Enlosed Track

Posting in the custom speargun builders section is by invitation only, see sticky. Thread moved to speargun section.

I'd be inclined to lose the 403 and go straight catalyzed epoxy with the graphite. If you can return the 403 and get some 404 even better. And unless you got the 207 for free, return it and get the regular slow hardener. 207 is clear and pricey.

Microfibers act as wicks that will allow moisture to pass along the fibers. Yeah you get strength from them but if your track is captive in the stock it's not really an issue unless you have a long, thin stock.

Using 404 and graphite, you'll want to go 25% / 75%. The 404 will bulk up the resin and still let the grahite do it's thing and as it's lighter and finer it will float to the surface of the resin while it cures. And here's the thing- you gotta really watch the heat buildup. If you're in an area where it's going to be 70F plus, toss the resin in the fridge for a half hour first. This will chill it and thicken it as well so you'll also have to be real aware of your pour, working the completed our to get the trapped air out with a few good raps against the bench and a consatnt vigil of offgassing.

Using moly would be OK if you could be sure that the stuff was encapsulated and so wouldn't contact the salt water. Since you're going to mill the track after it cures then all bets are off. I'd try to off the moly online and go find some graphite, perhaps the retailer where you got the 105/207 from has the graphite filler and will take the return of the 207.

If you're going to finish coat the gun with the 207, fine but realize that there's none to zero UV protection offered by it. It may not be a big deal to you, you might keep your gun in a case or bag all the time, but to keep the wood from cooking in the Sun under the 207 you'll need to wipe the fully cured coating with a very fine synthetic scuff pad and brush on a varnish such as Epifanes. Your labor and costs go up with the 207. A better finish coat is Envirotex- it's a one thick coat deal, has a good amount of flexibility to it and it's UV stabilized. Great shiney stuff. The best deal for it is online.

Those people that you read advocating the milled micro fibers are more than likely unaware of the potential for moisture wicking along the exposed fibers, they're all about how strong the stuff is. It's like making a track of angel hair pasta and then machining the track hoping that you never expose a noodle. It ain't gonna happen, but boy oh boy ain't she strong! Until the barrel gets soaked. Sure you could do a few passes of catalyzed resin to seal the wood proir to the the pour, so WHEN the milled fibers migrate the wood has some protection but there goes the $ and really, why? My contention is that the track is only as strong as what you pour it into and I'm a heavy mass gun kinda guy so I rely on the wood to do the majority of holding it's shape and stiffness. If you have a whippy length/shape, then you got issues. There I'd do a half pour with milled fibers and let it kick and pour a 404/graphite track over it for the milling. There's your answer. Actually the answer is to call Josh and get a track, butt I digress...

My preference having done it with balloons, wood dust, milled fibers, gorilla hair and every combination is to have a good solid stock into which you cast the whatever holds the graphite. The resin (105/206) is only the solid binder for the filler which does nothing more than bulk up the resin to fill the track slot. The graphite is what you're concerned with, getting enough of a volume by mix to have it in contact with the shaft at the surface of the pour and the subsequent milling. That's why you'll want the graphite bound in a high density filler like the 404. 404 in itself makes a hell of a solid and slick surface by the way and it's weight isn't a bad thing if you forsee having to add ballast.

All this is pretty academic but Winter's coming... I'm sure there are dissenting opinions, but this has worked well for me.

i don't know if you already seen this http://spearfishing.world/cust…/2567-bluewater-euro.html but i preffer the tube over a poured or uhmw track for several reasons. the tube is super strong, low profile allowing for a thinner gun, really slick and a perfect fit for a 5/16'' or 7/32'' shaft (thinner version tube). unfortunately, i haven't been able to find one to fit a 3/8'' shaft so i'm forced to do a poured in version but for those guns the stock is thick so...

I'm a believer that the whole using graphite because it's slick-thing is over thought. In a VERY close tolerance application where you want a bearing surface, yeah, but a shaft traveling along a track isn't it. With the as accurate as you can do on a routertable tolerances and the need to have the track a few thou oversize the water between the track and the shaft are what's doing the work of keeping everything straight. If you have a close tolerance track with whatever forming it, it's the water that's the lubricant. That's why a enclosed wood track will do the same thing as one with graphite applied. A milled track of whatever, ie Delrin, UHMW, polyethylene/styrene is just a degree of tolerance closer because you can't control what the wood does. That's why I was saying that for all intents and purposes, you could do a pour with a high density filler like 404 and leave the graphite out completely, sexy as it sounds.

I did a 404 track once just to see what happened and matched it to an exisiting graphite augmented track and the wear patterns were exactly the same owing to the tolerance of the track, the shaft being slightly out and the position of the bands. There were slight scuff marks in the same places and I could see where the carbon fiber was going to wear slightly worse owing to it not having the density of the higher load and impact resistance benefits of the 404. But it sounds like you're enamoured of the whole carbon fiber thing with the wrapping of the wood barrel with it, and that's cool. The experimenting and flash aspect of building your own stick is a good percentage of what makes this whole thing fun.

good luck and send the pics.

[quote='bajabound','http://spearfishing.world/forums/index.php?thread/&postID=42086#post42086']I'm a believer that the whole using graphite because it's slick-thing is over thought. In a VERY close tolerance application where you want a bearing surface, yeah, but a shaft traveling along a track isn't it. With the as accurate as you can do on a routertable tolerances and the need to have the track a few thou oversize the water between the track and the shaft are what's doing the work of keeping everything straight. If you have a close tolerance track with whatever forming it, it's the water that's the lubricant. That's why a enclosed wood track will do the same thing as one with graphite applied. A milled track of whatever, ie Delrin, UHMW, polyethylene/styrene is just a degree of tolerance closer because you can't control what the wood does. That's why I was saying that for all intents and purposes, you could do a pour with a high density filler like 404 and leave the graphite out completely, sexy as it sounds.

I'm in your camp on the water/shaft interface once the shaft is in motion. I don't remember your profession when you were in So Cal but your composites background applied to gun dynamics is sound in my book. This is a great informative post mate, good to have you here. :thumbsup2:

Cheers, Don

Muchos Don.
My So Cal experience was limilted pretty much to porn.

Like assholes, everyone's got an opinion and there's a few here that have expressed and called BS on this gun building rationale, but whatever. I suppose that's the difference between actually sticking fish, losing fish and figuring out how and why and then doing something about it rather than just pumping the same crap to the masses or painting some bitchin colors on it. With all due respect to Jay.

I think the importance of remembering that whatever you're diddling around with, the primary focus is a straight band stretch on a straight platform. After that it's just bling and BS.

One thing I neglected to add about the 207 hardener is that it's a stone bitch as far as bubbles in the cure. I mean a real pain in the ass. You can blow on them, apply heat from a hair dryer or a propane torch used soberly, but the stuff is a PITA.

IF you do go the 207 route for the final, get the resin and 207 as warm as the stock is and apply it at the end of the day or when you know the temperature is going to be dropping. That'll help with the off gassing. Sounds counter to the usual "keep it all warm and in the Sun", but there you go.

Unless it's Envirotex, I got one word for the rest of my guns. Oil.