Bear Stress Crack Question (dont beat me!)

[SlowBowke]

Ok, I like the Bear bows from the 60s as much as my wallet allows but ... without offending ANYONE, I don't understand what it is/was with the older Bear recurves that SO MANY of them have stress cracks and have noticed that others state that it's "normal" for them.

My 64 K Mag dont have a one but my just acquired 68 Super K does and in looking for another 68-69 I notice that this is true.

I probably look at 150 bows a week and notice it's ONLY the Bears that have this almost always.

Neither my 61 and 64 Howatts have even a tiny one, nor do my Shakespeares and it's common for me to see others without any.

Was there something in the glass or was it the finish that has made this so common in Bear bows?

Certainly does NOT hurt the shooting capabilities but I've never seen much said on why Bear bows just normally do. It also seems that the Super Ks are the group with more than the others.

IM SURE, lots of you have some that don't, being collectors, so I'm not saying that they don't exist. Im just saying that I rarely find one without some kind of stress cracks and it made me wonder.

OR?? Is it JUST the Super Ks? Or the late 60s ones?

Anyone have any history or info on this?

God Bless.

[Bjorn]

Some years were worse than others. I have seen them on all makes of bows-even some new ones.
But if you are looking at 150 bows a week you see about as many as the rest of us combined.......so you tell us!  

[Grant Young]

Steve- the biggest reason for the stress cracks in the older Bear bows is that climate control as we know it now just wasn't feasible in the sixties. Northern Michigan winters are awfully cold and when the bows were shipped to warmer climes they drank up the relative humidity, swelled, shrank back, and repeated. It is also important to remember that for every Bear that has them there is probably 150 or so that don't- They built a heck of a bunch of bows compared to other manufacturers. Shakespeares were buit in South Carolina the heat and humidity capital of the world. It was location, not QC. Howatts were rain forest bows as well. None of the bears I've seen from 1970 on have these issues due to available and advanced technology.    Grant

[SlowBowke]

Thanks guys. Makes sense. As for those 150 to 1 bows that dont have em.....they must be in Bowdocs storage, LOL.

kidding

Steve

[Blackhawk]

Howatts were made in Yakima, which is eastern WA and is very dry with cold winters and hot summers and long ways from the rain forest.

[d. ward]

I would like to say I have seen the cracks in every manufactures bow.Fact is I am working on a Ben T/D in my shop right now that has cracks in it and just finished a set of newer Black Widow limbs with cracks in them.
However I actually do not think they are stress cracks at all.They really have nothing to do with stressing.You may see the cracks your talking about on some bows running into the riser sections of the bow and sometimes on the riser overlays themself.The riser is way to big of a piece of wood to be flexing and causing fiberglass damage caused by stressing.Those cracks really have little if any to do with stress but are actually expansion cracks.Pics soon as it gets daylight in Seattle....bd

[SlowBowke]

You may see the cracks your talking about on some bows running into the riser sections of the bow

THAT had me wondering too, BowDoc.

There are light ones on face of the GRIP of this 68 Super K.......my first thought was ???????, no way. Plus the only "stress cracks" are on the grip and belly, none on the back which made ZERO sense to me if stress cracks and I wouldnt think a "compression" crack would be going the direction of the limb itself but would rather be sideways perpendicular to the limb. ??

I AM, hovwever, hardly an expert on what causes them so .......I'm here asking.

So, learning once again from all of you and appreciating it. No offense to the Bear line intended and not saying they are the only ones. It just seems to be the rule instead of the exception on Super Ks (or at least on ones for sale) from the 60s and figured someone would know here.

I even noticed some on the "Bear-ied Treasure" bows and was assuming few of these were shot much, which added MORE confusion in my mind.

I'n not at all afraid of them on a bow I'd be interested in. In fact, without them I couldnt afford one LOL.

I LIKE the sound of what you are saying guys and makes perfect sense.

I am, once again, indebted to all of you that reply.

God bless.

[TonyW]

Hey Don, do these cracks usually stop by the time you sand through the Fullerplast or do they go all the way through the fiberglass and even to the core?

In other words, if the "crack" doesn't split all the way from the belly to the back, is it really a crack?

If the crack does go to the core, let's say halfway from the surface of the belly to the surface of the back, should the bow be retired?

