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Re: Boomilever B/C

Posted: January 28th, 2014, 2:55 pm
by jander14indoor
As an alternative, consider the precision micro super glue applicator, two pins stuck though a stick that come together at their tips in a narrow V. See: http://www.gryffinaero.com/models/ffpag ... yaapp.html for a picture of one.

To use, pour out a drop or two of CA into a puddle on a piece of wax paper. REMEMBER WHERE YOU PUT IT, unless you want explain for the next week why you have wax paper glued to your elbow.

Pre assemble your structure with the parts fixtured where you need them and the joints TIGHT so nothing moves.

Dip the CA applicator into the puddle, a small amount will wick up into the gap between the pins (capillary action at work). Smaller pins, narrower V, small gap less glue, bigger pins, wider V, wider gap, more glue. Now touch the pins with the glue on them to one edge of the joint, if tight as they should be, capillary action will pull it off the pins into the joint.

This of course works best in relatively small joints, say 3/16 by 3/16 in area or less. Any length is OK if the thickness is low, less than 1/16 for a seam, might take multiple applications along the joint if long.

Oh, this works best with the THIN CA, don't worry about setting time for the puddle. One of the catalysts that makes CA set is moisture in the air, in our overheated winter buildings not generally a problem and the puddle will be good for at least a couple of minutes.

If you need the CA to set fast (even the instant stuff isn't in dry conditions) use CA setter, but NOT from a spray bottle (unless you want to replace that new bottle of expensive CA when some molecules drift through the air an get sucked in). Instead use a small pipette and apply VERY sparingly to the joint.

Comment on minimizing glue use. Your joints have to be VERY good, ie tight. The glue should never be used to bridge gaps due to sloppy building. Such joints are heavy and brittle.

Hope you find these alternatives usefule:
Jeff Anderson
Livonia, MI

Re: Boomilever B/C

Posted: January 28th, 2014, 6:02 pm
by iwonder
I actually use that capillary glue applicator on the cross member joints, but I wasn't sure how to use it to apply a continuous length of glue down the long narrow side of, say, a 1/32" by 1/2" by 18" member.

Also while we're talking about glue, I use superglue on my distal end and base connections. It's worked well some times, and other times the glue joint shears (i.e. I have no visible trace of both pieces of wood on the joint, they're all intact). A few of the times it's sheared it's only had 18 hours or so to set, and I've heard that CA takes a full 24 hours to reach full strength, but I always figured it couldn't be significantly weaker before that time. Is that true? Or is it really something like half or 3/4 strength after an hour?

Re: Boomilever B/C

Posted: January 28th, 2014, 7:59 pm
by chinesesushi
How are your scores doing guys? I'm finding difficulty in breaking 1000. :'(

Re: Boomilever B/C

Posted: January 28th, 2014, 10:52 pm
by xchampkevin
Just found some info on ca glue online today. You can use water as an accelerant (the moisture in the air is what cures it naturally). Also, you can use Teflon on your tsquares or your table so the glue doesn't stick to them. :shock:

Re: Boomilever B/C

Posted: January 31st, 2014, 3:31 pm
by denisenicole
do we need to bring our own bucket/chain? Please helllpp ill give you a cookie maybe :D :D

Re: Boomilever B/C

Posted: January 31st, 2014, 4:56 pm
by chinesesushi
No. Rule 2c "The Event Supervisor must provide all assessment devices, testing apparatus, hardware, level, two bucket stabilization sticks (refer to www.soinc.org), and clean, dray free-flowing material (hereafter "sand")."

Re: Boomilever B/C

Posted: January 31st, 2014, 5:41 pm
by iwonder
Nope. It says the event supervisor will supply all the testing equipment. Can I have a white chocolate macadamia nut one? :D

Re: Boomilever B/C

Posted: January 31st, 2014, 6:37 pm
by denisenicole
Thank you so much :D and yes of course

Re: Boomilever B/C

Posted: January 31st, 2014, 7:26 pm
by chinesesushi
Wait a second... I replied first, so that means I get the cookie? I'll take whatever iwonder was getting.

Anyways, on 1/27/14 there was a national scioly rule clarification for boomilever that was posted here: http://www.soinc.org/official_rules_clarif Personally, it doesn't apply to me but maybe for some of your guys' design it does, so I thought I'd just post it. Good luck!

Re: Boomilever B/C

Posted: February 1st, 2014, 5:17 pm
by Can_Of_Tuna
At Regionals, I used my third boomilever, which was a basic bass compression design, except that it had three half-ellipses instead of the standard bracing on the sides, and inside the triangle. After attaching the bucket, the glue appeared to crack, and after less than one kilogram, one of the side pieces snapped off,still completely intact. It probably would have been better if we had made the lowed contact point wider, and attached two side-beams from it to the tip. I plan on continuing to use the bent-pieces theme at state, but am not sure what design. Any suggestions are appreciated. One my my current ideas is to take an extra-long piece of wood, attach it to a base, and in the front have the prongs for the block. The whole thing would form a semi-circle or half-ellipse by two additional beams extending from the base, and one from the tip that would then slot together. Another option is the design mentioned above; extend the lower support,and remove much of the back, then use the extra length to attach two balsa beams from the tip to the support.
I would post a picture, but I don't know how... :| :roll:
Also, why is it that the newest posts get pushed back while older ones stay where they are?!? Seems rather odd...