Mortars?

[Thezoranator]

I currently have two high density polyeithliene mortars on the way in the mail, but I was wondering what you guys would prefer; HDPE or fiberglass?

[nater]

Either are good choices. I think HDPE mortars are a little more durable in the long as long as the plugs stay in good shape. I think the different colors of fiberglass mortars make it easier to spot when you are reloading at night, like during open shooting at club events. HDPE can get warm and soft with rapid reloading. Fiberglass can shatter, but the pieces will not travel far like with PVC. Another member reported injuries to a shooter when a handlit shell blew in a fiberglass mortar and pieces of it cut into his legs.

 

I have a mix of HDPE, fiberglass and steel in different sizes. Steel is my least favorite due to weight and danger. HDPE and fiberglass is a tossup. I prefer HDPE for commercial use where racks get thrown around and fiberglass for hobby use. I would choose whichever was easily available.

Edited May 8, 2014 by nater

[Thezoranator]

Right, I have not personally tried steel but i'm guessig

If it were to implode on itself the shrapnel would be at

Least as bad as a pipe bomb. Cardboard tubes are also

Pretty cool, because they are easy to make. Thank you

For the help

[nater]

Yes, steel mortars pose a big risk if the shell were to fail. Unfortunately they are still needed for heavy, multibreak cylinder shells. By burying streel mortars and using proper barricades, the risk is lessened but not eliminated. I feel steel should be avoided unless necessary and then used at greater distances to shooters. I will not handlight shells in them for any reason.

 

I have only used cardboard mortars for 1.3 once, and they worked great. I don't think the are as common now that HDPE is readily available. They are still used in many consumer kits.

[LambentPyro]

A lot of the consumer canister shells have switched to straight fiberglass and reinforced HDPE. I guess the manufacturers are stepping up their safety a bit. The only canister kit I've seen recently that uses cardboard is smoke n mirrors. I just put them in my HDPE racks though.

 

How far would you bury a steel mortar? I've seen half way in shoot setup videos. Shouldn't they bury them all the way so the muzzle is level with the surface?

[Thezoranator]

I know what you mean. Im pretty sure steel mortars go further down than halfway because there is still a risk of shrapnel

[ollie1016]

I've read that steel mortars are supposed to be buried in sand/soil 2/3 the height of the mortar.

 

When a steel mortar fails, it doesn't causes the amount of shrapnel that people think. Still wouldn't want to be around it though!

 

Stay safe all.

[bob]

One thing I want to say is steel is insanely strong! I use steel mortars and have had atleast 12 shells fail in the mortar and there has never been any damage. Although I wouldn't try this without the proper barricades, I am very confidant that I could fill my 3 inch mortar to the brim with bp, glue on a piece of plywood to the end, you could even wrape rope around it if you wanted, but it would not blow up. Of course this is not true with larger mortars, such as marks 8 inch steel mortar, however his also didn't blow up into a thousand pieces, it stayed in one piece.

Please note my limited experience and don't take my word as the Gospel.

bob

[Arthur]

Cardboard, GRP and HDPE all work as mortars for fireworks. HDPE ususally comes from the water or gas distribution industry, and needs plugging usually with wood which is likely to rot if damp.GRP comes from China and comes ready plugged. Card is now on the way out but well plugged it's good.

 

Steel is now out of use in the UK for shrapnel risk, Some USA places demand steel mortars so bury them deep enough to hold the shrapnel..

 

There is a lot to be said for firing shells remotely -more so as the shells get bigger.

[schroedinger]

You also can just put concrete into your HDPE Tubes to get a plug which isn't going to rot, but that one is going to be heavy

[nater]

For the U.S. NFPA 1123 is the codes for firework displays. In some places it is law, but everywhere it would be the industry standard and civil courts would expect it to be followed. It states that mortars shall be buried at least 2/3 of their depth. It then lists provisions for using racks. Steel mortars are not allowed to be racked. I prefer to bury them as deep as possible.

 

Do not underestimate their danger. While a single break shell with a color burst will most likely flowerpot and do no damage to the mortar, salutes will do extensive damage with shrapnel flying very, very far. Consider that most people are not firing single break shells from steel, they are firing large multibreaks which usually include a bottom shot. This is because steel is stronger and can handle the amount of lift needed for a 100lb shell when HDPE or fiberglass.would fail. If this shell fails to lift and goes in the steel mortar, the damage is great.

 

The incident I witnessed first hand left a crater and destroyed a barricade. Nobody was hurt, but steel bits were found hundreds of feet away and we never found enough pieces to account for the entire mortar. Another incident sent shrapnel through a shipping container and pieces were found a mile away.

 

Some members of the PGI have been testing heavy walled HDPE and reinforced fiberglass to see if they can handle lifting heavy shells without the shrapnel risks of steel. So far the results are promising. It would be nice to phase them out.

[Mumbles]

There are different failure modes for steel. Some will result in them just splitting or peeling apart, while others leave shrapnel. When I use them, I bury them most of the way, usually at least 3/4. You also have to account for any setback. Big shells can push a mortar deeper into the ground. You have to make sure that it does go below ground, or it's extremely difficult to remove.

 

I would trust a concrete plug much less than wood. It wont be friction fit, and the last thing I really want is concrete coming down from the sky. I've seen HDPE mortars fail in such a way that they're propelled out of the ground.

[nater]

Mumbles raises an excellent point that I forgot to mention. When you bury mortars, no matter the material, it is wise to place some bricks, railroad ties, or something solid under the mortar to prevent the recoil from driving them in. Some people have welded chains into steel mortars, I have also used duct tape to secure lengths of rope wrapped from the top down each side and around the bottom to help lift them out.

 

A few years ago we did a test of recoil on an 8" shell. On seemingly hardpack dirt, the mortar was driven in 4" more with only one shell. We have a 5" mortar we ended up burying completely because we could not get it out of the ground.

[Thezoranator]

I know that the shrapnel would probably not be lethal but

I am not sure if I want to take the risk of getting a minor to

Major injury. I think that I will probably stick with HDPE for now

Only because it is highly trusted. Also a steel rack would be

Quite heavy... With all of the metal. Thanks All

[nater]

Steel cannot be racked, it must be buried per 1123. I also think a steel mortar explosion could be lethal.

[LiamPyro]

Thezoranator, I don't think you need to worry about shrapnel, considering your going to be firing commercially made shells at least for now.

They are small enough to hardly scratch the paint if they exploded in the mortar.

[LiamPyro]

Thezoranator, I don't think you need to worry about racks yet, since you don't even have any shells.

Even the best mortar rack would be completely useless with nothing to fire from it!