HMS Bellona 1760 by SJSoane - Scale 1:64 - English 74-gun - as designed

[Siggi52]

Hello Mark,

 

for melting the pewter I would use a propane torch. You need only 270-300°C, that is't so much. I had a look where I buy my articles for casting and there the sell even a melting gear with esbit. I have an LEE "Precision Melter" Electric Pot with thermostat control. http://www.trackofthewolf.com/List/Item.aspx/1194/1 May be you have a shop near by who sells something like that.

 

The small pellets in the picture are the Bismuth pellets. You should use 2% of them. I would use it, it makes the pewter harder and it should better forming. It's for the cannons may be not so necessary, but for buttons it is. 

 

 

Because the rubber forms are soft, if you press to hard the cannons will not be round. Mostly I use two small boards to prevent this, or cover the form with plaster as you could see in the picture.

 

 

That is also what artist do with there forms. Before you look into your rubber form( with the master still inside), you cut away every part that hinders you to get it out of the plaster. Then you made, in this case, a two part plaster form. But if the rubber is hard enough, I think, it would't be necessary. 

 

The air vents I cut also after I have made the form.

 

I wisch you good luck,

Siggi

 

 

[EdT]

Hi Mark,

 

I took a short break from YA this morning to take a few pictures for you.  It only took a few minutes - once I found the melting pot.  I use this hotplate for boiling water for wood bending.  I plug it into an automatic 60-minute shutoff timer so I don't leave it on by mistake when I wander off.

 

The first picture shows the simple pot - still full of cold metal - on the hot plate.  I got rid of the arm so I would not bump into it and spill the metal.  I use channel-locks to pour.   I like the hot plate because you can hold the metal at a good temperature and you also have a place to toss the sprues as you cut them off.  Both of these things are convenient if you are doing many pours in a session.

 

 

The next picture shows the two part RTV molds in the Centricast disk.  They get bolted together for casting.  There are a lot of parts for the machine - to allow molds to be cast as well as castings.  Note the ring around the mold joint.  Some of these molds have been used for 100- 200 pours this one probably a few dozen.

 

 

Finally, a few castings to show what can be done with RTV in the way of complex castings.   They do not come out of the mold painted.  Many of the figures have cast parts added after casting and quite a number are multiple parts.

 

 

Happy casting.

 

Ed

 

 

 

 

 

 

[Maury S]

Ed, So you paint soldiers in your spare time?   Love the process lessons.

Maury

[SJSoane]

 

Ed, Wow, I had a hint from various comments you have made over time that you crafted miniature soldiers. It is really nice to see them!

 

I will try the hot plate first before investing in an electric melting pot. I have already sneaked the hot plate out of the kitchen for boiling wood; it will never be missed!

 

Best wishes,

 

Mark

[SJSoane]

 

Siggi,

 

I think I will need the plaster outer form. The first cast definitely squeezed the barrel into an oblong rather than a circle, even though I clamped the mould between two pieces of plywood. I thank you so much for your advice and guidance.

 

Mark

[SJSoane]

 

Hi everyone,

 

While waiting for my newer MicroMark RTV rubber, I started on the carriages.

 

I used double sided tape to hold the blanks onto the mill table, and milled them to shape including the rabbets for the axles. I then cut the individual blanks on the table saw, with the mitre set to 2 degrees on each side for the correct convergence of the carriage.

 

I am also showing a jig for cutting the curved lower edge, using a piloted bit on my router table.

 

Best wishes,

 

Mark

[SJSoane]

 

Hi everyone,

 

I have been working away slowly at the cannon and carriages. I successfully made the mould for the cannon, but have failed so far in my efforts to melt the pewter. I tried melting it on a hot plate, with no success, and am now looking at lead melting furnaces (having a propane torch is not an option for me). Does anyone have experience with a melting furnace?

 

So in the meantime, I continue to make parts for the carriages. 28 guns on the gundeck has an entirely new meaning, as I make all of the parts. One construction method of note: I was not able to cut off trucks from the blank by using the parting tool on the lathe, because it was too flexible. So I moved to the tablesaw with the sliding table and a flip-down stop, which allows me to cut each on at the exact same width. I had to stick the blank to a square extension with double sided tape, so I could cut trucks off all the way to the end of the blank.

 

Mark

[druxey]

Excuse the question, but why is a propane torch not an option for you? I've found this, with a cast iron ladle, the most convenient way of melting and pouring pewter.

 

Lovely work, Mark.

[SJSoane]

 

Hi druxey,

 

I have restrictions on fuel tanks in my workplace, and can use only butane. I can probably wait for the summer when I could do this outdoors, but I am getting impatient to see if the mould works!

 

I learned more today about why this is proving challenging. I purchased the pewter from a local jewelry supply house, and found out today that it consists of 92% tin and 2% antinomy. It's melting point is 525-650 degrees which is why my hot plate did not even come close to melting this. I just re-read the information about the rubber mould material, and it says that unusually hot materials will degrade the mould more quickly. So I am starting to think that I need to find another supply of metal that will melt at a lower temperature, easing the degradation of the mould and perhaps melting on the hot plate as Ed suggested.

