G'Day All - Bit of an Intro

[Nezwin]

G'Day everyone, joined up here a month or so ago and have been meaning to do an intro thread for a while. The bows have all gone pear-shaped, as they're wont to do, so here's a look at where I went wrong! Before I get going, many thanks to Sam Harper of poorfolkbows who inspired me to give it a shot and see what happens.

Anyway, here's the first shot at a thickness sander jig.

Thickness Sanding Jig 1

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Thickness Sanding Jig 2

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Shortened her up and beefed it a bit since that picture was taken but same concept. I run it on a cheap piece of junk I bought from Super Cheap Auto. Does the job. Sometimes. When the drive belt isn't slipping.

I cut by hand a lot but I do my lams & risers on a little Ryobi 9" bandsaw. It's not bad, really, and the decent blades from the saw place down the road make all the difference. Pretty sure it'll be dying on me soon though, poor little fella. I've pushed him a bit hard, I reckon.

Here's the forms, tack welded & made out of steel. (That's the old fella posing while I got behind the camera)

Old Fella Posing

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Finished forms.

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They've had a couple of coats of grey zinc since, which has made them look tidier. I'm not convinced by them though, especially the R/D/R, shorter form. Too much kink, not enough smooth curves. I'm probably going to flip them and go back to the old way I laid up where I would clamp & bend the bow woods using little blocks to get the lift/bend in it. A picture's worth a thousand words so I guess I'll have to show you all when I get round to it.

Here's some of the (un)finished products.

Finished 1

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So the one on the left is your standard R/D style, 70" (68" ntn), 2" R/D, Tassy Oak & Spotted Gun riser with Tassy Oak, Balau & Bubinga overlays. Limbs are all Balau with homemade pretensioned e-glass backing, few little offcuts & goats horn nocks. I've got a bit of a background in composites so I've found it easier to make my own glass lams, rather than buy them. All in the spirit of the hobby, eh? Not finished this bow yet but hoping to have her come in at around 40lb @ 28". Got one .001 taper & one .002 taper in her too, so it should have a nicer (well, more of a) bend to her too.

One in the centre is the first off of the R/D form, so same dimensions as the other fella. Came in at a whopping 10lb @ 28" - I call it 'Stephen', after a certain Mr. Amell. My old archery teacher in Canada is the tech on that show & told us about the 12lb bows they use on set. Nice. Spotted Gum limbs with only a .001 taper, Spotted Gum riser with a Merbau (?) accent strip, same nocks as above. Old piece of hardwood I had knocking about, can't remember what it is really. The glass lam came out well but I didn't grind it down enough so full of bubbles underneath. Ah well. Apart from that, it came up nice for a first hit.

The third bow is my little beaut. Unfinished, and will remain so due to compression cracks on the upper limb near the riser. Note to self - Balau is only for risers from now on. Like the other bows, the design is based on the Golden Ratio, but this time it's 62" (60" ntn) with 2" reflex on limbs, 1.5" reflex on riser. Riser is Tassy Oak, Spotted Gun & Balau with a Merbau (or whatever it is) accent strip. Limbs are a Spotted Gum core with a .002 taper, Balau on the belly, Glass on the back. Nocks are Bubinga & goats horn. Not too sure about the lack of smoothness in the limb curves, but the previous attempts (currently en route from Canada) have a bit of a nicer bend to them and were done without a form as such.

Finished 2

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Finished 3

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Finished 4

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I've learned a lot since making these three, and the other 2 I smashed in frustration which aren't shown. I picked up some Ironbark & Black Bean (seriously, is is really called Black Bean?) today so going to give them a shot in the next couple of weeks. The Balau will be relegated to risers & cores, I think, it doesn't seem to have the rupture coefficient that would be desirable in a compression wood. Can you get Ipe in Australia? I've had a look but no luck as yet.

I've been using epoxy resin as glue, which can get messy, but I get great penetration & adhesion and it's pretty cheap really. I use it for the glass lams so I buy it in enough bulk that it's worth it. In Canada, when making laminate bows, I was using Tightbond III - great stuff, but a bit dear over here in Oz. As you can tell from my timber & tool choices, I'm not exactly flush with funds at present... I used a marine epoxy a few years back and had nothing but trouble with it. What do all you other guys use? Smooth On? I've never been overly impressed by it, personally. For less money I've found much better products, like the epoxy I use now.

Anyway, there we go. Any feedback/thoughts/criticism/hell raising welcome.

[Mick Smith]

Hi Nezwin. Welcome to Ozbow.

I don't know enough about bowyer's tools and equipment to make any comments about yours. It's obvious that you're dedicated and devoted to achieving results though. I'm sure there will be other members responding shortly, members who are far more qualified than I am to offer advice on these matters.

