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

[SJSoane]

Hi Ed,

 

I read your Victory post on making the barrels. Very informative. How did you cut the cutters for the muzzle and pommel? I have blanks for the Sherline lathe, but I have never tried shaping one. Do I have to heat and quench?

 

Your Victory project is very impressive indeed, by the way. I am humbled by the number of ships you have built, all at the very highest standards.

 

Mark

[SJSoane]

Interesting that Michael and druxey at almost the same time wondered afresh about casting as the better way to go. In the spirit of full disclosure, and at the risk of high embarrassment showing my modeling failures, here are higher resolution photos of my casting failures, so you can see all its glorious detail.

 

I tried two moulds, the first has a funnel shaped pouring spout, as in David Antscherl's Fully Framed Model casting section. The second time, I tried a waisted-in pouring funnel like shown in an 18th century drawing on casting a barrel. I think this latter idea was a mistake, because you can see the metal was cooling before it fully filled the mould, as seen in the blackened cast barrel.

 

Notice also the discolored mould (with the funnel top). I used pewter purchased at a jewelry supply in Denver, and it seemed to have a lot of dross in it. It was not kind to the mould.

 

I put these away well over 2 years ago, and I see that the rubber moulds have already begun to break down in a few places (like at the button at the rear of the barrel).

 

If I chose to cast again, I think I would return to the Antscherl shaped funnel, increase the sizes of the vents, and try even more carefully to get a clean cut of the clay up to the master before pouring the first half of the rubber mould. I think I would also try the pewter from Micro-Mark, which seems to be tailored to model casting. Any thoughts?

 

Mark

 

 

 

 

 

[michael mott]

Hi Mark have you heard of Cerrobend it is a low melting point metal, I would think that it would be ideal for small parts like cannon. I have used this metal 50 years ago works well.

 

Michael

[SJSoane]

Hi Michael,

 

I was just looking at your trains on your thread! Very impressive.

I will look into Cerrobend. After putting the casting efforts away for a couple of years, I am starting to think that the metal I used was not the best.

 

Mark

[druxey]

I use the MicroMark lead-free pewter. As for all casting metals, you ned to skim off the dross before pouring. I can see that the urn-shaped opening might create a bottleneck/backup, allowing cooling to occur before complete filling of your mold.

 

If low melting point is an issue, there is always Wood's Metal - it flows at below the boiling point of water! I've no idea what blackening agent might work on it, though. Cerrosafe is a non-toxic alternative.

Edited November 12, 2018 by druxey

[allanyed]

Mark

One more option that you may want to consider.  I have never been able to cast the cannon with a mold made of two sides without a seam, no matter how careful and accurate the molds are made.  They have to be filed and finished which takes a lot of time and there is still the possibility of leaving filing and finishing marks on the surface.  I experimented and succeed using a one piece silicone rubber mold that eliminated the seam.  The barrels can be removed with little effort and no damage to the mold in my experience.   I tried both lead free pewter and casting resin.  Both worked well.   The only part that creates a problem are the trunnions which I added to the cast barrels separately as can be seen in the photo of the casting resin barrel.  

Just another idea you might want to consider.

[EdT]

Gaetan, I agree that your method is better for the reason you state - centering of the barrel bore - very difficult after turning the barrel.  Your method  also allows all the heavy turning to be done with the piece held at the large end - until the final turning of the pommel and parting off.  I would definitely recommend your method.  My Victory guns were the first turning project on my new Unimat ( in 1978).

 

I would probably cast these today.  Casting the guns in say, pewter, in an RTV mold would be easiest and the quality should be equal to turning.  The biggest problem I have had with casting in RTV - over 5000 military figures and artillery - is degassing the mold - especially in areas like the gun bores - I eventually resorted to a vacuum chamber and pump to remove bubbles from the molds before curing and a centrifugal caster to de-gas the metal - not something you would want to do for 100 or so casts - but for simple gun barrels careful brushing of the rubber over the pattern should suffice - plus of course, venting - if you go this route.  Turning every gun is not the best route - but with all our equipment we can't resist wanting to do it that way.  Have fun.

