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Making square blocks round!


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Well not quite round, but 'rounder'

 

The pre-drilled wooden rigging blocks supplied in many kits are not very realistic looking. They are square and not oval in shape. This is unavoidable due to the way they are produced. When the budget is not an issue, beautiful scale blocks can be obtained from specialist suppliers but it can get expensive for a large ship.

Model Expo sells a device which is pretty much a plastic cup with some glass-paper paddles inside, you drop the blocks in and turn the handle and the corners are worn off the blocks by a tumbling action against the glass-paper. I tried it, and while it does work, the results are hit and miss.Some blocks are good, others hardly touched. I am going to buy one of those tumblers used for polishing stones by rock collectors. They appear to be around $30-$60 for a reasonable 'low tech' one.

 

http://www.hobbywarehouse.com/101-MP-1-Rock-Tumbler-with-Accys?gclid=CMOSjNqtk7YCFUWd4AodF2EAsg

 

 

The trick will be finding out what abrasive to tumble the blocks with to get the right amount of 'corner' rubbed off.

 

Has anyone else tried this or am I 'boldly going where no modeler has gone before'..?  :huh:

 

Dan O'Neill.

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Haven't tried it. But if the silicon carbide (or whatever) rock-polishing grit is too severe, you might try what's used for cleaning/polishing brass cases for ammo re-loading --- corn husk or walnut shell pieces. I can imagine it being a nuisance separating your blocks out of those natural colored media!

 

Brian

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You are right Jan, I just thought it might be a bit more civilized in a machine!!!

 

I have some fine sandblasting silica glass beads for delicate materials, that might work, its white and will go through a sieve!

Edited by overdale
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Overdale

I use a rock tumbler from Harbor Freight $29, sometimes less on sale.  I lined the barrel walls,and the top and bottoms with 100 grit, I  let it run 24 to 48 hrs, while checking every few hours.  Seems to do a good job for a large number at a time.

I then usually end up finishing about 50%  of them off by hand.

Tom

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I've got one of those shell casing tumblers. I've been thinking about giving it a try with those square blocks. Surely someone on this forum has already gone down this road and will chime in. One problem. The blocks are not much bigger than the corn husk medium. Would be a bit of a chore to separate the blocks out.

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I never use the polishing grit meant for rocks and stones in the tumbler, just the sandpaper.

I use the method for making the block blanks shown on Jerzy Bin's site (http://www.jbmodel.eu/).  Then throw them in the tumbler.  I also use the ones supplied with the kits sometimes, but they are so unrealistic sometimes that it is easier to make new blanks than spend the time cleaning up the kit ones.  The kit ones usually are drilled off center as well, that can't be fixed unless you fill the holes with wood putty and redrill.

I experimented with 80, 100 and 120 grit papers in the tumbler and the 100 seemed to do the best job in the shortest time.  The 80 was too aggressive and the results were uneven (different densities in the wood I guess).

 

Eric O., I've not used that kind of tumbler.  It is true that when you run a batch of 2 or 3mm blocks, many of them can get under the sandpaper so it must be sealed tight against the tumbler walls.

 

 

 

Tom

Edited by twintrow
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I made a tumbler from one of those plastic film containers (remember films ?  ;) ) lined with sandpaper and mounted on a 2.35 mm arbor to be used with my hand-held drill. However, it did not work, as I only had a dozen or so blocks (1.5 mm long) to do. It needs quite a large amount of blocks to work. Perhaps I should have added some rice grains or something like this to make up the numbers - only thought about that possible solution just now  :( . With too few too small blocks they don't really 'tumble', even at slow speed, and themselves don't have enough weight to excert sufficient abrasive forces.

 

wefalck

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  • 1 month later...

I like the idea of adding rice grains -- would make it easier to distinguish the blocks. Has anyone tried doing it this way, with the small film canister?

 

I'm still at the stage of trying to sand small blocks and am having quite a large number disintegrating instead, so the idea of a tumbler is appealing to me and I have been looking at a few examples on this site -- including Janos' and the subsequent modification that was posted.

 

Tony

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I tried this recently. there were only 16 blocks to do. Sandpaper lining didn't work (insufficient blocks), so I tumbled the blocks with salt for several hours. The results were almost imperceptible, might need to be tumbled for a day or two to work. Constantly having to change batteries on the drill made this a waste of time. I do plan to make a tumbler conected to a motor that can run for several days uninterupted, but that's not needed for a year or so.

 

Regards,

Grant.

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The pre-drilled wooden rigging blocks supplied in many kits are not very realistic looking. They are square and not oval in shape. This is unavoidable due to the way they are produced. When the budget is not an issue, beautiful scale blocks can be obtained from specialist suppliers but it can get expensive for a large ship. . . . I am going to buy one of those tumblers used for polishing stones by rock collectors. They appear to be around $30-$60 for a reasonable 'low tech' one.

 

Dan, I hate to be the eternal pessimist, but if you are going to spend up to $60 for a tumbler (which you might use 'sparingly') would that not buy a lot of 'good blocks'?

 

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Jay,  

a set of seriously good blocks for a large ship would take quite a chunk out of $60.00. The blocks the tumbler would produce would not be top quality but a whole lot better than the standard issue square variety.

Using the the appropriate grit, it's also possible to polish metal parts and 'age' wood with the tumbler too. So I don't think $60 is too much of a gamble.! :)

 

Dan.

Edited by overdale
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  • 3 weeks later...

Thanks for reminding us, Hubert. That's exactly what I've been practising over the last couple of weeks. It's taking time, though, to achieve consistency so that the blocks all look the same size and shape. And I still can't get the grooves for the strops right. But it's certainly been worth the effort and I feel confident I'll get there in the end! I still might experiment with making a drum as a tumbler to put on my drill as others have done.

 

Many thanks for your excellent site, which continues to give me inspiration on how to do things without expensive machinery. I love it!

 

Tony

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  • 1 month later...

They don't look bad and the 'sheave' is rounded, which is good. However, you use the same photograph for all sizes on your Web-site. It would be good to see the different sizes next to each other so that one can assess the quality of smaller ones in particular.

 

wefalck 

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  • 6 months later...

I just tumbled all of my blocks for the Constitution (Mamoli Kit). I used the block buster from Ship Expo. The difference it made to the blocks was nothing short of amazing. They went from fuzzy, squarish blocks into nicely rounded clean blocks. I tumbled each set around 1 ½ minutes, then looked them to see if they needed more. The instructions tell you to use the drill at high speed. Since the paddles are spinning the centrifugal force keeps the blocks spinning against all the sanding surfaces (which is everything but the very top of the container.

 

Bill

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One more comment, if you please.

The square blocks many times also have the hole off center. This is particularly true of double or triple blocks.

So, be sure to sort the ones you want to keep.

post-246-0-07302900-1392512669_thumb.jpg

 

Furthermore, I don't understand that while machining the long straight rods of wood that generate the blocks have to be cut off at an angle. Let alone that the holes cannot be drilled the right way (Chinese or anywhere else for that matter).

Just have a close look at these parallelograms with holes of different diameters.

It would seem that even in large quantities this would be a simple thing to fix. Yet most or all kits still have them. I would think someone out there should listen to our concerns.

 

I am sorry, but despite the extra cost, I am for using the more expensive type, unless I know that the blocks are not or hardly visible on my model.

Edited by Modeler12
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  • 6 months later...

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