wood choice for mortar rack contruction

[nubs]

i am trying to build my first rack solo. i am attempting to build a 21 shot rack, each side on a 15 degree angle and 1 straight up(7-7-7). I saw a picture posted using 3/4 inch plywood and then it was "tied" together using what looked like a 2 x4. my attempt somewhat failed... i used 3 inch deck screws for contruction and had some spliting of the plywood on it's side rails. What is the "recommended" wood choice and what screw length will provide adequate "holding" power?
Now obviously, i am pretty stupid, but any help will be appreciated?
even a design would be cool...
thanks!

[Deweycoon]

Is this what you are looking at building?
http://www.pyroreview.com/gallery/showphoto.php/photo/4181/sort/2/cat/520/page/2
1x4" pine boards are a popular building material. make sure you predrill all your holes when working with pine.
I use 2x4's on the bottom and sides of my racks that are ripped to the width of the mortars.
The boards on the bottom/sides are 2 1/8" wide for fiberglass mortars and 2 3/8" wide for HDPE mortars on my racks.
Here's some other pictures for you:
http://www.pyroreview.com/gallery/showphoto.php/photo/3884/sort/2/cat/520/page/2
http://www.pyroreview.com/gallery/showphoto.php/photo/4180/sort/2/cat/520/page/2
http://www.pyroreview.com/gallery/showphoto.php/photo/3893/sort/2/cat/520/page/2
http://www.pyroreview.com/gallery/showphoto.php/photo/3341/sort/2/cat/520/page/3

[ken150]

i am trying to build my first rack solo. i am attempting to build a 21 shot rack, each side on a 15 degree angle and 1 straight up(7-7-7). I saw a picture posted using 3/4 inch plywood and then it was "tied" together using what looked like a 2 x4. my attempt somewhat failed... i used 3 inch deck screws for contruction and had some spliting of the plywood on it's side rails. What is the "recommended" wood choice and what screw length will provide adequate "holding" power?
Now obviously, i am pretty stupid, but any help will be appreciated?
even a design would be cool...
thanks!


Something else you will have to look out for is when you predrill your holes you will have to get your drill perfectilly streight or you will have the screws comming out of the sides, because the holes will be at an angle if you dont. when i do my rack building i use 9/64 drill bits, After the hole is drilled, run the bit up and down this will get the hole a little bigger an the wood wont split. For screws i use phillips II high preformance ( pine colored,this is for looks only) 3 inch number 8, these seem to work best for me. another thing that i do is use a small squar ( i think that is what it is called ) it has a moveable end to it. this is very good for measuring the wood to the middle or 1/2 the thickness. you can then mark the top piece of wood and know where the middle of the wood is underneith it is, this also will prevent the wood from splitting because the screw will be in the middle of the wood. make sure that you also counter sink the screws to, this will prevent the top piece of wood from splitting. I hope this might help with your splitting problem. one other thing you are not stupid, you have taken the first step to getting something done. the first thing that i see that was smart is that you knew to come to pyro universe where peaple know a lot about fireworks (even more than me)and can help with building your new racks. so never call yourself stupid because if you say it enough you will start beliving it, and if you say it enough to other peaple they will start beliving it also.

[nubs]

thanks..that last rack link is what i was trying to emulate.... i had pine, but i saw someone ,somewhere said it was too soft....thats why i went to the plywood....

[jokerman]

The lumber store I went to only had pine, some cedar, but it seems that pine is the wood generally used for construction. 2x4's are generally fir and some trim materials should be available in different types, but pine and fir make up most of the wood. Plus. it would be expensive to think of making racks out of more expensive wood types. I used pine and it seems very sturdt. Just follow the tips that others gave about construction and pine should work.

[ken150]

As for me pine has always done good. The only splitting that i had was because of me not predrilling at all, or the predrilled holes not being deep enough.

[skole]

An item like this will help with drilling and countersinking. The kit comes in various sizes and the bits and sinks are numbered as #6, #7, #8 ect.

A 1 5/8th in. deck screw is a #7. A 2in. or 2 1/2in is a #8. The numbers correlate to the screws width and head size and its listed on the box. So if using a 2in screw use the #8 bit and you get perfect sized holes and countersink for that screw.

