Elmer's and cardstock for laminating fins

The Rocketry Forum

Help Support The Rocketry Forum:

scadaman29325

Catching up and tripping all over myself.
Joined
Feb 6, 2004
Messages
389
Reaction score
65
Location
Clinton, SC
Man, oh man, I've read alot about laminating fins... Tissue to fiberglass... I'm glad I did because y'all weren't talking about Kleenex tissue, it was that aircraft stuff... I didn't even think of that until someone finally gave me a clue.

I don't want to get into glassing yet, plus I'm just a lowpower guy, and it sure seems like ALOT of CA to cover your fins if you go that way...

I've used elmer's yellow to coat my fins before with pretty good success, but I need to step it up a little this time.

Big Daddy, possibly 2 stager.



If I spread the Elmer's out just right and

lay the cardstock on just right and

then squeegee just right and

press them 'tween some panes of glass just right,

it might just work!



So, I'm thinking "I've got lots of Elmer's and Cardstock, why not?"

And that's what I'm asking y'all. Why not? Paper bubbles?

Has anyone tried it and it didn't work / did work?


I'll let you know, I trying some tonight on some larger scraps, it may take a couple of days.


Phil
 

limd21

Well-Known Member
Joined
Jan 3, 2004
Messages
207
Reaction score
0
Your cardstock + elmers weighted under glass will work fine and be very strong. To help avoid curl, try to coat both sides with the glue as simultaneously as possible and get them laminated and under glass as quickly as you can.

If weight is any concern at all, you may be interested to know that laminating with plain old white paper (like used in a copy machine) also adds a lot of strength to a plain balsa fin, and will be a lot lighter and thinner than cardstock.

I happen to use 3M "Super 77" spray adhesive and white paper as my normal laminating combination. This adhesive doesn't cause the balsa to curl so I don't need to keep it under a sheet of glass while it dries.

To finish up, I drip on a coat of thin CA glue on the edges of the fin so that I can sand them to a super-smooth profile without having the edges separate or get furry.
 

jetra2

Well-Known Member
Joined
Jan 25, 2009
Messages
2,795
Reaction score
2
Originally posted by scadaman29325
I don't want to get into glassing yet, plus I'm just a lowpower guy, and it sure seems like ALOT of CA to cover your fins if you go that way...
Do me a favor an don't use CA when glassing fins. It'll work, but as the CA cures, it'll make a heckuve NASTY smell that'll burn your nose and eyes. Use "20 minute Finishing Epoxy" that you can probably find at the same place you buy your CA from.

I've tried this technique before - limited success, since I didn't use glass to press it down. I'm sure that if you do this, you'll be fine.

Jason
 

powderburner

Well-Known Member
Joined
Jan 18, 2009
Messages
7,399
Reaction score
6
the technique that limd21 describes (with the 3M spray) sounds pretty good, you might want to give it a try

if you are using white or yellow water-based glues, I recommend that you thin the glue first
I cut mine approx 1:1 with plain water to get it good and runny---this gives you better penetration into both the balsa and paper, a lot more working time, and makes it much easier to spread evenly on the materials

if you press the mess really well (don't forget the waxed paper covering to keep it from sticking to your desktop) and work fairly quickly, you won't usually have any problem with bubbles or wrinkles

if you end up being unhappy somehow with the surface of the paper, it is very easy to spray on some primer/filler coats and sand it just as smooth as you want

I don't use glass, I use waxed paper and old phone books to stack under and over the fin sandwich (with an extra pile of old magazines on top), and they 'give' just enough to push the laminate tightly to any curved surfaces

one last thing--I don't know if this is obvious or not, but you will want to sand the balsa leading and trailing edges before you do the laminating
 

scadaman29325

Catching up and tripping all over myself.
Joined
Feb 6, 2004
Messages
389
Reaction score
65
Location
Clinton, SC
Originally posted by limd21
I happen to use 3M "Super 77" spray adhesive and white paper as my normal laminating combination. This adhesive doesn't cause the balsa to curl so I don't need to keep it under a sheet of glass while it dries.

