I've tried a few different ways.

The one that seems best for your purposes is to make a good, hopefully clean hole in the fuse that fits the wing.  Then take a rat-tail file and make some notches in the wing hole.  I used four on top & four on bottom, evenly spaced, but I used epoxy/microballoons for fillets.  Read on and maybe you'll want more.  Make them all the way across the width of the fuselage, and 3/32 to 1/8" deep.

Put in your wing, get it where you want it, then use a syringe of some sort to inject epoxy into the notches.  I used those plastic-bulb glue applicators, like these:

[url]http://www.amazon.com/Dave-Brown-Products-Drop-ETS-Applicator/dp/B0006O4EBG/[url]

Here's a "Reprint" of a somewhat related piece published in Stunt News years ago.  More to do with getting a tight fitting fuselage to wing joint then the glue up, but it may help someone.

Part3

Part5 with the related text:


Copy and Paste starts:

      "Profile fuselage-n-wing joint technique, "what worked for me""
        Tips and Techniques
        In keeping with Tim McTigues thread here's another one from the : "you may already do this file". I believe that this item has been covered off under another thread some months back, but here goes again.


        Profile Fuselage: Wing -n- Fuselage joint.
        As per the previous thread mentioned above, many of us have used different means to get a close fitting joint at the wing fuselage interface on a profile build. As a kid we just hogged out the wing cut-out on the Ringmaster fuselage plank until the wing slid through the hole. Whatever the size of the hole turned out to be was of little concern as we just filled the offending gaps with scrap wood and epoxy, or whatever was to hand. Each of us have a favorite technique we use. Some plug one side of the gap with tape, then pour epoxy mixture in along the gap from the other side, ..kinda' like a casting method. They all work well, or good enough in many a case. Well I decided that with the re-build project on going with my near 20 year old Twister that this was not going to be good enough. There had to be a better way. So with this in mind I went with the following technique, old hat for some, maybe, new to rookie builders or perhaps not. Here it is for what it's worth.

        Back-ground on the re-build:
        The Twister in question was crashed due to a line change mix up that ended up with a reversed control system during a hand launch. The plane went about 4 ft, then promptly nosed straight in which in effect broke the nose off at the L.E., and split the fuselage end to end. The wing was for the most part intact when all was said and done. BTW, I'm totally responsible for the crash.  I changed the lines, and even having "Wiped Out" the controls prior to launch, did not pay attention to actual control surface movement relative to control handle input. This was 1998.

        Re-build: Needed parts:

        1) New fuselage, with a two inch stretch for C.G. concerns, and all related ply doublers etc.
        2) New stab/elevator assembly, ..of longer span,...3/8 stock for stab, 1/4 stock for elevators
        3) New vert stab and rudder, ..replaced in kind as per factory, ..with adjustable offset feature .
        4) New wing flaps, ..full span, increased cord at both root, and tip, resulting in increased area, from 3/8 stock.
        5) Slider leadout guide installed, home grown "Big Mouth" assembly.
        6)Tip weight box install.
        7) Alum. gear.
        Alum. arrow shaft control system with ball-link technology.

        A) The fuselage was laid out on the new 1/2" plank by a rough tracing of the old pieces from the crash. From here the actual required cuts could be arrived at. I cleaned up the layout with the use of a tri-square and rulers as needed to ensure that all cuts would be, a) in the correct spots, and b) incidence on all area's, engine, wing, tail surfaces, would be maintained at zero/zero. I left enough material in excess to allow for sanding to final shape once the unit was complete. Key for me was to maintain at least one edge of the stock to use as a ref. point edge, ..from here all other measurements and alignment would come from.
        Not having a rib profile to use as a template for the fuselage wing cut-out, ..I simply traced the wing tip profile onto some cardboard stock, then cut this out for later use. This tracing was rough at best and was done undersize to error on the side of safety. I was also doing some engine mount mods on the this new fuselage, but will not get into that area here.
        A centerline ref. point was drawn through the location of the wing cut-out on the fuselage side. On the Twister this line falls inline with the engine center line.

        B) Using the center line from above, and the positions of the L.E. and T.E. I laid the cardboard template for the wing cut-out on the fuselage side and aligned it's centerline with the one drawn on the fuselage plank. I then traced around this template. This gave me a rough shape and location for the wing cut-out.

        C) Taking the same cardboard template of the wing profile I then put it back in place on my earlier tracing but this time I dropped it down about 1/8 to 3/16th's of an inch, toward what would be the bottom of the fuselage. This extra 1/8 to 3/16" on the top side would be "sanding material" for the wing install to "dead nuts" profile.

