So I have been using a double sided carpet tape this summer for holding my XPS foam down.
works great. Thin, holds well but still easy to remove.
Its getting colder here in MI and it seems the lower temps are affecting the adhesive of the tape.
any ideas for other options?
I can’t do the entire cut in one day (too long of cuts), so using a heater is not an option.
I will try the painters tape and super glue, but I expect i will have the same result
i use the painters tape and glue method. last weekend i did a cut with pink foam and it held. temp was around 2*C during the run and it held good still. its -7 now so i will be trying again to see if i will have to put the primo away for the winter. its in an unheated porch
Thanks. I will give it a try.
It’s 32F this morning.
What if you keep just the tape indoors?
@jeffeb3. That was my thinking too and it still does not hold well.
Thanks for the suggestion though.
Some random thoughts:
You could screw some boards along the edges of your stock to supplement the tape and provide a significant improvement in lateral holding. These boards can be shorter than the XPS foam to allow for facing the material.
I’ve used pieces of 3mm to 5mm underlayment or thin plywood with slots cut into it as clamps for XPS foam. The solution is low profile and the clamps can be much larger than a traditional CNC clamp. The larger clamps provide great holding while limiting any damage to the foam.
Never tried it, but the last clamping method could work if you sliced into the edge of the foam and stuck the clamp into the slice. This would provide vertical and lateral holding while leaving the face of your piece exposed.
If you try the blue tape method, be sure to burnish the tape on all surfaces.
If using the blue tape method and your XPS foam has any kind of a bow, I suggest an alternate to CA glue. I find that 3M Super 77 or 3M 90 works better for stock that has a bow. I imagine these spray glues are temperature sensitive at application time, so you’d have to apply them indoors to the piece on the stock and/or warm the environment when applying the glue.
@robertbu Good idea, but my “spoil board” is 1/2" XPS - probably not ideal, I know, but it works. I have a 10" Z axis and didn’t want to try facing wood at that length. Felt there would be too much movement with harder materials. Works great with a foam spoil board.
I could screw through the foam though.
I did leave a section of blue tape on the foam outside and seems to be holding. I think it works better since you can burnish the tape down (like you mentioned) for better adhesion. which you can’t do with double sided tape - at least not on both sides.
I tried the supper 77 (with blue tape) but didn’t think it worked all that well. I could try again, but yes temps might come into play with that too.
Just picked up some supper glue so I will give it a try and let you know.
Update. So far the blue tape and super glue is working. Temp is 36*F.
Let me know if you have any issues with the blue tape + super glue. I too live in MI and my MPCNC will be going into my unheated garage once it is finished.
@Atom will do.
What area of MI are you in? I’m in the west michigan on the lake shore
Must be close by, I live in GR and work in Holland
Did you like that flurry we got today? I’m thinking when it gets real cold I might try carving some 
could be fun to play with.
Ha! I’m just the opposite. I live in Zeeland and work in GR.
When all this craziness we are currently in is under control we should connect.
I’ve been to Zeeland! I took a work trip to Gentex in Zeeland one time. I loved flying out of the grand rapids airport. There were 6 tsa employees and no other customers when I went through. Compared to Denver, where there are always at least 50 people in line (precovid).
@riptyde i drive though there at least once a week… we probably have passed each other on the freeway XD. cant believe that we have the 4th highest covid cases in the state (kent county) its scary stuff. but when its all over we will have to connect and talk CNC for a while ^_^.
@jeffeb3, i have been all over this country, and the GR airport is one of my favorites. its just big enough to go everywhere but small enough to not have issues. they are fast friendly and it is laid out well. if you ever find your self back in the area let me know, i will buy you a beer for all the help you have given me 