20 replies to this topic

[Ritual33]

Hey guys,

I coulnd't find a topic on this already so I thought I'd start one myself. Heres my question to start the topic off.

Where can I find of these to buy, it would need to be a solid design that can withstand alot of pressure. I've found comet presses on wolterpyrotools but £100+ is a little much for a simple tool to press BP with.

A simple-ish way to make one of these myself. I don't mind small projects but I'm a busy guy and would prefer to buy one to be honest.

If I don't find any other options I'll probably end up buying up the biggest comet press wolterpyrotools do.

How does everyone press there pucks?

Regards,
Drew

[Creepin_pyro]

I don't have a press myself, but Dan Williams' site has a nice tutorial on making the things. You're probably not going to be able to find one to buy other than from Wolter, unless you find someone willing to machine/cast one for you... I've not seen them for sale anywhere else, apart from one which was one Ebay a while back...

http://www.pyrotechn.../powderdie.html

[Ritual33]

I brought a nice 10 ton sealey press for £175 including delivery the other day, first time I've used or seen one, hope it's not too big! I may well just buy the super-cool wolterpyrotool comet press.

If anybody else has any ideas please let me know.

Regards,
Drew

[phildunford]

I think there is a lot of overkill in these things...

All you need is a tube and a rammer. I just use a wooden disk with an aluminium plate on the end and press against a flat plate in my press (using a jack). The issue is, what should you make the tube out of, something non-shatter seems to be the general agreement. My thought is that if a quantity of compressed BP went off that close to me, the material would be irrelevant as I would not know much about it!

In the BP factories they used to just put the loose powder between plates and pressed the stack, the surplus just fell out at he edges - that way no tube was required - don't know if that would work on a small scale though...

[Mortartube]

I use HDPE yellow gas pipe, the sort often used for 2" Mortars. The walls are very thick and will withstand lots of pressing, it's also shatterproof. I have seen a tube that a 2" Spanish maroon went off in, and it just looks as though a dog chewed it. No fragments.

[Ritual33]

You know where I can grab one of these? Also what would I use as a rammer? Money is not such a big deal but paying £100 plus for something that I'll use every now and then seems as bit of a waist.

Drew

[Anders Greenman]

I've made one myself. They are very simple. Just find some sharp edged sand, polyester resin and a strong (preferable HDPE) tube. Mix the sand and the polyester and cast it into the tube (wich is greased to make the cast let go). Cast two pieces. An end plug and a piston. Check out Dan Williams site for more info.

[Ritual33]

The idea sounds good but I don't know where to get the resin from, if i didnt I would definatly make one of these because they sound pretty easy.

[Frozentech]

You know where I can grab one of these? Also what would I use as a rammer? Money is not such a big deal but paying £100 plus for something that I'll use every now and then seems as bit of a waist.

Drew

I just bought a couple pieces of 3" diameter aluminum rod from onlinemetals.com as pistons , and I use heavy3" PVC conduit ( the kind with an aluminum sleeve that threads on to it) as the cylinder . Total investment, about $12 US as I recall.

[phildunford]

Can anyone explain to me why Dan (who I greatly respect) goes to all this trouble to make a rammer?
Its under compression and a round piece of wood works fine! I cover the end with aluminium sheet to make it smooth and to stop the damp powder soaking into the wood - cheap as chips, simple, available - why be more complicated?

for the press I use a frame of 4x2 timber held together with 10mm studding and bolts. A two tonne car bottle jack (about £10) provides enough pressure to compress 1 1/2" pucks to the correct density.

Total cost (even if you bought all the bits - check the local skips!) probably less than £30

[BigG]

Can anyone explain to me why Dan (who I greatly respect) goes to all this trouble to make a rammer?
Its under compression and a round piece of wood works fine! I cover the end with aluminium sheet to make it smooth and to stop the damp powder soaking into the wood - cheap as chips, simple, available - why be more complicated?

for the press I use a frame of 4x2 timber held together with 10mm studding and bolts. A two tonne car bottle jack (about £10) provides enough pressure to compress 1 1/2" pucks to the correct density.

Total cost (even if you bought all the bits - check the local skips!) probably less than £30

To a degree you are correct. I think you can make a fairly ok corned BP with the method mentioned. However, if you want to compete with commercial quality BP, you will discover that you will need to start at about 10 ton to get a comparable performance. Some of the hobbyists in the USA make amazing BP. You have to see it in tests to believe.

I will leave it at that. There were some posts about this in the relevant BP thread. Let’s stick to the topic here.

[phildunford]

Sorry if you think this is off topic big, but the guy was asking about what rammer he needs to make BP and looking like he was ready to spend alot more money than he needed to on his set-up.

My setup presses 1 1/2" pucks to a measured density of 1.7 g/cc. Sure, it could not do big pucks but 1.7g/cc is the same if you get it from a 1 tonne press or a 100 tonne press.

Will shut up now...

[Mortartube]

Ritual33, polyester resin is used for glass fibre, you can get a small glassfibre kit in many DIY places or if you have a specialist works nearby they will no doubt sell you some at a good price.

[phildunford]

Halfords as well, for car body repairs - they do both clear resin for use with fibreglass and 'car body filler' which might also work.

[Ritual33]

Excellent, I have a halfords just down the road, I'll go take a look sometime (press hasnt arrived yet, no rush). Question: How in the world do you measure the density of the powder? Do you use somekind of physical method or is it simply mathematics?

BigG: When you mean "start" at 10 tonne, do you mean that some would even go beyond this amount of pressure? Do I need to get a bigger press eventually? (sealey 10 tonne).

Frozentech: How well machined are these rods? Would you recommend them over the resin cylinders I could make?

Regards,
Drew