Secrets of Casting Bronze Blocks, Part 1, S2-E74

See how bronze blocks are made. Boat builder, Bob Emser takes us through the process of designing and creating a bronze block for his sailboat. After a brief discussion about different types of sheaves patterns are made in preparation for casting in bronze. Using the sand casting method of casting bronze a bronze block with a stainless steel sheave is created.
“If you’re going to make it, make it beautiful.”
Bob Emser
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[@michaelc.3812]

it’s always a pleasure to watch you at work Bob. Keep up the beautiful work.

[@barongerhardt]

Don't forget to stamp in your makers mark on one side and maybe the name of the boat and her launch date on the other.

[@knut8556]

Looks like jewellery for a beautiful boat 😀

[@mattevans-koch9353]

Those blocks are going to be some serious bling for Skylark. Well done, sir.

[@joecioe8566]

You always do beautiful work. I enjoy seeing how you approach the task at hand.

[@eddybear771]

Never a disappointment. Beautiful work Bob.

[@TrapShooter68]

Better videos than most of the trash on TV. Thanks, Bob!

[@eloydiez394]

Hi! nice work. Shouldn't you use the round side of the hammer to peen the rods? it makes the riveting easier and the rod will not bend... also chamfering the holes (in the outside) before peening allows some rod material to flow in a bigger diameter making it even better secured for the centuries to come 😊

[@tomt9543]

I couldn’t figure out for the life of me what that glue up was for! Then you dazzled and amazed me! WOW! Great job, but we’d expect nothing less from you!

[@gbw-jwc1356]

Hi Bob, Impressive techniques and superb artistry. A pleasure to see your work in action. I heard you say that you intend to make lignum vitae sheaves that are one inch in diameter. I did find a Herreshoff drawing on the MIT website that indicates the minimum sheave diameter for 5/16 line should be 1-1/8. It might be instructive to check both sizes with your intended lines.

[@marcosrobertojuppa2107]

Hi Bob, I follow all your videos on KZbin and I never tire of watching them, they are very well designed and I'm looking forward to seeing Haven 12 1/2 sailing. Congratulations on the beautiful and careful construction. Fantastic! I'm very curious to know what the next projects will be. Allow me to leave a suggestion for a classic SHARPIE 12m boat (Kroger - German). Congratulations. M. R. Juppa - Brazil

[@TheArtofBoatBuilding]

Hi M.R. I'm so happy you have been enjoying the Haven 12 1/2 build. I have several projects in mind. As for what they will be stay tuned. My studio/shed is at it's longest 12.4m long so sorry to say the a classic Sharpie is not on the list. Thanks for watching! Cheers, Bob

[@marcosrobertojuppa2107]

Hi Bob, thanks for getting back to us. Sorry I didn't understand you correctly, the Sharpie sailboat I suggested is much smaller and for some time it was an Olympic boat. It is 5.99 m long, the hull weight is 230 kg. and has a sail area of ​​approximately 12 m². I'm very grateful for your channel, you're fantastic. Congratulations!

[@michaelkelley6158]

My first thought was, "Wow, beautiful!" Thank you for sharing.

[@jimc4731]

Nice job! I suggest larger peening pocket chamfers in the side plates for greater anti separation strength. Keep up the good work! JIM ❤

[@TheArtofBoatBuilding]

I appreciate the suggestion. However I will not be adding a chamfer. Here's why. The pin had a very tight tolerance by peening as I did it only had to expand a few thousands to be firmly (permanently) attached. It is my desire that that once the cheeks are polished it will be very hard to see the axel. Thanks for watching! Cheers, Bob

[@DerLaCroix1]

From an engineering standpoint, drill the holes undersized and use a lathe to put a shoulder on each of the pins ends. Right now, they could easily be crushed and pinch the lines. The shoulder, held by the riveting, would make them much sturdier.

[@aerobill8554]

Wonderful !

[@Rsama60]

This is reall nice. I know you don‘t have a metal lathe but you have friend who does. I would modify the design of the upper pin a bit. Turn the diameter at both ends of pin maybe 1/8 of an inch smaller. The leng of the middle thicker part should be as long as the width of the shim or a tad bit larger. Drill the holes according to the smaller diameter. Thus you have two shoulders your sides could rest on when riveting, a smaller diameter to peen over. The downsides, two more machining steps and smaller effective diameter that is a bit weaker. I love your casting videos btw. This is a fine art that is not wasteful either, you always can remelt scraps. Can’t wait to see Skylark in the water under sails.

[@TheArtofBoatBuilding]

That is a good idea. A couple of months ago I did acquire a HF mini lathe. It should be up for the task. I’ll have to give it a try. Also will eliminate the need for a spacer when peening the pins. Thanks for the suggestion and watching. Cheers, Bob

[@gordonrobertson4125]

May I add to your suggestion: countersink the holes so that peening the pins will expand the bronze to lock the pins in place. This is common practice when rivetting plates. For the turning block that will be mounted on the mast, increase the diameter of the top pin then drill the mounting hole down through the pin or make the pin from a thick wall tube.

