what grit?

[rockkiller]

What grit sandpaper are you guys using to grind out lams?

Thanks for any info
Al

[Roy from Pa]

I use 60, and a lot of guys use 36.

[fujimo]

i use 120- cos thats what i have- but i was worried for the longest time that it was not coarse enough, but apparently the smooth on literature recommends 120- that was a fluke on my part!!- but everyone i have asked uses 60

[Troy D. Breeding]

50 grit

[talkingcabbage]

X2 on 50 here.  Just makes quicker work.

[Bob T.]

X3 on 50 here

[LittleBen]

I've done everywhere from 100 to 36 grit, all sem to work just fine in terms of gluing, obviously coarse grit makes the work faster, so I usually go 50 grit or less.

[Bowjunkie]

I've used 36-50... prefer 40.

[fujimo]

a quick question, does the coarser grit, allow the lams to compress more on the ground surfaces- thus changing the stack thickness?
dumb question maybe!!???!!

[LittleBen]

You know Wayne, I've been wondering the same thing actually.

I was thinking that really coarse grit make like ridges along the length of the lam, when I caliper the lam IU am measuring from the top of the ridges, but when you stack the lams, if the grooves/ridges fit together then the stack might be a little less than expected.

I haven't devised a way to prove or disprove this, and since my bows are all wood and get tillered anyway, the answer wouldn't change my process.

Might matter for glass bows though .... would like to hear other peoples thoughts

[Roy from Pa]

I've been told that 36 grit causes those ridges to be seen under clear glass.. Wayne ya got a point there too.

[LittleBen]

Good to know Roy.
I think when I go to my next lam grinding setup (and a bandsaw to pre-cut the lams) I'm going to move to using 120grit instead of the 50grit.

I think it wouldn't matter too much on a real drum sander with auto-feed. With my hand fed lam grinder it is just a matter of too much sweat at 120grit.

[beachbowhunter]

80
lower grit makes me nervous as I am sneaking up on my target thickness. The surface is rough enough for good gluing.

[fujimo]

i think it was kenny that said, that smooth on recommended a 120 - have to ask the pink jammie guy!   :D

[Roy from Pa]

Most likely because smooth on requires a smoother surface for gluing. Jammie Guy..  

[Bowjunkie]

36 grit grooves can be seen under clear glass if you look really close, against some backgrounds/woods, not all.

I'm not worried about Smooth On's recommendation because my strongest glue joints are those I prepped with the toothing plane, and its grooves are deeper than those made by 36 grit.

You don't want a handle to pop off? Grind your belly lam and handle piece with 36 or 40 grit and use Smooth On... it can be treated like one solid piece of wood.

[Crooked Stic]

60 grit here for everything glued except the glass and I think it is sanded 80 grit.

[bigbob2]

Guess I'm swimming against the flow as I still use 40 grit but in light of all that's been said might go a bit finer in future.

[redbeard126]

I use 40 grit as well. Haven't noticed being able to see grooves under the glass.