Thanks. The slot in these bases is too wide for the 1/8" acrylic, but too thin for 1/4". I may try making my own bases instead. But, I don’t quite follow what you mean by the tabs on your bases; do you have a close up picture?
I have that problem with the ones I get on eBay. I stuck a piece of paper into the slot and traced the top of the slot on to it. Then I scanned that into Corel (you can use Inkscape) and joined that to the bottom of whatever I’m designing to be inserted. Then I set that shape to engrave. I make the sign out of 1/4" acrylic and set the base shape to engrave. Takes a couple of tests to get the power/speed set so it gets shaved to just the right thickness for a press fit.
The advantage is that you fill the slot so it stands straight and keeps light from leaking between the acrylic and the base where small thickener tabs might leave a gap.
It adds a couple minutes of engrave time for each one you make but it’s worth it. The bases I used have a wave to the top so that’s why I had to do a trace. But if it’s got a flat top it would be pretty easy to just measure a rectangle you weld to the bottom of your sign.
To zero in the settings, make a little stump of acrylic vs the final object. That way you don’t waste a bunch of acrylic. Or hold the big piece of acrylic down with magnets so you can cut your piece out but put it back in to do another pass for the engrave.
I just cut Self adhesive black felt from the craft store in the same size as the tab on the acrylic that slides into the base. Super easy, can laser or cut with scissors. I’ve found that putting it one side of the Proofgrade acrylic was enough for the bases I had. Can double up if you need more. It seals light and has a little give to snugly fit.
Lot’s of ways to deal with this, as folks have pointed out.
I have loads of .222" clear acrylic. Using thicker acrylic for the signs makes it seem sturdier and gives depth potential. That means I have to engrave some relief in the bottom where the acrylic slides into a pre-made base that has a narrow slot. It does take some finesse, testing, to get the right depth of the engrave so you have a tight fit.
I’ve also done spacers, acrylic or other material.
Right now I am working on my custom bases so I can just slide the acrylic in and it holds.
The popular LED bases seem to use a 0.15 inch plastic insert. There HAS to be a way to procure this somehow, and this is a priority for two reasons.
1- Yep, it takes longer on each print to engrave a reduction in thickness, but that’s not the big one.
2 - Engraved acrylic diffracts the light out, as intended, except the engraved part inside the base sends a lot of light away, instead of into the acrylic above.
So where do those chinese manufacturers get all their .15 in acrylic?