I’ve been cutting a lot of things out of 5mm plywood with my K40. I’m sure the GF will cut through it like butter when it arrives. Better focus, better lenses, better everything really. For now, I need a locally source able material that cuts easier than plywood. It should be stiff, But I don’t need the strength of plywood. Did I mention paintable, water resistant, and CHEAP? It will probably be made primarily of Unobtainium, but if anyone has suggestions I’m open.
5 Likes
How much strength do you need? Thickness? - Rich
2 Likes
None for this project. I’m cutting out letters and gluing them to plywood. Foamcore strength would be great. 5mm thick or so would be great.
1 Like
So I assume this is an outdoor sign and the letter should be water proof. A number of plastics come to mind. Not all of them cheap and some not laser friendly. I’ll bet you have looked at some already? - Rich
1 Like
It’s a temporary sign, so it only needs to be waterproof for a few days. Cardboard won’t cut it, although I could probably resin it, same for MDF, But this K40 is going to have just as hard a time with MDF as plywood I would imagine.
1 Like
Then use corrugated plastic. Its like cardboard, waterproof. Check if it is laserable, it is cheap and easily cut. - Rich
5 Likes
I’ll look into it. Thanks. I’m also looking into Gatorfoam, although both solutions may be pricey.
2 Likes
Another possibility might be acrylic. A trip to your local plastics supplier might result in cheap if not free cast-offs. From what I have read, acrylic is wonderful to work with on a laser cutter.
4 Likes
Along the same lines of the plastic supplier, I recently made a good score at a Goodwill. I found a massive box of 100 brand new acrylic restaurant menu holders (like you see the wine list or dessert menu in). The box cost me $10 and must weigh 30lbs. I have already cut a dozen or so down into flat sections for laser cutting.
10 Likes
also know by the tradename Coroplast
6 Likes
Now that your plane is complete I’m guessing the construction area is full of Glowforgeable supplies?
1 Like
How wide do you need it… just rip down some pallet wood to 1/4" or even cheap construction lumber to whatever thickness you need?
1 Like
Let’s just say our ever growing material stock is going to keep us busy for quite some time. We still can’t leave Costco without grabbing a few sections of cardboard.
2 Likes
Use cardboard, simply purchase colored wax to dip the letters in. You get waterproof (for a few days) and the color you want all in one process 
9 Likes
How did you know if they were acrylic versus polycarbonate?
1 Like
Polycarbonate (also known as Lexan) is extremely durable/flexible. Acrylic is quite prone to breakage. After some time around both, you can easily tell just by flexing the material. Acrylic is quite a bit stiffer and will give almost no feedback before it snaps. Polycarbonate depending on thickness can be bent over in half and will return to almost flat.
There might be other ways of identifying, but that is how I have come to identify the two.
For most things I actually prefer Poly/Lexan. The stuff is just about indestructible. Unfortunately, based on my reading it will have limited use with laser cutting.
2 Likes
I gotcha…not only from your reading but mine and others experience with polycarb and lasers…just melts in an ugly fashion! Going to have to start bending some of my acrylic sheets so I get the feel of them 
3 Likes
What I have yet to find a good way of determining cast vs extruded acrylic. Pre laser, I have never had a need.
3 Likes
Another way to tell the difference is acrylic edges polishes clean with a flame (or laser). Lexan/poly has a dull edge.
7 Likes
When you laser engrave clear cast, it frosts. Clear extruded is still clear-ish.
Cast usually has paper backing. Extruded usually has a plastic backing.
Neither is foolproof but both tend to be good rules of thumb.
15 Likes