To finish up, I drip on a coat of thin CA glue on the edges of the fin so that I can sand them to a super-smooth profile without having the edges separate or get furry.
That does sound quick, clean and cheap(?). I think my wife has some of that Super 77 around the house somewhere.

A big thanks out to all of you for your input!
 

Mad Rocketeer

Well-Known Member
Joined
Nov 30, 2009
Messages
741
Reaction score
0
Educate me. Why sand the edges before laminating? I can see it if the lamination will go over the top of the leading edge. But otherwise, why not just sand the paper along with the balsa and just let them blend into one another that way? Or sand the leading edge, laminate over the leading edge and sides, then sand the trailing edge. Share your experience and expertise with this lowly seeker.

Would water-thin CA wicked into the edges make up for the lack of paper right on the edge itself?

Grasshopper ;)
 

DynaSoar

Well-Known Member
Joined
Mar 15, 2004
Messages
3,022
Reaction score
0
Originally posted by scadaman29325
I don't want to get into glassing yet, plus I'm just a lowpower guy, and it sure seems like ALOT of CA to cover your fins if you go that way...

LocTite has a bottle with an application brush in it that allows you to spread what you need and not over apply. Would still use a bunch of CyA, but not as much as other ways, and it'd be evenly apllied. Not saying I recommend it, but there's a technique to make it more doable.
 

powderburner

Well-Known Member
Joined
Jan 18, 2009
Messages
7,399
Reaction score
6
Originally posted by Mad Rocketeer
Educate me. Why sand the edges before laminating?

I guess it's just personal preference----if I am going to airfoil the fins I think it's easier to do it before laminating. Sanding after laminating will remove a lot of the paper, which kind of defeats the purpose? If you think it is easier to do after laminating, go for it.

Yes, some CA on the edges of a square-edged fin will do wonders to help seal it up and make it more 'finish-able' when you start applying filler/primer coats.
 

limd21

Well-Known Member
Joined
Jan 3, 2004
Messages
207
Reaction score
0
I have laminated before and after sanding in the airfoil. And thought I've made both ways work, this is what I do now:

As my most common airfoil these days is a rounded leading ege and a sharp-tapered trailing edge, I have settled on pre-shaping the trailing edge before lamination, and sanding in the rounded leading edge after lamination.

The thin coat of CA on the edges really makes the paper/balsa lamination much more unified (it soaks well into both materials) and makes shaping very easy. It especially helps on the trailing edge to help that sharp profile be more ding resistant, as well as helping with final touch-up sanding.
 

sveinbjorn

Member
Joined
Jul 27, 2004
Messages
16
Reaction score
0
Just out of curiosity, has anyone tried tracing paper for laminating? Also, do you laminate over the leading and trailing edges, or do just the faces of each fin and try to sand the edges of the paper smooth with the balsa? Obviously, I have never done any fin lamination before so I am trying to learn all I can about it.

TIA,
Ed
 

sandman

Well-Known Member
Joined
Jan 18, 2009
Messages
10,563
Reaction score
11
I used 110# cardstock on my Little Joe II kit and laminated it onto the balsa fins with just Elmer's.

I apply a bead and squeegee it smooth with a scrap of cardstock before I apply the card.

Works great!
 

JoJo

Well-Known Member
Joined
Apr 24, 2004
Messages
147
Reaction score
0
CONGRATULATIONS!!! i happened to be looking under the threads part on the right and this is thread number 666in the techniques section. i'll bet you're proud;)
 

GuyNoir

Well-Known Member
Joined
Jan 18, 2009
Messages
1,433
Reaction score
123
Location
Woodstock, IL
Originally posted by scadaman29325
If I spread the Elmer's out just right and
lay the cardstock on just right and
then squeegee just right and
press them 'tween some panes of glass just right,
it might just work!
I've also used plain brown paper tape, the kind you wet to adhere to a package? You'll need to sand your fins to their finished shape first, and cover both sides as once. I used a single piece of tape to do that.

