Howdy guys and gals,
Finally I will be mixing up smooth-on and putting my very first limb into the press and hotbox. I did a test run of the hotbox last night, and it holds about 180 degrees pretty good.
Any special tips I need to know before I go for it? I've been working on this bow for over a year. It should have been done months ago.
I will post some pics as I make progress. It will be a belly-mounted TD longbow.
Brett
Good luck. Secure the lams down well with tape or whatever method you choose. Air the hose up in increments, check everything at 20# air pressure or so, if everything is still in place you should be good to go. Don't forget to take plenty of pictures. Looking forward to this one.
I've got washers on the form to keep the lams from sliding out the side. Plan to use filament tape to secure everything down. I will take pics tonight and post them up, even though my stuff looks like an elementary school kid made it.
Brett
A couple tips...
1) Don't get in a hurry with the glue up. You have plenty of working time with smooth-on.
2) Don't be afraid to lay it on thick. It will squeeze out everywhere and be a mess, but that is much better than ending up with voids under the glass or between the lams.
Wax your form and cover with plastic wrap. As stated above air up slowly and check things, use enough glue on both surfaces and let everything cool down before you take it out of the form...extra hands are also helpful on the first one- once you add bow snot it's a bit different than your dry test run.
I plan on cooking the limb in my oven for about 3 hrs at 180 then shutting it down and removing everything in the morning, after about 6-7 hours of cooling. Is that ok?
Brett
re the cooking time I do go against the flow a little 'cause when I first started I was advised that smooth on themselves suggested a cook time of 8 hours at 180F. This might seem excessive but its how I go.
You should be good with those times.
It may be to late but double check your hose to make sure it isn't leaking any air. Had a valve stem leaking once and it cost me a bow.
Cory
Ok I did it!
Everything went ok as far as I can tell. Took the limb off the form this morning. I ended up cooking it in the hot box for 4 hours.
First 2 hours it held at 170-180 degrees, but at the 4 hour mark it was at 210. Is that going to kill my bow?
I will update with some pics when I have time.
Brett
This is probably going to be a wimpy bow, but it is my first (and I have a bad shoulder I am nursing).
Limb stack:
.050 brown glass
.040 bamboo taper
Wedge
0.40 Maple lam
.050 brown glass
should be only .180 thickness.
Because this is my own design, I will just have to see what #'s I get. I bet 45 or less.
Brett
:thumbsup:
Hey Brett,
These are the stack thickness' for the mentioned bow and the poundage taken from Binghams chart online. FWIW
Mike
68" Take-Down Longbow
(measured without wedge inserted)
35#.............................. .328"
40#.............................. .344"
45#.............................. .359"
50#.............................. .374"
55#.............................. .389"
60#.............................. .404"
65#.............................. .418"
70#.............................. .427"
Shallow Reflex/Deflex
:archer2:
The geometry of my bow should be a 16 inch riser with a 61 inch string (amo 64 inches).
I figure that will add a bunch of pounds.
I will try to take some pics tonight.
Brett
Pics of riser, hotbox, and my first laminated limb.
(http://i161.photobucket.com/albums/t230/brettmccown/8089b564-3c4c-4847-a6a2-d87367d061c5.jpg)
(http://i161.photobucket.com/albums/t230/brettmccown/limb.jpg)
(http://i161.photobucket.com/albums/t230/brettmccown/hotbox.jpg)
Looking good!!
Got the second limb laminated yesterday.
I will sand the boogers off them and trim them a bit tonight. I'll try to post pics.
I've messed up a few places, but I think I can still make this into a shootable bow.
It will be no exotic Schafer Silvertip or anything, but I think I can make it sling an arrow.
OK, so I drilled a limb last night to mount to my riser. Used the Bingham's jig. After numerous attempts, I could not get the hex bolt to screw easily into the riser insert.
I horsed around with it, cross threaded it, and ended up pulling out the riser insert!! I was not pleased.
Now I have ordered a new set of riser inserts, and I will flip the riser over and start over.
Brett
You could put a hardwood dowel in it, epoxy it in with smooth on, grind off the current overlay on the limb pad, replace it and redrill. Sometimes the riser inserts are tapped crooked and the hex bolt will be so tight through the wedge that it will not start straight.
Instead of tinkering with that too much when that happens, I'll just make the bolt hole larger and drill two pin holes instead of using one pin and the bolt to keep it straight.
Dave
I got both of the inserts out (with some difficulty), So I plan on just laminating a piece of phenolic on the other side of the riser and re-drilling.
Brett
Make sure when you tap the hole the tap goes in straight. Don't ask me how I know. :rolleyes: I do feel your pain.
Use a small square when you start tapping the thread, eyeball the square and the tap on the sides and front/back as you run tap in going very slowly as you cut the first few threads. Just lineup the edges and as you get down past first few threads and establish your thread you should be good to go.
Ok I laminated a strip of phenolic on the other side of the riser and re-drilled it. Got the inserts in and limbs bolted on.
I had to make some minor adjustments to get everything put together, but now it actually looks like a bow. I will post more pics when I have time.
Hi, I'm anxious to see what the poundage ends up at.
I was looking at the picture of your riser and if I'm seeing the drawn lines correctly it appears that you will be attaching the limbs to the belly of the riser. If this is correct then the limb attaching bolt inserts, not the alignment pins, need to be on the outer end of the riser.
Please correct me if I am not seeing the riser drawing correctly.
It is a belly-mounted limb. I may put another alignment pin in if I have to.