Split glass at end?

[Mike L.]

So I’m working on my 3rd build, and this time I wanted to use 3/16” dowels as pins to keep things from slipping during glue up.  I marked and drilled the center of the riser, center of the press, and then after cutting the lams to 33” long for a 62” bow (I wanted to leave some room for error), I drilled holes at the ends of the stack.  On one end, I didn’t put anything under the lam stack, and the bottom glass split.  The split goes just a quarter of an inch past 31”.  I think I gotta trash the glass.  Is it trash, or should I proceed with the build? 


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[Roy from Pa]

I'm no glass guy but I would use it.

You could put an overlay over it after the bow is out of the form.

Put thin super glue in the crack to stop it then put the overlay over it a little past the end of the crack.

[skeaterbait]

I was thinking pretty much the same as Roy. But I would also suggest not using the dowl. I have heard of people drilling and inserting toothpicks at the middle of the bow to deter movement but when putting a bow in a press you will have mis-alignment at the tips, lengthwise, simply because of the contours of the bow. So if there is anything at the tips it's going to effectively push back on the bow and cause issues.

[kennym]

I would use it if I were keeping the bow and its on the back where the overlay covers it. You won't want it on the belly to show.  The nocks should be right at the 31" line.  The overlay will keep stuff glued together.

As Lonnie pointed out, if you have the center drilled on form , riser and lams under riser, you have that much less to line up on top of riser .  And I'm not sure if you drill them laying flat they will line up when pushed into the curve of form, assuming the limbs have some curve to them...


Or I know somebody who has glass...

[Bvas]

I agree with the above comments. I only pin the center not the tips to avoid binding. 
Tip overlays should cover the cracks. I’d also consider putting tip wedges in the stack to keep the tips from flexing.

If the cracks scare you too much or get worse, you can always pike the bow and make it a 60”.

[Crooked Stic]

If you can get it good and flat when glued up Smooth on will get in those cracks then overlay it later.

[Shredd]

I am sure that you could probably make it work but why use it and start out on the wrong foot...  You have not even glued anything together yet...   Have some patience...  Order some more glass... Put it aside for when you make a shorter bow...

[Forwardhandle]

Instead of drilling the riser and lams you could drill some holes in the side of the form & use zip ties to hold every thing centered ,Big Bob 2 turned me on to that trick it works good & keeps every thing lined up well!

[Mike L.]

Damn, drilling it when it’s flat on the bench would have been a complete disaster.  I think I’ll go for it.  It’s for me, anyway.   I was thinking the smooth on would fill the crack, I just wasn’t sure if it would continue to split later. 


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[Mike L.]

I did the zip ties for the last bow, and it worked out, but I was thinking both might be even better. 


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[Mike L.]

It didn’t occur to me last night (this morning) that it wouldn’t line up.  Thanks for the advise!


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[monterey]

The zip tie trick has worked for me too.  Ya just have to be mindful of the the position of everything while you tie it down.  One thing that works for me is to modify the form to allow centering a clamp on Top of the riser to hold everything in place while the zip ties are applied.

I would order a new piece of glass and use the cracked piece in another project.  Be sure to carefully cut the cracked portion off cause those cracks will run with handling.  Well, at least the way I handle things. :(

[Flem]

First off, sorry that sucks. I did that once, with a common twist bit. Core bits for glass work well.
if I was trying to salvage that piece, I would first try to reposition the fibers as much as possible, pre-heat the glass with a heat gun, apply some low viscosity epoxy, heat gun it again to get the epoxy to wick into the cracks and clamp it flat. then do what the others have recommended.

[Mike L.]

Well, I have a couple of extra pairs of glass on hand... maybe I will just set it aside to make a 60” later.  That won’t set me back any time and then I won’t have to worry about it.




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[Mike L.]

I found a really cool jigsaw bit specifically for cutting fiberglass, btw. 


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[Mike L.]

Well, I had some extra glass on hand, so I didn’t risk it.  I did glue it with a little CA and put it back on the shelf for later.  I finished the bow I was working on, well, except for the finish, anyway.  I’ve got 3 now to finish with Krystal and have a Fuji semi pro 2 sprayer.  Been practicing on this chess board with water based, and a little intimidated to spray the bows.  I’ve wiped the finish off 3 times cause it keeps going on nasty.  Also, I learned that black and white ebony can be pretty nasty stuff if you don’t pay attention to the dust.  Need to up my dust collection system, which currently consists of a Festool.  lol. 


Mike

[skeaterbait]

Nice job Mike. Did you make the chess board as well?

[Roy from Pa]

Sharp looking bow.

Yes you need a good dust collection system asap.

I learned that the hard way too.

I've never used Krystal but can tell you the thunderbird finish goes on real sweet.

[Mike L.]

Yep, and the pieces.  Got a couple more pawns to turn and then I’ll have to figure out what to use for a finish on the pieces as well.  I tried a couple different water based finishes on the board, and they seemed to go on grainy, and then I upped the spray volume just a tad, and it went on thick.  I’m thinking the Krystal might be a little easier to work with since it’s intended as a spray finish to begin with.


Mike

[Mike L.]

I guess I get to not paying attention, cause when I went out to do clean up, everything had a pretty good layer of dust, and I’ve been coughing my ass off for 3-4 days.


Mike