Better material

[hdtheater]

I have been carving a sign out 3/4" MEDEX as regular grades of MDF tend to crumble with fine details. However, the details on this sign are too fine for MEDEX. Hoping someone might recommend a material that won't crumble with fine details.



You can see the edges of the letters crumble off. My only other choice is to make the pocket tool path shallower, but I am at 1/16" depth now.

Thanks,

-Eric

[Leo]

HDU is a better material.

[hdtheater]

Thanks Leo. That is on my list. My only concern is that it is a composite material that could come apart like MEDEX. Wondering if there is a solid material that could work. I thought I might have to make a mold out of resin after a good carve.

[kzeyus]

HDU, PVC (not expanded PVC), Corian, Nyloboard

[hdtheater]

I have some Corian. Did not think about that.

What kind of feeds and speeds does Corian require?

[Leo]

Thanks Leo. That is on my list. My only concern is that it is a composite material that could come apart like MEDEX. Wondering if there is a solid material that could work. I thought I might have to make a mold out of resin after a good carve.

Medex is a material like HDU, but enhanced a little for moisture control. It is not an exterior material like Extira is. It is wood (paper) fiber bonded with a bonding agent. It is not particularly stable or strong especially with small detail.

HDU - is a plastic foam and is a molded product. Unlike Medex or MDF or Extira - it is a single solid (as solid as foam can be) product. It is not a composite of a few different materials like Medex is.

The HDU will hold better detail than Medex.

Corian is a LOT denser and harder than HDU - but still a plastic material. Corian cuts very nicely and can take some very intricate detail. It IS brittle and can break easily. You can sand it file it and paint it.

Another nice material is PVC. You can buy it in sheets or at the big box stores like Lowes or Home Depot. It is the PVC trim boards. PVC is a little tough to paint after the surface skin has been cut away, but with a good several coats of Primer - it will paint nicely. PVC is a plastic - harder and denser than HDU, but softer and looser than Corian.

[hdtheater]

Thanks again. I appreciate the detail on the materials.

I borrowed some HDU scrap from a friend and have some Corian to attempt to resolve my issues.

I need to find a local supplier of sheets of PVC too just in case.

Finished this sign is about 20" in diameter.

[dealguy11]

HDU is intended for carved signs. It comes in different densities - 15 lbs and 20 lbs are typical. Both take a lot of detail and are intended for outside applications. They also paint very nicely. 20 lb. is stiffer (and heavier, if that matters) than 15 lb. but either should take the detail required for this sign.

[Peter Stenabaugh]

Another thought for material like MDF (I am not familiar with HDU - we dont see that in Canada under that name. However for mdf one solution you can try is to get some 'wood hardener'. Such a product is available from Min Wax. this is actually designed to be used on semi rotten, or soft corky type of woods. It is some type of plastic product, but it has the ability to soak into the wood and when it cures you have a very hard durable surface that should be good for routing where you need strength and rigidity.

I dont know if this is suitable for exterior applications or not but checking on the MinWax website may reveal more information. I have some of this stuff although I have never used it yet, so I am not speaking from experience, but this is exactly the type of application this product is designed for.

Another product that might work is a substance like 'Cactus Juice' or similar products that people are using for infusing soft wood for turning pens etc. This stuff as well as the Minwax product are basically 'wood stabilizers' and the liquid is a very water thin material that soaks into the wood and then needs to be cured. MinWax, I believe cures on its own, but the Cactus Juice or similar products need to be baked in a low temperature oven, so that may not work for large projects.

Here is a link to a product similar to Min Wax - http://www.colonialmedical.com/rotted-w ... -2615.html - This material appears to be suitable for outdoor use.
Minwax link: http://www.minwax.com/wood-products/mai ... d-hardener This also appears to be outdoor safe.

Pete

[Leo]

I know a few people in Canada that use HDU.

HDU is not a brand name, it is a material. High Density Urethane.

There are several brands. DunaFoam, CoraFoam, SignFoam, Precisionboard (Coastal Enterprises) to name a few.

Some are more expensive than others.

Density weights are not the same from one supplier to another.

Look at sign supply places for a source.

[Peter Stenabaugh]

ok, great Leo, thanks for the heads up.

Pete

[James M]

I haven't seen the PVC material at the big box stores up here in Calgary, Alberta Canada either.

James