Printing nylon--new Garolite LE (McMaster 8474K141) very warped!

As recommended by Taulman 3D, I purchased the Garolite LE (12" x 12" x 1/4") part number 8474K141 for printing 618 nylon. As delivered, it is unusable as a print bed, because I measured the middle of the sheet and it dips more than 0.1" from the edges (also highly visible w/o measurement). Furthermore, the sheet is very stiff and I do not believe it can be pulled or clamped flat onto the bed or other stiffer backing material.The McMaster catalog says the flatness tolerance is not rated. (Gee--now I know why! ).

Have others had this problem with the McMaster Garolite LE? Other than using a flycutter to machine the surface flat (my flycutter and mill are too small to do this), has anyone found a way to deal with this problem? Perhaps my sheet is atypically warped, because in all my research of online user reports, I've not heard of this complaint.

Given the warp, I cannot recommend this material, despite Taulman's recommendation that it's usable for a "precision bond." Given the extreme warp, I doubt a thicker sheet could be trusted either and it would be even harder to somehow pull flat. In order of my preference for part adhesion, these are the materials that I've found to be satisfactory, so far:

1. Unfinished poplar (impossible to find large enough to cover my 10" x 11" bed, so far).

2. Nylon 6/6 sheet.
[www.amazon.com]

3. Uhu glue stick on glass.

4. Phenolic Sheet (180 grit belt sanded).
[www.amazon.com]

The performance of #1-#3 have proven to be very similar. #4 is somewhat less satisfactory. None of above materials result in perfect retention of thick, blocky parts and there's some lifting at corners (though I can achieve perfect retention printing the part in ABS).

Tips and user reports are most appreciated!

it sticks to copy paper, if you can glue a thick piece of copy paper onto some glass, that would work.

Thanks, aduy! I'll try that too.

I've been using thinner Garolite successfully but in smaller sizes. 1/8" thick works pretty well at 6x6 or even 6x8 but I have more trouble when I push out to 6x10 (my max print area) with the flatness (or lack of). If you have a rigid flat bed to clamp to, thinner Garolite should be feasible to clamp down flat. Also I've used both Garolite LE and CE and they seem nearly identical for sticking but CE is 2/3 the cost of LE.

Garolite LE does absorb some moisture, so it could be that one side has just been exposed to higher humidity. You could try putting it in the sun, expanded side up, to see if flattens out. Also, you could try resting the 4 corners of your sheet on 4 chunks of wood and put a weight in the center to hurry it along.

Tom at Taulman 3D and I have been discussing methods for flattening the sheets. Just heating the Garolite, as I do to dry 618, has no effect on it. The process will require both heat and a press, I think.

I have a 5/16" Mic-6 bed and thinner Garolite probably would be better for me, because it would be easier to flatten with clamps on my bed. However, if the thinner sheet is warped like my 1/4" sheet (a compound curve too), it would probably be too stiff to flatten with clamps on the bed too. If I choose to machine my 1/4" sheet flat, it'll end up being 1/8"--it's that badly warped!

That heat + pressure *might* work.

Take the racks out of your oven and build a platform out of bricks on the floor of the oven. Sandwich the garolite between 2 baking sheets. Line the top baking pan with some tin foil then load it up with some more bricks. Pop it in the oven, set it to 240F and let it go for an hour or two? Mcmaster says Max temp for LE is 235F - exceeding this a little bit may allow it to soften enough to be flattened.

Alternatively, you could sandwich the garolite between two sheets of steel and C-clamp it flat, then try that oven trick.

I dunno if this will work, just thinking out loud.

---

- akhlut

Just remember - Iterate, Iterate, Iterate!

[myhomelessmind.blogspot.com]

The problem is the resin is probably a thermoset, heating it has no effect on softening it, however the heat would probably get rid of the moisture. also milling that will eat through your bits.

Garolite uses a thermoset resin, it's not going to self level with heat.

Idea:
Glue the Garolite sheet to a thick plate of glass with Epoxy (JB Weld), Polyurethane, Silicone (Household Goop).

Sandblast, acid etch the glass so the glue can grip the glass.
A cheaper grade of glass is easer to acid etch (soda glass?).
[en.wikipedia.org]

Verify the flatness before gluing, to do this:
Clamp the Garolite down with the shinny side up without glue, then take your measurements.
You can adjust the clamp location to adjust the flatness of the Garolite.

FYI:
Rice Paper Printing surface
[www.thingiverse.com]

My 1/4" Garolite is warped so badly, it can't reasonably be machined flat (I'd waste nearly half of it and also the cutting too like, as A2 advised) nor can it be pulled flat using any reasonable sheet of glass (the glass is likely to break first, because the Garolite is very, very stiff). The only prospect for using the Garolite is to at least level it significantly with heat and pressure. Taulman has received both very flat and very warped samples of Garolite LE. The stuff is very inconsistent.

Though less convenient, I took aduy's suggestion. I'm using textured card stock (unknown composition but probably pulp). I wet the back of the card stock and used Elmers Wood glue to glue it to as glass plate. I used a wet plastic squeegee to smooth it out and accelerated the drying time by heating it in my convection over (< 100 C). It's the best surface I've tried yet.

I wonder if spray on hair would work... lol
I read that it contains tiny fibers.

Heavy paper stock sounds good, but I think it will delaminate?
Maybe a sacrificial sheet of paper glued to a plate of glass will work?

A2

try using like a manilla folder, the fibers are probably more tightly packed than that of the cardstock.

A2 Wrote:

> Heavy paper stock sounds good, but I think it will
> delaminate?
> Maybe a sacrificial sheet of paper glued to a
> plate of glass will work?
>
It actually didn't delaminate. The problem was my hot-swappable glass plates are only 2.5 thick and they are normally clamped to my 5/16" thick heated Mic-6 aluminum bed (and I've not found the heat to be useful for nylon). The print and paper remained attached but the glass was warping badly and I thought IT was going to break! I aborted the print and soaked the plate in water. The paper and glue released from the glass slowly and evenly and I recovered the glass plate.

I have another Mic-6 sheet. My next step is to fabricate an unheated bed (no wires) with it, to which I can glue stuff and then remove the bed and soak it in water, when necessary.