Wednesday, December 14, 2022

Super Glue (and other things) In Low Power Rocketry? TIPS, Part 1

On Forums and Facebook, I often see questions about construction and finishing.
What usually follows are recommendations from other "Newbies" who may only have experience building two or three rockets.
I never claim my methods are better than others. But, I've had decades of experience in Model Rocket construction. The following ideas are presented for consideration.

SUPER GLUES (CA)
"I tack on fins with Super Glue then follow up with wood glue fillets."
There is a problem - That initial CA glue will seal the root edges of the fins and the wood glue fillets won't be able to soak into the balsa or body tube! 
Wood glues have to be absorbed into the surfaces that are being bonded together.
If you are impatient, try using less wood glue when initially setting the fin on the body tube. A little less glue will dry a bit faster and not effect the strength of the fillets that follow.
CA Glue may initially stick, but can get brittle over time. Fins and launch lugs can pop off during boost or landing.

CA glues do have a place in Low Power Rocketry - 
I use it to seal the ends of body tubes - just about 1/4" down around the inside surfaces. Apply with a Q-tip. Let dry and sand with 400 grit to smooth.
I also use CA Glue to fill mold seams on plastic nose cones. Run a then bead down the recessed seam. Let dry and sand with a block. Be careful! That bead of CA Glue will run and drip! Do one side at a time and set the nose cone up on it's side with the glue line facing up until dry.

WATER SLIDE DECALS
"I dread water slide decals. They always grab in the wrong spot."
Like most builders, I would add a small drop of dish washing soap to the decal soak water. 
The dish soap is supposed to lubricate and allow the decal to be repositioned after transfer on the model. It sounds like a great idea!
On YORF, Micromeister brought up a good point. That dish soap could break down the adhesion layer on the back of the water slide decalI've had "moments" with Micromeister, but he makes a good point. Somewhere in the past, the drop of dish soap idea was published and passed on.

Now I don't use a drop if soap in my soak water. I rub water on the surface of the model, then slide on the decal. The water underneath the decal allows for slide repositioning.
Model surfaces should be smooth, glossy (and a little wet) for water slide decal transfers.

2 comments:

  1. I occasionally use CA to tack on fins - two very small spots spaced apart - so far the tacked-on fins have been just as resistant to popping off on impact as those attached with a traditional double glue joint. But I see your point Chris about the CA sealing the root edge - using a full bead of CA at the root then adding PVC to the fillet area would definitely not be as durable as just PVA.

    ReplyDelete
  2. I have never used a drop of soap in my decal water, and have never had an issue, except where the decals are extremely thin. In that case, building up the decals would be a better option than soap, in my opinion.

    ReplyDelete