sis
Seasoned Member
Posts: 113
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Post by sis on Jun 26, 2018 18:07:36 GMT
For me there are two parts to the equation. Firstly there is the design work, the accuracy of the model, the research, the time to build the 3D model or traditional pattern. Then there is the execution, the lost wax or other casting, the edm, CNC, CAM, manual machining or fabrication. You need both parts for a fantastic result. All the approaches add to the hobby, pick the approaches and suppliers that work for you and enjoy it.
Recently there was a thread complaining the forum was moribund. I couldn't disagree more strongly. Apart from the lack of EDM activity I don't think there is much else missing.
Regards, Steve
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Post by simplyloco on Jun 26, 2018 19:40:01 GMT
SNIP Recently there was a thread complaining the forum was moribund. I couldn't disagree more strongly. Apart from the lack of EDM activity I don't think there is much else missing. Regards, Steve At the time I started the thread in question the forum was in fact moribund. Your 14 posts in the last six months tend to support that supposition... John
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44767
Statesman
Posts: 535
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Post by 44767 on Jun 27, 2018 9:32:42 GMT
For me there are two parts to the equation. Firstly there is the design work, the accuracy of the model, the research, the time to build the 3D model or traditional pattern. Then there is the execution, the lost wax or other casting, the edm, CNC, CAM, manual machining or fabrication. You need both parts for a fantastic result. All the approaches add to the hobby, pick the approaches and suppliers that work for you and enjoy it. Quite correct! It doesn't matter which method of casting is chosen but the research and drawing or CAD modelling is fundamental to the end result and costs up to this stage will be similar. I really meant my initial question to be about the extra cost of investment casting- the process itself. It is a very involved process which typically takes two weeks to deliver a finished casting. I'm talking about the shell method here not that for the lower melting point alloys which can be done in a plaster-of-Paris type material. It involves moulding the wax, attaching it to a tree, dipping the tree into the slurry, sanding it, waiting for it to dry, dip again, dry...several times, burning the wax out in a kiln, refiring the shell to harden it, perhaps reheating again to bring it to temperature at casting time, pouring the metal, braking the casting out, cutting off the tree, bead blasting. Along with the materials (wax, ceramic etc.) and the people employed to do all these different jobs, this is why lost wax casting is so expensive. It becomes a production technique because parts, generally are not possible any other way or because multiples (hundreds on a tree) becomes cost effective. Somewhat like the "laser cutting versus hack sawing and filing" argument the option is there now, especially for those who've taken CAD modelling on board, to make some outstanding castings.
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Post by Oily Rag on Jun 27, 2018 20:07:47 GMT
Mike, do you think you have an answer to your question ?
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44767
Statesman
Posts: 535
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Post by 44767 on Jun 28, 2018 7:34:06 GMT
Mike, do you think you have an answer to your question ? Not yet! No one has stated how my extra they'd pay for a lost-wax-no-finishing-required-exact-scale casting over a currently-available-mediocre £35.00 sand casting. Cheers, Mike
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Post by simplyloco on Jun 28, 2018 7:49:01 GMT
Mike, do you think you have an answer to your question ? Not yet! No one has stated how my extra they'd pay for a lost-wax-no-finishing-required-exact-scale casting over a currently-available-mediocre £35.00 sand casting. Cheers, Mike I'm quite sure that 'parsimony' is a word invented by a ME committee!
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Post by 92220 on Jun 28, 2018 8:17:36 GMT
Hi Mike.
There are model engineers who are prepared to pay 'proper', or even 'silly', money for investment castings when they want perfection. They may be few and far between, but they are there. I am one of them. You want to know how much I would pay for a 'perfect' set of investment cast wheels? Back in 2002/2004 (can't remember exactly when) my set of wheels cost me £800. The company charged me £2000 but gave me 3 sets. My set cost me £800 because I sold the 2 spare sets for £600 each; so there are others out there who will pay for perfection. Yes the price was high, but there were almost double the number of wheel castings that would be needed for more popular model locos.
