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Can MDF be made more durable?

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Forum topic by BluesMatt posted 02-13-2021 04:00 PM 871 views 0 times favorited 20 replies Add to Favorites Watch
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BluesMatt

4 posts in 87 days


02-13-2021 04:00 PM

Topic tags/keywords: mdf

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.

-- Keep in mind that everything is made twice. Everything (1st) begins as a thought and then (2nd) gets made.


20 replies so far

View SMP's profile

SMP

3941 posts in 983 days


#1 posted 02-13-2021 04:26 PM

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

View splintergroup's profile

splintergroup

5101 posts in 2300 days


#2 posted 02-13-2021 04:33 PM

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

View tvrgeek's profile

tvrgeek

1859 posts in 2727 days


#3 posted 02-13-2021 05:17 PM

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.

View JAAune's profile

JAAune

1941 posts in 3395 days


#4 posted 02-13-2021 05:21 PM

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.

-- See my work at http://altaredesign.com

View JohnDon's profile

JohnDon

159 posts in 2247 days


#5 posted 02-13-2021 08:18 PM

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.

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Madmark2

2640 posts in 1666 days


#6 posted 02-13-2021 08:48 PM

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.

-- The hump with the stump and the pump!

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LeeRoyMan

1703 posts in 805 days


#7 posted 02-13-2021 10:11 PM

Forget the witches brews…..Use different material.

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CaptainKlutz

4439 posts in 2572 days


#8 posted 02-13-2021 11:13 PM

+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.

-- If it wasn't for bad luck, I wouldn't have no luck at all, Doom, despair, agony on me… - Albert King - Born Under a Bad Sign released 1967

View DS's profile

DS

3745 posts in 3498 days


#9 posted 02-13-2021 11:18 PM

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

-- "Hard work is not defined by the difficulty of the task as much as a person's desire to perform it.", DS251

View tvrgeek's profile

tvrgeek

1859 posts in 2727 days


#10 posted 02-13-2021 11:33 PM

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.

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.

- JAAune


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JAAune

1941 posts in 3395 days


#11 posted 02-13-2021 11:47 PM

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.

-- See my work at http://altaredesign.com

View 1thumb's profile

1thumb

373 posts in 3234 days


#12 posted 02-13-2021 11:48 PM



and would like to make projects that move

- BluesMatt

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

-- I actually have two thumbs and they oppose.

View 4wood's profile

4wood

94 posts in 1032 days


#13 posted 02-14-2021 02:02 AM

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

View tomsteve's profile

tomsteve

1161 posts in 2297 days


#14 posted 02-14-2021 11:52 AM


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.

View PCDub's profile

PCDub

262 posts in 1322 days


#15 posted 02-15-2021 02:38 PM

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

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