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-   -   CA or Epoxy ? (https://www.rcuniverse.com/forum/kit-building-121/809701-ca-epoxy.html)

torp 05-28-2003 12:01 AM

CA or Epoxy ?
 
Hi , need to join a LE and TE section of balsa .Did not follow instructions closely enough !!!{GP Corsair}
Will splice joint at 45 deg.
Do i use medium ca or will i need epoxy.
Also does this build a weakness into the wing ?
thanks, torp.

CafeenMan 05-28-2003 01:02 AM

CA or Epoxy ?
 
Are you saying that you have two sticks that are too short? Do these parts get reinforced in any way?

I suggest you replace them with full length pieces if that's the case. I would not use CA for the splice. Carpenter's glue or epoxy should work.

If you use carpenter's glue be sure to double-glue the joint. What that means is you put glue on both parts, give it some time to soak in (a couple minutes), then apply more glue and put the parts together.

I'm not really clear on what you need to splice though and it makes a difference how the component is built.

William Robison 05-28-2003 01:36 AM

CA or Epoxy ?
 
Torp:

Butt gluing an LE or TE is begging for a wing failure in flight. Recommend you not consider it. However, if it's a sheeted wing (Yes, I saw Corsair) you can probably get away with it.

Bill.

torp 05-28-2003 05:11 AM

Have pics
 
1 Attachment(s)
HI ,
Yes i need 20" lenghts .
I have one at 14" and 6".{LE+subTE}
And yes the wing is sheeted 4" at LE top and bottom .
The sub TE is sheeted top and bottom 7/8".
Have attached a pic of the same problem islewis had .
Inset is sheeted wing{Thanks for pics islewis}

greenboot 05-28-2003 04:26 PM

CA or Epoxy ?
 
You can splice this joint if you cut both pieces at a shallow angle. This gives much more glue area. You can also put a small splint on the backside of the splice. It will be plenty strong.

I would use Elmers, but all these glues are stronger than the balsa.

Tom

JNorton 05-28-2003 11:37 PM

CA or Epoxy ?
 
Torp,
If it was my plane I would buy new pieces so as to have a non-spliced LE and TE. Sanding them to shape goes really quickly with 60 grit and a long aluminum bar. I wouldn't trust a splice. How much is your plane worth compared to $4.00 worth of balsa to do it right?

Just my 2 cents,
John

torp 05-29-2003 09:52 AM

Compromise on all suggestions.
 
thankx, fellas.
Have decided to make a new TE .
Will splice and splint the LE and glue with 30 min epoxy. As the wing is sheeted at the LE {see prev pic} ,will be enough stenght
.torp.

TexasAirBoss 05-29-2003 03:32 PM

CA or Epoxy ?
 
If it were me, I would go buy a piece of wood that was long enough.

A friend of mine that flys electric once gave me an interesting article to read. It seems the electric guys don't deal with the vibration that us glow guys do. For this and other reasons they tend to build lighter and try to build right to the edge of the minimum strength needed. The article he gave me was about something called "stress Risers". Essentially what the article said is that you want the flexibility or the rigidity of the wing to be more or less uniform. If one point is more flexible than the sections on either side, you might have a failure at that point. Likewise, if you have a section that is more rigid than the adjacent sections, one of them is likely to fail.
I would be concerned that the un-uniform strength of the leading or trailing edge might create one of these stress risers. A point of likely failure.

William Robison 05-29-2003 06:14 PM

CA or Epoxy ?
 
KWB:

As I said initially, an in-flight wing failure waiting to happen.

Bill.

greenboot 05-29-2003 06:34 PM

CA or Epoxy ?
 
Gosh guys, I don't understand why I can't splice a LE stick. After all, the main spar is spliced right in the middle where bending is a maximum.

Here is another example...

My FunFly's wing was sheared off (got too close to a bird house), I spliced ALL the spars. That was a hundred flights ago. Maybe I've been lucky.

I have fixed lots of damage including spars. I don't add gobs of fiberglass either. Just try to imagine the strength of the original stick and make the patch just as strong. You don't want to make it stronger, just the same.

Tom


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