No Weld Pipe Jets (Again)

[vturbine]

I keep thinking about the problems of those without welders. Mike has a fabulous pair of pipe fitting designs -- The Ugly Stick and Pipewood here:

viewtopic.php?t=1643

The only problem is that two of the reducers ( 2x1, and 2x3/4) are hard to find locally, and builders in metric system countries have an even harder time finding anything close.

I did find an internet source for the fittings for US builders here:

http://www.plumbingfittingsdirect.com/black1/60600.html

For builders without access, Mike has suggested substituting 2" pipe caps instead of the reducers and drilling and tapping for 1" and 3/4". But you need the taps and a good sized tap wrench for that.

I was trying to think of alternatives as well, and I thought I'd toss out an idea. Don't know if it's any good....

The main problem with trying to build simple weldless pulsejets is you need some way to attach a pipe inlet or outlet or a CC or all 3 to a flat surface, and this is where welding is usually required. Likewise in snorkel jam jars we need a flat end on the bottom of the CC, and a pipe entry at the other. Both usually require welding on a cylindrical CC.

To try to solve this need for ends and flat connections to small pipe, I was thinking that if we used two pipe floor flanges connected back to back with 4 long bolts through the supplied mounting holes, we could trap a section of wide diameter CC pipe or tube between them, and tighten to compress it in place. Then we could attach smaller pipes at either end. Or in the case of a snorkel, plug one end with a pipe plug.

floorflange.jpg (7.63 KiB) Viewed 10244 times

So, as an example, building Mike's Ugly Stick, maybe use two 1" pipe floor flanges, with a section of 2" pipe trapped between them. Or a section of 2.3" dia. fence post tubing -- I think it will fit in there as well.

Then for the inlet end that needs 3/4" pipe, use a 1" to 3/4" reducer (these are common) to fit the inlet to the floor flange. The other end fits the designed 1" pipe already.

The nice thing about this system, is that the CC can be pretty variable in size, depending on your available stock (and the design requirements). So it should be possible to accommodate metric sizes easily. (I sure hope floor flanges are common outside of the US). Be sure to use the proportions Mike has worked out if sizes are varied slightly -- as in the case of a metric version.

It might also be possible to have the bolts run inside the CC, rather than outside it -- though I wonder how badly this will affect running.

The problems I can see with this scheme are that if bolts run outside of the CC, differential expansion during running may put too much pressure on the CC, or flanges. That may not happen if the bolts heat up fairly quickly and expand as well, and I'm guessing they will. Keeping things tight but not overly so may be a problem -- then again, maybe not.

Packing, if necessary, might consist of muffler sealant or furnace cement. Floor flanges are usually castings, and not always very true. You may have to file the flange or CC tube to make a good fit. Some floor flanges aren't solid, but webbed on the bottom, so filing or grinding with a Dremel type tool may make fitting more of a job.

Well hope that helps. This is all presented in the spirit of experimentation and, of course, no guarantees it is even a good idea.

[metiz]

vturbine, check out this thread. might be worth to start posting again in here. GRIM made a very nice bolted up pulse-jet engine - mine failed misserably

viewtopic.php?f=3&t=5003&start=15

[PyroJoe]

FWIW
Like the Kazoo for a no weld engine. Keep thinking there should be a easy way to "hard fold" it and maintain the gap at the narrow portion behind the CC. Maybe a pliable soaked piece of wood the correct thickness, or strap of lead that can be placed internally while folding, then baked out after the fold is complete. Next time I obtain a longish section of 4" drive shaft pipe, will give it a try.

[vturbine]

Well pitch is a traditional support for chasing/metal working that can be melted out. Dates back at least to Cellini's time: Here's some recipes:

http://www.repoussetools.com/pitch.htm

And here's a definition quote from that site:

WHAT IS PITCH?

Pitch is one of those ancient "basic" substances. Most pitch was used for caulking boats and ships was made from tree sap, pine resin or "pine tar". In metalwork it is the pliable backing that supports thin plate for repousse'.

Pitch is made a variety of ways. Modern repousse pitch is made of a mixture of things including pine resin or asphalt tar, waxes and fillers like fine clay and sand. The more and coarser the clay or sand fill the stiffer the pitch. The more beeswax the softer the pitch, other waxes can harden the pitch. The heavier the work or the finer the detail the stiffer the pitch needs to be. For some work in steel lead was used. Today soft zinc or tin is a better choice.

For heavy plate some smiths use compacted gravel, or an open support (no backing).

