quite cautious and safety conscious. I even wear additional eye protection under the face shield if I think it warrants it. My face ain't pretty, but it can get considerably uglier. Gotta protect it!! |
Doug Miller wrote: Eye protection, hell! I've said it before, many times, and I'll say it again: there are *other* things on your face that are worth protecting *too*, not just your eyes. I wouldn't fancy catching one of these MDF bombs in the teeth. Face shield, face shield, face shield! Yes and the face shield can often be dropped down to protect the throat too. -- FF |
|
On Sun, 10 Apr 2005 02:24:02 -0500, Patriarch
wrote: Australopithecus scobis wrote in ie: On Sun, 10 Apr 2005 03:07:15 +0000, Jason wrote: I started to slide the mdf into the blade, got about 14 inchs into the cut when the wood seemed to explode! While we wait for answers from people who actually know what they're talking about, I'll wave my hands and say "steam explosion." Water in your glue couldn't get out and saturated nearby areas of mdf, then the sawblade superheated that area. And it wouldn't have happened with hand tools, right? When was the last time the dozuki kicked back? Patriarch, also in smartass mode... dunno.. ask Steve Knight.. mac Please remove splinters before emailing |
|
Speaking of face shields...
After a few minutes of sawdust generation, static electricity causes mine to get covered in a thick layer of dust. All attempts to wipe it away are temporary at best. Has anyone solved this dilemma, or am I the only one with this problem. Thanks, Tim |
|
On Thu, 14 Apr 2005 01:22:33 GMT, (Doug Miller)
wrote: In article , lid (chipGeek) wrote: Speaking of face shields... After a few minutes of sawdust generation, static electricity causes mine to get covered in a thick layer of dust. All attempts to wipe it away are temporary at best. You obviously haven't grounded it properly. g,d,&r Damn! I thought that was my job... -- LRod Master Woodbutcher and seasoned termite Shamelessly whoring my website since 1999 http://www.woodbutcher.net Proud participant of rec.woodworking since February, 1997 |
|
Andy Dingley wrote:
On Thu, 14 Apr 2005 00:29:28 +0000, lid (chipGeek) wrote: Has anyone solved this dilemma, Use an old face shield. A dirty one is less insulating, so stores less charge. You can also try "anti-dim" (anti-condensation) pastes wiped onto them - these have a similar effect. I sometimes use the stuff supplied for Soviet gasmasks, because it's cheap in the surplus shop. How about fabric softener spray or tissues? Seems to me that back in the "golden old days" of computerdom (you know, mid'-80's) there was more fear of static in the office than, say, acetone, static discharge in DC's, or stain on cherry, than anything else. I recall that folks were spraying fabric softener around the computer to defeat static. Since it supposedly softens and prevents that dreaded "static cling" it's probably worth a try. |
Unquestionably Confused wrote:
Andy Dingley wrote: On Thu, 14 Apr 2005 00:29:28 +0000, lid (chipGeek) wrote: Has anyone solved this dilemma, Use an old face shield. A dirty one is less insulating, so stores less charge. You can also try "anti-dim" (anti-condensation) pastes wiped onto them - these have a similar effect. I sometimes use the stuff supplied for Soviet gasmasks, because it's cheap in the surplus shop. How about fabric softener spray or tissues? Seems to me that back in the "golden old days" of computerdom (you know, mid'-80's) there was more fear of static in the office than, say, acetone, static discharge in DC's, or stain on cherry, than anything else. I recall that folks were spraying fabric softener around the computer to defeat static. Since it supposedly softens and prevents that dreaded "static cling" it's probably worth a try. I had forgotten the tricks you mentioned. :-) We use computer monitor cleaner with an anti static component in the mix to clean face masks.. There was a lot of build up of fine sawdust on the mask (better there than in the lungs I suppose) - -- now the spray/cleaner gives us longer between cleanings. -- Will Occasional Techno-geek |
|
Unquestionably Confused wrote: Andy Dingley wrote: On Thu, 14 Apr 2005 00:29:28 +0000, lid (chipGeek) wrote: Has anyone solved this dilemma, Use an old face shield. A dirty one is less insulating, so stores less charge. You can also try "anti-dim" (anti-condensation) pastes wiped onto them - these have a similar effect. I sometimes use the stuff supplied for Soviet gasmasks, because it's cheap in the surplus shop. How about fabric softener spray or tissues? Seems to me that back in the "golden old days" of computerdom (you know, mid'-80's) there was more fear of static in the office than, say, acetone, static discharge in DC's, or stain on cherry, than anything else. I recall that folks were spraying fabric softener around the computer to defeat static. Since it supposedly softens and prevents that dreaded "static cling" it's probably worth a try. Just don't use fabric softener around your microfiber cleaning cloths. They work by using static cling. |
Charlie Self wrote:
