I used a scrap of 5/8″ MDF to set a thermometer on while calibrating it in a steamer. The resultant expansion surprised me.
An unsteamed piece of scrap is shown for comparison.
First, the amount of expansion was way more than I’d expected.
Second, the expansion was all in one dimension, thickness, and none to width or length.
Thickness exactly doubled (at the ends where the weight of the thermometer did not inhibit movement)while length and width directions of the original board were unchanged.
BruceT
Edited 4/12/2009 3:35 pm by brucet9
Edited 4/12/2009 3:37 pm by brucet9
Edited 4/12/2009 3:41 pm by brucet9
Replies
I think as it dried it shrunk so much the image completely dissapeared. =)
~ Ted W ~
Cheap Tools! - MyToolbox.net
Meet me at House & Builder!
Edited 4/13/2009 4:13 am by Ted W.
I take it the image that I can see so clearly in my post is invisible to you?http://lh6.ggpht.com/_4WLhW9EccE8/SeIlcjbhGjI/AAAAAAAAAMU/pnjuZVFM6Z0/P1050152.JPGThe link is to an image in a Picasa web album. I wonder if that is viewable only by password?
BruceT
Bruce, the image from picasa isn't working. I don't need to see it, since your description explains it very well. Also, having seen MDF left out in the rain. But for other's sake maybe you should just use the attachment tool. You'll have to make a new post, since you can't attach a file when editing an existing post.
I gave up on trying to use images at other url's a long time ago, for just this reason.
btw, thanks for sharing this information. A lot of people don't realize just how sensitive MDF is to moisture. Sort of like dropping a dry celulose sponge into a bucket of water. ~ Ted W ~
Cheap Tools! - MyToolbox.netSee my work - TedsCarpentry.com
Nothing for me either and for me the link doesn't work. The best way to post photos is using the "attach files" button. Just be sure you resize them down to 80k or so. Otherwise we're all looking at the photos from an inch away.
Runnerguy
"Nothing for me either and for me the link doesn't work."Would you try it again, please? I changed that album setting to "public", so it should be visible now.
BruceT
No go Bruce. Both in IE and FF.
Here's what I get when clicking on the link:
Google
Error
I get a 404 not found
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Not an April Fool's joke...I can see the picture of the two scraps of mdf placed on what appears to be the top of a table saw.
Question: If I build a single story house in Florida with mdf and the weather becomes steamy, will I end up with a two story house, or just cathedral ceilings? :-)
They'll make you tear it down because it will infringe on setback lines
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I can see it now but why didn't you at least have the basic courtesy in your last edit to note you've added the image (or follow it up once you saw it yourself)? Here we are trying to help you out and then all our in-thread feedback now makes us look like schmucks.
Runnerguy.
"Here we are trying to help you out and then all our in-thread feedback now makes us look like schmucks."
I didn't think anybody looked like a schmuck until just now.
"I can see it now but why didn't you at least have the basic courtesy in your last edit to note you've added the image "Easy, big guy. Don't blow a gasket. The image link was there from the beginning. Several variations of editing the link did not help. Turns out the problem was that Picasa's server blocks access to images unless the poster specifically unlocks them. After I unlocked the picture, I had to rush out, so I fugured I'd send you a post when I got back to see if the fix had worked.Sorry if I ruined your day.Happy EasterBruceT
still not fixedNot Found
The requested URL /_4WLhW9EccE8/SeIlcjbhGjI/AAAAAAAAAMU/pnjuZVFM6Z0/P1050152.JPG was not found on this server.
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I was only mildly annoyed until you started messing with runnerguy's head.Now I'm not speaking to you.AitchKay
Sorry you feel that way, Aitchkay, I enjoy reading your posts. I get a little peeved when a guy tees off on me for a simple mistake. Most guys here would have, and in fact most did, simply suggest another way to insert a pic.I thought Picasa would be an easier way to do it, but I'll just have to revert to Photoshop and Taunton uploads from now on. Lesson learned.BruceT
Irfanview is one free and real easy photo resizer many here use, mysellf included...no photoshop, or hoops to upload a bunch of pics easily.