In standard work the pitch is melted and poured against the metal in a mold box or pitch bowl. Then the metal is worked with various small hammers and punches the pitch supporting the work but moving out of the way where needed. At some point the metal may become work hardened and need to be annealed. The pitch is heated and removed, the metal heated to anneal then the pitch molded to the metal again. This provides a new flat back surface and better support for the metal. In some case the pitch is poured on the opposite side in this step so that the metal can be worked from the front. Work from the front is called "chasing".

Pitch is not necessarily used in armour work, even when repousse is involved. Work in steel is often done against wood forms and lead as noted above. In armour it would only be used for fine decoration, the bulk of the forming done by other methods.

[PyroJoe]

He also includes his own recipes which are often more useful than versions derived from general text books.
Have seen the linseed oil (1 part), turpentine(2 parts) mixes mentioned by the ancients.


Referenced from the site:


ARTISTS and JEWELERS PITCH RECIPES
From vicopper - anvilfire.com


1. 6 parts chaser's pitch, 8 parts plaster of Paris or brick dust, 1 part linseed oil or tallow. Source: Metalworking Techniques for Craftsmen by Oppi Untracht.


2. 4 parts roofing tar (the kind roofers melt in tar kettles), 3 parts pumice powder, 1 part turpentine, 1 part linseed oil. Melt tar in pan, stir in turps, add pumice. Let a small amount cool and adjust amount of linseed oil to get desired consistency. Source: My own recipe.


3. Equal parts of beeswax and plaster of Paris. This is good for very thin, fully annealed non-ferrous metal worked shallowly. Again, my recipe.

When mixing any of the recipes for pitch, remember that some or all of the materials may be flammable and take appropriate precautions with regard to open flame, etc. It's a good idea to keep in mind that hot pitch sticks to you and keeps on burning much longer than is bearable, too.

For steel or relatively thick (greater than 16 ga.) non-ferrous metal, you want the pitch to be stiffer than you would for softer or thinner metals. The stiffer the pitch is, the sharper the detail you can get, because it doesn't distribute the force of the punch as much as softer pitch does. For preliminary bumping of the gross forms, I use a softer pitch, and then switch to a stiffer consistency for detail work or chasing from the front. Sometimes, depending on the nature of the project, the initial bumping can be done over a sand or shotbag, or over a depression in a wood block or stump. If it is important that the perimeter of the piece be very exact, it's sometimes easiest to leave it large and cut it to the final contour after all the repousse'/chasing is done.

Remember that whatever surface is present on the end of the punch or hammer is going to be impressed into your work. If you want a smooth surface, polish your tools to a shine. Conversely, you can texture areas by using tools with pitted, grooved or checkered faces. Sharp tools run the risk of cutting the metal, so it's a good idea to radius the corners of tools. Oppi Untracht's book mentioned above has some good and useful information on the techniques involved, as do many other jewelry making books.

[vturbine]

Joe, when you say hard fold it, do you mean bending it around in a half circle to make the inlet point in the same direction as the outlet?

[PyroJoe]

Yes, pardon the quirky terminology. Not sure what size radius could be created. Also the crushed planes(of intake and exhaust) would need to be parallel instead of 90 degree. Thanks for the pitch suggestion, it may make the folding technique much simpler to accomplish.

[vturbine]

Kazoowood?

[vturbine]

Lockzoo?

[PyroJoe]

Locky Kazoo:
viewtopic.php?f=3&t=262

ha.

[vturbine]

I like that this topic opened up beyond pipe fitting no-welders, since maybe something could come of new no-weld suggestions.

But maybe I should change the thread title from no-weld pipe jets to no-weld pulse jet ideas?

[Mike Everman]

Ah, Locky Kazoo, my first jet. I think I posted a spreadsheet that does the area conversions, and lengths per the Snecma style drawing from Kentfield's paper. Need a good hydraulic press to eliminate the welding on this one. I tried making instructions for using lumber and a car jack, but I completely destroyed my car jack making a motor! ha ha I kept cranking and the jet wasn't squishing any more, and then I finally looked at the jack more closely, and it had been folding like a tent for the last ten cranks.

[vturbine]

But did you ever bend the tail around to parallel the intake? I couldn't find that in the thread.

What is a Lockwood? I thought they were a linear bent into that fishook shape? Or is it just a linear pipejet.

(There's probably a set of definitions for all the valveless types set out clear as day in the Beginners Read THIS Here Before You Ask Dumb Questions Elsewhere section.) That I naturally missed

[vturbine]

You kinda got me wondering what would happen if I put a piece of tube into my slip roll and, uh, cranked it, first with just some pressure on the entry rolls, to get the flat started, then maybe other passes with the third roll doing some of the bending work. Maybe do the transitions by, uh, other means.

[Jutte]

Has anyone thought of bolting together stainless steel sinks?( hand wash bowl basins )
to make the CC and bolt on the intake and tail pipe to that?