Just dampen the adhesive side of the tape with a sponge, attach to one side, flip, cover the other. Let dry, and trim.

They'll need a coat of primer or two, but for sport models, it worked OK.
 

Mad Rocketeer

Well-Known Member
Joined
Nov 30, 2009
Messages
741
Reaction score
0
I guess, like a lot of things, it depends on what you're doing. I've laminated only one rocket's fins before, so I wanted to pick the brains of those of you who have done this more.

The one that I did was a Quest Zenith II that I flew (and lost to high wind) at NSL this year in Hearne, TX. I sanded the fins together, then rounded the leading and tip edges and tapered the trailing edge. I was trying to do as close to a true airfoil as I could, complete with thinning the fin as it went from root to tip. It worked out pretty well for a first attempt with nothing but my hands and a piece of sandpaper. Next, I applied a spray adhesive and papered the fins with 20 pound copier paper, folded over the leading edge. Finally, I glued the fins on and filleted them (all with yellow aliphatic glue). I didn't weight the with anything while laminating them, and the edges were ragged and didn't stick to the fins well, leaving gaps.

I'd like to do better next time.

How's this for a technique? Pick it apart, give pros and cons, make suggestions, hold nothing back. :)

1.) Sand fin edges, while holding them together, to get the starting shape and size the same.
2.) Round the leading and tip edges, taper the trailing edge, and round the edge-to-edge corners slightly.
3.) Carefully remove all sanding dust.
4.) Apply a thin (fin-wide) strip of masking tape along the root edge of each fin to try to keep spray adhesive and tissue off of it.
5.) Cut out some pieces of Japanese tissue so they can be folded over each fin's leading edge and overlap all the rest of the edges. Make a few pencil marks on the tissue, so I'll be able to see quickly where to place the fins on it later without having to think about it.
---Steps 6 and 7 for one fin at a time---
6.) Lay the tissue open again, and spray it with 3M Super 77 adhesive.
7.) Lay each fin onto the surface of the tissue, and grabbing it by the edges, fold it over the leading edge, trying to keep it tight and wrinkle free.
-------------------------------------------------
8.) Place the fins between sheets of waxed paper, and press them between stacks of old catalogs, magazines, newspapers, or some other heavy but flexible items. [Could also put foam rubber sheets on each side and weigh it with books, bricks, or whatever.] Leave them overnight to bond as well as possible.
9.) Remove the masking tape.
10.) Lightly sand and/or trim away the excess tissue hanging over the non-leading edges.
11.) Glue the fins to the rocket, and fillet them. Wait for this to fully cure/dry.
12.) Apply water thin CA to all fin edges, soaking the edges of the wood and tissue alike. This is to toughen the edges and help the tissue to stay bonded. [Could CA the whole fin surface, if that would be an advantage. Have to do it outside with a fan blowing though.]

Critique? The CA would make the sanding more effective if done before the edges are shaped, but would that make the paper attach less thoroughly?

How would the technique differ if I was using plywood instead of balsa? G-10? Is tissue strong enough to help plywood at all, or is that more a job for fiberglass or carbon fiber?

What is best to reinforce fins with? Pros and Cons of each? Weights of cloth to use?

I have access to carbon fiber fabric (0.32 or 0.032, can't remember which, per square yard) at one square yard for $16. Is that a good deal? Does carbon unravel too easily to be worth the trouble of using on medium power rockets?

Etc. Educate the new BAR who's never flown anything larger than a single Estes D but has a new LOC Graduator in a box and an itch to move into medium power and possibly even build the Graduator to H-power strength for an L1 attempt.

Thanks all!


