14 replies to this topic

[tajmiester]

Hi,

Does anyone know where you can get thick cardboard tubes in the UK? Fountains & some other small things can be rolled using toilet roles and craft paper but thicker, stronger tubes for things like: small mortars and mines etc... are harder to find or make! Does anyone know any uk pyro suppliers that don't require licences or other sources for such tubes.

Regards

Tajmiester :flames:

[bernie]

Buying is much easier for certain! Rolling larger bore tubes is not as difficult as you might think. Anything under 1 1/2" can be rolled up with just a little practice. Good quality kraft paper and some heavier tag paper rolled in one fell swoop should bulk up the tube wall. Be sure to allow for shrinkage with larger bores. A good alum or similar former will take you a long way.
Be sure to use plenty of paste on your former. No, wooden dowells don't work to good.

You can also try drapery and upholstery shops. Fabrics come rolled up on fairly good tubes. They are free for the asking where I work. We throw out several each day.

[Edited on 20-6-2003 by bernie briden]

[Steve]

If you go to a news printer then they often haave cardboard rolls that used to have the paper on. They are 3" iD and thick enough for moartar use.

STeve

[lord_dranack]

I've managed to get one of those tubes, and am going to treat it with calcium chloride and sodium silicate soon.

What is the best material to seal up the bottom of a mortar tube? Previously I have used clay powder but only with smaller tubes (up to 1.5"). Would wood (no pun intended) or epoxy resin work safely?

[PanMaster]

stick it in the ground, works a treat with steel tubes, use a hammer

[adamw]

Wood is the material of choice in proper mortars. Turn it so its a good fit and pop 4 nails into it. Also maybe seal with glue.

[lord_dranack]

Thanks!
Four nails through the sides of the tube?

[Richard H]

Yes, say at angles of 90 degrees to each other. Glue and nails will make a good solid plug that should not blow out.

[crazyjim]

Hmmm,

I was at a mechanics lecture last month, and the lecturer filled a small tube with sand and held it in with tissue paper. He then inverted it, and put a piston in the top. Then he pressed it a bit, and nothing happened. Finally he stood on the piston, and the tissue paper held his weight! (actually the friction of the sand on the side of the tube did, and it [the friction] increases exponentially as you add more sand). So I reckon the cheapest way to plug a tube would be to use two tiny bits of card, with a lot of sand betwen them. The domonstration had the length of sand about 10x the diamemter of the tube, but you might be able to use less.

-Jim

[Mortartube]

Use turned wooden plugs, they work and the professionals use them. Why try to invent new ways of doing a job that has a proven, cheap and reliable method already?

[lord_dranack]

length of sand about 10x the diamemter of the tube

Also, for a 3" mortar, you're talking 30" of sand!

[Matt]

I have used sand quite a lot. I put about 3 inches of sand in my 2 inch mortars, they are also backed up my 19mm pine (nice sturdy rack, overkill really)

-Matt

Edited by Matt, 27 November 2003 - 10:43 PM.

[Bonny]

I hope this info is not posted here already...I couldn't find it anywhere.
Where I work I have an almost unlimited supply of 3" ID heavy wall spiral wound cardboard tubes. They are mainly 40-48" long, so I can cut to any size I need. My question is about the wall thickness. Is 3/8" wall heavy enough for 3" shells or should I use the 1/2" wall only?

thanks

[Pretty green flames]

I hope this info is not posted here already...I couldn't find it anywhere.
Where I work I have an almost unlimited supply of 3" ID heavy wall spiral wound cardboard tubes. They are mainly 40-48" long, so I can cut to any size I need. My question is about the wall thickness. Is 3/8" wall heavy enough for 3" shells or should I use the 1/2" wall only?

thanks

I use 5mm (a tad under 1/4") walls on my mortars, and they've held up to some pretty powerfull lift charges and a couple heavy shells (think double break), they show no significant wear, apart from being charred a bit on the inside they are still holding up very well. So my opinion is that the 3/8" walls will be sufficient for any type of shell.

Cheers

[Bonny]

I use 5mm (a tad under 1/4") walls on my mortars, and they've held up to some pretty powerfull lift charges and a couple heavy shells (think double break), they show no significant wear, apart from being charred a bit on the inside they are still holding up very well. So my opinion is that the 3/8" walls will be sufficient for any type of shell.

Cheers

Awesome, wasn't looking forward to lugging around a mortar rack with the 1/2" wall tubes...