Unquestionably Confused wrote: Andy Dingley wrote: On Thu, 14 Apr 2005 00:29:28 +0000, lid (chipGeek) wrote: Has anyone solved this dilemma, Use an old face shield. A dirty one is less insulating, so stores less charge. You can also try "anti-dim" (anti-condensation) pastes wiped onto them - these have a similar effect. I sometimes use the stuff supplied for Soviet gasmasks, because it's cheap in the surplus shop. How about fabric softener spray or tissues? Seems to me that back in the "golden old days" of computerdom (you know, mid'-80's) there was more fear of static in the office than, say, acetone, static discharge in DC's, or stain on cherry, than anything else. I recall that folks were spraying fabric softener around the computer to defeat static. Since it supposedly softens and prevents that dreaded "static cling" it's probably worth a try. Just don't use fabric softener around your microfiber cleaning cloths. They work by using static cling. FWIW, fabric softener does not have much effect on the static cling of microfiber. I made the mistake of buying a microfiber jacket a while back. It has been fabric-softened several times and will still pull the fur off a pushstick at 20 paces. -- --John to email, dial "usenet" and validate (was jclarke at eye bee em dot net) |
In article , No Spam wrote:
(Doug Miller) wrote: - You may be insulating yourself from the ground. Wear shoes with *leather* soles, or go barefoot. Shiver. I went barefoot ONCE into a store area in the house where I [snip gruesome tale] Workshops are no place to even contemplate bare feet - even for a few seconds. I quite understand the hazards, but I think that thirty seconds with a sander would be sufficient time to make the proper experiments, without posing any significant risk. -- Regards, Doug Miller (alphageek at milmac dot com) Nobody ever left footprints in the sands of time by sitting on his butt. And who wants to leave buttprints in the sands of time? |
|
On 14 Apr 2005 03:35:21 -0700, the inscrutable "Charlie Self"
spake: Unquestionably Confused wrote: Andy Dingley wrote: On Thu, 14 Apr 2005 00:29:28 +0000, lid (chipGeek) wrote: Has anyone solved this dilemma, Use an old face shield. A dirty one is less insulating, so stores less charge. You can also try "anti-dim" (anti-condensation) pastes wiped onto them - these have a similar effect. I sometimes use the stuff supplied for Soviet gasmasks, because it's cheap in the surplus shop. How about fabric softener spray or tissues? Seems to me that back in the "golden old days" of computerdom (you know, mid'-80's) there was more fear of static in the office than, say, acetone, static discharge in DC's, or stain on cherry, than anything else. I recall that folks were spraying fabric softener around the computer to defeat static. Since it supposedly softens and prevents that dreaded "static cling" it's probably worth a try. Just don't use fabric softener around your microfiber cleaning cloths. They work by using static cling. Y'mean you guys don't have monitor squeegees? I love mine, and it works on the TV, too. Mine came from giveaways at COMDEX. http://www.promowebsite.com/screensweeppage.htm http://www.4imprint.com/Screen-Sweep...333/~CA333.htm I use a damp cloth on my face shield (which seems to work fine) but wonder if something like Rain-X or Fog-X would help not only the static but the smaller scratches. I'll have to try it. ---------------------------------- VIRTUE...is its own punishment http://www.diversify.com Website Applications ================================================== |
Larry Jaques wrote:
I use a damp cloth on my face shield (which seems to work fine) but wonder if something like Rain-X or Fog-X would help not only the static but the smaller scratches. I'll have to try it. I don't think that Rain-X will do anything for the scratches and might react with the plastic. I'll have to check - for some reason I thought that there might be a warning against using it on plastics or getting the solution on the car's finish. What might work better - asssuming one can find it is a product called "Slipstream" an aircraft polish that was made to polish the plexiglass windscreens, etc. on aircraft. That I HAVE used on plastic and it does a great job. Also a great job on painted metal. I think I still have some left and I know I have a face shield that needs to be thrown away. If I can find both I'll introduce them to each otherg |
On Thu, 14 Apr 2005 06:17:39 -0700, Larry Jaques
wrote: snip I use a damp cloth on my face shield (which seems to work fine) but wonder if something like Rain-X or Fog-X would help not only the static but the smaller scratches. I'll have to try it. larry.. I used rain-ex anti fog on the inside of a face shield.. good news: It worked great and never fogged... bad news: the smell of the stuff never went away and I couldn't stand wearing the sucker.. mac Please remove splinters before emailing |
On Thu, 14 Apr 2005 06:17:39 -0700, Larry Jaques
wrote: I use a damp cloth on my face shield (which seems to work fine) but wonder if something like Rain-X or Fog-X would help not only the static but the smaller scratches. I'll have to try it. I have used Pledge spray furniture polish to deal with fine scratches in face shields and polycarbonate glasses. It works well for that, but I can't say that I've really observed what it does as far as static cling is concerned. -- "We need to make a sacrifice to the gods, find me a young virgin... oh, and bring something to kill" Tim Douglass http://www.DouglassClan.com |
| All times are GMT +1. The time now is 02:45 PM. |
|
Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004 - 2014 DIYbanter