P.S. Just noticed that the previous post was by our fearless leader! Good forum when the NAR brass is here. :cool: :)
 

sandman

Well-Known Member
Joined
Jan 18, 2009
Messages
10,563
Reaction score
11
I have access to carbon fiber fabric
Be warned...it is nasty stuff to work with!:eek:

Take precautions!

Unless you plan on Mach2 leave it alone...yer getting into the "overbuilding" syndrone.
 

Mad Rocketeer

Well-Known Member
Joined
Nov 30, 2009
Messages
741
Reaction score
0
I've heard that carbon is terrible about unraveling whenever you so much as look at it cross-eyed. I know epoxy is nothing to get on one's hands if one can help it, as allergies will develop over time, and CA is obnoxious to breathe (except for the specialty "fumeless" kind). I haven't heard about carbon being nasty though. Educate me. Is it just grimy? An irritant? Other?

As to overbuilding, I'm just floating questions at this point. I.e., is carbon worth it for mid-power if the price is good enough? Sounds like no. How about fiberglass? If so, what fabric weights and used to reinforce what? Fin-tube joints? Fins? Tube? Centering rings? All of the above? Other? :confused: :)

Is paper always enough reinforcement for mid-power and L1?

Overbuilding is what I want to avoid, so I definitely appreciate the feedback on that.

Mach 2? :eek: For that. I'd probably want to use an all-carbon tube, building it up over a removable mandrel, so it would be as light as I could get it, yet strong. Maybe use an Aerosleeves carbon sleeve to make it easier. I guess fin slots would have to be dremmeled out, etc. Not something I want to consider any time too soon.

I might build an Apogee Aspire for a Mach 1 attempt some time, but where I fly, I doubt I'd ever find it again. Ditto if I flew it on a long, low-thrust motor and went for the mile+ altitude it can deliver. I'd love to have one though, just to know what it could do. :)

Any feeback on the paper laminating ideas/process I proposed? I tried to put something sensible together, based on stuff I've read, but I could be missing something obvious or something which is gleaned through more experience than I gave in that area.

That's why I love it here! :D
 

scadaman29325

Catching up and tripping all over myself.
Joined
Feb 6, 2004
Messages
389
Reaction score
65
Location
Clinton, SC
Clarification: Worked like crap!

Ok, I didn't use 3M Super 77, I used Elmer's spray craft glue, (cause that's what we had)...
Sticky as anything I've ever used, I looked like a comedy show trying to get scrap paper off my hands...

Sprayed it on pretty well and then sandwiched it in between some wax paper and books... waited an hour (per instructions) and checked... some of the edges weren't stuck at all and the paper peeled off like it was a "post-it" note.

Maybe Super 77 works better, but I think I'm going to try elmer's yellow next time (tonight?)...

Later
Phil
 

limd21

Well-Known Member
Joined
Jan 3, 2004
Messages
207
Reaction score
0
As the one who uses and suggested Super 77, it and spray craft adhesive have nothing in common except that both come in aerosol cans and both can make a mess if you're not careful.

The spray craft adhesive is more like 3m's "repositionable" spray adhesives, where the "post-it" like light tackiness is all that is provided. It's meant to allow you to pull apart and restick.

The Super 77 is applied to both surfaces, allowed to "tack-up" (sort of like traditional rubber cement) so it is no longer liquid, and only *then* are the pieces put together. Once the surfaces touch - it's stuck *permanently* and very solidly. There's *no* chance to reposition things, and the edges will not lift.

Here's my fin lamination recipe:

-Cut balsa fins to shape.

-Sand trailing edge to a taper, leave leading edge square for now.

-Lay all fins on a sheet of newspaper to catch overspray and minimize mess.

-Spray one side of fins with light, but even coat of Super 77. Set aside

-Spray a single piece of copy paper, again with a light, but even coat.

