Riser failure

[buckeyebowhunter]

Can't remember if I said or not but the one that broke is the only riser I've made where I've actually sanded completely through any of my accent stripes.

[buckeyebowhunter]

Maybe I'm wasting my time here? What are your guys thoughts. My thought process is at least if that lower accent tries to fail maybe the whole riser won't break in half when shooting it, like gray one did. I just don't know if I could get the overlay to cover the whole front without taking a bunch more material off.

[Mad Max]

That one looks better because the limb butts are bolted down hold the riser together better.

The past can tell you what to do, this is a 1961 bear Kodiak special with the white and black overlays on the riser




On your next one If you leave it flat on the back the glass overlays can do the job.
Black and white overlays, wood and white again

[buckeyebowhunter]

Those are sweet!

[Kirkll]

This photo with the grain of the wood following your riser shape , you will have no issue with at all. its when you get grain run out, or end grain exposed is where you need to cap it.  id have to see photos of the whole riser to check out your grip area.... Kirk

[Crooked Stic]

Just because one broke don't mean they all will. How close is that accent to the deepest part of the throat? And as said before a couple of layers of glass on the front will help.

[Kirkll]

A good rule of thumb is never sand through your footing lines, keep the depth on your grip throat at 1.75" depth and no smaller in circumference than 4.75" , and always cap any end grain with an overlay.  You should be running a cap on those limb pads to tie it together. Either wood or phenolic works fine.

Another thing to consider is any bows over 55# you should give the type of wood you are using, and footing material in mind for strength on those S shaped risers. I recomend using an Ibeam for riser flex on anything over 55#.The radius back risers with full overlays are much stronger and will have less flex to them, as do a one piece with glass running around the back of the riser.

.02 cents worth....  Kirk

[buckeyebowhunter]

Thanks for the advice guys, I really appreciate it. I think I just tried to get too cute with it on the gray riser that broke. Here is a little better look at the side of my riser.

[buckeyebowhunter]

Kirk would you just cap the limb pads with 1/16" phenolic?

[Kirkll]

Kirk would you just cap the limb pads with 1/16" phenolic?

That’s what I typically use on my flair shaped risers is linen phenolic 1/16” . Glass doesn’t work well because it splits sometimes. If you were to cap the limb pads with hardwood I’d go 1/8” to 3/16”.

I’ve done a few full S shaped overlays in the past for both looks and strength, but it’s a time consuming process that needs to be done prior to mounting your limbs so it looks right…. Here is an example with a black walnut riser.  But this one was 55# so I used an offset G-10 I beam to stiffen it up.

https://goo.gl/photos/mxuQUGwQuUK9GAbq9

[Kirkll]

Keep in mind I’m just trying to be helpful and am not criticizing your work or design at…I just want to give you some ideas and things to think about in the future…….. but you may want to remove a bit more on the belly side of your arrow rest and strike area.

While it does add a bit more mass to the upper section of the riser, and gives it a bit a a built in overdraw capacity, having it overhanging that far back over your thumb can and will put more downward pressure on the throat area and the back portion of the shelf . I’ve seen the back of the shelf split before on this design.

Same thing with the arrow shelf itself. Try to keep that shelf no more than 5/8” wide, and sand a bit more off the edge with fletching bevel.

Here’s what I’m talking about. Look at the edge of the shelf here.

.

[buckeyebowhunter]

Kirk I really appreciate the advice. I actually love the constructive criticism because it's how i learn to be better. Those risers look great. I would like to avoid using an ibeam however, unless absolutely necessary. I would much rather do glass overlay than an ibeam. My only reasoning is that I don't much care for the look of the exposed ibeam and I'm not really sure I want to go through the work to hide it. Of course I do not want another riser to break, but if I can get by with glass overlays and leaving my grip throat thicker I think that is the route I'd like to go.

I really like the way you beveled the edge of that shelf. That is something I am going to start incorporating. The pic of the full riser is my personal bow and one of my earlier bows so it is a little rough on the edges. But I have put that bow through a lot and it has held up well so far haha.

[Kirkll]

A lot of guys don’t like the looks of the Ibeam, and that’s why I offset them on many risers…

Here’s a little story for you….

When I first started out I had a lot of western curly maple, and black walnut to work with. It grows wild here and was easily obtained, and quite beautiful too.
The problem is…. It’s not seriously strong material and can be brittle at times. The wild grained stuff was unpredictable in strength properties, and even on one piece bows with glass wrapping the back I found that I was getting way too much riser flex just using straight accent lines.

Then I set up footing jigs both radius and flair shaped (S shaped). This increased the strength a bit more, but not enough. So I experimented with I beam construction and it was a game changer. I could not believe how much performance was lost in riser flex alone until I mounted the same limbs on two different risers. I was shocked….less hand shock too.

Going to using G-10 for an I beam was another positive step adding more mass weight to the riser and I as getting zero riser flex… that stuff is stronger than steel.

But,,,, using g-10 has its down side too. Many bowyers do not like it because the MC levels in the wood it’s laminated to have to be perfect. It’s not uncommon for the wood to swell and crack the finish along the G-10 and in some cases even open up a crack…. I’ve had to refinish my share of them…. But I love the stuff.
You cannot match the strength of that material.

Kirk

[buckeyebowhunter]

Where are you buying your g-10 Kirk? Also have you ever done a full G-10 riser? I've seen some interesting ones in the army green g10.

[buckeyebowhunter]

How is everyone clamping the limb pad caps to risers once the angles are cut?

[Kirkll]

Where are you buying your g-10 Kirk? Also have you ever done a full G-10 riser? I've seen some interesting ones in the army green g10.

Yup....But  the full g-10 riser weighs a ton. You could make some pretty skinny risers with it if you wanted though...  I buy mine locally at professional plastics in 24" X 48" pieces in both 3/8" and 1/4" thickness, and i only use the black stuff myself. Buying smaller pieces isn't cost effective with shipping for me.

There are many other materials that are similar but have different milling & strength properties. I've used a canvas phenolic material laid up with a hard epoxy resin that was outstanding material that some might consider it it a Micarta .... Here's a description of that for you.   https://en.wikipedia.org/wiki/Micarta

If you want to geek out on differet types of composites, this is some good material.

https://www.tandfonline.com/doi/full/10.1080/23311916.2018.1446667

[Kirkll]

How is everyone clamping the limb pad caps to risers once the angles are cut?

Very carefully....

Personally i mill my limb pads on a vertical mill, then just use a block of wood on top of the cap and use the router bit to push it down flat.   I use thick viscosity super glue.

In the past i made a jig with a wedge i tapped into place.  Sometimes i just use clamps and wedges . I use masking tape to hold it in place, then clamp it.     btw.... I always check for square again after doing those overlays on limb pads.

[buckeyebowhunter]

Appreciate all the advice! I've really enjoyed this thread. Although not what I wanted, I certainly can learn a lot from the broken riser.

[buckeyebowhunter]

This is what I was able to get on the front of my heavy bow. It's black glass, wood, another piece of black glass and two 1/16 pieces of phenolic. Hopefully it helps.

[Mad Max]