Problem???

[arachnid]

Hi guys.

I went field testing my new spliced limbs longbow. shoot great, smooth and sweet.

After shooting a while, I`ve noticed these white spots:
   

       

These white spot weren`t there as far as I remember,
Question is, is it a sign that the splice is doomed to fail? Or I shouldn`t worry `cause the glass holds it all together?

Any input will be great.
Thanks
Dor

[kennym]

Dor, I'm not sure what you have going there. What kind of glue did you splice with?

Only think I can think of is the glues weren't compatible or the splice glue started to fail in the hot box.

How thick are your spliced veneers?

[monterey]

Could it be the finish?

[Bvas]

Is this possibly just a thick glue joint. I can only see the spots on the walnut. Which the walnut usually sands much easier than the maple, possibly leaving low spots in the veneer.

On another note. I believe that it is recommended that you run your splices in opposite directions to create an “X” to reduce chances of limb twist.

[EvilDogBeast]

It looks like the glass is stressing to it's upper limit in that spot.  I would suspect either the glass is compressing too much right there or you have two small disbonds.  I would use a coin similar to the size of a US quarter to gently tap the light spots and the surrounding areas.  Hold the bow in your hand so the sound isn't distorted by a table while tapping from one good side, across the light spot, and onto the other side.  You want to hear a solid sound that resonates, if it sounds dead and has no reverberation it's disbonded.  I would also outline those areas with a grease or wax pencil to see if they are getting larger for the next few uses.  These are the evaluations I use on aircraft fiberglass and carbon fiber to check for damage, but they should translate over just the same.

[Crooked Stic]

Veneers How thick? Type of glue on the veneers. Was it a clean sand job with no glue residue left in the splice joint? Walnut soaks a lot of glue to. If there was residue there the smooth on may not have took hold. if the veneers are too thick there may be a weak spot at the splice and delam.

[arachnid]

First of all, thanks for the replys guys.
As for your question-

I used ea40 for the splice.

I didn't criss cross the veneers when I glued them- note taken.

The veneers ar 1.5mm thick.

When I do glue-ups I spread glue, wait, spread, wait again and then spread a final layer of glue so I don`t think it`s a starved glue joint.

I do think that this praticular veneer didn`t had a perfectlly tight glue joint on the splice. I may had a little gap.

So, Do you think it`s fatal?

[arachnid]

Shot some 120 arrows tonight.
The spot doesn`t seem to grow and the bow shoots just fine.
I`ll keep on testing but I`d like your opinion plz.

[kennym]

Really no way of telling except what you are doing.  Keep an eye on it!!

[Crooked Stic]

!.5 calculates to .059 pretty thick for a veneer with a splice. Dont know if it is too thick. I do know that it bends there and no continuous grain will be a weak spot it too thick. Those spots are either bad glass or dry spots. I would lean toward the latter.

[arachnid]

Thanks Crooked.
How thick should a spliced veneer be?

[arachnid]

When you say 'dry spot' do you mean there's no glue between the glass and veneer?
That spot is on the edge of the limb and there's no gap between the glass and veneer there. It's bonded really tight.

[fujimo]

did you use rubber bands on your form, or an airhose?
and if rubber bands- did you use a stout pressure strip?
when i have done rubber bands i have use a good strong, yet flexible pressure strip- then a piece of tightly woven rope down the center of the pressure strip- to ensure that i get even pressure across the full width of the bow- and not just on the outside edges!
just my .02c     :D

[mikkekeswick]

your glue-up must have been good or else you wouldn't have got to this point!
Spliced veneers should be around 0.040 maximum. Of course it doesn't really matter on a straight limbed bow but thicker spliced lams can break on bow with 'curvy' limbs.
Could it be that those spots have residue of EA40 on them and you didn't grind them far enough to remove? Is it ion just the one limb or both? Same spots on both?

[Crooked Stic]

I use .030 veneers. If you say it is bonded really well then the glass must be blemished. I have had those type of spots that look bonded but were not. I would say shoot it and keep an eye on it.

[arachnid]

Crooked, what do you mean by "the glass must be blemished"?

How come?

[Crooked Stic]

If you say it is bonded good and there is no left over residue from grinding b
then was the glass good and clear before glue up. What I mean by blemish is a imperfection in the glass, Some of the Gordons glass has that problem. I do not think that is it being where it is. So shooting it and time well tell.

[arachnid]

I'll try to shoot it daily and see what happens.
How long can be a good indication it's gonna hold?

[mikkekeswick]

The more I look at it the more it looks just like reside left on the lams from splicing and not ground away fully.

[arachnid]

Originally posted by mikkekeswick:
The more I look at it the more it looks just like reside left on the lams from splicing and not ground away fully.

What fo you mean? Leftover glue from splicing?