-Wait 5-10 minutes until adhesive on both paper and balsa "tack-up" (no longer liquid). Don't touch either fins or paper until this has occurred or you're going to get gooey, hard to remove adhesive all over your fingers.

-Put fins adhesive side down on top of spray coated side of copy paper

-Flip the whole thing over and "squeegee" with finger, popsicle stick or a flexible piece of plastic. This is to eliminate any gaps in the lamination.

-Trim out each fin from the sheet of paper using a razor knife.

-Repeat for the other side of the fin

-Drip thin CA on leading, trailing and outer fin edges, sand rounded profile into leading edge.
 

scadaman29325

Catching up and tripping all over myself.
Joined
Feb 6, 2004
Messages
389
Reaction score
65
Location
Clinton, SC
I'm glad you cleared that up, 'cause the elmer's sure didn't do the trick. In the mean time I went ahead and did the yellow glue with copy paper technique. It worked pretty good, I think I should have squeeged a little better, because it left some puckers on a few sides. I'll post some pics later.

Phil



EDIT

USED 110# CARD STOCK, NOT COPY PAPER

Phil
 

BKROSNEY

Well-Known Member
Joined
Sep 10, 2004
Messages
77
Reaction score
0
I might as well jump in, I've tried strengthening balsa fins through lamination and have tried a couple of things. All work, it's just a matter of where your preference/skill level/time etc. line up.

I've tried "glassing" balsa fins with light and medium Silkspan tissue and finishing epoxy resin. I call it poor man's fibreglassing. Basically I coat both sides of the fin and then wrap a piece of silkspan tissue around the leading edge. (obviously this works on fins with a single straight leading edge). I wet the cloth out with some additional epoxy finishing resin. Usually I use one of those disposable acid swab brushes and also make sure I'm wearing through-away gloves. Epoxy can be SO messy. Then with the fin between two sheets of wax paper and resting on a firm surface I squeege (note that's squeege with the wax paper underneath the squeege) away from the leading edge to the trailing edge. Basically I'm trying to remove excess epoxy off the aft edge of the fin and draw the tissue tight to the leading edge. Flip the fin and do this for both sides, and then press between wax paper under some books or heavy weight. Nice thing about the silkspan tissue is that it's NOT as pliable as fibreglass cloth and is actually easier to flatten to the fin without it moving all out of position. No weave to fill, minimal epoxy added, minimal weight BUT LOTS of strength. Once dry you DO have to trim any excess tissue and epoxy on the edge. But a heavy Exacto blade and some 220 grit sandpaper does the job. The only thing I don't like about this method is that invariably I wind up coating the root edge of the fin with epoxy and effectively seals the root edge. Can't use wood glue to attach to the BT, but are pretty well committed to epoxy the fin on.

I've also tried the lamination technique with paper and glue. Haven't tried the 3M #77 Spray adhesive (worried about getting it all over the place), but I have use an adhesive called Rollataq which dispenses a very thin layer of glue from a roller dispenser. I think this stuff is big with the scrapbooking crowd. Coat my paper (usually 20 lb. photocopy paper) lay a fin on and then press. Once dry I trim the paper and then repeat for the other side of the fin. Dry and trim again. This does not wrap around any fin edges and I then usually seal with CA, sand, etc. Again very strong. Someone suggested tracing paper. I actually have a pad of tracing paper or "onion skin" as it's sometimes called that I want to try on a set of fins. Personally I think the 20 lb paper is overkill and that the tracing paper will work just as well and be lighter. Nice about the paper technique is that the root edge does not get sealed and I can still join to the BT with good ole wood glue.

... Bill
 

Stymye

Well-Known Member
Joined
Jan 21, 2009
Messages
7,599
Reaction score
6
lots of good ideas here, I haven't had much luck with laminating
I'll have to try that super 77 spray next time.

the only thing I've learned from my trials so far is
don't use a glue that shrinks !
 

stevem

Well-Known Member
Joined
Jun 7, 2009
Messages
1,613
Reaction score
0
give that 3m 77 a shot for sure - I use that stuff all the time. First read about it somewhere using it to glue corrugated wrap on the Estes Saturn V. I don't recall if it was in the instructions or if I read it somewhere on TRF.

