Alternative to MDF for Signs


(Pete) #1

Does anyone have an alternative material to MDF that machines well, and accepts paint? I am making some signs/decorations with MDF right now and I am not a big fan. The material powders when it is machined and leaves a lot of fuzzy edges and fine hairs on painted surfaces. This leads to a lot of extra finishing work.

I was thinking something like Renshape, but I know that is very expensive compared to MDF. I would be willing to pay more for a material that machines well and finishes easily. What are some other materials you guys use for signs and decorations. Both inside and outside.

Thanks


(Griff Carpenter) #2

You could try basswood, poplar or birch. I’ve made a lot of decorative pieces from these materials. Basswood strings a bit but a few passes with a fine wire brush will clean it up.

The fine hairs and fuzzy edges you’re seeing with MDF are purely a matter of end mill choice and speeds and feeds. A sharp, upcut endmill will provide the best results in MDF. In my experience anyway.


(Patrick Andersen) #3

Yes MDF is terrible for the finishing work required on the edges. I have not used it but many signmakers use a solid rigid PVC material that goes under a number of different names.

Celuka Foam Board, Signex, Nycel and Maxi T

It maybe worth checking a signmaker’s shop to see if you can get an offcut piece to try.


(Idan) #4

Try using the green high density MDF. Unlike the cheap brown one, it doesn’t tear out and in my experience machines much better.


(Temujin Kuechle) #5

I don’t know what kind of router bit/ndmill you are using, but a compression or down cut type could help.
The suggestion to use higher quality MDF can help a lot too.
I have also read about creating your own Renshape-like material in a discussion (cut and pasted for your enjoyment):

Renshape alternative

Jallit,

Maybe I can make your day.

I have been looking and

My experimenting took me down all paths, MDF, to Fiberglass resins (epoxy, polyester or vinylester) waxes and different timbres.

To cut a long story short, because all up I tried over 500 different recipes over a few months and I finally came up with something that machines very well and is easy to make.

I take measurements by volume (but when adding hardener you need to know your resin weight, so take care to take note).

Mix:
1 cup of corn flour, or corn starch
1 cup of resin
*Use a polyester resin, mix and stir slowly so as to not cause too many extra air bubbles (not important as you will see in a few minutes).

Their is a reaction that takes place between the polyester and the corn flour. It degasses itself!!!

Degass: Let sit for so 20 minutes
AMAZING! Maybe an industrial chemist could tell us why.

Add hardener but do not stir too much. We don’t want those bubbles coming back.
In 10 minutes your block is set, in an hour you can machine with it.

Now because we use fifty percent volume (actually about 10 percent of the finished block (you will see what I mean) the plastic is less fragile and less prone to break outs. It is fairly soft on the tools and no louder than wood to machine.

I pay about 10 soles ($4) for a litre of resin and 2 soles for the same volume of corn flour. That makes my 20 x 300 x 300 blocks cost about $5.

I am now machining this material with some great results. The detail I can obtain is amazing. Obviously this is not renshape, but it is just as good for my use. I’m sure you guys will love it.


(Griff Carpenter) #6

I just pulled this piece, cut in Birch, off my machine. Zero post processing.

All toolpaths generated in V Carve. Final cut with 2.25 degree, 1mm tapered ball mill consumed 3 hours of time (a couple of episodes of GoT :upside_down_face:).


(mark robinson) #7

Love the finish,Have a link for that bit?


(Griff Carpenter) #8

Found it, here you go

4pcs/package Assorted CNC 2D and 3D Carving R0.25 & R0.5 & R0.75 & R1.0 with 1/8" (3.175mm) shank Tungsten solid carbide Tapered Ball Nose End Mills and cone cutter HRC55 with coated https://www.amazon.com/dp/B01N7S00BH/ref=cm_sw_r_cp_tai_Wk.jBb1SST540

Not bad for $28.


(mark robinson) #9

Ok thanks,I had this set on my amazon wish list but was on the fence about them.I will check them out now :slight_smile:


(Pete) #10

When you go through the CAM operations with these bits do you just put in the radius of the ball nose? Is there a way to define the taper, is that necessary? What is the benefit of these versus just using a 1/8" or 1/16" ball nose?


(system) #11

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