 

Druxey, do you know if trying resin in my mould to see how it works, will make subsequent pouring of metal in the same mould more difficult?

 

Ah, the fun of learning new skills!

 

Mark

[druxey]

I've no idea if resin will affect an RTV  mould if you want to subsequently use it for metal. I use Micro Mark's lead-free pewter, MP 575F. No problem with propane, which I do in my home workshop. I've no idea to what temperature butane will heat. The propane torch I use is a Canadian Tire one that has non-refillable cylinders. I'm sure that the equivalent item is available in the U.S.

[Siggi52]

Hello Mark,

 

what is that for a pewter with a melting point between 525 and 650K! Pewter has a melting point by 505,08K (231,93°C). Lead has a melting point by 600,61K (327,43°C). So, when your alloy is 92% pewter, 2% antimony (has the same effect as bismuth), what is the rest? Mostly lead.

 

I would say, go to your local muzzleloader supplier or the internet and buy you a melting station. They are not so expensive, it must not be the best one and you have always similar temperatures. Look for one that has the sprout a little higher, so that you could hold your mould under it. You could work also continually and have not to look in which hand to held the torch and the ladle or where to lay it down, because it is all hot! This are not the only cannons you have to cast. When you are ready, you could sell the station as antic at eBay

 

Regards,

Siggi

[EdT]

Resin should not effect an RTV mold.  Very hot metal will affect it over time.  I believe it will make it hard and  brittle.  I began using lower temperature metals to avoid this problem and because its safer to handle, but I was looking for life over 100's of pours on very intricate molds more susceptable to damage.  Lo temp alloys or blends that include may be more expensive, not sure, I believe $15-20 per pound?.  You usually pay a premium at Micromark.

 

I am surprised your hot plate won't melt the pewter.  I have used this method for many years on various metals.  I prefer the hot plate to the torch for safety reasons and also because it is easier to hold the metal at a good pouring temperature.  This may be more critical on complex molds than for use on the relatively simple cannon barrels.

 

I will do some temperature tests with my hotplate and let you know what temp I can achieve.

 

Ed

[EdT]

Mark,

 

Some quick hotplate test results using a surface pyrometer:

 

1 lb 10 oz of metal at 60 deg F

 

200 F at 5 minutes - began to melt at 250F   Hot Plate surface 775 deg F

 

400F at 11 minutes - I would pour at this point -  then cut back the hot plate to hold it.

 

500 F at 13 minutes

 

600 F at 15 minutes  Hot plate auto shutoff - probably a hi temp safety feature

 

650 F at 17 minutes - should hold at this temp and I think would go higher - probably over 700F.

 

This is obviously a lower melting point alloy and not pewter, but the heat up rate should not be different - only the melting point.

 

This suggests you should be melting a similar weight of metal in around 15- 20 minutes.  You probably only need to melt a few ounces at a time, so that would go much faster.

 

Of course, it could be the hot plate.

 

Hope this helps.

 

Ed

[SJSoane]

 

Thanks, Ed, this is very helpful. I think it might be the hotplate. I "borrowed" my wife's hotplate that looks like something from the 60s.....

[druxey]

Maybe you weren't pedalliing fast enough, Mark....

[SJSoane]

Hi everyone,

 

I purchased something to melt my pewter; will try tomorrow and see what happens. Druxey, I wasn't peddling, I was rubbing sticks together very vigorously...

 

Meanwhile, I kept working on carriages. I learned a few helpful techniques.

 

The photos of the saw sled are showing how I have a flip-up stop to cut each truck to the same width. The stop has to flip up after setting the blank against it, so the cut off part doesn't bind against the sawblade after it is cut. But the parts fly away if not retained in some way. I finally hit on putting double sided tape on another small piece of wood; I push this up against the blank after flipping up the stop and just before cutting. When cut, both the truck and the small piece of wood gently slide aside, but don't fly. Ignore the snake on the wall in the background in the 3rd photo; it has nothing to do with where the loose pieces fly, I keep telling myself....

 

The photos of the lathe are showing a nifty setup for cutting the rear axles. The cylinder is centered in a rectangular but not square blank, and so a four jaw chuck is needed to hold the blank. Rather than trial and error getting the center of the cylinder aligned with the center of the lathe, I set it up with a dial indicator. I used the Sherline quick change tool post boring head holder, to mount my dial indicator to the Y table. I could then swing the opposite sides of each side of the blank towards the indicator, measure the discrepancy between the two sides, and then dial in the jaws until they were equally distant from the center of the lathe.

 

The last image is showing an A2ZCorp attachment for the Sherline. A shaft goes through the center of the lathe head, forming a stop so that each blank can be inserted exactly the same distance into the chuck for repetitive cutting.

 

All for now; thinking about melting pewter tomorrow at last.

 

Mark

 

 

 

Edited February 28, 2015 by SJSoane

[dvm27]

I believe the Nobel Prize is in order for figuring out how to keep small sliced pieces from flying off the saw table! Also love that Sherline accessory. Does it have a special name?

[druxey]

There's your problem, Mark: confusing pedalling (as in bicycling) with peddling (selling cheap stuff door to door). Sorry. Couldn't resist that one!

