What Raw Material Are You Using For Transition Sections?

[lakeroadster]

Tim Van Milligan suggests "Bristol Board" in his book Model Rocket Design and Construction.

What are you folks using?

I'm wondering if cardboard from a cereal box might be a good choice since it has a glossy surface and is about 0.020 thick?

 

[rharshberger]

Usually for smaller transitions I use 110lb cardstock, and then harden with CA, larger ones regular posterboard works again CA hardened. If either needs to be stiffer then a wrap or two of 3oz fiberglass over the CA hardened transition.

 

[Mugs914]

I like cardstock for the smaller transitions too, but for the Larger sizes (say, 29mm on the small end), I like to use 1/64" plywood, sealed with thin CA. No 'glass required, light and just about bulletproof.

 

[Nytrunner]

I like cardstock for the smaller transitions too, but for the Larger sizes (say, 29mm on the small end), I like to use 1/64" plywood, sealed with thin CA. No 'glass required, light and just about bulletproof.

Intriguing! where do you get this plywood? And how large have you created with it?

 

[kuririn]

+3 on cardstock painted with thin CA. Feels like vacu-formed styrene. And I haven't tried it yet, but for tougher transitions there's this:
https://www.asp-rocketry.com/ecommerce/G10-010-Sheet.cfm?item_id=1151&parent=67&navPanel=
.010" thin fiberglass sheet. Cheers.

 

[Mugs914]

Intriguing! where do you get this plywood? And how large have you created with it?

I usually get it at Michaels. I think some Hobby Lobby stores have it as well. Good use for a 40%coupon 'cause its a bit pricey; almost $20 for a 12"x24" sheet, but that will last a good spell unless you are making something really big.

The biggest I have used 1/64" ply for was BT 101 sized (I,think) for a Launch Pad AGM-12c Bullpup and it was stronger than the tube by a good bit. If you wanted to do something real big it would be easy to laminate two layers.

Great for built-up fins too...

 

[prfesser]

60 or 110 lb cardstock (got a ream of each), soaked in laminating epoxy. Made five transitions, nested them tightly together and heated to cure the epoxy. The result is quite tough, I don't think I'll have to fiberglass it. I'm gonna glass the main airframe anyway so I'll probably include the transition.

Best -- Terry

 

[neil_w]

For LPR cardstock is fine. Coating with CA and/or double-layering (what @hcmbanjo calls a super-shroud). I do most of mine with 65 lb cardstock, only double-layer if it's large. In the one instance where I needed *really* large (APRO II) I used posterboard.

Cereal box cardboard, I think, will not bend smoothly.

 

[Gary Byrum]

110# for everything and poster board I've been finding at W'mart for the larger shrouds. Don't know the thickness of the poster board but it's firmer and thicker than the 110#. You just have to dig in to what they have and feel for what you are looking for. There usually are no thicknesses noted on any of the labels. My shrouds are usually glued with overlapping tabs so giving them a good CA treatment stiffens the paper up and any imperfections can be sanded away. Overlaps, oversized ends yadda yadda. CA is also very useful when you have tube cuts that need to keep their shape. They wont relax like an untreated tube will.

 

[heada]

Either Balsa or Basswood (linden) turned on my lathe. Balsa for LPR and Basswood for HPR. Largest one I made was 4in to 3in that was 18 inches long end to end and I coated it in thin epoxy after it was turned. Since it was also used for inter-stage coupler as well, I notched it to fit around the sustainer fins.