# Can MDF be made more durable?



## BluesMatt (Feb 10, 2021)

Hello everyone, Matt here, a newbie to this site.

I have wondered this for a while so I thought I'd ask. Does anyone know of a way to make MDF more durable?

I am rediscovering my scroll saw and would like to make projects that move using gears and linkages (not necessarily clocks). I'd like to use MDF because it is inexpensive, readily available, stable, and does not have a grain but I fear MDF will not be durable enough. I'm thinking linkages or gear teeth will quickly wear and change shape. Is there a way to "harden" MDF?

Maybe use super glue or epoxy and coat the parts? Maybe use some kind of finish that when dried, forms a hard layer?

Thanks in advance for any suggestions.


----------



## SMP (Aug 29, 2018)

Can you find HDF where you live, that would be a better start


----------



## splintergroup (Jan 20, 2015)

Super glue is good for hardening edges when using MDF as router templates


----------



## tvrgeek (Nov 19, 2013)

I have used thinned polyester resin to soak into the edges to seal them doing speaker cabinets. Not sure if you could find an epoxy thin enough.

For normal woodworking, thinned varnish will soak in quite a way. Easy oin edges, but if you want it to go far in the surface, then scuff it first.

Experiment, but basically, I suspect MDF or even HDF is not your best choice.


----------



## JAAune (Jan 22, 2012)

Super glue will harden up the MDF somewhat but the fast cure time means less soaking time. A good, slow-set epoxy will wick into MDF edges for awhile.

I'd recommend making some parts in mdf, doing the epoxy soak then attaching the apparatus to a motor for lifecycle testing. That's the only way to know if you'll get an acceptable lifespan out of your parts.


----------



## JohnDon (Mar 14, 2015)

Superglue works great for small areas, such as tapped threads for throat plate leveling screws. For larger areas, such as cog surfaces, try Minwax Wood Hardener.


----------



## MadMark (Jun 3, 2014)

Soak it in a bucket of 50%-50% poly-mineral spirits overnight or until bubbles stop, whichever is last. Liquid mix won't harden until exposed to air.

Put it in a pressure cooker using 15 psi air as charge (don't heat) to really soak it in. Or buy a wood stabilization system.


----------



## LeeRoyMan (Feb 23, 2019)

Forget the witches brews…..Use different material.


----------



## CaptainKlutz (Apr 23, 2014)

+1 Don't use MDF and skip witches brew.

Use exterior rated composite panel, like Extira.

Can also find MDO plywood with exterior rating. commonly used on outdoor signage. 
BORG carries some MDO, but not best quality. 
Best to find a commercial lumberyard to buy these materials.

Light duty machine gears are often made from phenolic laminates. Paper phenolic (XX grade) s cheapest, and machines like MDF. Linen phenolic (LE grade) is used on gears, castor wheels, and pulleys; and is more durable.
Phenolic is heavy stuff, and best to find a local source if you can. USPlastics.com and others sell the phenolic sheet online.

Note phenolic resin stinks if you burn it while cutting. You will want dust collection on scroll saw for any phenolic laminate.

Best Luck.


----------



## DS (Oct 10, 2011)

I would think that a void-free plywood like Baltic Birch would be suitable for gear making.
My 2 cents


----------



## tvrgeek (Nov 19, 2013)

Can you suggest a epoxy thin enough to wick in? Even West is too viscus. Poly resin is a little thinner, but needs to be thinned to get more than a mm or so soak. You can get poly varnish, thinned 25% or so to soak in more like 3/8 of an inch but it takes 3 or 4 treatments as it does not carry that much each time. A pressure/vacuum pot might do better.



> Super glue will harden up the MDF somewhat but the fast cure time means less soaking time. A good, slow-set epoxy will wick into MDF edges for awhile.
> 
> I would open up the McMaster or other catalogs and pick a more appropriate material.
> 
> ...


----------



## JAAune (Jan 22, 2012)

Thinnest pure epoxy (no solvents) I'm aware of is System Three Clear Coat.

That being said, the penetration doesn't need to be deep for most moving parts. 1mm is plenty because any gear teeth that wear more than 1mm will probably get too sloppy to function well.


----------



## 1thumb (Jun 30, 2012)

> and would like to make projects that move
> 
> - BluesMatt


https://www.thisiscolossal.com/2018/12/ghostkube-by-erik-aberg/?platform=hootsuite


----------



## 4wood (Jul 12, 2018)

Here is product used by boaters. I used it 40 years ago and they are still making is. I just copied the add. Maybe it will work for you.

Image result for Boat Life Git-Rot Penetrating Epoxy Pt. Kit
GIT-ROT is the perfect cure for dry rot. Restores strength of wood. Pours into finest openings, penetrates deep and completely saturates wood, arresting progress of dry rot by encapsulating fibers.Cures into tough, resilient adhesive that bonds wood members together with mass


----------



## tomsteve (Jan 23, 2015)

> Maybe use super glue or epoxy and coat the parts? Maybe use some kind of finish that when dried, forms a hard layer?
> 
> Thanks in advance for any suggestions.
> 
> - BluesMatt


you want to use MDF because it is inexpensive then throw time and money into attempting to "harden" MDF.
hard maple isnt that expensive.


----------



## PCDub (Sep 24, 2017)

Abatron makes a liquid epoxy that is meant to soak deeply into rotted wood to stabilize it, so it may work for this use.


----------



## Lazyman (Aug 8, 2014)

I would also try CA. The kind used by turners as a finish takes longer to cure than the glue varieties so will give maximum penetration. I would get the thin version. Another option may be Minwax wood hardener. I've not tried it on MDF so I don't know if it will cause the the MDF to expand but it is thin and really soaks in well on porous wood.

EDIT: I've also used water base poly on an MDF bench top and it make for a really nice hard finish with no ill affects. I know that Matthias Wandel uses WB poly on the gears he makes from plywood because he says the poly makes them slide better.


----------



## StarBright (May 9, 2020)

You have to factor in the cost of quality epoxy. By the time you buy the epoxy, mix it, wait for it to harden, it's likely into you for more $$$ than using a more suitable material. Your original post says that you are using MDF to make gears. Wood gear projects are a lot of fun. MDF is not a suitable material to make gears. It will not stand up to the repeated compression and friction of the gears against each other. Plywood gears, if properly made and sized, will stand up to years of use and you have the added benefit of being able to use wax to lubricate the plywood.


----------



## BluesMatt (Feb 10, 2021)

Thank-you all for your replies. I will certainly try out a number of these suggestions. Thanks again!


----------



## BillWhite (Jul 23, 2007)

I'm with Captain Klutz on the Extera. It is heavy (big time) but solid. Rated for outside use.
I used it on colums for a house front and back porch with good results. THose colums are 15 years old, and still look and feel solid.


----------



## woodbutcherbynight (Oct 21, 2011)

> Forget the witches brews…..Use different material.
> 
> - LeeRoyMan


----------

