Giving it a shot... My First Laminated Glass Bow Build

[Major Boothroyd]

Mark Daniel, got it... thank you!  

bigbob2, thanks for your tip, too!

[Mad Max]

I haven't seen any dents with final sanding on the back of the bow.

Some pressure strips are thinner, I could see that  leaving dents.

[Major Boothroyd]

I did a dry run test today... I didn't bother with plastic wrap, or waxing the form yet, as this was just a dry run.  Everything looks pretty good to me, overall.  I did do a little more hand sanding of my fades after this test, and I pinned the laminations after the test, so that the butt ends of my laminations now have zero void space, as opposed to how they appear in the photos below.  I also drilled a couple more holes for additional zip ties near the ends of the fades.

I think tomorrow may be the glue up day, although it will depend on the weather.  It was a little uncharacteristically damp out today (for SoCal), but it should be dry and warm by tomorrow or Friday at the latest.

Laminations laid out and organized..
         

Dry run test with firehose inflated to 60 psi:
         

Riser section (prior to pinning the laminations):
       

After pinning the laminations, there was no space between the butt ends of the bamboo laminations.

Close up detail of the accent strip fade.  I did little more hand sanding of the fades on the riser and the accent strip after taking these photos of this dry run test.
       

That's all for today.

[Mad Max]

You need to get rid of those gaps, and I did not know you where going full length on the fiber glass on the belly .
You need to splice the butts of ALL of your  lams together.
Much more easy on the glue up
Page 2
  http://www.tradgang.com/noncgi/ultimatebb.php?ubb=get_topic;f=125;t=001165;p=1

[Major Boothroyd]

Yes I was planning on doing at least one more dry run test to make sure I've gotten rid of the voids/spaces before gluing up (maybe more than one if necessary).

And I was coming around to the conclusion that I should splice my lams.  I saw that done in a video by a guy on YouTube who has a series of videos called The Bowyer's Den."

I guess that's what I'll do today!

Thanks Mark Daniel!


 

Originally posted by Mark Daniel:
You need to get rid of those gaps, and I did not know you where going full length on the fiber glass on the belly .
You need to splice the butts of ALL of your  lams together.
Much more easy on the glue up
Page 2
   http://www.tradgang.com/noncgi/ultimatebb.php?ubb=get_topic;f=125;t=001165;p=1  

[Major Boothroyd]

Okay, so here's the update for today.  I didn't have a lot of free time, so all I did was sand the angles for scarf joints for my upper limb and lower limb lam pairs to be joined, as shown in the thread Mark Daniel linked two posts above.  I glued all the ActionBoo lamination pairs together, but came across a problem with the Eucalyptus burl.  It seems that Eucalyptus Burl veneers don't want to bond with CA glue (cyano acrylate).

I'm guessing it could be natural oils that might be present in Eucalyptus wood.  The veneers don't seem to be oily to touch, nor can I detect any scent, but the glue just won't seem to set up, and it did great with the bamboo laminations.

I'm thinking of trying Titebond III, since the joint is just to connect the pairs together to make the real glue up easier and to keep the pairs from sliding around and separating.

I am a bit concerned now, however, about whether or not the epoxy will bond properly to those veneers.  I'm guessing/hoping that it'll be fine, since more than one bowyer supply vendor carries Eucalyptus burl.  I'm second guessing whether or not I should play it safe and just use some Myrtle veneers I also have lying around, or take the gamble.  What do you guys think?

[kennym]

How long are you clamping the euc burl? CA will dry and seal on coco and other oily woods to seal for finishing.

The CA may not soak into it like it does on boo so it may take longer to dry. If I coat both pcs , I leave it clamped longer too. Also on the thin veneers, you don't have as much glue surface to hold it together.

[Major Boothroyd]

Well, the CA cured in less than 20 minutes with the ActionBoo.  I gave up after 45 minutes on the burl.  It just didn't seem to be working at all.  After 45 minutes, the CA was still completely liquid, and the lams slid apart without any apparent bonding having taken place.

How long does cocobolo and other oily woods take to bond with CA?


 

Originally posted by kennym:
How long are you clamping the euc burl? CA will dry and seal on coco and other oily woods to seal for finishing.

The CA may not soak into it like it does on boo so it may take longer to dry. If I coat both pcs , I leave it clamped longer too. Also on the thin veneers, you don't have as much glue surface to hold it together.

[kennym]

It usually dries on coco in about a minute or less when sealing with it. I usually leave the lams clamped for probably 10 minutes. What kind of CA are you using?

[kennym]

Also how long is your scarf joint, longer is better....

On veneers, I go 3/16 to a quarter, depending on thickness, and on say a .100 lam, it ends up an inch or better.


Oh, and I use loc tite from wally world . The thin stuff, hate gel CA.... That's just me tho.  

[Major Boothroyd]

kennym, on the veneers, I have about 1/4" overlap for the scarf joint, and I would say about an inch for the bamboo lams.

The CA I used is Gold Tip brand, because it's what I had on hand.  I normally use it for fletching feathers on Carbon arrow shafts.  I store it in the fridge, and keep it in a ziplock bag.  It worked great on the bamboo lams.

