Hello everyone…just wanted to throw in some info on a test cut I just did. I have mainly been using my GF with Proofgrade material, mainly acrylic but I have ventured into cutting some birch plywood. I bought some first at Lowe’s and while it did ok…the results varied greatly even on the same piece of wood. I was also a little concerned about the possibility of inhaling formaldehyde, even with the filter I have. I had heard about the Purebond brand from Home Depot that uses a soy based glue and is formaldehyde free. They also claim to be completely void free. So I thought what the heck and purchased a a big 4’ x 8’ sheet ($29). Cut it down to 12"x 19" and just ran my first test and I have to say WOW!!! This thing cuts like soft butter. I did a total of 13 circle test cuts ranging from 185-270 speed on full power. Now I found when cutting the Lowe’s plywood that the best results came from 185/FULL. The best cut I just got on the Purebond was 210/Full. It actually cut a complete circle at 230/FULL but when I tried to do something fancier, I did a fancy L, I found that it cut 90% of it but when I bumped it back down to 210/Full it cut the entire L completely. I am so happy with these results!! It left just a light tan color on the edge where as the other birch I used from Lowe’s was very black but couldn’t get it to cut through all the way on a higher speed. So as of right now I highly recommend the Purebond birch from HomeDepot. I will mention that after cutting the entire sheet of plywood down and cutting these test cuts I found 0 voids in the material!!..Hoping that the consistency remains true when I ever need to get another sheet!! Again settings for simple shapes I think can be done at 230/Full while more intricate designs I would try at 210/Full. Also I did want to mention this, the 1/4" Purebond Birch measures .203. I did have the focus set at .21 though. Not sure if adding an additional .007" matters a whole lot (LOL) but I had great results so I’m sticking with it. (editing to add that my GF is a Plus)
Thanks for the heads up!
I have some items flowing through the design phase that should be able to make use of this nugget of information.
Absolutely!! If you order it online and have it shipped (I believe it’s free shipping) they will actually cut it down to whatever size you want…I was too impatient, hahah, and just went to my local HD and had them cut it in a more manageable 2’x4’ for me and then I cut the right size when I got home. But just so excited with these results!!
Is this just the columbia wood products stuff?
haha yes indeed it is. Great stuff!
I just had 2 sheets cut down friday. Very pleased with it so far. Not quite as smoothly finished as what I ordered online, but way cheaper in the long run to do it this way.
Fascinating example of what I remember or don’t remember. I recall Columbia Forest Products discussed many times. I didn’t remember the PureBond part of the description.
Lesson learned: read the fine print.
This is great to hear, thanks for sharing!
Can you sand it without sanding through the veneer?
So after cutting 2 12x20 sheets today I have found that the settings weren’t quite perfect when trying to do more intricate cuts. I had to lower it down to 190/full and that seemed pretty good but I also experimented with 270/full with 2 passes and that seemed to really be the ticket that works for me…so depending on whether you like to do 1 or 2 passes…it’s definitely worth playing around with considering 1 12"x20" sheet is approximately $2.
Yes, I would say with a very fine paper though…it is pretty smooth already. I just took a quick swipe with a very fine sanding block (I can’t remember the number exactly but I think it was a 220) and it was pretty smooth and took paint really well.
A perfect cut is where the beam just makes it through. Because wood is a natural product with variance in density, cut settings can never be just perfect, even across the same piece, but you can usually get away with a little higher than perfect to make sure you get clean cuts.
1/4" Material is thick enough that there is more chance of significant variance within the material, so “higher” needs to be substantially higher to get reliable clean cuts - but that can affect the edge finish.
So, as you say, “playing around” (testing) is definitely needed to get satisfactory results. I had used 1/8" primarily for the first couple of years, but started using thicker materials more recently and as a result, testing various settings. I have found you can get cleaner, consistent results by setting focus height aprox. mid-way thru material, rather than at the surface which is what the default settings use.
I bought some 1/4" purebond walnut and maple. Have you noticed the kerf seems huge with this material? It visually looks huge, and after measuring, it’s 2x what a normal kerf is.
“Normal kerf” depends on material. 1/4" Material is twice as thick as “normal” 1/8", so to cut twice as deep, you would expect more power and a wider kerf.
Using the kerf jig, I’m getting 0.29mm kerf. Figured my laser focus was off, but measuring it manually or auto focus gives the same result.
Does that seem normal even for 1/4" or just fine? It’s for the 1/4" walnut ply.
I don’t know what Purebond uses for a core. Is it even just one layer?
Focus height can make a big difference on cut width, but I’ve never tested to this degree on plywood. On thicker material, the amount removed from the surface is always going to be wider. Here’s solid maple, the difference is visually obviously:
I ordered 1/4" and 5/32" Purebond about 2 weeks ago. The core is just one layer. I’ll try to take a picture of it for you tomorrow.
It’s more about what it’s made from, which likely isn’t obvious from a picture.
GF Proofgrade “Medium” has an MDF code, but according to info here, the “Thick” doesn’t.
Well I figured as smart as you are that you could tell by the photo
Looking at the questions and answers on the home depot page, the seller said “This is not an mdf core. It is an all wood, veneer core product.”
Do you generally like to focus at 1/2 height yourself for cuts?
No, but I used a fair bit of that and other thicker material recently, and did not like how it cut, so I decided to do some experimenting. I don’t have anything definitive, but just pointed out that you might get a narrower kerf if you don’t focus on the surface. You’ll need to test with your material to see what works best for you.