questions about mdf

Chupa · 21st July 2004, 02:31 AM

2 qs...

first off, picked up some 1/2" mdf today to start on a box. in the bed of the truck, ran up stairs to take a shower, started to rain, ran outside and grabed it and brought them in the garage.
THe boards got a little wet, they werent sitting in standing water, just drizzled on a bit, no visible damage after they dried....

Is it safe to use them or should i not risk it....

2nd question..

is it better idea do go with 3/4" instead of the 1/2"? the box is going to be for some subs....

Immo_G · 21st July 2004, 11:18 AM

Water makes it expand a bit off memory, i guess if its not falling apart in layers its still fine. You might have a pattern of raised spots on it.

1/2 would be 12.5mm, 3/4 would be .. calculator ..
19mm. I used 18mm MDF for my sub box, and don't usually recommend anything under that. 12mm is probably too thin. Use it for a false floor or speaker spacer i guess, or parcel shelf?

pol · 21st July 2004, 07:47 PM

the wood is still good. unless like the previous statement.... ( if it has rised spots.) but it is still dense no? n e ways, u r using it for subs right? r the subwoofers heavy? how big is the woofer? you can use 1/2" mdf, u can use 5/8 mdf... hey what ever fits ur taste! let me tell u a true story.... mdf isn't air tight!!! end of story but that doesn't mean to throw it away. it is in fact true that it is REALLY RIGID! i still use it. take 3 pcs of 3/8th mdf... 4 inches by 4 inches take a vacuum put it at center... start the vacuum... viola! the 3 pcs r stuck together! end of story buddy... after u use the wood seal the inside of the enclosure with fiberglass or polyurethane. that'll help. 8 inch woofers to 10 inchers... i'd use 1/2 to 5/8 mdf... if they r heavy however use 3/4 mdf of heck double up on it! good luck!

richie00boy · 21st July 2004, 08:08 PM

MDF is airtight. You will find that if you simply lay two smallish pieces of MDF together and slide them across each other a few times to create a vacuum you get the same effect as what you just described. Basically you remove all the air inbetween them and MDF is so flat and smooth that it can hold itself together... just.

If your vacuum cleaner could suck through MDF you would never move it across the floor!

Chupa · 22nd July 2004, 12:05 AM

i decided to go with 3/4" mdf.... its going to house some kicker compVR 10s...

what kind of glue should i use to seal the box? i was just thinking liquid nails, or is that a bad idea?

21st July 2004, 02:31 AM	#1
Chupa diyAudio Member Join Date: Jul 2004 Location: FL	questions about mdf 2 qs... first off, picked up some 1/2" mdf today to start on a box. in the bed of the truck, ran up stairs to take a shower, started to rain, ran outside and grabed it and brought them in the garage. THe boards got a little wet, they werent sitting in standing water, just drizzled on a bit, no visible damage after they dried.... Is it safe to use them or should i not risk it.... 2nd question.. is it better idea do go with 3/4" instead of the 1/2"? the box is going to be for some subs....

21st July 2004, 07:47 PM	#3
pol diyAudio Member Join Date: Jun 2004 Location: las vegas	the wood is still good. unless like the previous statement.... ( if it has rised spots.) but it is still dense no? n e ways, u r using it for subs right? r the subwoofers heavy? how big is the woofer? you can use 1/2" mdf, u can use 5/8 mdf... hey what ever fits ur taste! let me tell u a true story.... mdf isn't air tight!!! end of story but that doesn't mean to throw it away. it is in fact true that it is REALLY RIGID! i still use it. take 3 pcs of 3/8th mdf... 4 inches by 4 inches take a vacuum put it at center... start the vacuum... viola! the 3 pcs r stuck together! end of story buddy... after u use the wood seal the inside of the enclosure with fiberglass or polyurethane. that'll help. 8 inch woofers to 10 inchers... i'd use 1/2 to 5/8 mdf... if they r heavy however use 3/4 mdf of heck double up on it! good luck! __________________ " You wanna race? My bass waves will travel faster than ur car..."

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21st July 2004, 11:18 AM	#2
Immo_G diyAudio Member Join Date: Sep 2003 Location: Vic, Au	Water makes it expand a bit off memory, i guess if its not falling apart in layers its still fine. You might have a pattern of raised spots on it. 1/2 would be 12.5mm, 3/4 would be .. calculator .. 19mm. I used 18mm MDF for my sub box, and don't usually recommend anything under that. 12mm is probably too thin. Use it for a false floor or speaker spacer i guess, or parcel shelf?

21st July 2004, 08:08 PM	#4
richie00boy Did it Himself diyAudio Member Join Date: Nov 2003 Location: Gloucestershire, England, UK	MDF is airtight. You will find that if you simply lay two smallish pieces of MDF together and slide them across each other a few times to create a vacuum you get the same effect as what you just described. Basically you remove all the air inbetween them and MDF is so flat and smooth that it can hold itself together... just. If your vacuum cleaner could suck through MDF you would never move it across the floor!

22nd July 2004, 12:05 AM	#5
Chupa diyAudio Member Join Date: Jul 2004 Location: FL	i decided to go with 3/4" mdf.... its going to house some kicker compVR 10s... what kind of glue should i use to seal the box? i was just thinking liquid nails, or is that a bad idea?