Practice on a short disposable piece.
If it doesn't work out - take it to WM and pony up the 10-15 bucks to have it done.
Or - do what I do a lot - sew a eye in with whipping twine and a needle (pass the needle through both pieces, wrap, through, wrap - twice the diameter of the line). It looks nautical and I've tested eye's with my 190 pounds.
Having a topping lift drop the boom into the cockpit is not fun.
Go for it. On new line it really isn't too hard. On used line it gets tough, but Samson documents an eye splice for old line that is a lot easier.
I did my first eye splice in a class and it was useful to do one in that environment and see the mistakes that everyone made because then I could learn how to account for them. That was well worth the $10 or $15 that the class cost me. If you do make mistakes you can undo steps on the splice at any time and fix them.
For a topping lift I would personally use Amsteel. 1/8" or 5/32" Amsteel is much easier to splice than double braid and a lot lighter. That light weight is an advantage on a topping lift because it blows it out behind the sail and it will never catch the sail during a tack, even in the lightest winds. I even made one topping lift using 2mm Amsteel, but that is much harder to splice because it is so small (fids don't fit down the line).
chucklesR: Your method of tying the line back on itself like that would be okay for low-load applications, but I don't think it will come close to retaining 90% of line strength. This is especially true for core-dependent lines.
The double braid to amsteel splice is really useful for halyards or lightweight tapered sheets. His instructions for the brummel splice are easy to follow. If you get into splicing you should also try out his method for making a soft shackle, it is pretty easy and works very nicely.
True, any bend/knot reduces strength. Topping lifts aren't exactly high load, even on my 16 foot boom/500+ sq mainsail I can pick the whole thing up at an estimate of 120 pound of weight.
Truely, so what since the line is rated at 1000+ pounds.
chuck: This is a thread about splicing first, the fact that it is for a topping lift is secondary. I'd hate for someone to read your post and have them use nothing but a whipping in a halyard or other important line. A bowline is a lot stronger (at about 50% of line strength).
A topping lift sees much higher loads than the weight of the boom. It only takes one gorilla pulling on the mainsheet of a small boat to put a 400-500lb load onto the topping lift. I'd also expect the loads to be higher when the sail is being reefed in high winds and the boom is bouncing around with the sail.
I've had good luck splicing to exact lengths at home by marking the old piece of line and bringing it home with me, then making the new one to match.
It is not that hard. In fact, I think it is much easier than it looks. Follow the video from New England Ropes and pause at each stage. Last week I was splicing 5/16 line for lazy jacks and found that using the the next size smaller fid to pull the core through the cover made it much easier. Use the proper size fid for everything else though.
Other things I learned:
- tape the core/cover to the end of the fid before inserting in case you lose the end of the fid.
- When pulling the cover back over at the very last step, keep tension on the core so it does not bunch up. His tip of snapping the cover is great. You may have to snap it a couple of times to get it perfect.
- Use a water soluble pen if you do not want to see the pen marks on your final eye.
- Mark the core with 1, 2 and 3 lines respectively to know exactly where you are.
- Be patient. You can do it.
A couple of years ago I was exactly where you are...needing to do some double braid eye splices and never having done one before. I did the research you did and read and re-read the instructions a few dozen times to make sure I understood them.
My first couple of attempts were not quite right and looked like crap. With each succeeding splice the splices got better and I could do them faster and had to refer to the instructions less and less.
The hardest parts are inserting the core back into the cover and the final milking of the cover. The best tape I found for wrapping the end of the braid before pushing with the fid was Priority Mail packing tape.