I used to put the wraps on my Roachwerks Little Joe form Sandman and like limd21 said - once you stick this stuff down its pretty well stuck!

picked mine up at Wally-world
 

Mad Rocketeer

Well-Known Member
Joined
Nov 30, 2009
Messages
741
Reaction score
0
Bill K.:

Would the silkspan (or Japanese tissue) work with aliphatic (yellow) wood glue as well as with the epoxy? It could save your root edges for more yellow glue. Yellow and white glue shrink though, and it sounds like that's a bad thing. I guess if the Super 77 doesn't shrink or seal the edge against wood glue penetration, it may be best. I saw a post here that showed how to use it without becoming a walking Post-It Note disaster.

The tracing paper sounded good to me too. I haven't tried it yet, as I don't have any at the moment. Let us know how it works out if you try it.

An idea I had, but haven't tried yet, is to place the root edge against a strip of masking (or duct?) tape then trim around the edges. Once the lamination is done, peel off the tape. Seems like you'd get some seeping under the edges of the tape and some soaking into the wood through the uncovered sides and edges where they meet the root, thus sealing part of the root edge anyway though.

Here's another idea. If you're planning to use wood glue to put on the fins, double gluing is recommended for full strength anyway. That involves coating each surface to be joined (e.g. fin root and sanded tube) with a thin layer of wood glue and letting it dry or very nearly so, then applying a thin layer again to one of the surfaces and pressing them together until they set. So for laminating fins, use this technique to get the wood glue soaked into the fin root's wood fibers before the epoxy or Super 77 is applied.

It would go like this.
1.a.) Smear the fin root with wood glue, and let it dry. Apply it a bit more heavily than usual, leaving some extra thickness of glue on the surface. (Be careful to restrict this wood glue to the root edge only. The adjoining edges and sides could be masked for this step, removing the masking tape before beginning the lamination step.)
1.b.) Smear the sanded tube with a thin layer of wood glue at the same time.
2.) Laminate the fins as usual.
3.) Sand away the excess wood glue on the root edge, taking with it any epoxy or Super 77 that may have strayed onto that edge. Remove any sanding dust or other gluey spooge from the fin.
4.) Smear the fin root with another thin layer of wood glue, and attach it to the prepared tube.

The excess wood glue thickness would used as perfectly fitting mask for the edge, and the wood glue would have the opportunity to fully penetrate before any other glue or preparation was applied. Sanding into the wood glue ensures that a clean wood-glue-only surface is available for comleting the double glued joint.

Thoughts?
 

BKROSNEY

Well-Known Member
Joined
Sep 10, 2004
Messages
77
Reaction score
0
Hey Mad.... (I feel strange calling someone that ;-) )

As for silkspan and wood glue, don't think it would work. The idea behind silkspan is just like glassing. The tissue (as fibreglass cloth when glassing) has lots of strength, but is very pliable and provides no support. Epoxy is very hard, but also very brittle. But the combination.... the finishing resin/epoxy basically soaks into the tissue and wood surface and solidifies creating a solid structure. Wood glue does not really solidify as such. It has a high moisture content (I think) which either soaks into the wood or just evaporates away. You want to solidify the tissue and create a rigid structure bonded to the wood.

The idea of masking a root chord when laminating does have merit though. I've thought a little about perhaps creating the fin a little oversize and then cutting off some at the root chord to expose some fresh wood surface. Your idea achieves much the same and I think is probably better.