The kit is relativly inexpensive. It seems like its less than $15.00 and has 4 sizes of bits and sinks. There are several brands and combinations available. I know both Dewalt and Hitachi both make the sets.

http://img.photobucket.com/albums/v738/skole1969/spread%20rack%20modification/01xcountersink.jpg

Shane

[lamrith]

Nubs - Just make sure like these people are saying, use SCREWS for main fastening. I have seen people use glue and brad nails or stables like used for mortars, they do not always hold! For convenience and speed I use my nailer to tack the pieces together and stack them aside. this lets me get them square and lined up without having to hold and drill and scerw all at the same time. Then after I have a batch prepped I go back and drill them all, then go and screw them all down... It is a number of steps but I am also usually doing 20+ at a time so it helps speed thigs up...

[Deweycoon]

All the 1.3 racks I have seen are put together with nails.
Can the 1.3g guys tell us why?

[liftngwaght]

Pyrogear.net staples their's.

~Thomas

[kenbeuken]

All the 1.3 racks I have seen are put together with nails.
Can the 1.3g guys tell us why?

Racks are made with nails to allow them to move and shift. If you screw and glue together the racks too much, they will become rigid and have no give. You want them to be able to give a little to help absorb the shock. Nails allow the rack to shift and twist a little. Too many screws and glue will cause the boards to split, instead of giving at the joints.

[Deweycoon]

Racks are made with nails to allow them to move and shift. If you screw and glue together the racks too much, they will become rigid and have no give. You want them to be able to give a little to help absorb the shock. Nails allow the rack to shift and twist a little. Too many screws and glue will cause the boards to split, instead of giving at the joints.

Thanks Ken, I know why nails are used but I wanted others to read it from a qualified 1.3g shooter.

[lamrith]

Racks are made with nails to allow them to move and shift. If you screw and glue together the racks too much, they will become rigid and have no give. You want them to be able to give a little to help absorb the shock. Nails allow the rack to shift and twist a little. Too many screws and glue will cause the boards to split, instead of giving at the joints.

Maybe we are talking about different parts of the rack?? The 1.3g company I shoot for assembles racks from premade pieces at each show. They have a incrediuble safety record and my instructor is a Sr PGI member and also deeply involved with NFPA and WA legislators on Pyro safety, he has been shooting for 25+yrs.

There is the main package that has 4 sides and a bottom and the tubes are in it. Then there are endboards at each end to hold the packages so the tubes are veritcle or angled.
http://www.pyrohouse.com/images/forest6405/rackclose.jpg

The packages with the tube in them are ALL screwed together. Otherwise the force of the lift charge will blow the sides and bottom off...
http://www.pyrohouse.com/images/july405/finalerack.jpg

Now the Endboards ARE nailed, this will let the individual packages flex a bit as they fire off at different times, also the force is not great enough to blow the nails out as the screwed together packages contain that force....

[shrapnel]

[QUOTE=skole]
A 1 5/8th in. deck screw is a #7. A 2in. or 2 1/2in is a #8. The numbers correlate to the screws width and head size and its listed on the box. So if using a 2in screw use the #8 bit and you get perfect sized holes and countersink for that screw.


Actually, the number on the countersink bit has nothing to do with the LENGTH of the screw, It has to do with the diameter of the screw and head, you can buy 1 5/8" wood screws in #6 and #8 and #10 diameter for example, the countersink bit should have a set screw to adjust the internal bit to fit the length of the screw. A 1 1/2" and 3" #8 drywall screw have the same size heads and require the same size countersink bit, ;)

[skole]

Thanks for clearing that up Shrap.

I did mean to state that the number of the screw and the number of the bit and counter sink refer to its width and head size. I did not do such of good job of making that clear.

There may be different numbered deck screws, but to date I have not found any. 1 5/8ths screws seems to be a #7, and 2-2 1/2 in screws seem to be #8.

Still that little gizmo I talked about is a real time saver. and takes a lot of the work out of drilling a hole with a countersink.

Shane

[nubs]

ok i finished...here are some pictures!!!

http://i40.photobucket.com/albums/e244/weave5dog/IMG_1801.jpg

http://i40.photobucket.com/albums/e244/weave5dog/IMG_1800.jpg
sorry it's sideways

http://i40.photobucket.com/albums/e244/weave5dog/IMG_1799.jpg

what do you think?

[Bmiller]

NICE !! nubs, looks like my 18 shot 20 degree I just built out of SYP (southern yellow pine) SYP has a good give to the wood and will flex until it gets too dry. I leave my racks outside most of the year and only dry them out one week before a shoot. I have used cedar but prefer pine even though you MUST predrill all holes. I use fine thread drywall screws but do not countersink the holes. (let the screw heads do thier own thing!)
Some of my racks are 4 years old and still are not loose in any way, if I was shooting 1.3, it would be a very different story