Greetings from Canada

Greetings from a Canadian new member.  I am new to crossbows but have already learned quite a lot from lurking here for a short while.  Woodworking is one of my hobbies and recently I tried my hand at making a bow, oak pyramid board bow, and it turned out not too bad. Years ago I shot sporting and match rifle and enjoyed that very much.  Building crossbows seemed like the perfect way to combine the woodworking, rifle shooting and bow making so here I am.
 
I’m in the middle of my first build but will save that for another post in the appropriate forum section except for a couple of questions if you don’t mind.
 
Up to what weight can I safely use paracord as my bow string until I make or buy a proper string? I will serve it in the nock area.
 
The prod I’m using (the third design) is two fiberglass chain link tension bars. Can I leave it braced when not shooting?
 
Looking forward to benefiting from all of your knowledge and experience.
Thanks, Mike

Welcome, to the board.  You will certainly get lots of good info here.

I haven’t used paracord for string material  so defer to others here.  However, I tried to make a bastard string from it but found it frustrating even for that application as it was so damned stretchy.  It might work for lower weight prods for a couple of test shots, if you can get the stretch out of it. Realistically though, the quality you want in a string is basically the opposite: little stretch and a high strength to weight ratio, hence the use of stuff like B-50 Dacron.  I suspect you will be frustrated by making a paracord string and find it immediately stretch beyond usability.

Welcome, Woodsmith. Hotspur is right about the paracord, I use it sometimes as a stand-in during construction, but only on lightweight, smaller projects, like the one I posted today. I don't think I'd try it on a loose-laminate of two of those tension bars, if that's what you're planning. If you're not actually draw it or fire it, but just use it to help set your brace height and determine the correct length for your string, that would probably be OK. Just remember to measure it while it's spanned, or you'll come up short! It is pretty stretchy. For instance, the one I'm working on now, the paracord measured 39.5 inches when spanned, but only 37" in relaxed state. And that is on a fairly lightweight prod system.

You shouldn't have any trouble leaving fiberglass spanned. So what happened to your first two prod designs? I'm just as interested in the process as the final product.
Gnome

Thanks Hotspur, I'll get some B-50 and make a string once I know the final length I need. There's an archery shop at the gun range where I took my restricted firearms course so they should have it.

Gnome, glad to hear I can leave the fiberglass spanned. The first prod was my attempt to make one out of wood which was basically a mini pyramid red oak board bow, backed with burlap. It is 30" long, 1.5" at the riser, 1/2" at the tips and 1/4" thick. I knew it would be weak but wanted to have something to design around and to test out the trigger/release mechanism. Then I read Ken's post about using the fiberglass tension rods and thought I could loose laminate one of those to the belly of the wood. I put it on the tillering tree and when I got to about brace height there were all kinds of snap crackle popping sounds so I quit before getting injured. So now I have the two rod version like Ken's except the ones around here are only 1/2" wide versus the 3/4" ones I believe he had.
Originally I was going to order one of the 80lb Taiwanese fiberglass ones from Amazon but since they are replacement prods for a pistol crossbow, which are prohibited in Canada, they don't ship here.