Glueing methods of 'silkspanned Wing' to Fuze ?

[Ron Varnas]

Hi all,

I'd like to know the best method for epoxying a 'pre-silkspanned' wing to the
Fuze  ?
I read a similar topic on S/S but this tread deviated into 'stress loads, shearing etc'
I'm "not" interested in the engineering factors, "only" the actual methods of expoxying
the wing to the fuze simple as that.

I don't think I'm alone when this topic of 'precovered' wings pops up,
if a wings already silkspanned, there must be certain amounts of dope already applied,
as such there would be a lustre or film surface correct?
If so how can epoxy penetrate this precovered surafce?
because in theory a standard fuze in thickness would be 1/8" balsa with say 1/32"
ply doublers......not much area here for gluing a whole wing saddle, let alone it attaching soley to thin 'tissue' .....

[Jim Thomerson]

One thin coat of nitrate won't slow the epoxy down.  Ideal thing is to put masking tape over where the epoxy will go so as not to get dope on it.  Carefully mark where the sides will go and then take a exacto #11 and stick it in to the width of the sides, parallel to wing span, every 1/8 in or so.  That will let the epoxy wick into the wood for sure. 

[Ron Varnas]

Jim,
interesting method, have you ever made up a test sample (section)
from scrap pieces to 'break' off the simulated fuze side from the 'slikspan/balsa'
area to see if shears off the wood with it ?

[Bob Whitely]

Not to worry, I do this all the time with precovered wings and stabs.  This does not work with any iron on coverings only with doped on coverings.  I know it works cause I have crashed enough planes over the years and the fuse/joint was just as strong either way.  RJ

[Ron Varnas]

Bob,
Ok, so you 'leave' a raw or undoped area of the silkspan approx. the
width of the fuze sides correct?

would it pay to have a slightly wider 'untouched' area say 3/8"
from inside the fuze sides to allow for a glass cloth reinforcement tape?

RV

[Bob Whitely]

Oh sorry, I didn't make myself clear on this.  Take the wing as an example.  If indeed you use glass cloth or carbon fibre to reinforce the center section however you do this is strictly personal preferance.  Depending on how the wing is built I may or may not do this.  Now on to the covering whether it be silk span or polyspan.  I almost always double cover the center section of the wing by over lapping the covering out past the fuse sides maybe 3/4 to an inch past the sides.  I do this whether the center was reinforced or not.  Generally the wing has 5-7 coats of clear on it when it is installed in the fuse.  However you glue the wing whether it be Sig or epoxy or JB Weld matters not.  The covering is stuck to the wing just as strong as if you had glued wood to wood.  Again on the ones that I had the chance to see after I crashed  there were big chunks of sheeting still stuck to the fuse that had ripped off the top and/or the bottom of the wing.  Any stronger than that then the plane was overbuilt.  Hope this helps.  Just make sure that you have good fits in all the joints with no gaps.  RJ

[Ron Varnas]

Bob,
 
So I'm on the right track)
 
the Fuze is glued to the 'pre -doped' wing you don't
leave a masked off 'untouched' area correct?
 
what grade (wt) of silkspan do you use ?
 
what type of dope Nitratrate or Butrayte ?
 
Are the dope coats full or thinned ?
 
 

[kenneth cook]

          Ron, I usually try to do what the others had mentioned about taping off the area to be glued. I have used silkspan over the entire center section as well. When I've done this, I carefully mark around the fuse with a pencil then I put small pin pricks just inside of the line. This gives the epoxy somewhere to go besides outside of the fuse. Some feel this could be setting up a fracture but I've never had a problem.  Ken Cook

[kenneth cook]

             Well, I see above that Jim mentioned doing the same with the #11. Guess I should of read all the posts first.  Ken Cook

[Kim Mortimore]

....... Just make sure that you have good fits in all the joints with no gaps.  RJ

To me this is the tricky part, especially on the wing/fuze joint.  Am I the only one?  Any tips, other than "Buy a really good laser-cut kit?"