 

Ed

Edited November 12, 2018 by EdT

[druxey]

I agree that, with a cast gun, boring the barrel accurately is tricky. I made a molded fixture to hold the guns consistently vertical and centered in a machine vice so that the drill entered concentric to each gun.

[EdT]

More on casting.  The mold shown in you photos would be improved with a vent out of the bottom end - at the pommel.  This will cause the air to be forced out by that route and will allow the metal to flow through the mold taking some gas with it.  I would support Druxey's recommendation of lead-free pewter.  I used various blends of metals, from linotype metal to Cerrobend - but most of those cantain lead and I would not use those today - even though my painted figures have - some pure lead - have help up for up to 40 years under their acrylic paint.

 

Allan, I would love to hear and see more on your one-piece mold process.  Results look great.

 

Ed

[SJSoane]

Thanks, everyone, perhaps I will try casting one more time before turning to turning...

 

Allen, can you tell me a little more about your one piece casting method? Specifically:

 

1. what rubber mould brand did you use? I used Micro-Mark 1-to-1/ Rapid RTV Silicone, and it was surprisingly fragile. You can see how it broke out in the mould I showed earlier. Did you find something more durable?

 

2. Did you provide any vents for gasses, or is it not needed with such a simple form?

 

3. When you pour the metal, do you leave the rubber mould in its forming box so it doesn't distort?

 

4. Do you use the Micro Mark lead free pewter?

 

Thanks in advance for your help!

 

Mark

[EdT]

I would use 1 to 1 Rapid.  It held up for me with many pours and deeply undercut patterns.

[dvm27]

Mark - there is a nice video on making a form tool for the cascabel of a cannon on You Tube:

https://www.youtube.com/watch?v=N3-XFfc82ew

In fact, all of his videos (including turning a cannon barrel) are mesmerizing.

[SJSoane]

Hi Greg, thanks, that was exceptionally informative. I also looked at the previous video starting the cannon, at https://www.youtube.com/watch?v=ZuxYcbxPuiI&t=2s

I hope to get to cannon again soon, after finishing up a few more hull parts.

 

The last photos show more of the center decking and fixtures installed, and the masts in again to ensure alignment of the mizzen partners. Nice to have those hatches and partners finally glued down after all these years.

 

The photos with blue tape show the upside down carved pieces, the last planks of the wales. These show two versions of how the wale might curve up to meet the hull at this very awkward and difficult to visualize corner. The one with the tape on the left has the lower edge of the wale smoothly curving into the hull, leaving an awkwardly sharp triangular corner to be filled by planking. The one with the tape on the right has the lower edge of the wale hitting the hull a little more perpendicularly, which I think would be a more realistic landing for housing the planking at this piont. I can't find anything contrary to this, and it seems a more logical way to house the end of the triangular plank in this area.

 

Mark

 

Edited November 15, 2018 by SJSoane

[druxey]

The lower photo (repeated) looks about right. I believe that it was Longridge who stated that this troublesome piece was shaped from solid rather than steam bent. I found that I had to slide that triangular piece in from above (if the hull is right side up!) and aft, down and forward, for a nice fit.

[EdT]

Hi Mark, 

I evidently missed your post on the tools question.  Attached is a pdf from Sherline on tool grinding.  If you have Sherline or other HSS tool bits, this should be helpful.  Hardening these should not be necessary and is not mentioned in the instructions. 

 

If your are using mild steel for the tools or unhardened tool steel you may use files to shape the cutters.  Hardening the shaped area after shaping may then be done easily using a torch, pliers and a soup can half full of olive or canola oil.  See Naiad Vol I for more detail on the heat treating. 

 

HSS or hardened bits may be shaped them by grinding using diamond grit burs or files, or you may anneal the cutter by heating to cherry red then allowing to air cool.  Pass a file over the blank to determine if it soft or if you get the distinctive "ring" from a hardened tool.

 

If you have YA Vol II, there is some information on the CD about making lathe tools that may be helpful.  If you do not have this, pm me.

 

Ed

grinding.pdf

Edited November 15, 2018 by EdT

[michael mott]

Mark the photos of your hull upside down show what a fine job you have done on the frames and fairing.