We have lots of old codgers who love nothing better than messing about with bits of wood, fiberglass and glue.

[Stickbow Hunter]

Well it looks like you have been rather busy. It's great to see you having a go at making your own bows. There are a few things I will comment on after looking at the photos.

You description on the different bows is a little confusing. In the first photo of the bows the bow on the right of the picture is of reflex/deflex design and the other two are of deflex/reflex design.

I think the kinks in the one form are too severe also.

It appears as though none of your bows have little, if any, fadeouts. The ends of your risers should fade into the limbs gradually or you will end up with very high stressed hinges at the end of the riser.

If you are only glassing the back of your bows this may be over powering the belly wood and causing it to fail under compression.

Lastly, it would be great to see some close up photos of your glass and even an explanation of how you make it if you didn't mind disclosing that of course.

All the best with your next ones mate.

Jeff

[Nezwin]

Thanks for the replies, fellas.

Re: bow design, there are two R/D (on the left & in the centre of the first picture) while the third, on the right of the picture, is a R/D/R (so, reflexed tips, deflexed inner-limbs, reflexed riser). It's my idea of a horsebow-Flatbow hybrid, which I've not seen before elsewhere. The proportions of where & how much the bows start to make their transitions I've based as much as I can upon the golden ratio, so try & find as best a balance I can. How does everyone else decide where to start their reflex & by how much?

Re: form kinks, agreed. Will give it one more chance and they go back to my old way of doing it. I'd always wanted to use steel forms though - the one time I did use timber it just didn't hold up. Has anyone else had any luck using steel on their forms?

Incidently, I found this picture of a layup we did in Canada. It was all parallel lams (no grinder or sleds back then) of 1/8" thickness - vertical bamboo, red oak then a short Ipe lam (I think you call these powerlams?).

Canada 2013

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In this picture all that's clamped up is a couple of layers for the riser but you can see where there's little pieces of timber under the curve. Gives you an idea of what it was about anyway.

With the glass, it's pretty simple really. I took a length of 50x50 RHS, cut it in half lengthways and use that as my mould. Once it's polished & has a layer of release agent dried on, I put a layer of resin down, then take the glass itself and clamp it at one end, heave it tight and clamp it at the other end to hold the tension. Then it's just a case of laying in the rest of the resin & rolling the air out. It won't be preloaded to the same degree as Gordons, but a quick look at the degree of bending it will undergo on the bow means that the pretensioning will shift it enough up the Youngs curve to make a difference. I'd previously clamped board bows into the form while the resin was wet, allowing the bow to glue to the glass as it was formed, rather than taking the glass out, cleaning it up, then gluing it to the bow. I'm toying with the idea that next time I'll put my back-most lam in there with the glass...

I've always been a bit puzzled as to why people put glass on the belly of the bow. My father, who designed & made composite parts for F1 cars back in the 90's, and my lecturers at uni, all claimed that any fabric/resin matrix relies solely on the resin in compression. Makes sense to me. I could make up some resin-only lams for the belly but it would be kinda like cheating, to me at least I think the reason the R/D/R bow failed at the riser/limb transition was due to poor workmanship on my part, really.

On that poor workmanship aspect, I've had a bit of an issue with fades... My bows that I would usually reference from are enroute to Australia at the moment so I've not been able to take a look at how it's done properly (and I've never needed to look too closely either). To form the shape of the riser, I first brace the prepped riser block against the form, draw the curve, then cut it. At the fades I've been drawing straight lines from the tips to about 2" either side of centre - should these straight lines be curved? How would I go about planning the correct curve for this? Or is it just eyeballed off of a bent piece of wood?

[Stickbow Hunter]

Re: bow design, there are two R/D (on the left & in the centre of the first picture) while the third, on the right of the picture, is a R/D/R (so, reflexed tips, deflexed inner-limbs, reflexed riser).

You have got your design types confused mate. The bow on the left and the centre one are both of deflex/reflex design and the one on the right is referred as being of reflex/deflex design. They are not all of reflex/deflex design. Note with the bow on the right the riser and limbs firstly reflex from the handle and then deflex where the other two do the opposite.

DEFLEX-REFLEX: A bow design where the unbraced limbs curve toward the belly of the bow then reverse direction about mid-limb, reflexing away from the shooter. Reflexing replaces the braced limb stress lost by deflexing.

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The backs of the bows are facing toward the left of the screen.

In relation to your fadeouts they should be more like this so they blend into the limbs better and not cause a high stress point.

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I hope that helps.

Jeff

[Gringa Bows]

Welcome to Ozbow Nez....

[GrahameA]

Welcome.

