Festool Owners Group

GENERAL DISCUSSIONS => Workshops and Mobile Vehicle-Based Shops => Topic started by: RobS888 on June 14, 2021, 05:19 PM

Title: MDF MFT outfeed table, is it strong enough?
Post by: RobS888 on June 14, 2021, 05:19 PM
Hi,

I found the basis for this drawing on 3d warehouse, can't find it now, so I can't give credit. It was in French.
(http://)
It seems to be connected with 5mm dominos, there are 5 vertical support pieces, so i'm not sure if it would work.

I can't see the image I attached...

Rob
Title: Re: MDF MFT outfeed table, is it strong enough?
Post by: tallgrass on June 14, 2021, 05:29 PM
MDF always seems to let me down over time. If it is actually being exposed to loads over time.
Title: Re: MDF MFT outfeed table, is it strong enough?
Post by: afish on June 14, 2021, 07:32 PM
MDF has its place but I would not use for that.  If you do at the very least seal it up real good.  It will help it preserve it.  That stuff is like a sponge and will swell if it gets wet.  I get a lot more life out of my tops when they are sealed.  I usually use whatever I have extra of at the time.  Last few times it was lenmar pre cat sanding sealer.  Even though its made to be sprayed I just rolled it on with a 4" foam roller and it works fine. 
Title: Re: MDF MFT outfeed table, is it strong enough?
Post by: RobS888 on June 15, 2021, 12:02 PM
MDF always seems to let me down over time. If it is actually being exposed to loads over time.

That's my concern as well. I'm not sure about the joints in any material, just seems so large for end grain to side grain.
Title: Re: MDF MFT outfeed table, is it strong enough?
Post by: jeffinsgf on June 15, 2021, 07:20 PM
I like MDO plywood for shop furniture. The last sheet I bought was a little different. Instead of a sheet of paper-like veneer on the surface, it had about a 1/8" thick top  and bottom veneer of MDF. It checks a lot of boxes...plywood strength; smooth, nondescript paintable surface; relatively flat (compared to normal plywood products) and good price (compared to other sheet goods, none of which are cheap these days).

I have a real hard time committing my few shop hours to building anything out of MDF.
Title: Re: MDF MFT outfeed table, is it strong enough?
Post by: AnthonyE on August 03, 2021, 07:36 AM
I would consider building the base cabinets out of plywood and even the bottom pieces of the torsion box.  I would have no problem using MDF for the top with some sort of finish applied. I used a mix of poly, turpentine and BLO for my top and love the finish. It soaked into the MDF and has a great surface finish.

I posted a pic of my unfinished tablesaw outfeed mft table.  I still need to install drawers.
Title: Re: MDF MFT outfeed table, is it strong enough?
Post by: Packard on August 03, 2021, 09:08 AM
Here is the engineering data on MDF.  You pretty much have to be an engineer to work with this data though:

https://www.makeitfrom.com/material-properties/Medium-Density-Fiberboard-MDF

Easier to understand and use is the Sagulator which calculates the load the material can carry (like how much weight a shelf can hold).

https://woodbin.com/calcs/sagulator/

Title: Re: MDF MFT outfeed table, is it strong enough?
Post by: RobS888 on August 03, 2021, 03:17 PM
Thanks for the help guys,

I went with 3030 aluminum extrusion. 46 x 46 base with 46 x 57 top section. Base is 21 inside and top is 5 inches inside. castors and 2 3/4 MDF make up rest of height to be even with table saw. I ordered 21 1/8 high vertical pieces and they came exactly that long.

Still assembling drawers out of scraps of ply and MDF. Even 1/2 inch MDf is pretty good for drawers. I have my old MFT style top on it, but need to get a full sheet of MDF and make a new one.
Title: Re: MDF MFT outfeed table, is it strong enough?
Post by: Packard on August 03, 2021, 04:24 PM
All lumber has gotten expensive, but it is shocking to me to see the prices of MDF which at Lowes is $44.48 per sheet.  The stuff used to cost $11.00 a sheet.  I don't use it often, so that price might be very old.  :But $44.00 was the price of nice red oak plywood, not MDF.
Title: Re: MDF MFT outfeed table, is it strong enough?
Post by: squall_line on August 03, 2021, 04:59 PM
All lumber has gotten expensive, but it is shocking to me to see the prices of MDF which at Lowes is $44.48 per sheet.  The stuff used to cost $11.00 a sheet.  I don't use it often, so that price might be very old.  :But $44.00 was the price of nice red oak plywood, not MDF.

3/4 MDF is down to $39.98 per sheet now, at least locally.  Almost 10% off!   ::)
Title: Re: MDF MFT outfeed table, is it strong enough?
Post by: tallgrass on August 04, 2021, 02:54 AM
As an engineer, the data on MDF is interesting.
Title: Re: MDF MFT outfeed table, is it strong enough?
Post by: Packard on August 04, 2021, 08:34 AM
As an engineer, the data on MDF is interesting.

Can you explain what some of the mechanical properties mean and how they are useful to us.

I am only familiar with shear and axial compressive loads.  The rest are all Greek to me.  The Sagulator is an easy site to use and the information is useful.  (I only hope it is accurate.)