Flaw under clear glass

[Old man of the swamp]

I have made two bows so far and both have ended up with the same flaw in the clear glass. Flaw looks like an etched worm track in an area about the size of a quarter. Glass was purchased at different times months apart and flaw is in different places on the two bows. Is it something I am doing or is it in the glass? I use Smooth On epoxy on both mating surfaces and an air pressure form @ 60#. I am curing the bow at 150 Degrees for 5 hours as per can instructions.

[TradBowyer]

its  hard to say without seeing it but i have had the same issues. I usually set my pressure at 70psi but I still get some limbs that have these milky spots. Its about enough to drive you nuts. Nothing like building a set of limbs with nice looking veneers only to have this happen. And people wonder why bows cost so much...bowyer has to eat those limbs so the money has to come from somewhere.

[Mike Most]

I have to say my form pressure is usually 65#, and knock on wood so far no flaws in the clear glass, (purchased at binghams)

Mike

[mater]

I think those are air bubbles that didnt get pushed out. Ive had those before. I used to have alot more trouble when I used rubber bands instead of the airhose method. Try more air pressure. I use maybe 80 #

[Roy from Pa]

I've only made 1 glass bow so far, but a friend told me to lay the glass at the side of the limbs and slide it across onto the other lams, supposed to limit the air bubbles more.

[Robertfishes]

What I have been doing is to use a bicycle tire pump and start off slowly with a couple of pumps, check for lam slippage, slowly add a couple of more pumps, check whole bow again,repeat until I get psi up to 55-60 then using my compressor bring pressure up to 65psi..I think that by pumping up the hose slowly with the hand pump I am eliminating the air bubbles better and I have not had slippage issues either. I have adjustable washers on the form to hold lams and riser from slipping side to side. I also use the metal pressure strips from Binghams.

[jess stuart]

Robertfishes give sound advice.  I too use a bicycle pump and inflate slowly.  If you inflate to quickly you can trap bubbles within the limb.  By inflating slowly it allows time for the air to be pushed out.

[Jason Kendall]

I do kinda like Robertfishes, I go to 30psi, let it sit and ooze while I wash the epoxy off my hands then finish it off to 65-70psi.

[Robertfishes]

Jason, to keep glue off of my hands I use nonpowdered VINYL gloves(not Latex or Nitrile) from Harbour Freight, they are cheap and loose enough that I can slip them off and put another pair on during glue up.. I use a 1 3/4 inch wide "bondo" squeegee to spread glue. I'm still a rookie so I have not developed a good clean technique,Without the gloves I would get Smooth On all over my hands, then everything else I touch....so thats why I use the gloves.

[Old man of the swamp]

I love it when the cure doesn't cost anything extra. I will raise my pressure slowly on the next one and try about 75#. Really hope this does the trick because I'm fixing to build several more out of some beautiful Bamboo. All my glass is coming from Bingham so I kind of figured it was me and not the glass. Thanks for the info guys.

[ranger 3]

In the mean time put skins on it then no one will never know.

[VRB]

I have seen striation in the clear glass about 50% of the time.They are filaments in the glass that show badly on darker veneers.I talked to Elmont Bingham,he said they have no control over it,that is the way it comes from Gordon Composites.He suggested using the streaky glass on lighter veneers and they won't show so bad.
 With all the things that can happen in building bows it would be nice to have clear glass that was clear.

[Old man of the swamp]

Haven't tried skins yet but if this thing is the shooter I think it is going to be then that is a great suggestion. Does that add any poundage because it came out a few pounds to weak?
VRB I don't think this is striations. After reading what other people had to say, I agree that my problem is probably air bubbles that moved around trying to work their way out from between the lams.

[Mike Mecredy]

I had one strip, a few glue-ups back, that had these little white flecks on in the glass.  No air voids just looked like tiny white check marks here and there.

I've gotten clear glass that when I glued it up there was a white line a few inches long in the center of the limb, I had a piece once with a quarter sized cloud in it. Several others with smaller clouds.

I've made up my mind to just not use clear glass anymore starting this year.  When it's perfect it's great, when it's flawed it's ugly.  I may loose a few sales but I'm not buying the crap anymore.  It's $5.00 more per strip, it should be $5.00 better.  I've never had a problem with black, brown or white.

-Mike

[kennym]

I look at every pc of clear I send out,sometimes you can see flaws,sometimes not till you glue it up!

It would be nice if it was all flawless,but once in a while some is flawed(usually what I've seen is streaks running hit and miss the full length of the pc).

It doesn't seem to hurt the bows performance or longivity,but it hurts the bowyer,cause most will build another to replace and then have a streaked bow to get rid of.

That said,all I put in my own bows and ones built for friends is clear. Gotta see the wood!!

BTW,the colors have the same probs,you just can't see em!!  

[Kanga]

look at every pc of clear I send out

Which is why I get all my glass from Kenny.

[Mike Mecredy]

"BTW,the colors have the same probs,you just can't see em!!"

Yes, that's why I only use colored glass now.  

I just wish I could get green like the old bows used to have.

-Mike

[Old man of the swamp]

Like I said earlier, my first bow had this same problem in a different place but it doesn't seem to have hurt anything. It has spent it's life bouncing around in the bottom of an airboat when it wasn't flinging heavy fiberglass arrows at Red Fish. Other than combat dings the glass shows no problems with the flaw. I'm used to it now and the Red Fish don't seem to mind. It just takes away from the looks so far.

[kennym]

What better life than bangin around shootin fish!!

[BigJim]

In the beginning when I first started building bows, I would get a few of the airbubbles. Certain wood was worse than others.
I went to using a painting knife and kind of force the glue in to the veneers going back and forth. I then let it sit while I spread glue on all other laminations and then put another layer on top ov veneers. No more airbubbles. I don't inflate slowly ever. I use my compressor. stop and check pressure then inflate again, check pressure and top off to about 80+ psi.
I would say that I've not had an airbubble in the last 100 plus bows. I have never built a bow with colored glass and don't plan on it. the woods look too good.
BigJim