Anyway, there we go. Any feedback/thoughts/criticism/hell raising welcome.

IMHO If you want to build forms from steel you need to use traditional steel working methods - ie get some rollers so you can roll the curves ..... and spend a small fortune on somewhere to store them.

If you are willing to do some work then build them from MDF. It is probably a little more labour intensive however, it works and you get smooth curves.

If you can live with slightly ripply surfaces then you can clamp them up and if you want all nice an smooth then you will be going down the road of Air-Hoses.

You may also need to discover the "Lucky Dragon" - ie the shop that sells cheap imported chinese tools so you do not go broke buying clamps ..... or consider other clamping methods.

Since you live in the SE Qld you need to go the NAFA Easter Shoot.

Well done on making a bow - and welcome to club of people who have made bows that overly light and overly heavy ..... and who have put bows through the bandsaw and into the garbage bin.

[Nezwin]

You have got your design types confused mate. The bow on the left and the centre one are both of deflex/reflex design and the one on the right is referred as being of reflex/deflex design. They are not all of reflex/deflex design. Note with the bow on the right the riser and limbs firstly reflex from the handle and then deflex where the other two do the opposite.

I stand corrected! Cheers for clearing that up, Jeff. Incidentally, why does no-one produce Reflex-Deflex bows? I haven't found any commercially except horsebows which is why I wanted to make my own, just to see how it shoots.

I've been considering your comments on risers and that'll be my next major change in the production process I think. Previously, I've never run lams up the fades, I've only glued risers either on the back and/or belly, so this is my first time at it and it's been a bit of a challenge getting it all to glue up without voids.

Apologies for the poor pictures (I've not got a fancy scanner I'm afraid) but here's where my thoughts are with it -

Riser Template Ideas

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Riser Template Ideas 2

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So, am I going about this completely the wrong way? How do you guys plot your curves for your risers? The backside should be pretty simple - a line drawn off of the form - but the belly side could be anything. These particular curves are taken from a bent plastic ruler between the two designated points at either end. At uni I studied the construction of the Parthenon in Rome and read that back in the day the Romans would plot all their curves - whether it be an arch on a bridge or anything else - based on stringlines given slack under gravity and then inverted. Would that work here without the inversion? And I guess more importantly, how much slack should be sufficient?

If you are willing to do some work then build them from MDF. It is probably a little more labour intensive however, it works and you get smooth curves.

If you can live with slightly ripply surfaces then you can clamp them up and if you want all nice an smooth then you will be going down the road of Air-Hoses.

Re: Forms, I've been considering using MDF (glued up in layers) or a decent bit of timber to cut the initial curve (based off of a 1/8" strip bent between design high & low points), then overlay that with a strip of 3mm steel bar screwed in with countersunks. I'd get the durability of steel on the facing surface that way while maintaining the smooth curve cut from the timber/MDF. To avoid warpage I was thinking about sitting the form in a piece of steel channel too, or perhaps a few bits of angle glued & screwed to the edges, just to increase the rigidity a little.

In an effort to fix the kinks in my current forms I overlaid the surfaces with thick rubber foam but gave that up after one bow. The alignment issues were horrendous and I ended up with more twist than justifiable. I've had some other thoughts to that end but I think I'll just give up on that and move on.

I think I'll give airhoses a miss for now too - it sounds like something I'd screw up royally - and I've got a couple of dozen clamps now and more en route from overseas, so I should be alright with them. I'm curious about this 'Lucky Dragon' though... Google is giving me nothing of use, any insight into this, Grahame?

Since you live in the SE Qld you need to go the NAFA Easter Shoot.

I had a quick search for NAFA too - I'm guessing you're not referring to the Fishing Association... The missus & I have thought about joining up with Grange Bowmen when our takedown recurves & arrows arrive, so we may get to NAFA through them perhaps.

Well done on making a bow - and welcome to club of people who have made bows that overly light and overly heavy ..... and who have put bows through the bandsaw and into the garbage bin.

Thank you!

As a bit of an update on where I'm at I took my handheld belt sander apart and reimagined it at 90 degrees as a tiny little edge sander. It came out better than my bow making, surprisingly, and the drive belt doesn't slip like the bigger belt sander. The plan there is to adapt a couple of pieces of angle into a new thickness sanding jig but we'll see.

I'm also planning the next bow to be made up out of Ironbark & Black Bean with a strip of Spotted Gum in the riser. Just a simple Deflex-Reflex formed by my old tried & tested method. In spite of the rising unemployment rate though, I managed to find a job so things will be going a bit slower from now... More time for deliberating, less time for rushing in...

[rodlonq]

Welcome to Ozbow Nezwin.

Cheers.... Rod