[OP]
Contributor
I need to face glue up several panels that are too wide for clamps out of two layers of 3/4" MDF (30" x 23"). Is it safe to do this in a vacuum press or would I risk warping the final glue up? It seems that since a vacuum press applies pressure from all sides that it would not tend to warp but has anyone does this successfully?
THX
Contributor
As long as your base platen (table) is flat, the glued up MDF will be flat.
John
In Memoriam
Would definitely get 1.5" MDF rather than glue.
Vac., may help but uniform glue lines and pressure will never equal the flatness of a 1.5" production squished panel.
Moreover, you will have 2 density gradients in your sandwich, one with a thick slab.
Contributor
I have made thicker MDF panels many many times for speaker enclosures. Easy and works great. Never had a delamination and panels stay naturally flat. I just use regular Titebond I glue and smear it on but not too thick. Panels get real slippery! Then clamped using cauls, various jaw length clamps, even cement blocks on huge panels. Just use oversized pieces and trim to actual size after glueing as is too hard to hold the pieces perfectly in alignment while glueing as they will slide on you. I have used 5/8" and 3/4" and made panels up to 4 layers thick. I was never able to source thicker MDF panels locally but as Pat says, that would be the ideal easy solution.
Contributor
Actually I face glued two thicknessess of 1 inch mdf using unibond 800 and vacumn pressed the lamination, worked great but it was a lamination along the lines of 18 x 84. Having said that if I could find mdf in the proper thickness I would use that product as a first course of action... I see you are in Raleigh NC, might want to check with the Wurth Wood group in Raleigh, they carry lots of sheet goods, them having 6/4 mdf wouldnt surprise me one bit..Originally Posted by David Kuzdrall
Member
I wouldn't want to have to be the one handling a 6/4 sheet of MDF. 3/4 is plenty heavy for me. I reckon that weighs 'round abouts 135 lbs. Would you use a full sheet of that? If you don't, got a place to store it? Got a means to move it when it is in your way?
Thickest I've seen is 1".
Member
I have never had a problem face gluing MDF. I do spray water on the show faces of the MDF as an attempt to equalize the sheets accounting for the water in the glue faces. I like to leave the glue up in the press for a good while but I back off the pressure after 45 minutes to an hour. My neighbour builds prototypes and for jobs that don't have the budget for tool board he laminates MDF life a madman.
Member
I have successfully glued 2 panels of 3/4" MDF using Titebond glue. One thing that I did was to use a notched trowel to spread the glue. I got a very even distribution of the glue that way.
Contributor
make sure you have an even spread of glue and not too much. I use adhesive rollers I get from the depot. They look sort of like one side of velcro and you can get a really nice even spread easily.
Steve Jenkins, McKinney, TX. 469 742-9694
Always use the word "impossible" with extreme caution
Member
Like a previous poster said - if your platen is flat the MDF will be flat. I use my vacuum press more for stuff like this that I do for veneering (which is why i got it in the first place). I can't imagine trying to handle and cut accurately a 4x8 sheet 1.5" MDF even with a track saw and a few buddies. I do my 12" Delta RAS table every couple of years - 1.5" laminate out of 2 3/4" MDF sections - I then level the new top to the saw and check with a 4' machinists straight edge - it is as perfectly flat as the stock MDF it was made from.
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