[SJSoane]

 

 

Druxey, so that explains why neither neither rubbing sticks nor peddling got me very far....;-)

 

Greg, thanks for the Nobel prize. It is still a little fiddly to renew the double sided tape on the end of the small stabilizer piece of wood every 6 cuts or so, but it reliably keeps the cutoff on the table and out of the way of the sawblade after the cut. I once got lazy and did not renew it even when it was no longer sticking, and sure enough the snake on the wall ate my flying piece.

 

I wonder what archaeologists in the distant future will make of all of the tiny abandoned machined pieces found lying around in the remains of our houses.

 

I purchased the lathe depth stop from a small firm in Denver. It works really well. I also bought the additional end pieces, so I could stop very small parts. You can find it at:

 

http://www.a2zcorp.us/store/category.asp?Cguid={E7EADB42-05AE-43E9-965E-4A4011A47E6A}&Category=LatheDepthStop:Sherline

 

Best wishes,

 

Mark

[SJSoane]

 

I finished up the rear axles and trucks, except for drilling the retaining pins and rear eyebolt.

 

I learned something interesting about much repetitive use of the four jaw chuck.  I assumed that as long as I loosened and tightened the same adjacent jaws when changing blanks, the setting would always hold. But over time, the setting slipped and the cylinder was no longer centered. I had to throw away a number of pieces after I realized what had happened. So I had to check every five or so and readjust. Does anyone know a trick for tightening and loosening a four jaw chuck to keep the settings over a large number of pieces?

 

I had backed off one side while tightening the opposite to center the piece, but then I tightened both towards the center before cutting. After time, one of the jaws definitely felt like it was backing off. I wonder if I should have left one backed off, opposite the one I tightened and loosened while changing blanks?

 

 

Mark

[Siggi52]

Hello Mark,

 

life would't be so interesting if there where no problems to solve. Your parts are looking great. I think, I turned mine, "at the great lathe" and made then the center parts, all by hand! I did't have such nice machines then you have. The cannons where my test if I could do such small things. Since I have to wear glasses, it's not so easy for me and for these small things I have to wear extra strong glasses! 

 

Because of the flying parts in your shop. I think I have one of these black holes in my cellar that sucks up parts or whole universes. Parts disappears before they hit the ground! It's very mysterious. May be they are now somewhere behind the Mars ;-)

 

Best Regards,

Siggi

[SJSoane]

 

Siggi,

 

You know, I never thought to look behind Mars; all of our lost pieces might be hiding there!

 

Mark

[dgbot]

On my 4 jaw chuck I would mark the two jaws that I moved. After the part was inserted I would then tighten then. As for checking I would mark the measurement of my cutting tool and bring it to the piece. If the part is large enough I would mark the center with a dead center in the tail stock. This usually did the trick.

David B

[michael mott]

 

Does anyone know a trick for tightening and loosening a four jaw chuck to keep the settings over a large number of pieces?

I'm thinking about it.

 

The wheel cutting trick is a nice one.

 

Michael

[SJSoane]

 

David, nice idea about checking with the dead center. That would be much faster than my approach. I'll try that on the final 14 front axles today.

 

Michael, you are a master machinist, including holding to tolerances I can only imagine doing; I look forward to your thoughts.

 

Mark

[bizibilder]

I wouldn't bother with the four jaw at all - make a thin walled tube from brass that will just take the rectangular pieces within itself.  Cut longitudinally through the tube wall in one place (use a hacksaw and files as you need to be able to close the tube slightly).  Put the tube in the three jaw (or, preferably, a collet) and tighten up.  The pieces will be held dead centre every time.

 

That is how clockmakers hold square or rectangular stock for machining.

 

Another trick is to get some plastic tubing (unused fuel tube or windscreen washer tube for motor cars) and cut 1" lengths of them.  Slice a strip out of them longitudinally so they can "close up" and use them in the three jaw to hold round timber for masts and spars.  Result is a secure hold and no marks at all on the timber.

Edited March 1, 2015 by bizibilder

[SJSoane]

 

Bizibilder, those are both very clever ideas. So in the first one, do you close up the brass tube all the way to the shape of the rectangle? Or is it enough that it gets to an oblong shape?

 

Mark

[druxey]

A variant of this technique that I've used is to take a piece of round stock. Drill out one end, then shape the hole to square or oblong as needed and put it in the collet or chuck.

[steven sturgis]

I just came upon your build it is fascinating and I can only say wow.

Edited March 7, 2015 by steven sturgis

[SJSoane]

Here are all of the main wooden parts for 28 guns for the gundeck, 32 pound behemoths. I still need to make the stools and quoins, and drill a few more ancillary holes for attaching metal parts. And then there are the metal parts. But it is nice to have the main carriage wooden parts all ready to go.

 

 

Thank you Stephen for your nice comment. A work long in progress!

 

Druxey, very clever idea using round stock with a square hole. That would control both location on axis and depth. Next time I have to make this many pieces, I will try that. I have 46 more guns to go after finishing the guns for the gundeck....

 

I got the pewter melted at last, only to have my mould split apart during the pour. So back to more work on the mould....

 

Mark