Glassine on MMT's

OK, so I'm building a L1 cert HPR and have read quite a bit about sanding the glassine coating off the MMT before applying glue/epoxy. (cardboard/wood kit) Question is: are you just roughing up the surface, or are you trying to completely remove the shiny coating on the tube? The first is easy, the second takes more work and I'm concerned I might cause structural damage to the MMT.

Thoughts?

Thanks,
Erik

emckee said:

are you just roughing up the surface, or are you trying to completely remove the shiny coating on the tube?

Click to expand...

Both answers are correct. You want to remove the glassine so you get good adhesion with your glue or epoxy. It is quite easy and quick to remove the glassine and then I cross-hatch the area where I will use epoxy, ie scratch sand at an angle one way and then scratch sand at an angle the other way. BTW I use 100 grit and have never damaged a MMT. If using wood glue, extra abrading is not necessary. IMHO.

Good luck and show some pics.

OK, here are some pics...

I took some 80 grit sandpaper to the glassine coating on the MMT after finding that 220 grit was getting me nowhere. The left side of the 1st pic shows the results.

At the edges, I noticed that a layer had begun to peel back from the ends of the tube, so I took a deep breath, grabbed the thin sheet and began to peel, praying I wasn't permanently disassembling my MMT.

1st pic is halfway through peeling off the glassine layer
2nd pic is fully removed
3rd pic shows the backside of the glassine layer where it covered a cardboard seam in the MMT. Certainly evidence that I hadn't removed the full thickness with my vigorous abrading!

The end result is a naked cardboard tube, which I further abraded with my 80 grit, although probably unnecessarily at this point. I feel quite certain that whatever adhesive I apply is going to be there for a LONG TIME.

Here's hoping I didn't misunderstand all those posts about glassine!

That's exactly what you want. Ya done good.

Next time just get an edge and peel it will save much time & effort.