mdf small parts

[larry senen]

need to make some small parts and mdf is the logical choice.
has anyone found a way to strengthen mdf such as soaking in some solution to harden it. but still allow it to bond to itself?
it just frays when machined and some way to keep it together would be great.t.i.a.

[Wayne Lomman]

First, make sure you have a good quality mdf. Buy a recognised brand that is made to code. It will make a difference. Secondly, after you have machined the parts, drop them in some low viscosity clear epoxy to soak for awhile and then let them dry. It will take a bit of research to find something suitable. Different products available here. Otherwise any 2 pack low viscosity coating will do. It won't help to coat before you start as the coatings won't penetrate the face much. Cheers

[Larry Frank]

On small things or screw holes in MDF, I use some superglue. It soaks in and dries hard and quickly.

[John K Jordan]

How small are these parts? How about using something besides MDF such as baltic birch?

[larry senen]

First, make sure you have a good quality mdf. Buy a recognised brand that is made to code. It will make a difference. Secondly, after you have machined the parts, drop them in some low viscosity clear epoxy to soak for awhile and then let them dry. It will take a bit of research to find something suitable. Different products available here. Otherwise any 2 pack low viscosity coating will do. It won't help to coat before you start as the coatings won't penetrate the face much. Cheers
that's what i was thinking, some really thin epoxy ,any experience with specific products?

[glenn bradley]

Hot Stuff is CA with a consistency of water. Great for leeching into very small cracks. With all the bother to make MDF "good" why not just use something else? Just curious as to what is driving the decision to use MDF.

[Martin Wasner]

Yep, thin CA glue turns mdf into concrete.

[Wayne Lomman]

I used a water thin epoxy made by Jotun a few years back. I can't remember the product code. It was to provide a slip coat on the inside of rail cement wagons.

Mdf is a good choice when you have short grain no matter which way you orient the piece. Cheers

[Art Mann]

If your application requires any kind of strength, I strongly recommend that you make some parts and use destructive testing to see how well the MDF holds up. My opinion is that no material, water thin epoxy or anything else, will penetrate far enough to provide any mechanical strength. All you can expect from surface treatments is wear resistance. I know I am contradicting others but I have had a fair amount of experience machining MDF for mechanical parts with my CNC router.

[Malcolm Schweizer]

http://m.homedepot.com/p/Minwax-1-pt-High-Performance-Wood-Hardener-41700000/100376253

Here is what you are looking for. Minwax wood hardener.

[Larry Edgerton]

I make all my patterns out of mdf. I treat the edges with a liberal coat of West System. Quite a bit will sink in. When it starts to get tacky I wipe any excess off with alcohol. Its still MDF, but the epoxy keeps the bearing from sinking into the MDF. I have made hundreds of parts off of MDF patterns treated this way with no degradation. May not work for your situation. That will be 2 cents please.

[Steve Demuth]

I discovered this myself a while back. I needed some thin mdf panels and only had 3/4" stuff, so I "resawed" 9" "boards" of mdf down to 3/16" and edge glued them back into large sheets with thin CA glue. The joints were way stronger than the actual mdf and the surface where I wiped up the squeeze out was as hard as melamine.

The only drawback is that when I sanded the resulting sheets in my drum sander to thickness and flatten them, the glue lines clogged and glazed the drum almost instantly if I took any depth at all. Even 24 hours after gluing the CA joints, though solid mechanically, were still sticky when machined.

I've since send painted on CA to harden up a couple of small mdf jigs.