Props4ever

Lately i have been thinking how do guys fuse two halfs together to make one part out of them. For example if i were to cast to fuselage parts in there molds, then how would i fuse them together and at what stage?...

I have seen pictures of guys casting separate sections and then making whole part but when and how they are joined together is usually not mentioned. Plus when you fuse sections do you add reinforcing fiberglass tape from the inside to the full length and both top and bottom of fuselage or its not required....

I would appreciate if guys who are doing this sort of stuff can explain these steps and whole process for my future reference and knowledge to newbies in the molding field. (I am one of them too)

Thanks in advance..
Sam

wkevinm

Props4ever

I have typically used either tape (about 1� wide or excess material from one side laid over the other when the fuse halves are joined (still in the mold). Often cabosil / epoxy paste is used on the edge as well to fill voids, but do not add so much, weight can become an issue if you are building a racer or other competition airframe.


There are many threads in RCU, some under this topic on composites, lots under pylon racing threads (where there is a lot of experimentation with materials and methods to maximize strength and minimize weight) and I assume lots in the glider sections as well.

Following is a thread I had on laying up a Q500 fuse, there are others on V tails and vacuum bagged wings.


http://www.rcuniverse.com/forum/m_73...tm.htm#7301190


http://www.rcuniverse.com/forum/m_75...tm.htm#7525521

regards, wkevinm

Props4ever

Hey Kevin,

Went through both of your links but still i am out of my answer i was hoping for with a procedure how its done. G8 threads though with great info in them

Can anyone else share some thoughts or light on my question....thanks

Ed Smith

When making glass fuselages and joining them in the mold, one has to think ahead at the mold making stage. When the mold is closed access to the inside is needed. So as many holes as possible must be built into the mold. The obvious ones are, the nose ring, engine hole if the engine will eventually stick out, and the wing saddle. The most difficult part of joining in the mold is reaching down to the tail end. Usually there will be a vertical stab slot cut into the top of the fuselage. There is little point injoining the seam at this position only to cut it out later. So I do not bother to join the fuselage top there. I have a slot in the mold at this position. this allows me to access to the bottom of the fuselage at the tail end.

I use those acid brushes stuck on the end of a dowel to reach in. I also bend the brush end at 90deg. I join my fuselages in the mold while both halves are still wet. It is abit of a chore but the joint is much stronger then when joining cured halves.

Doe this help ?

Ed S

Props4ever

Thanks Ed,

Yes it does make sense how you explained it, now if you were to do larger lengths and wider fuselages would you still join fuselage half's with same methods or with large fuselages you would use different methods with tape and resin to add more strength from inside to the joint seam?.

I was also wondering how to get into the tail end of the longer and larger fuselages, so now with a access hole in that area it could be done without making a slot or hole in the stabilizer saddle.

Sam

Ed Smith

I do not use tape to join the halves. Lets see if I can explain this. Getting the tape down the length of the fuselage was always a hassle. I lay up one half. I trim say the bottom of the fuselage layup to the joint line and leave 1/2" flange along the top. When I lay up the other half I trim the top of the fuselage layup to the joint line and leave a 1/2" flange along the bottom. This allows you to close the mold halves with a sideways movement, ensuring that the two flanges always go into the mold. It is then a fairly easy matter to go in with the brush and pat the seam down. If the joining flanges are on the same mold half the mold has to be closed with a straight down movement. This usually results in the flanges catching on the other half and bunching up.

Was that clear????

Ed S

AllanU

http://www.rcuniverse.com/forum/m_74..._2/key_/tm.htm

There is also info in the most recent posts in above thread.

Al

Props4ever

Sorry for the delay reply guys, i got tied up with my ongoing Arrow restoration.

Ed its clear to me now how to join the fuselage halfs in the molds while its still wet, i like the idea of overlapping with extended 1/2" cloth vs usage of tape. Allan's pictures showed it all and it's clear how this step is done. I also like this method instead of overlapping with one half only, its better to go 50/50 between the two halfs. (One half Top and other half bottom)

Thanks guys for your help and explanation and when time comes and if i ran into problem/s i will consult with you guys again. Really appreciated it.

Sam

Deadstik

My Feedback: (8)

Sam,

One more thing I'd like to add to Ed's comments and that concerns what happens after you put the two "flanges" together. There are two issues here. The first is being able to absolutely, positively be able to push down those flange pieces without having the wetted cloth fold over on you. This is accomplished by using a very high power light source and time. When you think you have every single strand pressed together.. back off and look at it again. If you don't get it right it will cause voids all along the seam line. Now, the voids really don't hurt the fuselage strength a lot as the pieces are still bonded together BUT.... when it comes to finishing the fuselage you will have to add filler which is additional weight for no reason. The second issue is (if you have the vertical stab integral to your mold) getting the leading edge bonded correctly. I lay a bead (about 3/8") mixture of microballons and epoxy mixed slightly thinner than peanut butter and put it on both sides of the vertical stab. When you invert you mold and let it cure (I use a hot box) the epoxy from both sides will run together and form a leading edge that is almost indestructable!!!

hope this helps..
Good luck with your project,

Dan
Carolina Custom Aircraft

TeamSeacats

Joggle it.

http://www.teamseacats.com/index.php?s=joggle

stealth assassin

I know how a joggle gasket works but, I don't think I ever saw how It worked on your join at the web site. Did I miss something?

Thanks,
D

TeamSeacats

I haven't photographed that process. I trim the half with the inset lip so that the lip is about 3/16 to 1/2" tall. I then place that half back in the mold it was made from. I have a series of blue foam "sticks" that are cut to fit inside this half to keep outward pressure on the molded part so that when the top piece goes in, it doesn't deform the half with the lip and press it inward. The foam "sticks" have a small line tied between all of them. Once that's done, I brush on some epoxy thickened with microballoons and add some black tint. With the other half in it's mold, I then gently put the two together and let them cure. Once cured, I pop them out of the mold, cut the access hatch in the deck, and pull out the foam sticks....which is very easy since they are all strung together (as long as they don't get glue dripped on them!