71 replies to this topic

[Arthur Brown]

Also the bottom of the rack is what spreads the impact of a shell launch over a larger area so that is why racks often have a substantial bottom bar -like 2 to 3 inches thick this stops tubes driving themselves into the ground or damaging the surface. USA practice includes having the lower side rail up to the height of the top of the plug and the upper side rail from the 3/4 point up to nearly the top of the mortar. This leaves the most likely place for a blowout - mid tube free for shrapnell and blast to travel with minimum disruption to the rest of the tubes.

[Spyrotechnics]

would it be a good idea to work out a number of tubes (in different sizes) that could fit in the same width rack, thatway you could connect the racks together regardless of the size of tube (we do it for our 75mm and 100mm in both fanned and straight configuration and it works well )

[BrightStar]

I spotted an interesting approach to wooden racks here:

http://www.pyromaste.../SS Rackits.htm

Their design seems to work with the inherent strength of the tubes rather than just boxing them up...

Edited by BrightStar, 29 May 2009 - 04:23 PM.

[Mixologist]

I spotted an interesting approach to wooden racks here:

http://www.pyromaste.../SS Rackits.htm

Their design seems to work with the inherent strength of the tubes rather than just boxing them up...

Smart, wonder what the prices are like for the metal ones.

[Firework Crazy]

Some interesting designs there.

[pyrotrev]

Yes, an interesting design. Plus points on the wooden ones are:

1) multiple side-to side fastenings increase the strength and prevent side rails coming off and tubes scattering.
2) narrow footprint on the floor reduces twisting strain on the bottom of the rack when firing them angled.
negatives are:
3) the tubes are clamped rather too high up at the bottom. I've had steel bolts snapped or stripped lower down than that when a shell detonates.

The metal ones look a lot better, much like my MK3 design, though strangely, they've lost the bottom central rail.

[cooperman435]

I have done much like Starsky said and all my racks are of the same length regardless of tube size. They differ in width obviously but it means all can be fastened by a wooden slat running down the length of them should you choose to do so.

here's a picture of some I made new a while ago. There made from 1" marine grade ply, screwed and glued together with 1" spacers between the tubes. Tests have shown that 5" shells destroying tubes only dents the neighbouring tubes and the rack survives.

From my design the wood that is used to make them all is modular so an 8' by 4' sheet can be cut down into many 3" lengths and a few of the tubes widths then at the end all the offcuts are used to make spaces so there is as good as no waste.

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[phildunford]

here's a picture of some I made new a while ago. There made from 1" marine grade ply, screwed and glued together with 1" spacers between the tubes.

They are excellent racks, but lifting them nearly gave me a hernia! - lol

[cooperman435]

and they were 3" racks! Imagine the 6"ers then mate!

[portfire]

What are peoples thoughts on using MDF ? My fan rack is made from 9mm MDF (I know many have seen it, quite the crowd pleaser it would seem) and the only problem I've had (once) was the bottom been "pushed" out, (only the right side mind) this was my own fault, due to me over lifting the 50mm Bag-Mines......15g for 50g of D1

The reason I ask is that I'm going to build a couple of bigger racks (for 3") 1-Fan-5 tubes and 1-5 straight.......3/4" MDF

Any thoughts ? apart from waterproofing of course

[Mixologist]

MDF can be of varying strengths throughout it due to the manufacturing process.

For this reason to start with i`d go for something else, the last thing you want to be doing is repairing your racks all the time....

[phildunford]

I've seen MDF go so soft with moisture that it literally falls apart - would not be my first choice...

[Arthur Brown]

I'd be cautious about MDF as racks always get damp, by rain or just dew in ground contact, and MDF behaves badly in the damp.

Yes cakes are paper! But cake cases are made to be one time use and disposable.

[portfire]

I do know about MDF and moisture, that is why I said "apart from waterproofing" in my original post The racks would be heavily waterproofed