The reason for the high cost was for exactly the reasons you give, and the fact that I made their job that much harder by making the moulds for the waxes in Perspex instead of aluminium that can conduct the heat away much quicker. Plus the fact that they could only cast a small number of wheels at one time due to the quantity of stainless involved, and they only normally produced small castings for customers. My coupled wheels were some of the largest they had done on their equipment. In fact the waxes were right on the limit of their injection moulding capacity.
Could you not work out a price that you would be prepared to sell a set of Britannia wheels for, and advertise it on your website, to see if you get any enquiries and eventual orders? I think that is really the only way you will get a definitive answer. Anyway. Good luck. I hope there are others, like me, who are prepared to pay for your quality of castings.
Bob.
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Post by simplyloco on Jun 28, 2018 8:22:41 GMT
Hi Mike. SNIP Could you not work out a price that you would be prepared to sell a set of Britannia wheels for, and advertise it on your website, to see if you get any enquiries and eventual orders? I think that is really the only way you will get a definitive answer. Anyway. Good luck. I hope there are others, like me, who are prepared to pay for your quality of castings. Bob. Agreed. My Brit tender wheels look like small cowpats, and they will require a lot of fettling to reach the standard required. I wish I could find better! John
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Post by RGR 60130 on Jun 28, 2018 8:33:56 GMT
When weighing up the pros and cons in a situation like this I use £10 an hour as a yardstick. Cleaning up a sand cast wheel casting would possibly take 3-4 hours each. Therefore, going back to the original question with a straight answer I'd say £70.
However, depending upon the loco and how true to scale I wanted it, and any deadlines I wanted to meet etc I could be persuaded to pay more. On top of that, some sand castings will never be 'right' no matter how long you spend cleaning them up. Delivery time is another factor. Buying high quality wheels to save time doesn't really pay off if you have to wait 6 months for them.
Reg
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Post by ettingtonliam on Jun 28, 2018 10:46:45 GMT
Mike, do you think you have an answer to your question ? Not yet! No one has stated how my extra they'd pay for a lost-wax-no-finishing-required-exact-scale casting over a currently-available-mediocre £35.00 sand casting. Cheers, Mike If you want the raw truth, (and this is a personal opinion, because of my own requirements) I wouldn't pay any more for a lost wax casting over a decent (and I mean decent) sand casting. Prtobably not the answer you wanted to hear, but you did ask!
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44767
Statesman
Posts: 535
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Post by 44767 on Jun 28, 2018 11:19:24 GMT
That's entirely your choice and I respect that.
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Post by silverfox on Jun 28, 2018 12:23:08 GMT
IF more people took up the option of this system the price might reduce look at PC and TV prices 20 years ago to now, BUT it is a limited market and more of a cottage industry. Take a CAD to a big and they will charge ?? However an enthusiast who does CAD more for the love of the hobby than a living wage and profit,is not as interested in the firm is in the bottom line I do Wedding Car hire, I price it to cover the running costs it matters not if i get work or no. There a businesses out there that charge 4 times what i do, for exactly the same product They have to live. I enjoy getting the old van out and making a brides day. Until the whole shebang can be done in someones shed, for the love of the hobby, plus a few beers then it will always be in the realms of those whose bank statements look like an USA phone number. As i see it The time spent is surely in the drawing stage, and programming the machine to cut the mould. the pouring costs cannot vary that much Take Adam as an example He wants a certain part for his loco so he draws it and sets up the CNC bit to get the mould. Then gets it cast Does he bill himself? Doubt it. It is his hobby But i would expect him to bill me for the drawing and CNC bit and possibly spread that over the interest shown. As i said earlier. put feelers out for a widget then work out what each person would pay to cover yout initial time. I would love castings like that to have, but cannot justify the expense to the boss or even myself, so it is the old sand ones for me. If the good ones were say, plus 30% over a traditional casting, then i could justify it.and i daresay a lot more ME bods. So really the ball is in the new tech lads hands to get it rolling along
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jasonb
Elder Statesman
Posts: 1,222
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Post by jasonb on Jun 28, 2018 12:35:58 GMT
As I said at the start for me it would very much depend on the actual item, this was before you mentioned wheels and the wheel price was just an example of cost. To me that wheel you posted would not be too hard to clean up if it was an average sand casting as there are not that many spokes and the gaps between are easy to get at. Also will you be doing this one at a discount price as to me it looks like it is going to need some filler in that ding and looks like the junction of spokes to rim may need a quick touch with a die grinder. If I was paying top dollar I would want what you call a "no finishing required" casting
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dscott
Elder Statesman
Posts: 2,440
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Post by dscott on Jun 28, 2018 23:29:40 GMT
I have of course held this lovely casting and totally admired... The problem begins with wanting all the wheels being at the same quality! My mornings and cooler evenings are spent mending the house (OUTSIDE) Then, at its hottest I go and fettle Black Five bogie wheels same size as above... I got 3 almost done and snapped another rod saw!! Wheels are in full size quite rough as you go towards the BR standards! Early ones like Asia need to be better finished!
