27 replies to this topic

[Night Owl]

I just bought some fibre glass mortar tubes and decided to ask on here which tube is thought to be safest to use? if a shell failed and blew in the tube, which one would you prefere to be crouching next to for your saftey, Plastic or paper tubes??? has this been tested? I'm not asking anyone to test this but if anyone has info on this, I would be most interested.

[neo]

paper for sure.
fiberglass makes very sharp hmm.. whats the english word.. anyway, it makes very sharp edges if it brakes, and it is very hard.
but then, fiberglass is cheaper in the long run, beacuse paper mortars need to be changed quite often.

what size is the mortar?
if it is 2,3" then I wouldn't be so worried..

[adamw]

My 'would rather be next to' list:

1] Fibreglass
2] Paper
3] HDPE
4] Metal!

[Pretty green flames]

Adam, that is rather odd that you list HDPE only on the 3rd place. Would you care to explain why you think so. Most of the hand fired shows i've seen (on film), HDPE is used as it is supposedly safer than fiberglass, shrapnell wise. Don't take my word for it but someone was killed by a piece of fiberglass when a 5" titanium slaute went of in one. This was mentioned some time ago on rec.pyro so the information may not be very accurate.

[BigG]

Adam, that is rather odd that you list HDPE only on the 3rd place. Would you care to explain why you think so. Most of the hand fired shows i've seen (on film), HDPE is used as it is supposedly safer than fiberglass, shrapnell wise. Don't take my word for it but someone was killed by a piece of fiberglass when a 5" titanium slaute went of in one. This was mentioned some time ago on rec.pyro so the information may not be very accurate.

well, fiber glass type tubes are very common in the UK, and they powder quite nicely when things go wrong. I must admit that HPDE is quite rare in the UK. haven't seen much of it at all.

[Richard H]

In one test we did, we placed a 2" Chinese shell upside down in a typical 2" fibreglass wound mortar tube. The shell in question had a very powerful flash break. Upon functioning of the burst charge the bottom half of the tube completely disintegrated and we could only find tiny strands of resin impregnated fibreglass cloth. The top half of the tube was still relatively in tact, albeit rather frayed at one end.

Fibreglass does not seem to present a major threat to the operator in terms of projected debris in the event of a malfunction. It is certainly becoming the tube of 'choice' by UK operators. Partly because they are relatively lightweight, strong, and of course the price from China is good. While HDPE might be the better choice, its availability, price and the increased weight/volume of racking precludes its widespread use.

[Night Owl]

In answer to Neo, the tubes I have bought are 4", Shrubsole sometimes after lighting a rack or group of shells some may feel like running like hell but in a show you have to stay and light the next bank of shells lol, on the whole I believe paper tubes are used most in the UK, I have had plenty of tubes fail and not noticed in most cases until take down of the racks, I must add in my experience shells failing in the tube are most rare, the shells that have damaged my tubes have simply been too strong a lift, be it higher grade bp or too much bp, not shell failure.

Does anyone recall the accident in Scotland in 1988 when a guy using an 8" metal tube had a shell blow in the tube and lost his leg? I have detailed info on this but cant find anything on the net about it.

[Mortartube]

In answer to Neo, the tubes I have bought are 4", Shrubsole sometimes after lighting a rack or group of shells some may feel like running like hell but in a show you have to stay and light the next bank of shells lol, on the whole I believe paper tubes are used most in the UK, I have had plenty of tubes fail and not noticed in most cases until take down of the racks, I must add in my experience shells failing in the tube are most rare, the shells that have damaged my tubes have simply been too strong a lift, be it higher grade bp or too much bp, not shell failure.

Does anyone recall the accident in Scotland in 1988 when a guy using an 8" metal tube had a shell blow in the tube and lost his leg? I have detailed info on this but cant find anything on the net about it.

I recall the incident you speak of. It was Princes park in Edinburgh I believe. I used HDPE quite a lot from the scrap pile of our local water company and although heavy, it did a great job.

[Mortartube]

So these fibreglass ones come from China...

Can't we (or someone who deals with such things) make our own?

I mean fibreglass is actually something we CAN get in this country without restrictions! (makes a nice change!) - you could even get your friendly local fibreglass molding company to knock one up for you and make up any story you want for ordering a tube. (Water feature in the garden )

How thick are the walls in such a device? Is it blocked at one end with anything?

Just buy them off of someone who imports them. It would cost you about 5 times as much to make one as to buy one. Talk to Mike at Brighton Fireworks. I'm sure he can get some for you.

[Richard H]

Typically 3-4mm thick walls, and sealed with a resin bung at one end with an outer wrap of cloth around the base, and secured with nails passing through the side walls at regular intervals.

Personally I would not like the mess of making my own, but if you are not friendly with any local firework companies, then I suppose there is nothing to stop you! (apart from all the polyester resin fumes that is!).

[Pretty green flames]

I tried myself about two weeks ago at making fiberglass mortars, the result was not very impressive and beeing choked by polyester resin fumes is not very pleasant. Also the type of fiberglass cloth most commonly sold is the "mat" type which is a bitch to roll as you must be very gentle with it or it will rip apart, not very practical when you are trying to roll a dense tube with it. There's also the problem of getting the finished product off the former, mine got always stuck on it. To sum it up, it's really not worth the effort. I feel sorry for the 8pounds i payed for all the materials, might as well had bought rolls of quality craft for that money

You are welcome to try but don't be dissappointed when it doesn't turn out as you expected.

[Blast Happy Fool]

If anyone is in the St Ives/Huntingdon/Cambridge area there is a load of dumped blue HDPE water main pipe by the painted mini-roudabout on the Lakes technology park at the A14/A1096 (behind whippet coaches!)

Also all the trees are willow and the thined them out last spring, there are logs everywhere.....