Sorry, Bruce, I should have thrown in one of those smiley faces -- I was joking.I have no idea why runnerguy was so ticked. I understand that large pictures can be a problem with dialup, old computers, etc.But those of us with relatively new computers and/or high-speed internet don't regularly abuse others for their stone-age equipment, do we?After catching a bunch of flak a few times, I finally figured out one way to dumb-down my pics -- I choose them from iPhoto on my Mac, and click on the email option. It offers me the option of re-sizing at that time. Then I can send it to myself, and post it from the copy in my inbox.There's got to be easier ways, and it's on my list of questions for my next session with a computer guru.Meanwhile, I've at least found one way to keep out of trouble here on BT!AitchKay
I should have picked that up. As I remember now, you have shown a sort of dry wit in your posts.Mac stuff is so much better than PC. I might change over when this PC box gets too tired to run anymore, but then I couldn't have the joy of messing with anti virus programs anymore.BruceT
Edited 4/13/2009 11:06 am by brucet9
I don't think that's the problem necessarily. I use Picassa a fair amt.I agree with Ted that you have good info there. I was going to guess 60-80% wet expansion, but it does vary by what brand it is.But the point of the criticism is that you obviously wanted to share information. One of the basics of communication with an audience is to speak in a language used by that audience.This forum has the tools to attach photos very easily. There is your audience and language. Fiddle-farting around with a hybrid piglatin can be a fun exercise and sometimes educational, but it depends on your POV I guess, whether it works to get an idea across.
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Drat, I thought Picasa would be an easier way to re-size and post than resizing in Photoshop, saving the smaller file, uploading to Taunton and then copying that link into the post. Sorry for all the drama.
So here it is at last where all can see, assuming anyone cares by now. It sure did open my eyes about using MDF where wetness is a possibility.
View Image
BruceT
From what I can see, I am unsure that that IS MDF, you sure it's not HDF? HDF is commonly called "Particle Board" like Counter top and shelving boards..also used as underlay/subfloor in some manufactured homes on wheels.Either or, I suspect both would swell quite a lot with steam.
Here I was thinking "That's an awfully light colour for MDF"without it ever registering in my mind it might be something else.
Good catch, Malo old boy, have your master give you an extra dog bone!MDF will swell an awful lot though, even tho this photo might not be same product.
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The foreground hunks look either ragged from huge particles or sawn with a ditch witch.
sure that isn't canine incisor tracks?
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Beaver trax.
I didn't see any beaver furr there
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The dog ate the beaver..LOL
C'mon guys, give my poor old Delta band saw a break!By the way, I don't know if I should look for advice from guys who can't tell a beaver from a band saw. :)(I'm pretty sure there's another potential joke lurking in there somewhere and one of you guys is bound find it.)
BruceT
I think that joke has something to do with keeping your fingers safe by not getting too close to either one, doesn't it?
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LOLI knew you wouldn't let me down.
BruceT
that was ditch witch....
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming<!----><!----><!---->
WOW!!! What a Ride!
Forget the primal scream, just ROAR!!!
"Some days it's just not worth chewing through the restraints"
Nope, it's MDF not HDF. BruceT
thanks...
ya had me wundering...
try http://www.irfanview.com instead of photoshop... KISS all the way thru...
lots of threads on how to here if ya care to search...
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming<!----><!----><!---->
WOW!!! What a Ride!
Forget the primal scream, just ROAR!!!
"Some days it's just not worth chewing through the restraints"
Thanks for the irfanview idea. I don't mind the Photoshop part, especially since I can adjust sharpness, brightness, contrast and color correction when necessary. I just don't care for the slow and relatively clumsy Taunton upload and insert process. BruceT
you either...
and the dial uppers get timed out on the uploads if the file is one KB too large...
Irfanview seems to be about as painless as it could be...
you can do the same with irfanview...
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming<!----><!----><!---->
WOW!!! What a Ride!
Forget the primal scream, just ROAR!!!
"Some days it's just not worth chewing through the restraints"
I've seen such products expand 2x and more when they get wet. They expand in thickness because that's the direction they were compressed in manufacture -- kinda like one of those thick pieces of paper you throw into the water and it expands into a sponge.
I generally wouldn't trust any wood composite material in a use where it might get wet unless it was rated for exterior exposure. And even then it can be iffy.
Did you experiment on exterior mdf also?
John
Nope, this was more of an accident than an experiment.Seems like exterior grade would have to be a whole lot better.BruceT
Yes, the exterior grade MDF I tested in the 90's was excellent. After 48 hours in a bucket of water a 1" by 2" chunk was still 1" by 2" and the thickness grew by .002". It was .750" material, BTW.The brand was "Medex" and only Paxton's in Denver carried it back then. It has a pinkish cast and cost about double the price of regular MDF. Also, it did not stink like regular MDF. They mostly marketed it for exterior routed signs. I have one sign I routed that has been outside on a post for 10 years with only latex paint to protect it, and no worries yet.Bill
I've used a lot of exterior Medex over the years.But I think they must have changed something in the formula 5-6 years back. Doesn't seem to perform as well any more.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Piffin,That is sad to hear. Whatever happened to "onward and upward" as our society's motto?Bill
regulated out of existence.
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