Inquiring minds want to know.

[Earl E. Nov...mber]

The fiberglass in bow limbs has no cross weaving of the glass. All strands are parallel, with only the resin bonding them to each other.. Most likely it is some form of expansion and contraction going on, but I doubt it is humidity.. Hopefully the finish will seal them up from that.
The good thing is since the cracks are parallel with the glass fibers (Or reasonably so), very little structural damage has occurred, the glass fibers are still intact, and unless the strands are letting loose from the core (Delamination) the cracks would have to be pretty bad to become an issue with the bow.
My $0.02

[Hud]

It is possible the stress lines in the older Bear limbs is were more noticeable because of the climate control issue, but I think Bear continued to use the parallel glass when others had already switched to the multi-directional glass. Does anyone know when the multi-directional glass came out?  I know the approximate date. The use of the newer improved glass pretty much eliminated the problem.

I suspect, the problem originated in the manufacturing of the glass and the curing process. I don't think the problem was due to Bear's manufacturing process, unless Bear was curing the bows at a temperature near what the glass was manufactured under.

Too Fred's credit, he replaced a lot of bows that developed this problem amd he absorbed the loss.
I heard it nearly caused the demise of the company.

Frank Eicholtz was a pioneer in using composites to make laminated bows. He introduced Howard Hill to fiberglass. Frank's first bows were backed with plastic sign material. He bought the plastic and later fiberglass from Narmco (now Narmco-Conolon). They developed woven fiberglass during WWII. Frank eventually used this product and was building recurves, flight bows and other bows using the woven fiberglass by 1950. Harry Drake set a flight record with one of Frank's fiberglass bows.

If you do a Google search for Conolon fiberglass you will find, it was the first fiberglass fishing rod. The company is now owned by Garcia Rods.

Frank Eicholtz was the inventor of the micro-flite arrow shaft. The company died when Frank's business partner was killed in a car accident, and he did not have legal authority to continue the business.

Here is a partial list of his inventions:
 1. first to use plastic in a laminated bow.
 2. Maple bow laminations
 3. fiberglass face and backing
 4. graphite to replace fiberglass
 5. fiberglass arrow (Micro-flite)
 6. Bowlock, hand held release devise
 7. the first center shot take-down bow

Frank died in 1983. He was amazing, weighing about 125 - 135 lbs, he could pull and shoot a 120 lbs bow.

[Hud]

To give credit, most of the info on Frank Eicholtz can be found in Fred Anderson's book, The Traditional Way.

[Hud]

Bear Archery made the switch to woven glass some time in the early 60's. They may have completed the change over by 1962-63. It may explain why there are so few 1961 Kodiaks, and why there are so few heavy weight bows in collections.

[d. ward]

Hi Tony yes they generally go into the glass and yes some do go right into the corewood.I personaly have never seen a bear or any other bow NOT shooter do to the stress or expansion crack.bd

[Hud]

Doc, your saying the stress cracks do not impair or prevent the bow from being used? I think your right, and if the bow is going to be used much it should be reconditioned the way you do it.

[SkookumDon]

Anybody know of a tutorial on how to repair stress cracks? Maybe bowdoc will let me shadow him for a few days.

[wadde]

The bottom line is where the bow has been and how it has been stored all these years. In the garage rafters, in a humid basement. If properly stored in a case in the house is where you find your nice vinatge bows. A lot of people used to stick them up in the garage rafters in the off season. You will know when you come across one that was well taken care of.

[Hud]

Seems like an appropriate subject for the 4th.
If you search for Restoration 101, you will find a number of threads, including the one Bowdoc did on several restorations with this title. It was a long running topic that will show you how he does it. Great stuff.

[BrokenArrows]

Accoding to Belcher at Belcher bows, the "stress lines" are nothing to worry about, the bows are safe to shoot. "Stress" has little to do w it, nor does the weather where they were made. Expansion, not separation, along the fiber lines is as good a way to look at it as any. Some bows that have been used little will show more of it than some that have been used a lot. Had to do w the type of glass used then made by 3M and Gordon. I've seen it in old Shakespeare, Pearson, and Browning bows too. Can be particularly bad on the early Bear clear glass bows.