Thanks,
Kim Mortimore

[Bill Little]

For a long time, I didn't apply any covering to the wing befopre I put it in the fuselage.  Then I wqatched several tapes from Windy where he finished the ENTIRE wing (and stab) up through the silver blocking coat stage before he put it in the fuselage.  He did nothing to *prepare* a gluing surface on the wing.  Since then, I haven't worried about it either.  

No strength is compromised if the wing is *finished* before you glue it in, just like alfadawg (Bob Whitely) said.  The silkspan is so firmly attached that you will break the balsa before the wing separates. 

[Bob Whitely]

Yessir, that is correct.  As for getting all the joints and fits as they should be you need to invest in 400-500 #11 blades.  Always use a new blade when trying to get a custom notch or tight fit anywhere on the plane.  Blades are cheap by the hundred pack.  The downside of this is the quality of the blade is lousy and they won't last very long.  I go thru boxes of these really fast.  #11s' are like sandpaper meaning do not try to save a buck on these items.  Always use new.  Takes just a little more work to make a nice plane as a crummy one so go ahead and do it. You will be glad you did.  RJ

[Doug Moon]

Yessir, that is correct.  As for getting all the joints and fits as they should be you need to invest in 400-500 #11 blades.  Always use a new blade when trying to get a custom notch or tight fit anywhere on the plane.  Blades are cheap by the hundred pack.  The downside of this is the quality of the blade is lousy and they won't last very long.  I go thru boxes of these really fast.  #11s' are like sandpaper meaning do not try to save a buck on these items.  Always use new.  Takes just a little more work to make a nice plane as a crummy one so go ahead and do it. You will be glad you did.  RJ

DING DING DING!! A few years ago, 6 or 7 actually, I started doing this.  I start each plane with a box of 100 blades.  Sometimes I get through with one box bu if not who cares?  But the building if the model is so much easier and accurate with sharp fresh blades along the way.  Great tip!

Also to those who are thinking of cutting away the covering to get back to wood that is highly dangerous.  If you go through the covering and cut the wood you perferate it and can create a HUGE stress rise right on that line.  There is already a ton of pressure at the fuse joint during flight any little holes or notches, not noticed during slicing, could be very bad.  Dope applied coverings like ss, pspan, or carbon is so attached it will pull the wood apart if it comes apart.   Also slicing through it takes away all the advantages of pre covering prior to installation.  Pre covering adds tons of stregth across the center section.  I cover all mine outside of the fuse then fill some and get it semi ready for final fill then install.  Makes for a much easier finishing process as well.  Hope this helps.

[Bill Little]

Yessir, that is correct.  As for getting all the joints and fits as they should be you need to invest in 400-500 #11 blades.  Always use a new blade when trying to get a custom notch or tight fit anywhere on the plane.  Blades are cheap by the hundred pack.  The downside of this is the quality of the blade is lousy and they won't last very long.  I go thru boxes of these really fast.  #11s' are like sandpaper meaning do not try to save a buck on these items.  Always use new.  Takes just a little more work to make a nice plane as a crummy one so go ahead and do it. You will be glad you did.  RJ

Thank you, Bob!  So many of us try to cut costs in all the wrong places, or else are just not aware of how much difference it makes in using sharp tools for our work.

Several years ago I went back to scalpels.  I use the #11 in a #3 handle (you can even get the handles with a built up *grip*) and for heavier work I use *Rib Back* (trade name) #24 blades in a #4 handle.  The *T* rib on the top of the blade makes the blade almost impossible for it to bend.  Boxes of 100 are about as cheap (if not cheaper!) on da bay as #11 hobby blades.  And they are so much sharper that there isn't a comparison.  I keep #11 X-Acto blades around, but use them less and less.

I also got into the habit of buying full sleeves of sandpaper from the auto/body shop.  A LOT cheaper in the long run.

Bill

[Dave Nyce]

Hi Bill.  I had trouble finding out where to buy the "Rib Back #24 blades and a #4 handle", that you suggested.  Do you know a good place to buy them?  Thanks.