 

Michael

[SJSoane]

thanks, druxey, I have now completed the lowest pieces, except for some final refinement of the lower sweeping curve. I can see why this had to be carved in the real ship; the lieutenant standing on top of the wale shows how large this lower piece is, and it curves all over the place. Since I am not planking the lower hull, it does look a little strange to have the wales hanging down at the stern at the corners, but they would obviously have done so to house the ends of the lower planking.

 

Thanks, Ed, this is very helpful. And I apologize; I had entirely forgotten about the instructions in the Sherline manual. I think at the time I bought the machine, I did not think I would ever be making my own cutters, and so eventually forgot about it. My needs and confidence have risen since purchasing the machine.

 

A few more days cleaning up the wales, and it is time to think about the cannon again. I have decided to re-cut the master, since my first efforts necked in the muzzle end too much. So I will get a little more experience with cutting a gun on the lathe, and think about whether I want to go that direction or try casting again, from a new master. Good thing I am retired and in no rush.

 

And thanks, Michael, it is fun to see the hull upside down again. Somehow the full beauty of the hull does not quite show up when it is right side up.

 

Mark

 

[EdT]

I look forward to seeing your results with the guns, Mark.  One additional thought I had about casting:  I don't know if you are dusting the mold with talc before pouring, but that will reduce surface tension in the mold and improve the finish of the castings.  Just dust it on the mold with a brush.  Some people use baby powder, but here is a link to purpose-made stuff:

 

https://contenti.com/jewelry-casting-supplies/mold-making-supplies/mold-release/talc-powder

 

Ed

[druxey]

Good suggestion, Ed. Also, might I recommend respiratory protection when dusting with talc?

[John Allen]

I don't believe you can call this a model.

 

Its more like a creation of thousands of masterful hand made parts and  hand machined that end up forming the whole.

Anyone can make a model this well beyond. As well as a few others posted on this site.

 

Well done

[SJSoane]

Thanks, Ed and druxey, I am resolved to do a better job on the cannon this time around. Good thing I had to put that project aside while retiring and moving. A little time away made it very clear that I needed to do better. And now I have renewed energy to tackle it again.

 

Thanks, John, for your kind comments. I have come to think of this as a lot of separate parts, each of which needs full time and attention. I have continued to be inspired by Remco's comment "Treat each part as if it is a model on its own, you will finish more models in a day than others do in a lifetime".

 

Here are a few pictures of the wales refined a little more at the stern. I temporarily attached the mouldings at the stern, made many years ago and just waiting for their time again.

 

Reflecting on the wales, now they are almost done, It is pretty remarkable how a series of relatively short planks can be fitted together not only for structural strength longitudinally, but also how they can accommodate to a hull curving gracefully in several directions. The individual parts recede in emphasis, revealing the beauty of the collective whole. Like so many things on these models, the individual parts will likely not show themselves in the final model, but we all know they are there!

 

Mark

 

 

[dvm27]

Extraordinary work, Mark! Those small filler frames are so perfect they almost look fake. No gaps after all these years?

 

Just curious - were those moulding blanks cut to shape or steamed into shape?

[SJSoane]

Thanks, Greg, there has been little movement in the hull parts for these many years, although the annual humidity changes continue to affect the overall hull length. Now that I have a lot of longitudinal members in place, like the deck clamps and the wales, the hull adjusts by opening up a few gaps in frames here and there. Once the upper planking is complete, I hope this will not be noticeable.

 

The mouldings were sawn to the curves in both directions, and then refined on sanding blocks cut to the right curves. I don't remember how I made the sanding blocks, since they would have been a different radius due to the sloped inner face of the moulding. Maybe it was by trial and error. I sure hope I don't screw up when I try to cut the outer surfaces to the correct moulding profile....

 

Mark

[druxey]

Mark: a small point about the knuckle moulding (between lower and upper counters): the lower edge of this moulding sits about an inch below the lower counter plank surface to form a drip edge. I discovered this from examining contemporary museum models. In the last photo it looks to sit about an inch above the planking.

