• This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn more.

Twisted Hobby’s Crack Yak 55

Ketchup

4s mini mustang
#1
I just got a 32 inch crack yak kit in the mail and was wondering about what type of glue to use. Twisted Hobbys sells both foam cure and welders, but I’m not sure which to use. I don’t really want to use hot glue because of the weight, and I have heard of welders glue cracking after less than a year. Has anybody had experience with any of these?
 

SquirrelTail

Well-known member
#2
I just got a 32 inch crack yak kit in the mail and was wondering about what type of glue to use. Twisted Hobbys sells both foam cure and welders, but I’m not sure which to use. I don’t really want to use hot glue because of the weight, and I have heard of welders glue cracking after less than a year. Has anybody had experience with any of these?
FOAMTAC!!!
 

Ketchup

4s mini mustang
#6
I’m sorry for all of the questions but are there any other differences between the glues? For example the bond strength or the brittleness? I was just wondering because I have found foam cure at a store nearby but I haven’t found foam tac anywhere but online.
 

AkimboGlueGuns

Biplane Guy
Mentor
#7
Foam tac you may have to order, it's not often just laying around in craft stores, but it's a strong and flexible bond, so it's a good pairing for EPP planes like the crack yak. I've built a couple of similar EPP models with CA and had good results, but the bond is fairly brittle. Foam tac will take a bit of time to cure, but not a ton. It's also a good idea to get yourself a 12 pack of soda to use a a jig while you're building the fuselage and tail surfaces. They're cheap and easy 90* objects with enough weight to keep all the pieces flat to the work table. Good luck building! I've never flown a bad twisted product, so you should have a lot of fun!
 

Ketchup

4s mini mustang
#9
The glue finally came! The order tracker said that it would be here on Friday at 8:00 pm... But it’s here!!!
Before I build though I have some small questions. After applying glue to a part should I give it a few minutes to tack up like with welders? And if I do, then how long would it need so that it sticks but is still slightly workable? Also, can I use a thin coat on the hinges to strengthen them? The build instructions say that I should strengthen the hinges like this but the instructions are also made for welders glue so... I know that some of these questions are in the instructions for the plane and the glue but I wanted to ask to make sure. Thanks!
 

SquirrelTail

Well-known member
#10
The glue finally came! The order tracker said that it would be here on Friday at 8:00 pm... But it’s here!!!
Before I build though I have some small questions. After applying glue to a part should I give it a few minutes to tack up like with welders? And if I do, then how long would it need so that it sticks but is still slightly workable? Also, can I use a thin coat on the hinges to strengthen them? The build instructions say that I should strengthen the hinges like this but the instructions are also made for welders glue so... I know that some of these questions are in the instructions for the plane and the glue but I wanted to ask to make sure. Thanks!
Push it against the foam a few times then pull it off and let it tack for 2-3 minutes. Also do the hinge thing with foamtac. It works just as well as welders if not better.
 

Ketchup

4s mini mustang
#11
I started building yesterday and I already have most of the airframe together. I have a few questions though. What should I use to attach the firewall? The foam tac really isn’t meant for plastic so I’m not sure if I should use that. Should I use hot glue or epoxy maybe?
 

SquirrelTail

Well-known member
#12
I started building yesterday and I already have most of the airframe together. I have a few questions though. What should I use to attach the firewall? The foam tac really isn’t meant for plastic so I’m not sure if I should use that. Should I use hot glue or epoxy maybe?
Foamtac once again works awesome! I use it on most of my firewalls instead of hot glue. I find it is a stronger bond.
 

Ketchup

4s mini mustang
#13
I thought I would leave a post showing my progress so here it is. image.jpg
I just glued on the rudder and I’m waiting for it to cure. The next step is to glue on the supports and after that I can put on the motor!
 

Ketchup

4s mini mustang
#14
Something odd just happened... I was using loctite to hold on the prop saver screws like the instructions said, but I didn’t know how liquid loctite was. I thought it was like a paste, so I squeezed the tube and it sprayed all over the prop saver and some got onto the motor. I then sprinted to a sink and rinsed off the loctite as fast as possible... Do you guys think that the motor will still work? Not much got into it but I still kept on rinsing for a few minutes after the loctite disappeared. I can still spin the motor though.
Just a side note but this is the first time when I really valued the knowledge that brushless motors are waterproof.

Edit: I forgot to add that it has been a few minutes already and I am leaving the motor in the water to soak. Maybe if there is more loctite inside the motor it will be easier to remove? I can’t see any more loctite though.
 

SquirrelTail

Well-known member
#15
Something odd just happened... I was using loctite to hold on the prop saver screws like the instructions said, but I didn’t know how liquid loctite was. I thought it was like a paste, so I squeezed the tube and it sprayed all over the prop saver and some got onto the motor. I then sprinted to a sink and rinsed off the loctite as fast as possible... Do you guys think that the motor will still work? Not much got into it but I still kept on rinsing for a few minutes after the loctite disappeared. I can still spin the motor though.
Just a side note but this is the first time when I really valued the knowledge that brushless motors are waterproof.

Edit: I forgot to add that it has been a few minutes already and I am leaving the motor in the water to soak. Maybe if there is more loctite inside the motor it will be easier to remove? I can’t see any more loctite though.
It should be good to go!
 

Ketchup

4s mini mustang
#16
It’s been a while since I have built anything, but today I was preparing the servo horns and ran into a problem. Doing the aileron control horns was easy enough because all I had to do was screw on the extender like in the picture.
image.jpg
But I don’t know what to do for the rudder and elevator servo horns. Do I use 2 screws to hold it on? Maybe just glue it with ca? In the build video the guy has servo horn extenders with a ring that goes around the control horn to hold it in place, but these have nothing. Btw, the hole in the extender is for the control rod, not for a screw.
image.jpg
 

Bricks

Well-known member
#17
You can do it a couple of ways use the screws and nuts that should of come with it or as I have done to some is wrap it with braided fishing line then run a little super glue being careful it does not get into the area that mounts to the servo. I will usually take some rough sand paper and rough up the control horn and extension.

Your picture of your aeilron horn is actually wrong the arm extender should be on the bottom of the servo arm closest to the servo that way the extender lines up properly.
 

Ketchup

4s mini mustang
#18
Thanks @Bricks. I will try to find some fishing line for it. Also, I glued on the aileron servo extender last night, so I can’t change it now. Oops! But at least the guy in the build video did it the same way as me, and if that guy flew his plane like that, I probably can too right?
 

Bricks

Well-known member
#19
Thanks @Bricks. I will try to find some fishing line for it. Also, I glued on the aileron servo extender last night, so I can’t change it now. Oops! But at least the guy in the build video did it the same way as me, and if that guy flew his plane like that, I probably can too right?

It will work either way just easier as the stem from the horn centers up the extension