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? (https://uploads.tapatalk-cdn.com/20190217/d50171421d578620362ee4ac838df8dd.jpg)
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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.
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.
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... :)
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".
If you can get it good and flat when glued up Smooth on will get in those cracks then overlay it later.
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...
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!
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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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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It didn't occur to me last night (this morning) that it wouldn't line up. Thanks for the advise!
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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. :(
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.
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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I found a really cool jigsaw bit specifically for cutting fiberglass, btw.
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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. (https://uploads.tapatalk-cdn.com/20190302/c3fa2a0cb1cc3e5076d1e6e51946dd66.jpg)(https://uploads.tapatalk-cdn.com/20190302/826dba7f635075b1eae25be6996b638a.jpg)(https://uploads.tapatalk-cdn.com/20190302/1f116937c9c72e4b513d4f8bf601e760.jpg)
Mike
Nice job Mike. Did you make the chess board as well?
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.
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
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
Thinking of getting a 2hp with a separator and venting outside. I looked at a lot of the 2 stage systems with the fine filters, but it seems like an awful lot of dough if I can vent the exhaust outside and not worry about it.
Mike
At 54 years old I am finally learning about dust collection and respirators but even now I get focused on what I am working on and forget to grab a mask.
https://www.oneida-air.com/dust-deputy/dust-collector-kits
These work great.
I came to the same conclusion Mike. Venting outside is the way to go if possible. Get those fine particles out of your shop.
That's a sharp looking bow btw.
Hey Mike, I'm not familiar with that particular Fuji, but sometimes with a HVLP their isn't enough pressure to push thick finishes and get good atomization. Have you tried thinning it to different viscosity? Also the tip needs to be matched to the type of finish. Typically smaller for solvent based. I always recommend a cheap Ford cup to measure viscosity as a point of reference. Make sure your turbine filters are clean, those things suck in a lot of air that can easily contaminate the finish. If you can place the turbine in another room, cause they exhaust a s-ton of air and can stir up a lot of dust. Good luck.
Thans for the info, lig. I did try thinning the water based stuff. It recommended no more than I think 10%? I got all weird about the math and it didn't do much but maybe take a couple of seconds off the viscosity cup. One thing that did help immensely is running it under hot water, but then as I tried to adjust the volume, it cooled off. Still, I think that's a good indication that the viscosity is the issue with the water borne (not based) finishes. Is Krystal solvent based? Do you happen to know what tip size they recommend? I've got the smallest one for doing cerakote, and a few more; in fact I think I have all but the #2.
Thanks, guys, about the bow. I'm really enjoying it. I've got 2 more I want to make already, but I'm pausing to put that cnc mill into play, first, and get the template sander set up. That last bow has two old buddies wanting to buy one. Won't charge them more than cost, but maybe some day soon I can start supplementing income doing crap I'd want to do for free!
I would not worry about the recommended thinning, just experiment till you get good atomization. Don't know about Krystal, does it clean up with water or thinner? Thats your answer. Is your gun gravity feed or pressure cup. I have always found it harder to get good finish with a pressure cup, takes more fussing with. Try cranking up the air flow and choking off the fluid flow, and slowly open up the fluid till you get a good pattern. Try experimenting with your tips also, HVLP's are harder to tweak, you cant really increase the pressure only the air flow. I abandoned my turbine for everything but spraying thinned sealer coats, mostly shellac.
Damn. I thought that was the way to go. It's a pressure cup, in that it has an air supply that goes into the top, but it's listed as a gravity fed.... I also have a 110v electric finish sprayer I picked up from amazon for like 40 bucks. I intended to buy it to spray latex on walls but mistakenly bought one for clear finishes only. Wonder if maybe I should give that at try before sending it back?
Mike
Hey I'm sorry if I sounded discouraging, not my intent. Your setup should work fine, just more fussy to dial in. I checked out Krystal. Sounds like good stuff, high solids and long pot life. I have a local store that sells Campbell's, going to have to try it out. They say its ready to spray at package consistency, I would still adjust it to your equipment. Your turbine is a 2 stage which typically require more thinning to push finish thru and get good atomization . If you don't want to catalyze and waste your expensive finish, you can experiment with Karyo syrup thinned with water and match viscosity with your Ford cup. If you do, make sure to flush it out really well, the sugar will eat up the metal otherwise.
No way, man, don't be sorry. I appreciate the advice! I'm no snowflake. Lol.
Mike
I use a 1.4 tip in a fenix 1000 HVLP gun. I spray Krystal unthinned, clean gun with Lacquer thinner.