[kennym]

I've never used GT glue, IMO you might try a fresh bottle of something different before you give up. I've glued all kinds of veneers with the lock tite brand. I lay a pc of plastic on a straight 1x2 on the bench edge, glue both bevels and line up on straight slat, then flip plastic over top of veneers ,put a small block on top and quik clamp to bench for awhile.

[Major Boothroyd]

Ha!  Well, it's too late to do something different.  I used Titebond III wood glue this morning to join the Eucalyptus burl with a scarf joint, and it seems to have worked great.

As for my method of gluing up my scarf joints (on the bamboo lams as well as the veneers), you described exactly how I did it!  So that's good.

I'm not too concerned about the Titebond being a problem, as it's really only on the minimal scarf joint, and oncee everything is epoxied together, it'll just be sandwiched between the riser an the fiberglass.

The adventure continues!

 

Originally posted by kennym:
I've never used GT glue, IMO you might try a fresh bottle of something different before you give up. I've glued all kinds of veneers with the lock tite brand. I lay a pc of plastic on a straight 1x2 on the bench edge, glue both bevels and line up on straight slat, then flip plastic over top of veneers ,put a small block on top and quik clamp to bench for awhile.

[Major Boothroyd]

I meant to ask... what ratio for Smooth On (EA 40) do you guys recommend?  I have seen a variety of answers from 1:1 to 2:1  (Epoxy - Hardener), with the majority being 1:1, by volume (not weight).

[kennym]

It comes to be mixed 1:1, but some mix 2 resin to 1 hardener. Supposedly better heat resistance, and one really good bowyer told me less air bubbles.

Do NOT mix extra hardener, I know one guy who did and it didn't set up. Seems all wrong, but he called smooth-on and they said not to do that....

I go 1:1

[kennym]

Good deal on the titebond. I was thinking maybe the glue you had wasn't agreeing with the euc.

I go a tad more part A... Weighing is easier... If I go 70 grams with 'A' I go about 60 grams with 'B'...  Its a win, win... You are guaranteed to have the proportions right, the bond may be a bit stronger and you won't have too much unused hardener wasted...
   I like to use tite bond on the wood scarfs and CA on the glass...
   Good luck on glue up... Keep a rag or two handy...

[breazyears]

Hows things going?

[Major Boothroyd]

I've been meaning to make a post... sorry about the time gaps in posting!

I ran into a minor setback.  In testing my oven a second time, I put the form in it, as has been suggested, to add thermal mass in order to get a more accurate idea of how much temperature fluctuation there will be.

Unfortunately, the fiberglass strip on the top of my lower form delaminated during the second round of oven testing.  I used contact cement to adhere it, but I wish I had done epoxy from the get go.  Anyway, I decided to sand away as much contact cement residue as I could from both the form and the strip, and then epoxy the strip to the form.

After seemingly endless sanding... contact cement does a great job of gumming up sandpaper, I finally got it cleaned up and ready for epoxy.  I re-glued it up yesterday, and now I need to do a little sanding and cleaning up of the excess epoxy.

That's today's project for later this afternoon.  Tomorrow or Friday I plan to do another dry fit test to see if I've eradicated the voids/ gaps around my fade outs.

One concern I have, however, is that when I glued up my laminations with scarf joints, the Eucalyptus burl veneers warped slightly in a few areas.  I guess the dry air and heat outside caused that while the glue up was drying.  In any case, I think they might possibly crack if I was to try to press them in another dry fit test.  I think when I actually use  epoxy, the Euc veneers may soak up the resin and become a bit more flexible, and hopefully that will prevent them from cracking or snapping, but for the dry fit, it could be an issue.

I'm thinking maybe I should leave the Euc veneers out of this upcoming test fit, since they are parallel .020", I'm hoping that leaving them out won't affect the areas of the fades that is what I am primarily concerned with (looking for void spaces, etc.).

What do you guys think?


 

Originally posted by breazyears:
Hows things going?

After all that sanding you better make sure your form is true...  Meaning fluid curves, Perfectly flat across and 90 degrees to the side...  Any slight deviations will be multiplied as you go further down the limb...  meaning you might end up with a twisted limb...  
   The dry fit does not need to go into the hotbox...  those extreme temps and humidity changes will mess with the wood...  Also when you do a dry fit anything that goes wrong, you want it to go wrong during then and not when you are gluing up...  If you are unsure about your scarfs, cut and reglue them or take the chance...  Sometimes taking an extra 10- 15 minutes is better than risking the quality of your bow...
   
   HOT BOX....

   In 85 to 90 degree temp I use 2- 70 watt bulbs and that will bring me up to 150 - 160 degrees...  Put a third bulb on for 45 minutes or so to get you up to temp quicker...

   As for me I don't put my form in the oven...  I had a problem with a form warping on me...  I glue my bow at room temp for 5 hours or over night and then pop it into the oven for 5 hours...  Its called post curing...

   Just giving you more info to confuse you...  Lol...  
    After you do 7-8 bows you will start finding what works for you and will have developed your own methods...