        D) Next I took the tri-square and using it's 45 degree angle edge, laid out a line running from the L.E. location on the fuselage 45 degrees back and downward to the bottom of the fuselage. I slid the Tri-Sq along the plank, and did the same for a line running from the T.E. to the bottom of the fuselage stock. As laid out, this would become a removed section of the lower fuselage.

        E) With the location and shape of the lower fuselage section laid out there is one important job left to do before cutting can begin, ..dowel location holes. Part of the plan from the start was to make the finished unit as strong, or stronger then the pieces before the start, ..to that end I had planned to dowel pin any cuts of major concern. The lower fuselage section is one of these area's of concern. So, with the fuselage on edge, gently clamped into a vice, I position the vice/fuselage under the drill press and blew two 3/16's holes through the fuselage edge at a 45 degree angle inside of my "lower fuselage section" lay out marks. The holes were placed such that the soon to be removed lower section, and the main body of the fuselage would both be penetrated by the drilled holes at both the L.E. area, and T.E. area. 3/16 hardwood dowel would go into these holes and tie the main body and the lower section back together again in fine fashion.

        F) The cuts: With the dowel holes drilled in the edge, next came the cuts. The lower section was cut along the 45 degree layout lines with my band-saw. Care was taken to make only one pass on these cuts to keep material removal to a min. As it is you are removing material equal to the kerfs of the saw blade. I used a band-saw, any other saw will do the job fine. Exacto or Zona hand saw in fact may be better suited, less kerf so less loss of wood.

        G) With the 45 degree cuts made at the lower section it was time to remove the basic wing cut-out area from what would be the main fuselage piece. I drilled a hole inside the template outline for the wing, and then passed my scroll saw blade through this hole, ..re-inserted the blade into the saw, and then cut out the wings top shape following the second layout line which is 1/8 to 3/16 inch below the actual target location line. The material left behind here will be sanded away to effect a near perfect fit of wing to fuselage. After this first pass with the scroll saw you will now have two pieces of fuselage, ..the main body section, ..and a lower smaller section which has a wing profile shape in it's top part.

        H) With the main fuselage body removed from the scroll saw, take the lower fuselage section and run it back through the saw. This time remove the rest of the "airfoil shape" which would in effect be the bottom of the wing shape in the fuselage cut-out. Leave the same 1/8 to 3/16" extra material on the lower section in side of the layout line. Again this will be for sanding to fit duty.

        I) Sanding to fit: At this point in the re-build the wing center section sheeting needs to be 100% ready to go. Same would apply for a new build. I replaced damaged wood here from the crash, and replaced wood removed for the control system up-grade. With the wing ready to install do the following. Tape a sheet of sandpaper over the center section sheeting area, rough side up. I used 150 grit here. Tape along the long edge (L.E. to T.E. on both sides of the fuselage location) so that the center section is clear of any tape. Now take the main fuselage section and lower it over the wing center sheeting/sandpaper. You will need to place the fuselage L.E. in place first and then drop the T.E. down over the wing, this is due to the wedge of fuselage material that angles back at the front lower area. Once the fuselage is in place slowly begin to move it back and forth over the sandpaper in a tip to tip span-wise motion. Watch as you sand closer and closer to your layout lines from the template. More important is the ref. lines on the fuselage that denote "zero incidence" and the location of the L.E center point and T.E. center point relative to these lines. Sand in this manner until you are close to (within a 1/16 inch of) the final wing location, regarding incidence. At this point you need to begin looking at the fuselage vertical alignment. Check the square of the fuselage placement, with a view from the front end, ...does it sit square to the wing when viewed from the front? As the Twister is constant cord and no taper a small square can be use to check "true" in this axis. If the angle is off, tilt the fuselage as needed and sand a little bit again until it sits true to the wing. With all sanding complete the incidence should be correct, the angle of fuselage to wing when viewed from the front should be true (90 degree's to each other with the Twister), and there should be no preload on the fit of the parts. By that I mean they should just sit atop one another with out required force. The fit of the wing into the fuselage should be near perfect with the sandpaper removed. Remove the main fuselage piece. Now take the sandpaper and tape it to the underside of the wing in the same fashion as before. With the lower fuselage section in hand begin the side to side sanding process again, moving slowly toward the layout lines. Word of caution here, take this one much slower in the sanding department. The reason is you do not have the bulk of fuselage material which helps you locate the position of this piece fore and aft, ..you only have a T.E. location of sorts to help spot the piece for the sanding job. So go slow and check the fit of the piece to the wing and other fuselage piece as need be to check your progress. As with the main fuselage component check for true in all axis. While your doing your checks you can slide the 3/16" dowel material into the holes you drilled ..this will help to spot the piece as needed. If the dowels do not slide in freely you may be off the mark a tad, ..but don't push the L.E. dowel through the wing sheeting, remember that this may be a shallow hole as compared to the T.E. dowel.

