1/2" MDF vs 12mm MDF?; also, sealing MDF?

The original specs for the Mendel90 "sturdy" call for 12mm MDF. Now, I live in the USA and 12mm MDF is a rare bird, but I can easily - and fairly cheaply - get 1/2" (12.7mm) MDF from Home Depot (my nearest supplier). My printed parts set, which I bought on EBay, is set up for 12mm. Has anybody successfully used 1/2" MDF with a printed kit meant for 12mm? What did you have to do to get it to work?

Also, while I am on the subject, what should I use to seal the MDF against moisture (or even oils and solvents) that doesn't cost a whole lot or require an exotic vendor (in other words, is anything likely available at my local Ace Hardware, Lowes, or Home Depot - or even Walmart)?

I think the only issues with 12.7mm MDF will be the nozzle with be 0.7mm off centre at (0,0), which is no consequence, and the spool holder brackets will not hook over the top unless you cut 0.7mm slots for them or remove a bit of the plastic.

Others have recommended several coats of acrylic pain for sealing.

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[www.hydraraptor.blogspot.com]

Thanks, Chris. Something else I am wondering is, would it help anything, or at least not hurt anything, to glue the seams on the MDF with something like carpenter's glue, in addition to screwing the frame together with the printed brackets? Seems like it would be much more rigid that way.

I can't see any advantage as end grain does not glue very well usually. The fixing blocks hold it solidly.

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[www.hydraraptor.blogspot.com]

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Rich K.
The original specs for the Mendel90 "sturdy" call for 12mm MDF. Now, I live in the USA and 12mm MDF is a rare bird, but I can easily - and fairly cheaply - get 1/2" (12.7mm) MDF from Home Depot (my nearest supplier). My printed parts set, which I bought on EBay, is set up for 12mm. Has anybody successfully used 1/2" MDF with a printed kit meant for 12mm? What did you have to do to get it to work?

Also, while I am on the subject, what should I use to seal the MDF against moisture (or even oils and solvents) that doesn't cost a whole lot or require an exotic vendor (in other words, is anything likely available at my local Ace Hardware, Lowes, or Home Depot - or even Walmart)?

My Mendel90 uses 0.5 inch MDF. I've had it for almost 2 years now without any real issues. I went to a hardware store and purchased a small can of black paint & primer in one. Used a roller and put two coats on. No biggie and haven't had any issues since. ...one thing, order a dibond sheet from nophead for the Y carriage. It's much more sturdy than what I used for the first 6 months.

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lions3
My Mendel90 uses 0.5 inch MDF. I've had it for almost 2 years now without any real issues. I went to a hardware store and purchased a small can of black paint & primer in one. Used a roller and put two coats on. No biggie and haven't had any issues since. ...one thing, order a dibond sheet from nophead for the Y carriage. It's much more sturdy than what I used for the first 6 months.

Yup, got the dibond Y-carriage, and a hardware/wiring kit from him as well. Right now I am trying to update the firmware on my Melzi, and I have all the vitamins for my build except for the MDF, so I am well on my way!