How to reinforce a cardboard tube? (Archive please)

[Scott]

This might sound incredibly stupid (and probably does), but... does anyone have any ideas on how to reinforce a cardboard tube like the ones inside rolls of wrapping paper without changing it externally?

 

[lordobin]

get a PVC pipe that fits inside, then, glue it in there. cardboard death stick

 

[Scott]

Hmm, good idea... only problem is finding a PVC pipe exactly the same size.

 

[lordobin]

is it one of the larger tubes, if so look where they have the thin wall PVC usually it's the low pressure type PVC. i think they go up to 4", so you can probably find what you need.

 

[Scott]

Hmm, I'll have to check around. Thanks.

 

[rayra]

if it's large enough diameter to get your hand inside, and the cardboard is thick enough, go for fiberglass or plaster muffler patching material.
Or just coat the inside with white glue, a couple times.

 

[bkuhl]

How about filling it with expanding foam?

 

[Scott]

Definitely not big enough to fit my hand in... and that would be a lot of white glue to get an effective coating, not to mention the fact that it would be hard to get it around the tube near the middle.

Expanding foam might be a good idea, but it's hard to hide around the ends... can't cap them off without losing authenticity.

 

[rayra]

sorry, but you are mistaken about the white glue. Several ounces will flow easily, or can be swabbed on the inside of the tube a la cleaning a rifle barrel. used to mess with rocketry, used white glue to reinforce carboard tube rocket bodies, often.

 

[Scott]

Yeah, I know what you mean, I used to do the same thing, but model rockets (even the Estes monster rockets) aren't 3 1/2 feet long. It's really hard to swab that out, and I'm afraid it wouldn't reinforce it enough.

 

[Sporak]

What are you making? Out of curiosity

Stuff it with newspaper?

 

[Rebel Hunter]

Cap one end and fill that sucker with resin!

 

[Scott]

Can't cap either end, and resin would be incredibly heavy.

I just want a plain cardboard tube, and it has to look like a plain cardboard tube... I just don't want it to fall apart from me swinging it around. If you read Penny Arcade, you know what I'm talking about.

 

[bkuhl]

Urethane?

 

[Great_Bizarro]

Just an idea here. Take fiberglass woven cloth cut to the exact dimensions of the inside(do this dry first) the roll it up around a dower that is smaller than the interior and soak it in resin. Next pour some more resin down the inside of the tube and insert the rod with the cloth and work it in place. This has to be done fast or the resin will harden and you will have a stick with cloth stuck on it. I have never tried this!!!

I picked up the etchant liquid for the other project this weekend and hope to try it some time this week.

 

[Scott]

That last is an interesting idea, lol... it could get messy. Would still be a kind of heavy tube though.

 

[thedap]

thin down some varnish (just slightly ,so it soaks in a bit) and pour it down the inside ,keep rotating the tube and tipping it level and so forth ,adding more liquid as its soaked up....just dont soak too much in ,the tube may uncoil.... once it dries, it will be stiffer...and you can recoat the inside with unthinned varnish to make it even stiffer

 

[clonesix]

OK, cardboard Wrapping tube. 1.5" dia. & 36" long, and you want to keep the carboard exterior?

To get to the inside, mount a 1/2" brush to a yardstick or lath. To get a 45 degree bend in the brush (the cheap disposable type) break it a the neck and epoxy into and angle. Do this to make better contact between the brush and the inner walls of the tube. Give it a coat of fiberglass resin and let cure. Don't put so much on that it soaks through and ruins the cardboard look on outside. After it has cured and won't soak through any more, give it another coat or two until stiff enough.

For extra credit, try this: a 1.5" diameter tube has a circumfrence of 4.7". Cut a 4.7" strip of 36" fiberglass matt and roll it up (lengthwise). Slide it into the tube and unroll. Use same paintbrush-on-a-stick to wet-out the matt. Let cure.

and there you will have your very own long siff tube. Knowing what to do with it is entirely up to you. Good luck!

 

[dkwd]

Other alternatives are to find thicker cardboard tubes. For example - shrink wrap has a much sturdier tube than paper towels. I believe shrink wrap can come in longer tubes like that as well - we used to use them to 'fence' with in the warehouse.

David

 

[mykulld]

All I did to get mine strong, was cut strips of sintra the length of the cardboard tube, and then hot glued the suckers inside the tube to the tubes lenght. I glued quite a few around the inside of the tube creating a I guess a sintra tube like shape inside... , but I also epoxied a few peices of the sintra together to strengthen those to.. so it was a quick fix, but it worked...