Best adhesive for MDF?

Space Garbageman · Post by **Space Garbageman** » Fri Jun 18, 2010 7:53 pm

I'm building a model using 1/8 inch MDF for the main body panels. It's an angular, roughly box-like piece and all the sides have 3/8 inch flanges for joining. I've cut all my sections fairly precisely and they need to be assembled precisely as well, this thing has square sides. I really want to use conventional wood glue for my joints, I think it is the strongest bond for the MDF. But the sections are small-ish and the fit is critical, not to mention that I can't really sand the joints after bonding because of the amount of detail I've clad on the sides. I'm imagining getting glue on my parts and then trying to clamp these little sections together and making a mess of things. So I'm considering using CA instead. My plan would be to clamp each section together, wick some thin CA into the joint and then move on to the next section. My concern is I have doubts about the long-term durability of super-glued joints, I think I've heard something about it becoming brittle after a few years. This model will rely pretty heavily on the adhesive strength. Any advice from fellow scratch-builders?

Lt. Z0mBe · Post by **Lt. Z0mBe** » Fri Jun 18, 2010 9:11 pm

CA does get quite brittle after a while; wit has excellent tensile strength, but relatively low shearing strength. The weight of the MDF may be enough to shear the joints free if the thing is jostled.

What about epoxy or scoring the joint surface and using epoxy putty? Also, have you considered old fashioned carpenter's glue? The stuff is damned near impossible to break free from wood once set; it will actually take the wood/MDF with it.

I hop this helps.

Kenny

scratchy · Post by **scratchy** » Fri Jun 18, 2010 9:27 pm

I would go with an outdoor wood glue, it will stand up to moisture. Do you have to use MDF, once any moisture hits it over time, the MDF will expand, possibly ruining all the work that you've done.

If you're looking for a smooth surface like MDF, why not try Crezon board, it's a sign painters plywood. It has a sheet of paper laminated to it and it comes primed or bare.

However, it sounds like you've already got most of the work done, hate to see you start over.

WarpeD · Post by **WarpeD** » Fri Jun 18, 2010 9:45 pm

Titebond. Accept no substitutes. I use this all the time at work for assembling MDF, and the bonds it makes are usually stronger than the MDF itself. It is also rather forgiving of voids in the joint, whereas CA would not be. Get thee to Home Depot, Lowes or Ace Hardware.

TazMan2000 · Post by **TazMan2000** » Sat Jun 19, 2010 12:40 am

Wood and paper glues will adhear to the MDF, but may not hold well onto styrene unless you take 100 grit sandpaper and roughen up the surface. As it ages it may lose the bond with the styrene.
Contact cement, when properly applied will last the longest.

TazMan2000

Space Garbageman · Post by **Space Garbageman** » Sat Jun 19, 2010 9:55 am

Wood glue 4, CA 0. Thanks for all the feedback. I'll keep y'all posted with some pictures soon.

Beaveranger · Post by **Beaveranger** » Thu Jun 24, 2010 8:28 pm

WarpeD wrote:Titebond. Accept no substitutes. I use this all the time at work for assembling MDF, and the bonds it makes are usually stronger than the MDF itself. It is also rather forgiving of voids in the joint, whereas CA would not be. Get thee to Home Depot, Lowes or Ace Hardware.

^this^

Grew up in a cabinet shop, so this is def the route you want to go. Used it on my speakerbox in my soft top jeep (lots of humidity and gets rained on occasionally.) The glued joints help longer than the screws did.....