3" & 4" dr 11

[cody138]

Anyone have the build specs for 3" and 4" racks using HDPE pipe?

[Mattp]

If you use the search function.. you’ll find some.. people have def posted them on here in the past.. funny I’ve made so many over the years.. and every time I have to redo the math.. instead of writing it down... but it also depends on how many tubes in the rack.. and if you want spacers.. so the specs can vary too... but definitely can find old threads with the info

[cody138]

I have searched it and found nothing with specs just people asking where to buy them and how many to put in a rack. I will looks again and if I cant find it I will just figure it out when I get my pipe, I was trying to get ahead and figure out all my lumber and have it before my pipe arrives.

[displayfireworks1]

If you are going to build your own racks no matter what size mortars, always place a spacer between the mortars. Particularly with the smaller 1.91 DR 11 ones. When you advance into an ATF license or have access to salutes etc. This helps somewhat in the event things start to blow apart. Some people build a rack as a rectangular box and just drop all the mortars in. When you starting getting into 3 inch mortars and higher, you going to need spacers and stronger racks. My suggestion is to just purchase them and make it HDPE pipe. If you have some higher level carpentry skills buy the pipe and make your own. People in the business that make , sell and ship these operate on a tight margin. Depending on your funding, I suggest most people just buy the racks.

[Salutecake]

Hey cody138, Dave as usual is spot on

I don't have the specs, but years ago I bought racks from I company I shot for, (they also sell racks and 1.3) then copied their design. If I remember correctly a 3" rack is easier than a 4", 3" use 2x4's no ripping down. Then you have to buy the pipe, buy the plugs, or buy the pipe plugged. Time and effort, unless you have the time and like the effort, just might be easier to buy.

[d34d3ND]

I have yet to find "exact" documentation on "how to build" a rack. Although, I have built a fair amount of 3, 4 and 5 inch racks. Yes, hopefully one day someone (including myself) will post some dimensions but even the NFPA does not state what a mortar rack should look like except some guidelines in NFPA 1123 Section 4.5 and 4.6. This is the excerpt from section 4.5:


The materials used in rack construction vary widely in the industry. There is no one single material or construction method that is uniquely acceptable for fireworks display racks. This performance based requirement addresses the concern about mortar rack construction and provides direction to assure operator and audience safety during fireworks displays.

If you do some really deep searching for rack design, you may come across a California Fire Code that takes it a step further. Being that it is more "strict", I have utilized these guides in most of my racks. Yes, it can make things heavier in some cases, but being safe is better than....well, I will let you fill in that blank.


Mortar (https://up.codes/viewer/california/ca-fire-code-2016/chapter/2/definitions#mortar) racks shall be limited to a maximum of 10 tubes per unit. The base and ends of the rack shall be nominal 2 inch thick lumber. The inside width shall be equal to the outside diameter of the mortar (https://up.codes/viewer/california/ca-fire-code-2016/chapter/2/definitions#mortar) tube. Each mortar (https://up.codes/viewer/california/ca-fire-code-2016/chapter/2/definitions#mortar) tube shall be separated by horizontal or vertical blocks nominally 2 inches thick and 4 inches wide. Side braces for mortar (https://up.codes/viewer/california/ca-fire-code-2016/chapter/2/definitions#mortar) racks of 3 inch size mortars (https://up.codes/viewer/california/ca-fire-code-2016/chapter/2/definitions#mortar) and up shall be 1 inch x 6 inch nominal lumber or 1/2 inch x 4 inch plywood securely fastened by nails, screws, or attached with construction grade staples along the top and bottom of the rack. A diagonal side brace must be employed on all mortar (https://up.codes/viewer/california/ca-fire-code-2016/chapter/2/definitions#mortar) racks with more than 5 mortar (https://up.codes/viewer/california/ca-fire-code-2016/chapter/2/definitions#mortar) tubes. Mortar (https://up.codes/viewer/california/ca-fire-code-2016/chapter/2/definitions#mortar) racks shall not incorporate steel (https://up.codes/viewer/california/ca-fire-code-2016/chapter/2/definitions#steel) brackets or other metallic parts in their construction with the exception of nails, screws, or construction-grade staples. Metallic braces shall not be fastened to mortar (https://up.codes/viewer/california/ca-fire-code-2016/chapter/2/definitions#mortar) racks at the firing site (https://up.codes/viewer/california/ca-fire-code-2016/chapter/2/definitions#site).

In the end, you will probably want to purchase your racks and HDPE from someone that makes them. They take some time to build. There is lumber cutting, ripping, screwing, throwing, and a lot more that gone into a rack vs. just buying them from somewhere that already has them pre-made. If you want to try your hand at making them, buy 1 and then copy it. I will say, HDPE pipe is going to be the hardest to get in most places unless you know a company that does not make you buy a truck-load!!!

[BMoore]

You may want to check out PyroBoom, LLC. I understand that he is starting to make some 3" and 4" display racks. They are brand new and I don't think they are even on the website yet but the FB page has some details. His racks for the consumer market are second to none, so I have no doubt these will be top quality. I'm considering a couple myself even though I really don't need any new racks this year.

[Salutecake]

Hi d34d3ND,

I came across that California standard a while back and the confusing part of that standard is the word "Nominal". Nominal does dot mean minimal, and I believe "nominal 2 inch thick lumber" would mean the standard 2x4 piece of wood is the nominal name and called by it's nominal name like a 2x4x8, but the exact measurement is 1 1/2x3 1/2 inches. Hope that makes sense.

[PyroJoeNEPA]

All the racks[3', 4', 5"] used by the company I shoot for are engineered to be the same length. That way, when building them into "pods" the ends all match up for the end boards and allows for different size shells to be put into the same "pod".
Also, FYI, our 3" racks do not have spacers, the 4" & 5" do.
Our 2 1/2" racks have 12 tubes in them since the typical finale chain has 12 shells. 3" are 10 tubes, 4" have 6 tubes.

[RalphieJ]

The Old Masters had such confidence in their shell-making craft (spolettes secured with fillets of linen twine and hot animal hide glue, even with their smaller 2" and 3" shells and salutes) that flower-pots and catos were unheard of, resulting in racks and battery boxes without spacers. Finale lines were buried 1/3 the length of the mortars and then banked with sand (provided by the sponsor), back-breaking work ("That's why they're called 'fire-works' and not fire-play"). However, troubles began with the use of imported shells, necessitating changes. That and the progression from single-fired multiple break shells for the body of the show to sky-puke for the whole damn shoot.

[cody138]

I have built 1.91 racks, and have a good many of theses built and in use but I have my ATF 54 and am taking some PGI classes for more experience and was looking at building some 3 and 4 inch racks but was looking for the board sizes, end board on a 3" im assuming is a 2x4 but not sure with the 4" "ie" using a 2x6 and ripping im guessing but was just looking to see what people were doing. As for length and other things that is easy to figure out lol just was looking to see what people were using to build some of the bigger racks.