        K) Final fit. With the main fuselage piece sanded to fit, and the lower pieced sanded to fit, dowels in place and everything looking good you may find there is a gap at the lower section 45 degree cut line interface. This I believe is due in part to my saw kerfs. I handled this gap by the use of a piece of 3/32 material slid into the gap and then run the drill bit through it to mimic the dowel hole needed. This is then glued in place on either of the pieces prior to final glue up.

        L) Ply doublers: With the balsa components sanded to near perfect fit to the wing it's time to do the same for the ply parts, ..the doublers. Using the 3/16" dowels, pin your balsa fuselage components together and lay them flat on your work area over the top of your ply stock. With a sharp pencil trace the exact shape of the wing cut-out onto the ply stock. Do this twice for both left and right side pieces. Heading back to the scroll saw, I then very carefully cut right to these traced lines in hopes of min. sanding in this area. As it turns out my efforts were rewarded, only a little clean up sanding was needed. The ply on the rebuild reaches back to the wing airfoil high point on both top and bottom surfaces. I dry fit all the fuselage components at this point to check my work. I clamped it all together leaving the wing cut-out clear so the wing could be dry fit also, ..here's where it got kinda' interesting, read on.

        M) To good a fit: With all the parts clamped together I tried to slide the wing into the "dead nuts" wing cut out, ...It would not go, ..it would not fit over the wing tip!!!. As the cut-out was accurate to the extreme, the near twenty year old wing was not. So all my work to this point was at first thought to be in vain. I could not assemble the fuselage in total and slide it over the wing without "hogging it out" as in days of old. Stop the presses. There is yet another way to go. If I assemble the fuselage components over the wing as I did to check fit during the cut and sand process everything would fit fine, ..so that's what I did. I glued the main fuselage piece (the top) to the top side of the wing first. I once again laid out the exact location with tape and pencil lines. TiteBond was used for this wood to wood joint. As the fit of the parts was so close little was needed to get a good joint. I glued this piece first and let it set for a few hours before moving on to the bottom section and dowel inserts. The beauty of this was that I was not rushed to get the piece set, lots of checks of alignment could be done before the application of weights to set the joint. I did not clamp this first piece, just laid on the weight to hold it in place then walked away. The lower section was then fit, alignment checked again, glue applied, dowels inserted and weight and a clamp used to secure the joint. This done I walked away again to let it set.

        O) Engine mounts: With the main component parts glued to the wing it was engine mount time. I assembled a pseudo engine mount crutch of sorts on the bench with epoxy. This design was part of the plan from the git go, but did lend itself nicely to the component style assembly the "good fit" necessitated. With the crutch epoxied together in a "H" format laid on its side, it was then epoxied into the front of the fuselage structure already on the wing. I used hard wood and clamps to ensure this crutch was glued true to the fuselage balsa structure. Wax paper stopped the clamps/wood from getting stuck to the engine mounts. I used 5 min epoxy here, but would go with a little longer setting mix next time, ..working time was against me after the leisurely fuselage fit up with the Titebond, .. the epoxy caught me off guard a bit.

        P) Doublers Install: Next was the doublers install. These were glued with slow set epoxy taking the better part of a day to set. Lots of clamps used here to ensure maximum contact of the whole surface area. Of note: With this style of component assembly the doublers are semi-self indexing to the structure. With the tight fit of the doublers to the fuselage and wing structures they are in effect indexed to there final locations. A little movement is afforded at the extreme front of the doublers at the engine mounts, so some fit up is required here for "top to bottom" alignment. Again wax paper was used to keep the wrong parts, (clamps etc) from getting stuck in the epoxy mix. In area's where I did not want epoxy to remain I masked them off with masking tape. I monitored the setting of the epoxy and as it reached just past gel stage I cut the excess at the masking, then lifted off the offending mess. Less clean up was required when all was said and done.

        Q) Approx. 18 hours after the glue up started it's finished and the parts can be cleaned up and sanded to final shape. I had a lot of sanding to do here by design. The run of both balsa and plywood from what would be the windshield/cockpit block to the front of the engine mounts was left square to the wood stock shape from start to finish of the job. This surface/line was the ref. line for alignment throughout the lay-out and construction phase, ..I always had a ref. point to get back to if need be. With the basic unit ready to go I have fashioned a semi-cowl as I had on the first Twister build of 1983. I used the same tape-n-sandpaper technique to get the trailing edge of the cowl to fit "dead nuts" to the leading edge of the wing. The excess material of the ref. line was sanded off with the bench mounted belt sander. A little un gamely with the wings attached, but it sure sped up the process.