Some of the most beautiful wheel castings in recent years have come out for Fair Rosamunde marketed by Polly Models! I believe they were cad drawn and cnc'd out!
David.
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44767
Statesman
Posts: 535
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Post by 44767 on Jun 29, 2018 6:14:11 GMT
Also will you be doing this one at a discount price as to me it looks like it is going to need some filler in that ding I refer to photographs when I do my CAD modelling, even if I am working off the works drawing. That ding was on the full size one- maybe a ding in their pattern?
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Post by Oily Rag on Jun 29, 2018 22:08:34 GMT
Mike, do you think you have an answer to your question ? Not yet! No one has stated how my extra they'd pay for a lost-wax-no-finishing-required-exact-scale casting over a currently-available-mediocre £35.00 sand casting. Cheers, Mike And if you do have some willing clients, the next ? will be if number of expressed willing clients is sufficient for the work. Considering also what is said and what will occur does not always be the case in the market place and with polling. The plural of anecdote does not equal fact. For me, I love investment castings and they are usually well worth the cost.
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Post by 4fbuilder on Jun 30, 2018 10:16:06 GMT
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Post by nick952 on Jun 30, 2018 13:37:06 GMT
Just as a guide that may help, for my Castle, the wheel castings that Polly Engineering offer are nice quality, with very little split line flashing and are at present £34 each. However the person that made the pattern got the shrinkage allowance wrong and the set that both I and Alan (Hagley) have are all significantly undersize, plus the centre boss and spoke forms are not correct.
Because of the undersize castings from Polly and also needing a later design of wheel (The Castle had 3 different styles of wheel over it's design life), with the crankpin between the webbed spokes as per the King wheel, I have ordered a set of this later type of wheel from another source and I believe that these may well be "lost wax" castings (I didn't ask). These are £72.40 each and are the first that will be made for 5" Gauge by this supplier (Any of the 3 types can be produced on request if required).
Nick.
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44767
Statesman
Posts: 535
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Post by 44767 on Jul 2, 2018 6:45:32 GMT
That's interesting that there's another source of the Castle wheels on the market; is it one of the usual suppliers? Mike
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Post by Stafford Road Design on Jul 2, 2018 8:40:08 GMT
Just as a guide that may help, for my Castle, the wheel castings that Polly Engineering offer are nice quality, with very little split line flashing and are at present £34 each. However the person that made the pattern got the shrinkage allowance wrong and the set that both I and Alan (Hagley) have are all significantly undersize, plus the cenrte boss and spoke forms are not correct. Because of the undersize castings from Polly and also needing a later design of wheel (The Castle had 3 different styles of wheel over it's design life), with the crankpin between the webbed spokes as per the King wheel, I have ordered a set of this later type of wheel from another source and I believe that these may well be "lost wax" castings (I didn't ask). These are £72.40 each and are the first that will be made for 5" Gauge by this supplier (Any of the 3 types can be produced on request if required). Nick. Nick, Who supplies Castle wheels? I've done some in 7mm scale and I'd be interested in seeing some in 5" (I did try and attach a picture but it wouldn't let me) Elliot
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