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Making fiber glass mortars


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Posted
I've seen and read about people making their own fiber glass tubing, and I would like to give this a shot. Almost all my research has come back fruitless. I assume the proses involves raping the desired id tubing with fiber glass cloth and some kind of resin, but I can't find what kind of resin. Any help would be appreciated!
Posted
I've seen and read about people making their own fiber glass tubing, and I would like to give this a shot. Almost all my research has come back fruitless. I assume the proses involves raping the desired id tubing with fiber glass cloth and some kind of resin, but I can't find what kind of resin. Any help would be appreciated!

I imagine just about any epoxy would do. It doesn't have to stand the heat for long. The epoxy used on commercial mortars is not particularly fire resistant. Just last Saturday at the MPAG shoot I saw a mortar that the epoxy had been burned completely out of the better half, leaving only the unsupported strands of burnt fiberglass holding the shape. It was used for a liquid fireball which evidently did not burn all its fuel in the air.

 

Obviously you would need to coat your former with something that the epoxy will not stick to.

 

Were I you, I would just buy some mortars. They're to cheap to bother making them yourself...And epoxy is expensive. You may hardly save any money at all.

Posted
Absolutely. Just buy them. Working with fiberglass is sticky and stinky, and the commercial ones are very cheap compared to what it would cost for the layup mat and resin.
Posted
Thanks for the responses. Obviously I didn't realize it would turn out to be such an expensive endeavor to make my own...
  • 4 weeks later...
Posted

Hello!

 

How thick is the wall of a FG mortar, let say about 6 inch mortar?

 

Cince I live in a country where is impossible to get HDPE pipes or FG pipes\mortars my only chance to get some mortars are to make ones myself! my idea is to take a suitable iron pipe, cover it with wax, 0,5mm thick, then laminate required thickness on it and after curing I am gonna heat the iron pipe inside with something(hot water, steam) until wax melts and then pull it and add a bottom plug.

 

Does anybody know witch resin FG mortas are made of?

 

Only polyester and epoxy resin comes into my mind but wich one? Polyester is cheap but not strong as epoxy, epoxy in the other hand is almost four times more expensive(at least where i live).

Posted

First it's madness to compete with Chinese tube production on cost grounds!

Secont here are the dimensions for one UK vendor of Chinese mortars.

bore____length__wall____ ID_____ OD ____Price

2” Tube 380mm 2.2mm 51.0mm 55.4mm £1.40

2.5” Tube 400mm 2.5mm 63.5mm 68.5mm £1.79

3” Tube 450mm 3.0mm 76.0mm 82.0mm £3.00

4” Tube 550mm 3.5mm 100mm 107mm £4.00

5” Tube 800mm 4.0mm 125mm 133mm £9.00

6” Tube 900mm 4.0mm 152mm 160mm £12.00

All prices are plus tax, but you simply canot compete with £1.40 for a 2" tube.

 

All (UK) GRP mortars have moulded integral end plugs. Which is possibly their greatet advanttage. A tube will have the fibre cloth to re enfiorce the end then resin poured in to make a plug about bore/2

 

I'd be really surprised if there is a place in the world where the water mains supply doesn't include HDPE pipe, or some industrial product doesnt come on cores that are the right bore.

 

Google for "Core winders" in your area

 

Getting the formers on which to wind your GRP will not be easy, and if you make them too straight getting the tube off the former will not be easy either.

Posted (edited)
Hello!

 

How thick is the wall of a FG mortar, let say about 6 inch mortar?

 

Cince I live in a country where is impossible to get HDPE pipes or FG pipes\mortars my only chance to get some mortars are to make ones myself! my idea is to take a suitable iron pipe, cover it with wax, 0,5mm thick, then laminate required thickness on it and after curing I am gonna heat the iron pipe inside with something(hot water, steam) until wax melts and then pull it and add a bottom plug.

 

Does anybody know witch resin FG mortas are made of?

 

Only polyester and epoxy resin comes into my mind but wich one? Polyester is cheap but not strong as epoxy, epoxy in the other hand is almost four times more expensive(at least where i live).

I would estimate the wall thickness of a 6" mortar to be about 8mm. I have never used polyester with fiberglass so I can't voice an opinion there. Epoxy obviously is suitable however.

 

EDIT: I guess I was wrong about wall thickness. Arthurs post sums up my thoughts pretty well otherwise.

Edited by NightHawkInLight
Posted

Of course there is sellers who sell HDPE pipes and I have 3" mortars made out of a cores witch i got from local store but HDPE pipe with diameter of 6 inch is pretty expensive, so i look for altenatives.