[SJSoane]

Thanks, druxey, I will look at that. I am sure I can move the pin holes to suit. Was there any profile to the drip edge, or just the full width of the moulding 1" below the counter?

 

Mark

[SJSoane]

One more thought about the wales at that difficult-to visualize corner. I have sketched over my photo to show how the planking immediately under the wale rests on the TOP of the lower edge of the wale, and then curves away from the wale to abut into the lower counter. But the little blue triangle of planking abuts into the SIDE of the wale. This leaves a little piece of the wale kind of hanging out at the corner, just where it curves at its lowest, aftmost extremity. You can see this in the color cover photo of Rob Napier's "Legacy of a Ship Model, Examining HMS Princess Royal 1773", and in the black and white photo of Brian Lavery's "The 74 Gun Ship Bellona".

 

Now i finally understand what is going on here, I have to say that I find this to be an awkward detail, both visually and functionally. These don't fair together gracefully, and the little triangle of planking with sharp acute angles is just asking for damage and rot. Perhaps it was the best the shipwrights could figure out for a very awkward design decision to chop off the stern to create those great stern galleries. A curved surface had to transform into  a square one in a very small space in which to resolve the two. One can see why the rounded and elliptical sterns eventually replaced this in the early nineteenth century.

 

I can imagine the original directive from the Admiralty to the shipwrights; "we want the stern galleries, so figure it out as best you can".

 

One of the joys of building this model is to see how the shipwrights melded form and function together in almost all aspects, from the largest shapes to the finest details. Here is one place where function and beauty could not be fully resolved, in my humble opinion. But this is the only design detail that I have so far found that would earn a B in an otherwise A+ design.

 

Mark

 

 

 

 

[druxey]

The models I saw did not have any moulded shape under the drip edge, Mark.

[Mark P]

Evening Mark;

 

Yes, this is an awkward little spot. You are right about the little triangle, which abuts the rear face of the wale planks on the outside; the side of the final curved end of the bottom planking on the inside; and sits under the counter planking at the top. This latter seam is then covered with the tuck moulding.

 

The end of wale is rounded on its bottom corner to fair in with the curve of those last few inches of bottom planking. ie the bottom end of the wale is a curve when viewed from abeam.

 

The amount of curvature required is controlled by the vertical difference between the height of the bottom of the wale, and the underside of the tuck mould. This distance seems to vary from ship to ship. In Endymion, below, it is perhaps greater than in some others, producing a larger radius curve than you will need to use for Bellona.

 

It might be the angle of your picture, but it seems that you might not have left the counter planking with an edge for the bottom planking to butt against. 

 

The last little curved part of the bottom plank which is against the triangle was often sawn from the solid.

 

The pictures of Endymion below show it quite well.

 

All the best,

 

Mark P

Edited November 17, 2018 by Mark P

[druxey]

Nicely put, Mark!

[allanyed]

Sorry for the very late reply, been traveling a bit this past week.

 

1. what rubber mould brand did you use? I used Micro-Mark 1-to-1/ Rapid RTV Silicone, and it was surprisingly fragile. You can see how it broke out in the mould I showed earlier. Did you find something more durable?  

I purchased molding and casting materials from Polytek (https://www.polytek.com/)   They were extremely helpful in selecting the right materials a they have many.  The next time I am in need I will likely use them again.  

 

2. Did you provide any vents for gasses, or is it not needed with such a simple form? No vents were used, but I was careful to tap and vibrate the mold for some minutes to bring any air to the top.   

 

3. When you pour the metal, do you leave the rubber mould in its forming box so it doesn't distort?   Yes, for both resin or metal.   For the resin I left the material in the mold for some hours to be sure it was cured.  For metal, I left it until cool enough to touch without burning fingers.   

 

4. Do you use the Micro Mark lead free pewter? The pewter was given to me by a friend/client some years back.  Their business is machining to make a variety of molds and items and had a lot of experience with materials, but I don't know any details on the metal itself.  They gave me about 5 or 10 pounds of the stuff so enough for a LOT of cannon barrels.  FYI If you go to resin, there are dies that can be added to make black barrels rather than painting, but I have not tried it.

 

Allan