Best glue/adhesive for MDF?

[rodsprit]

As topic says, what's the best adhesive for MDF?
Been reading for hours now.. People recommend so many different glues.. gorilla glue ( polyurethane ), liquid nails, Titebond II and III, and epoxy.

When I say best, I want the adhesive that would make the strongest join.
Another factor is drying, I don't want to start gluing on one side and then when I'm ready to mount it's already hardened where I started..

I have used epoxy before with MDF. It appears to be really strong. They use it to make airplanes.. so it should be the best. The downside is that it's really expensive!

The other adhesive I could use is Titebond II. Got no experience with this glue, but it is alot cheaper.
Perhaps Titebond will give a little weaker glue han epoxy. But is it worth it when comparing it with cost?

Finewoodworking has an article about this. They tested many different glues.
I didn't read it, but saw some results posted on another page. Was Titebond the strongest, closely followed by 2part epoxy? They glued on different types of wood. But not MDF, so I'm really unsure about what to think about it..

Unless someone says Titebond is better, I'm gonna go with 2part epoxy.

For those wondering, I am going to glue MDF plates ontop of each other., and also gluing a Sonotube(this is almost the same as MDF, its made of paperfibres) to MDF plates. It's for a sonosub, those interested can have a look here: http://home.lyse.net/dreier/atle/ht/ss12.jpg
Verry critical that it's airtight in the glues!

Can I have any input on which adhesive to use?

--
Dan

[Master Splinter]

Generally, all the modern glues from PVA on up, will give a finished joint that is stronger than the timber. The only exceptions to this are contaminated surfaces (ie teak) that aren't cleaned properly.

The big differences are in how waterproof they are, and how they react to load.

The bottom range of PVA glues are internal use only; the next step up are the cross-linked PVAs (I think titebond is a cross-linked PVA), which can be used outside. Then you have your polyurethane glues, and finally, epoxy.

PVAs (at least the bottom end ones) exhibit creep under load (joined surfaces can move over time); this isn't an issue with the cross-linked PVAs or epoxies.

Epoxy adhesives have the important extra attraction of being a gap filling adhesive; you can add specialised fillers and end up with something that is significantly stronger than the surrounding timber (http://www.westsystem.com/ss/testing-large-bonded-in-fasteners/). (or concrete (http://www.epoxyworks.com/21/index21.html)...). This can be particularly useful in MDF and chipboard when you want to use screws (for access) but you want to make sure you don't strip the holes.

Price wise - Selleys Durobond polyurethane or Titebond is about $20 for 500ml; marine epoxy (http://boatcraft.com.au/Shop/index.php?main_page=index&cPath=15&zenid=85d5b5c54f2ae71f2436112aeb86f558) is $35 for 750ml (not Selleys Araldite...its a ridiculous price, and its about the weakest epoxy on the market) - so that's 4 cents per ml compared to 4.6 cents per ml.

[Mr Brush]

I use Titebond III for MDF......one-part (no mixing...), long assembly time, water clean up, and the resulting joint is stronger than the MDF substrate.

MDF will delaminate long before the joint gives up.

[adhesive tape]

We use 2P10 thick glue from Fastcap (cynoacrylate glue), with the accelerator. Usually takes about 10 to 15 seconds to set. Sometimes the joint fails because the glue gets absorbed. Then we sand the end slightly to even out the joint (usually about 1 minute), and do it again, which takes another 10 seconds. Superglues are unforgiving because any real mistake will cause you to scrap the molding, and you only have a few seconds to set the joint properly. That said, it's been years since we used any yellow glue on MDF molding. Superglue is so much faster than anything out there.

[Master Splinter]

We use 2P10 thick glue from Fastcap ........

Spam the identical comment much???
Glue for MDF Mouldings (http://www.woodweb.com/knowledge_base/Glue_for_MDF_Mouldings.html)

Somehow, for something the size of a sonosub, (I'm presuming you haven't seen the pic) I think you'd go through several large ($20) containers of superglue, even if you could cover it all before it soaked in!

[kman-oz]

I've constructed many a sub enclosure from 19mm MDF in my youth and my experience has been this: 1) Any cross-linking PVA will be more than adequate, and 2) making MDF air-tight is harder than it might appear.

Before I started working with Titebond I used some basic yellow glue with MDF and found that the MDF would fail long before the glue joint ever would. For the laminated plates yellow glue is fine, but for filling gaps you'll need epoxy.

I'm not familiar with how a Sonsub works exactly, but if you're going to be dealing with very large air pressures inside you may want to consider a sealer for the inside and silicone for all the joints once it's constructed.

[Waldo]

Bostik AV180 for MDF. Why not use what the joineries use and save more expensive Titebond for the real stuff.

[kman-oz]

Bostik AV180 for MDF

I've never seen this, where is it available?

[Waldo]

I get mine from a local joinery/kitchen fitout place in Bayswater. If I knew the name of the place I could tell you :doh3: They are just off Mountain Highway where Seimens are.

[kman-oz]

Not retail then?

[Waldo]

They supply to the public. But I've never seen it in places like Bunnies. If Matrix sees this thread he could point you to a place that stock it.