        In closing: I shot a bunch of digital pictures of this process as it moved along, but do not have a place to display them on the web. Should any one care to see them I'll forward them along. This is old hat for sure to some, but others may find it of use, ..that's the intent. I'm rather pleased with the outcome and the way this componenent assembly goes. I'll be doing it again for sure. Regards.

        Tony "TigreST" Bagley

Addendum:  This technique is currently be put to use on a Brodak Pathfinder MkII build of my brothers.  We cut the lower fuselage section out and with a test fit to the wing it looks as if no sanding will be needed.  Credit to both Brodak for fine kit production, and to my brother for building a very nice wing.
     

OK, I'm the "old Pro" in some things, but there is a technique that I just can't seem to get right. 

I am about to glue the wing into the profile fuselage of a Ringmaster (believe it or not, I never built one before!!!). I know how to get the parts in perfect alignment, jig it straight, vertical and all, but how do you actually glue it without smearing glue all over the place?    I really want to avoid getting epoxy on the wing sheeting or fuselage sides so I can bond my leather fillets on neatly with Sigment. I can mask the fuselage OK, but there isn't room enough to slide the wing in with masking tape on it.

I want to use 30 minute epoxy for a strong joint. I can see that after getting the initial bond, I will have to fill some gaps with epoxy/microbaloon mix. That I can do cleanly using masking tape to eliminate slop over.

Surely this problem has been solved a multitude of times in a multitude of ways? Please help. 

Larry,
Here is what I do. When I'm ready to glue the wing into the fuse, I tack it with instant glue (Hate that stuff but find it necessary). Then I apply epoxy (30 min) and use a monocoat heat gun to make it runny. The stuff will go all the way through and run out the other side if you're not careful or use to much! Can be done with a couple applications if necessary.

Good luck, Jerry

Thanks for the input. Since the model is laser pre-cut, I couldn't do the fitting procedure so elegantly shown.  The fit wasn't perfect, leaving gaps in a few spots. 

What I did was the technique of masking off the fuselage sides and the wing beyond the joint, then gluing with epoxy.  Unfortunately I waited too long to take off the masking tape and had to dig some of it out of hardened epoxy.  I then re-masked and filled the gaps with Microballoon laced 30 minute epoxy, forcing it all the way through the joint.  This time I promptly removed the masking tape, and all is well! 

Again, thanks for the information. 

Tony, for those of us who have a large collection of Stunt News, which issue is that article in?

I had sloppy holes on my last couple builds, so I used CA to tack the wing into the hole and hold things steady in 3-5 different places, with shims as needed.   After the CA dried I made sure I did this right, measuring, triangulating, etc. Breaking a couple drops of CA is easy, and the few drops are enough to make the assembly rigid enough to handle without worry.

Then I masked off the fuse and wing so there was a narrow gap for the fillet.  I thickened epoxy using cotton flocking and packed the gap, and formed the fillet with my fingertip.  (I wear rubber gloves with epoxy)  When I pulled the tape off the not yet cured epoxy came away leaving neat fillets with no further cleanup or shaping needed.  (I still need to clean and sand the epoxy before painting though)

Phil

Phil,

As someone mentioned above, I fill my gaps with balsa and drops of CA.

On this latest build, the ARGO II. I'm trying to use as little material as possible AND as little Epoxy, especially straight out of the tube.

I try to improve my building skills with each new model build.  

Fortunately, my gaps needed little material and the small fillets I'll have, I'll add micro-balloons to the Epoxy.

I use no tape, just my finger so there's no tape edge to sand. I remove as much MBE, "Micro-Ballooned Epoxy," as I can, getting the thing completed in one mix for each top or bottom. Gotta be speedy with the 5 min. Epoxy mix.

I did my all R/C pattern ships the same way.

When I do the fillets on the ARGO II, maybe I'll place a photo.

Obviously, there's many ways to accomplish this task with success.

Charles

If the masking is far enough away from where the fillet should end then there will be no tape edge to sand away as the excess epoxy is pushed onto the tape.  Since I go out of my way to get 30 minute epoxy for this process, I have plenty of time after pulling the tape so I can come back with a scraper and remove any remaining glue boogers before the epoxy sets.  

There are many ways to do this task including CA and baking soda...which is pretty heavy really.  I have also just glued with model airplane cement and layered it up over several days.

Phil

I didn't want any epoxy on the fuselage sides or wing because I will be using leather fillets. They are very light, even, and dope soaks right in instead of trying to separate like it can on epoxy. 

If you still won't use thm, I'm not going to bother trying to give you good reasons to use them. 

If you still won't use thm, I'm not going to bother trying to give you good reasons to use them. 

OK Larry, I'll politely ask, "Please give me good reasons to use them."