The idea of excess wood glue prior to laminating I'm not quite sold on. Some would indeed soak into the wood, and sanding off any epoxy coating afterwards would indeed re-expose that wood, BUT I'm not sure it would reveal enough of the original wood glue. My understanding of the idea of the double wood glue joint is that the first layer soaks and bonds into the wood fibers. The second glue layer is actually bonding more to the first layer of glue than anything else. The sanding you would of done to remove the epoxy would probably remove much of the surface wood glue as well.

As for the tissue paper for laminating I hope to give it a try this weekend. School inservices for my two youngest have them with nowhere to go for this Friday and next Monday, so I'm taking a couple of days vacation and will be at home. Hope to do some rocket building with them. If we get a chance to try the tissue paper idea, I'll post my thoughts.

... Bill
 

Mad Rocketeer

Well-Known Member
Joined
Nov 30, 2009
Messages
741
Reaction score
0
Bill:
Call me Mad or MR or Steve. Heck, I'll answer to anything decent. ;)

Is silkspan diferent from Japanese tissue or other high quality papers of that sort? I've heard of it, but I've not seen it. I was assuming that if regular paper could be attached with Super 77 or wood glue, the good tissues could be too. I'd think that wrinkles would be the main issue, or maybe the water base in wood glue would cause some tissues to disintegrate rather than stretching out smooth.

I should clarify the excess glue part of my fin masking and laminating idea. Agreed that the idea of a double glue joint is to get a good soak into each surface then to get a good bond from glue film to glue film.

By leaving a layer of wood glue a couple of milimeters thick on the root edge (probably by applying the glue in thinner layers), you'd be able to sand it carefully to expose a thin and clean wood glue surface without going all the way to the wood. If you did acidentally go all the way to the wood, it would be wood with wood glue in its pores, but nothing else on or soaked into it. You could probably then re-apply a thin layer to it, let that dry, and proceed with the final glue bead and attachment once the re-applied film cured.

Also important is that the wood at the root edge will have its pores soaked with wood glue as far as it can penetrate before any other substance is applied. Even a perfect mask on the edge or a re-trimmed edge can't accomplish that. Once another glue, e.g. epoxy, is applied to the sides, it will soak into the root edge (just like the rest of the fin) from the side. This would leave a root edge that is partially filled with epoxy, even if the mask was perfect. Think of the edge-on view of the root as concentric rectangles with the outer rectangle epoxy-soaked. If the fin is thin or porous enough and/or the glue penetrated well enough (like water-thin CA), the whole fin thickness could be soaked. Trimming the edge back doesn't help on that score because the whole fin is filled to that depth by the epoxy. Pre-applying the wood glue solves the problem by filling the fin root edge with wood glue to whatever depth it could have achieved had the fin not been laminated. From the deepest wood glue penetration to the surface of the sanded/cleaned glue at the edge, no other substance but the wood glue and the wood intrudes.

Beyond the wood glue penetration, the epoxy will penetrate as usual, but this is wood the fin butt joint would not have soaked into anyway. If the fin is to be filleted with wood glue, I'd go ahead and paint that part with wood glue prior to lamination. The adhesive used for lamination will either be more wood glue or it will be something with good surface bonding characteristics, such as epoxy, CA, or Super 77 and so should stick well, even with the underlying wood filled with wood glue. Any paper that bonds less well at the edge due to the laminating adhesive soaking in less at that point will be under the fillet when we finish, so all is well.

That's my reasoning anyway. Probably worth what you paid for it. :)

Looking forward to reading the tracing paper results.
 

stevem

Well-Known Member
Joined
Jun 7, 2009
Messages
1,613
Reaction score
0
I doubt you'd want to use 77 with tissue or silk sapn - the glue is very very tacky and would probably come through the tissue. I dojn't think it ever really hardens. You'd wind up with a sticky mess.

