larger heated bed cover material solution found

hello,

I've been working for awhile on a heated bed that could be larger, and more durable than what is currently out there. these results will be updated in reprap wiki when complete, and i hope that some vendors will look at this as an option to there builds as well. I am not making any money on this project, and what works for me may not work for you.

I have been testing the following material 100% cotton fabric, fine thread like what is used in cloths and tablecloths particular fine threaded fabric. but must be 100% cotton and only fine thread. mine was from a bandanna for example

you then need an acrylic based gloss spray like a table gloss or wood gloss. it must be a spray. spray and coat one side of the fabric with 3 coats of paint. each coat let dry an hour.

after coating are complete and fabric is dry, about 24hrs later, it should be stiffer. The fabric should still have tiny holes in between fabric.

next size the cloth to fit the width of your heated bed, and the rollers under it for abp, then make it 1 inch longer. wrap the material around the heated bed, with the painted side outwards. keep the 1 inch extra on top of the bed as you need to now glue it.

use this extra inch to rub in and place Sodium silicate, or liquid glass. make sure it rubs into the fabric. try to place it in lines that are no more than 1/10 of an inch wide, but go along the length of the material width wise to be parallel with bed rollers. keep something on top to squish it down while it cures. an hour later heat up your bed. let it be about 100c for 2hours to finish curing. roll bed around several times for an additional 5 minutes.

finally coat the outside of the fabric with floor acrylic with the heated bed still on. be careful that the acrylic does not pour off the bed and into the bearings or sliders as it will gum those up. if you do get some there place 3 in 1 oil there and run part back and forth several times, then wipe away material that breaks free. evenly apply acrylic across top with 3 layers of coating waiting 5 minutes between each coat. then move heated bed around in a circle for an additional 2 minutes.


you now have a strong heated conveyor belt bed that should stay flat if it is stretched tight. additionally i am working on including vacuum design and a roller system that pulls the bed tight each time. it is far easier to design it that to build it.with family and everything else going on for me, it is hard to know when i will update the reprap wiki.

this bed works to 190C the only issues i have seen so far are the following:

acrylic gets into the mechanical parts. so be careful when applying floor acrylic
Sodium silicate is stiff, so it needs to be spread out in 2mm wide sections or smaller, otherwise it will require a lot of moving bed back and forth for it to move properly as the part with Sodium silicate does not bend easily.

some parts stick incredibly well, so make sure bed is adjusted for plastic to stick, but not too close,otherwise heat bed back up and pull off parts. bed does not rotate when this happens so it is detectable to avoid catastrophic failures like printing when parts are still on bed.


ends of fabric outer 2-5mm lift up .25mm. this can be resolved with a vacuum system.


other than that, the bed keeps flat, and the acrylic makes the top and bottom of the fabric somewhat sticky.

hope this is somewhat helpful to other rep rap folks.
Sodium silicate can be purchased from automotive stores. it is used to fix exhaust leaks in muffler.

I will work on a clutch system for conveyor bed, and finalize the design files, then post online.

Awesome. Thank you for posting that. You'll probably never see this but thanks a bunch!!