82 replies to this topic

[Sleipner]

and im not using a die on the plate under maybe that is effecting the weaving ?

Oh, hadn't noticed that. Yeah, that will definitely affect the weaving. If you have nothing guiding the thread, it will be laid at varying heights depending on where it happens to unroll it from the spool at a particular moment.

[Svimmer]

Oh, hadn't noticed that. Yeah, that will definitely affect the weaving. If you have nothing guiding the thread, it will be laid at varying heights depending on where it happens to unroll it from the spool at a particular moment.

 

Thats the next fix for the machine

[Svimmer]

http://bldr.no/BZx

 

http://bldr.no/BZy

 

wow i have a long way to go on this machine. have done alot off tests now and cant get the second layer nice. the first layer looks good.

 

The second plate have a die now but the hole through it is 8mm and the pipe is 6mm inside i think that a die with 2.5 or 3mm on the second plate and 2mm on the first plate might do the trick.

Edited by Svimmer, 25 February 2018 - 06:39 PM.

[Simoski]

Howsit ( thats how we greet each other in South Africa )

 

Keep up the good work Sleipner.

 

as for the composition, go with 5grams sugar , 5 grams nitrate for a slow fuse. 2 grams sugar, 5 grams nitrate for a fast fuse...

 

or somewhere there about,

 

less fuel  = faster burn rate

more fuel = slower burn rate.

 

I would remove the charcoal so it does not spit fire, or mill it longer, or use balsa or hemp charcoal, for a finer charcoal that is completely consumed.

[Svimmer]

Howsit ( thats how we greet each other in South Africa )

 

Keep up the good work Sleipner.

 

as for the composition, go with 5grams sugar , 5 grams nitrate for a slow fuse. 2 grams sugar, 5 grams nitrate for a fast fuse...

 

or somewhere there about,

 

less fuel  = faster burn rate

more fuel = slower burn rate.

 

I would remove the charcoal so it does not spit fire, or mill it longer, or use balsa or hemp charcoal, for a finer charcoal that is completely consumed.

 

Thanks for the tip. That was alot easier to granulate aswell so the powder flows nice.

[Svimmer]

i tried to coat the fuse with styrofoam but that did not work very well.

[Sleipner]

i tried to coat the fuse with styrofoam but that did not work very well.

Nitrocellulose lacquer is usually used to coat visco. If you can't buy it (getting difficult to find depending on where you are), the make shift alternative is to make it yourself from dissolving ping pong balls in acetone). These days it is often used in treating vintage wooden things (guitars etc).

[Svimmer]

http://bldr.no/Ba7

 

right after coating.

[Svimmer]

I also have a problem with the threads not collecting the powder as it should. there is coming a pile of powder under the plates.

 

 

 

Edit:

 

Could it be that the powder die dosen't have a V enough ? so the powder dosen't get correctly into the threads ?

Edited by Svimmer, 27 February 2018 - 08:57 PM.

[Simoski]

I've seen machines spinning at 400 rpm, its probably the number of turns of the thread per cm.

[Sleipner]

 

I also have a problem with the threads not collecting the powder as it should. there is coming a pile of powder under the plates.

 

 

 

Edit:

 

Could it be that the powder die dosen't have a V enough ? so the powder dosen't get correctly into the threads ?

 

 

You're making a lot of fuse it seems

 

I agree with @Simoski about the turns per cm being the cause of the spilling of powder. In the file I uploaded with all the design parameters, I calculated them for a "coverage" of 80% which I picked from looking at existing visco fuse. Looking at your fuse I think you have a fair bit lower coverage, giving holes that the powder can fall out of. I'd say you need to increase the turns/cm of the first plate a bit, and the turns/cm of the second plate a fairly significant amount. You could also get thicker thread if you have some.

[Svimmer]

 

You're making a lot of fuse it seems

 

I agree with @Simoski about the turns per cm being the cause of the spilling of powder. In the file I uploaded with all the design parameters, I calculated them for a "coverage" of 80% which I picked from looking at existing visco fuse. Looking at your fuse I think you have a fair bit lower coverage, giving holes that the powder can fall out of. I'd say you need to increase the turns/cm of the first plate a bit, and the turns/cm of the second plate a fairly significant amount. You could also get thicker thread if you have some.

 

The top plate spins 360 rpm. it might be that the collector drum is to small so it pulls the fuse way to fast. it makes fuse alot faster then other machines with engines ive seen.

[MrB]

In the file I uploaded with all the design parameters,

 

For what ever reason, the file doesn't seem to be available anymore.

 

 

The top plate spins 360 rpm. it might be that the collector drum is to small so it pulls the fuse way to fast.

 

The actual RPM isn't THAT important. The ratio, of revolutions, in relation to fuse feed length, is. To increase coverage you need to either add more spools of thread, use thicker thread, or slow down the feed rate. Or a combination. Also, i know people have been "tuning" the fuse production using straight up sugar. It wont burn, but is pretty much as cheap as it can be, and you can tweak the machine until you get a result that looks like it will be serviceable, and start using BP at that point. A bonus of that is, no fire hazard while tweaking.

Edited by MrB, 28 February 2018 - 08:00 AM.

[Svimmer]

 

For what ever reason, the file doesn't seem to be available anymore.

 

 

 

The actual RPM isn't THAT important. The ratio, of revolutions, in relation to fuse feed length, is. To increase coverage you need to either add more spools of thread, use thicker thread, or slow down the feed rate. Or a combination. Also, i know people have been "tuning" the fuse production using straight up sugar. It wont burn, but is pretty much as cheap as it can be, and you can tweak the machine until you get a result that looks like it will be serviceable, and start using BP at that point. A bonus of that is, no fire hazard while tweaking.

Takk

[Sleipner]

 

For what ever reason, the file doesn't seem to be available anymore.

 

I could hardly find it myself (that part of this forum software isn't easy to get an overview of), but here is a direct link:

 

https://www.amateurp...ign-parameters/

 

 

I updated the file as per your suggestions so it should be easier to follow.

[Simoski]

Thanks Sleipner

Edited by Simoski, 01 March 2018 - 06:39 AM.

[Svimmer]

http://bldr.no/BaI

 

Another problem. either i need to find a way to get the fuse tighter so it wont have that problem or i need another coating device lol.

 

Edit:

 

Also the thread dosent burn up. when i used polyester it did but not with cotton.

 

Burn test

Edited by Svimmer, 01 March 2018 - 04:54 PM.

[Mumbles]

Soaking the string in nitrate, or making your BP mixture a bit more oxidizer rich can help to eliminate the smoldering cotton.  

[Svimmer]

http://bldr.no/Bbv

 

Ive done few tests now. Im going to make a new machine im pretty sure the problem is the pulley wheels is not 100% round so it spins uneven. and yes the secound disc is going to spin faster on the new machine.

[vendrite]

  What good looking fuse!   I hope this helps as a inspiration to all present and future fuse makers.