[@porkchop955]

I enjoy watching you patterning techniques. They translate to many different projects. At 20:17 I was fearing for your thumb!

[@sartorst3376]

A black thumb nail gives character

[@sartorst3376]

While you're making you might as well make some with a becket for a good place to terminate a line and add additional purchase if needed

[@glencrandall7051]

Your finished blocks will be worth their weight in gold. And they will look like gold too.👍👍 Thank you for sharing. Have a great day and stay safe.🙂🙂 PS I have a block of Lignum Vitae that my grandfather gave me. It is about 4 x 3 x 3/4. I can't imagine what it might be worth.

[@billywhizz6483]

Fascinating to see the process. I'd try a magnet on the sheave from Amazon just to be sure it is stainless!

[@tomt9543]

There are alloys of stainless that are magnetic. Fabrication people refer to them as “sticky” stainless.

[@plainnpretty]

Beautiful work and very interesting video. Thanks Bob

[@John-jr7rs]

outstanding as always Bob

[@bishopkinlyside8477]

Hi, I’m really Amaya what you do I don’t think I have the patience to do all these things but I can really appreciate everything you do building this boat. Keep up the good work love the videos cliff from Logan City Queensland Australia🇦🇺👨🏻‍🦽

[@davidabaxter4424]

You do amazing work. Well done.

[@robertgroves6186]

It's always a pleasure to watch what you're doing & how you do it!!! Thanks you.

[@MCsCreations]

Stunning piece, Bob! Really beautiful work!!! 😃 Looking forward to the next steps! Stay safe there with your family! 🖖😊

[@tobhomott]

Great job, very interesting patternmaking approach! 👍

[@bake162]

Looks great, was surprised you didn’t ram the sand with a mallet

[@davidc6510]

I really enjoyed watching your other casting videos and it was great to see the steps you went through to cast the cheeks to make the prototype blocks. The prototypes were quite beautiful like all of your splendid mini projects that go into the master project. The Haven 12 1/2 is definitely my favorite (so far) in all your videos. I think a longer tear drop to accommodate the larger stainless steel sheave would look really good as well. It would be a shame to see you carve up your beautiful lignite mallet to make sheaves for the blocks. Thanks for sharing Bob. I eagerly await part 2.

[@TheArtofBoatBuilding]

Hi David, No worries I won’t be using my mallet. I was just using it as an example of lignum vitae. I have several pieces that I were gifted by my Grandfather and college professor. Thanks for your kind words and for watching. Cheers, Bob

[@davidc6510]

@@TheArtofBoatBuilding LOL how silly of me to have thought you would cannibalize the mallet.

[@MrRupertguy]

Love the dedication to detail. I work in brass and copper, but casting objects is my next step. thanks for the education.

[@NA-su3jk]

Thanks for making and sharing these videos!

[@rickestabrook4987]

Thanks Bob. Beaurtiful work.

[@jamesworsham125]

Very clever way to make the cheeks.

[@scottdiller1893]

Thanks again Bob, and Happy New Year!

[@marcelvandergrijn]

Always a pleasure and an inspiration to see your calm approach and experience as an artist implemented in every detail. :) Cheers from the Netherlands.

[@W4ABN]

Nice work. I got a small devil forge to make things but still in its box it came in.

[@guibellodi]

How will the stainless steel interact with the bronze in terms of galvanic corrosion? Thanks for sharing! Beautiful work!

[@JenkinsBoatWorks]

Great Video Bob. interesting, educational and fun. I wonder if some other hardwood would suffice for the Sheaves. I wonder about Osage Orange. It is tough stuff, super dense. I don't know if it would have integrity under a load, just throwing it out there. Live or white oak, maybe, too. on a side note, I've camped on and sailed in and out of Lignum Vitae Cay in the Bahamas!

[@OferNRaz]

Nice work. You may also need a few blocks with a bucket. Also, moving to wood sounds better. I have seen cheap sheaves rusting. You never know if it is all stainless.

[@tomt9543]

Becket?

[@OferNRaz]

@@tomt9543 Yes becket :)

[@TheArtofBoatBuilding]

The rigging for my boat does not require any blocks with beckets. So no beckets this round. There are however several specific attachments that I will make. Thanks for watching!

[@tobylakin1]

Very good.

[@tomtruesdale6901]

That block is beautiful. Bet that forge heated the shop up nicely.

[@TheArtofBoatBuilding]

It sure did. -14 F this morning. It was a welcome addition today.

[@tomtruesdale6901]

@@TheArtofBoatBuilding a balmy 24* here on the Texas gulf coast. Please keep that cold up there.