Dave

[Bill Little]

Hi Bill.  I had trouble finding out where to buy the "Rib Back #24 blades and a #4 handle", that you suggested.  Do you know a good place to buy them?  Thanks.

Dave

Hi David,

I buy all my #24 Rib Back off ebay.  The standard #11 scalpels and all the handles I can get at a local medical supply store.

Bill

[Dave Nyce]

Thanks Bill !

I've been wanting to get together with you again to help me some more with the stunt pattern.  But I've been so busy with work, masons, the orphanage, and other things.  I hope to get some time available soon.

Dave

[Bill Little]

Thanks Bill !

I've been wanting to get together with you again to help me some more with the stunt pattern.  But I've been so busy with work, masons, the orphanage, and other things.  I hope to get some time available soon.

Dave

Hi Dave,

I will be retired when this school year ends, so my time will be freed up a WHOLE LOT!   No money, but a ton of time! LOL!!

Bill <><

[George]

Gee! Doesn't anyone sharpen blades anymore?

I would suggest investing a little time to learn to sharpen...preferably taught by a wood carver. Even if you prefer new blades, you may run out of blades someday.

George

[Bill Little]

Gee! Doesn't anyone sharpen blades anymore?

I would suggest investing a little time to learn to sharpen...preferably taught by a wood carver. Even if you prefer new blades, you may run out of blades someday.

George

Hi George,

Using the *Scary Sharp process* gives you some *scary sharp* blades, that's for sure!  But a scalpel blade is already that sharp, and cheap..........

Bill

[Ron Varnas]

Oh sorry, I didn't make myself clear on this.  Take the wing as an example.  If indeed you use glass cloth or carbon fibre to reinforce the center section however you do this is strictly personal preferance.  Depending on how the wing is built I may or may not do this.  Now on to the covering whether it be silk span or polyspan.  I almost always double cover the center section of the wing by over lapping the covering out past the fuse sides maybe 3/4 to an inch past the sides.  I do this whether the center was reinforced or not.  Generally the wing has 5-7 coats of clear on it when it is installed in the fuse.  However you glue the wing whether it be Sig or epoxy or JB Weld matters not.  The covering is stuck to the wing just as strong as if you had glued wood to wood.  Again on the ones that I had the chance to see after I crashed  there were big chunks of sheeting still stuck to the fuse that had ripped off the top and/or the bottom of the wing.  Any stronger than that then the plane was overbuilt.  Hope this helps.  Just make sure that you have good fits in all the joints with no gaps.  RJ

Thanks to all with the good info. on this thread I began, seems theres quite a few that
have read this most important stage of construction over 400 hits

to Bob Whitely, Bob you didn't answer my question of what type of dope you use
for the silkspan Nitrate or Butrayte

on the blades I agree with Bill the scalpel's are much better than the old Exacto #11's
I try & grab 'Swan Morton' blades when I can find them

[Wayne Collier]

Hey Bill,  I got a problem with scapels -- I'm scared of medical suppply stores.

            My dad, a long time wood worker and carpenter, always believed in very sharp blades.  He always has several kinds of whet stones laying around and often sharpens disposable blades.  He taught me to sharpen hand saws, circle saw blades (before the carbide tipped ones were so common), and drill bits as well as lawn mower blades and such.
            When I was a kid he often cut balsa with a sharp pocket knife.  Cut a piece or two...sharpen the knife...cut some more...sharpen some more...      Don't try this with a stainless steel blade.

            My dad, experience and the guidance of other experienced people have taught me the value of sharp blades.  We are fortunate to live in a time when good sharp disposable blades are available.  Less time spent sharpening means more time for other aspects of building models.

             ... and then there is sand paper -- the other secret of a really good fit ...

[john e. holliday]

I will try to answer for Bob in as simple terms as I can.  If you are using nitrate stay with it until you are ready for butyrate.  Butyrate will go over nitrate, but, do not ever try to put nitrate over butyrate unless you want one big mess on your hands.  Have fun,  DOC Holliday