Silkspan is different than tissue in that it is more of a fabric and tougher than tissue
 

BKROSNEY

Well-Known Member
Joined
Sep 10, 2004
Messages
77
Reaction score
0
Hi Mad,

I agree with SteveM and probably should of pointed that out earlier. Silkspan reminds me very much of a woven cloth. Almost like a very light compressed matted cloth. I guess it's very similar to Japanese tissue used for balsa and tissue type airplanes. Or at least this is what my local hobby shop guy tells me. Tracing paper is just like normal typing or xerox or printer paper (except of course it is very light). Silkspan is more reminiscent of a cloth than a paper (at least to me). Hence, I always think of it as a poor mans fibreglassing. I'm sure it doesn't have the same strength as fibreglass cloth, and certainly not as pliable. But it has NO weave to fill and for small model rockets is a great way to strengthen fins. You probably could also "glass" BT's with silkspan tissue and epoxy resin. But I would consider that overkill. To each their own of course. My concern is not so much fins breaking or shredding from flying, but rather the unpredicabilities of the landing. I've always felt with these fins "hanging out there" they'd be the first to break on landing.

The glue idea is still interesting. You should give it a try on your next build and let us know.

My Edmonds Deltie Airshow came yesterday and I'll be building it with the kids this weekend. The gliders will be naked balsa, but I'm tempted to lightly paper the booster's fins with the tracing paper. I'll report back.

... Bill
 

Mad Rocketeer

Well-Known Member
Joined
Nov 30, 2009
Messages
741
Reaction score
0
Thanks SteveM and Bill for the information on Slikspan.

Bill, when I heard you say "tracing paper", I thought it sounded like an ideal solution. I don't have any right now, but I'll pick some up soon to play with. The only time I papered a fin, I used 20 pound copier paper and wrapped it over the leading edge. My technique wasn't great, so the result was mediocre. I bought some Japanese tissue some weeks back, and it has a few wrinkles now, but I'm itching to try it. Tracing paper gives a weight similar to the Japanese tissue, but it's easier to find and less prone to wrinkling. Not sure how they compare in strength.

Ya gotta let us know how it goes when you try it.

I'll try to remember to test my theory on masking fins and report back here the next time I laminate fins on something.
 

rbeckey

Well-Known Member
Joined
Jul 19, 2012
Messages
1,560
Reaction score
26
I have tried silkspan/finishing epoxy and was happy with the results. I have also used cardstock, self adhesive labels and 24 lb. printer paper and various adhesives. The only one I didn't care for was self adhesive full sheet labels, which doesn't seem to permanantly stick on fins, even though it sticks just fine to body tubes. I will try the Super 77 next time.

Sometimes I just go to lite ply for larger models. It is probably no heavier than laminated balsa fins.
 

Mad Rocketeer

Well-Known Member
Joined
Nov 30, 2009
Messages
741
Reaction score
0
OK, I have a mod-roc partially built (a birthday gift from one of my sons). Balsa fins, minimum diameter paper tube (for Estes A-C, ie. 18 mm, motors).

Lots of ideas. I could:

1.) Build it stock, which in this case means sanding the fins while in the sheet, cutting them out, stacking and sanding them, rounding the leading edges, gluing them on with wood glue, filleting them with wood glue, repeatedly applying and sanding white primer, then painting with red, black, and gray paint, pinstriping, and optionally clear coating.

2.) Using petroleum-based balsa filler. Fill. Sand. Repeat.

3.) Filling with diluted wood glue. Fill. Dry. Sand. Repeat.

4.) Laminating with:
(A.) Japanese Tissue
(B.) Copier paper
(C.) Card stock (110 lb.)
(D.) Thin packing paper (kind of old - may have been "cooked" in the attic)
(E.) Tracing paper (I'd have to go find some.)
Attached with:
(i.) Wood glue
(ii.) Super 77 (applied to both surfaces and dried to tacky first)
(iii.) Finishing epoxy
(iv.) Regular 30-minute Bob Smith epoxy

Thoughts? Experiences? I'll probably do whatever I do tomorrow evening.

I may try the root edge treatment I discussed above and report back.
 
Top