 

Ok I exaggerated the Impossible part, theres always a way but in my case quite expensive one!

 

First it's madness to compete with Chinese tube production on cost grounds!

 

Dude!

 

Nobody said nothing about mass production, I just need some pipes!

 

But hey thanks for the dimensions!

 

Got to run some tests!

Posted

6" pipe was expensive for me til I saw some being scrapped roadside, it's now yard and metre lengths ready for plugging all FOC. Stop busting wallet and engage eyes and brain.

 

If I see a pipeline job I always see what size they ae using If it's the right size I go back when they aare clearing up and .....

 

PS how are you going to carry a 6" mortar and not get noticed? Smokin' gun more like stinkin' gun the SMELL of a used mortar could be traced without a dog!

Posted

Many people over the world want a DIY option because they are not locally permitted to buy the retail option! If you make a DOY laminate tube be very careful that your GRP skills are adequate. Well made mortars will be much stronger than ones made by inexperienced people. so while 4mm night be firn for a pro mortar your laminating must be of good quality to match the strength/weight/thickness of a commercial tube.

 

With the integral plug GRP tubes are cheap and good value, they are also one of the safer options.

Posted (edited)
PS how are you going to carry a 6" mortar and not get noticed? Smokin' gun more like stinkin' gun the SMELL of a used mortar could be traced without a dog!

 

I dont get it. :huh: why would I carry it?

Edited by zero2rule
Posted

Im not a pro but I have some lamination skills, I have done some fiberglassing in the past

 

Many people over the world want a DIY option because they are not locally permitted to buy the retail option!

 

True!

 

I always shoot my shells from a ditch or behind some barrier, for extra caution, even with HDPE mortars. I probably do some testing before using homemade FG mortars for real event.

Posted (edited)
I never gave this subject that much thought... all these posts make me think i may be doing something wrong. I have just been using pvc plumbing pipe from home depot they sell it in 2ft sections. I dug holes in my back yard, capped the bottoms of the pipes, and burried them so the tops are just above ground level. I figured the earth will help them hold pressure. As a teenager I used this method for launching cement filled soda cans across the neighborhood at a 45 degree angle. Im sure im not the only person to consider pvc and you guys must have a reason for not using it... can someone give me a clue on what is wrong with pvc. I havent launched anything larger than 3" but soon i will be moving on to 4". If pvc is dangerous a heads up would be cool. thanks lol. Edited by PoorBoy
Posted

It is dangerous.

 

The danger comes in it's failure method. Fiber glass feathers and stops pretty quickly. HDPE turns into a banana and says in one or two pieces. Steel usually just splits, though it should ALWAYS be buried. PVC shatters into many small pieces. Think shrapnel. There is a legend that it doesn't show up on x-ray, although that is not true, I'd prefer not to find out first hand.

 

In larger sizes, the walls be proportionally weaker in comparison to the forces exerted by lift. I'm not going to sit here and preach, because I'm guilty of this myself. Burying it helps, and barricading it helps, but I still keep away from it. It's not worth it. I just don't think it's strong enough for repeated firings of larger shells.

Posted
Paper, GRP, carbon fibre, and HDPE tubes are professionally acceptable in the UK. Paper is cheap, the rest more expensive. They are accepted because they do the job safely and if they fail they fail as softly as possible. Paper falis to a confetti like mass, reinforced plastic tends to stay as a few pieces. HDPE stretches then bursts. PVC on the other hand explodes with the shell into thousands of sharp pieces which fly like shrapnel or like a grenade. Buried any tube is protected, but buried in what! Soft ground will absorb a blast but gravel turns into bullets. A friend of mine had a 3" mortar supported by a heap of stones and a stone the size of a house brick went through is car windscreen 100 metres away when he had a cato. SO use soft sand, or good soft growing soil, do not use gravel or bricks or rocks to hold a mortar up.
Posted
thanks guys, yea i actualy dug a hole in my yard. Its all black dirt with white sand. I apreciate the heads up, maybe i shouldn't fire a 4 in shell from pvc. I haven't had a cato in a tube yet so i have been lucky... that could be pretty nasty.
Posted

If you have a cato in a PVC tube you may well be in pain and in hospital while they pull out the dirty bits of plastic, hoping that the accident doesn't bring the police to your bedside.

 

The less your activities stand up to inspection, the more safely you must work so that no-one has need to investigate you.

Posted
A friend of mine had a 3" mortar supported by a heap of stones and a stone the size of a house brick went through is car windscreen 100 metres away when he had a cato.

 

We are talking about a fireworks shell and not a 3" military mortar round, right?

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