[@ErnieNoa3]

Always very nice work!

[@Beowulf-sd5gh]

beutiful pieces of art; I maybe would have considered to put a screw in one side instead of peening in case the quality of the 6$ sheaves is not what you expected and you need to replace them

[@GuilhermeOliveira-sj9nu]

Só não erra quem não faz! Abraço

[@TheArtofBoatBuilding]

É uma das melhores formas de aprender. Já foi dito que se aprende mais com os erros do que com o sucesso. Obrigado por assistir!

[@giovannizunino6046]

Troppo lavoro indipendente fantastici però personalmente preferisco quelli che avevi costruito in mogano si addicono di più a un'imbarcazione costruita in legno viva la sincerità certamente saprai apprezzare

[@robertbamford8266]

Result is beautiful (even if …). I was wondering what (if anything) the pin would do to keep the tops of the cheeks properly spaced. (Evidently nothing). With the stresses parallel to the cheeks I expect it would be unnecessary.

[@johnwelty281]

I understand the "availability" situation with lignum vitae. It may or may not be a viable replacement, but have you done any investigation of Osage orange???

[@TheArtofBoatBuilding]

Hi John, I haven't looked for alternatives as I have an adequate supply of Lignum Vitae that I was gifted to me by my sculpture professor many decades ago. Thanks for watching. Cheers, Bob

[@CircleOfLightStudios]

Very detailed information and great craftsmanship. Out of curiosity, would you have an guestimate of the safe working loads of these blocks ? When one buys these from 6main manufacturers they always quote SWL figures. It might be educational to try and see if the nice blocks out perform the plastic ones 😊 Greetings ireland

[@plakor6133]

Can the stainless sheave rotating diameter be adjusted with some lathe work?

[@ECHilscher]

You mention stainless steel sheaves with roller bearings. Where did you source that one? I have looked, but they all seem to be much larger.

[@ECHilscher]

Tried to edit, but couldn’t. Got my answer by watching the bronze block build.

[@howardmarshall5713]

@Bob Emser Are you having any more episodes soon Bob ?

[@TheArtofBoatBuilding]

In a day or two.

[@Snozzbucket]

Beautiful, Bob. How did you space the two cheeks so that the sheave would turn and not bind?

[@TheArtofBoatBuilding]

Thank you. When I was peening the bronze pins I had a small wood spacer so they would keep to proper spacing. Thanks for watching!

[@jimc4731]

I believe the axle of the pulley is a little wider than the outer wheel. In that way the axle is squeezed tight and the wheel turns freely He used a spacer to keep the sides parallel and properly spaced for peening. JIM 🎉

[@bikerXtrash]

Beautiful! I am curious---why didn't you use a 3D printer for your pattern?

[@tomt9543]

BLASPHEMY!!!

[@skippytwonder]

For parts that small, wouldn't lost wax casting be faster if you are going to make a bunch of them?

[@TheArtofBoatBuilding]

Lost wax is great for parts with high detail and undercuts. Parts like these cheeks sand casting is the most efficient.

[@skippytwonder]

@@TheArtofBoatBuilding I am aware of the capabilities of lost wax casting, but I also saw the failure rate of sand casting those little parts. Seeing this, It seemed obvious that you could make a whole tree full of those cheeks out of wax and knock out the whole process in one pour.

[@TheArtofBoatBuilding]

@@skippytwonder Hi Robert, Your being aware of lost wax process you will know there are several more steps to lost wax. Two big factors for a home foundry are 1. Having a ceramic slurry or investment material. 2. Having a burn out kiln. Both of which I don't have. Lost wax is not a fail proof process. I've had many unsuccessful lost wax castings. After sprueing up 20 or so wax cheeks ( which I would have had to cast in wax) and investing it I would need to wait for the investment to dry. (3-4 days). Then put in a burnout kiln, fire to temperature and let cool ( 1 day min.) I then could cast the bronze. and hope everything was perfect or repeat the process. With my small furnace, from a cold start the bronze is at pour temperature in about 40-45 min. In that time I have rammed up 3 flasks. The pour takes less than 1 hour. In one day I can easily do 3 pours. As I said in my earlier comment that Lost Wax is great. If you have watched my earlier videos (How to Cast Bronze by Lost Wax, S2-E56 kzbin.info/www/bejne/hpTLnYp3pKmrpM0)you will have seen that I have cast many of my parts with the lost wax/PLA process. For this part, sand casting is the most efficient process. That is one of the reasons that most production foundries primarily use sand casting. Thanks for watching and happy casting! cheers, Bob PS after casting several more cheeks with the proper venting I've had 100% success.

[@philareilly]

If you’d like, I’m happy to machine the cheeks on my CNC for you. It wouldn’t be as fun or interesting as casting, but the results should be quite good.

[@legend7ify]

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