Title
Crazy Modeler Brake Disc Tutorial

Author
dflett

Published
Wednesday, October 3, 2007

Crazy Modeler's photo-etched brake discs look fantastic but are not very easy to build. The ventilated disc is especially tricky, made by twisting 36 vanes through 90 degrees and gluing them into 36 corresponding slots on the back disc face and 36 slots in the front disc face.

The following steps are the best way I have found for assembling them to get good results. Once you get the hang of it, each disc can be made in about 10 minutes.

Step 1. Buy More Than One Set

Chances are you are going to mess up at least one disc, therefore it makes sense to have a reserve set. That way when you mess one up, you can just move on to the next, knowing that you'll still have enough for the car in question. Having a spare set also means that you can afford to sacrifice one center section to replace any broken vanes (see step 10).



[The full set of parts for Crazy Modeler's disc brakes]

Step 2. Get The Right Tools

A pair of pointed tweezers is essential for assembling the discs. Other than that, you'll only need a pin (to apply the CA glue), a knife (to cut off the photo-etch pieces) and a flat needle file (to clean up the edges after assembly).



[A pair of pointed tweezers will make things easier]

Step 3. The Back-Plate And The Vanes

Remove parts 1 (back-plate - right on picture) and 6 (vanes - left on picture) from the photo-etch sheet. Do not clean up the remains of the four sprues on part 6 - they come in handy in the next step. File off the remains of the three sprues from part 1. Be careful while handling the vanes - they are very fragile and bend and break easily.



[Start with parts 6 (left) and 1 (right)]

Step 4. Creating The Guide Vanes

Take part 6 and bend two opposing vanes fully through 90 degrees so that they are perpendicular to the rest. Locating the remains of the sprues is a convenient way of finding two vanes that are exactly 180 degrees apart.



[Using two vanes as guides makes alignment simpler]

Step 5. Prepare The Remaining Vanes

Twist the remaining 34 vanes through approximately 45 degrees. You don't want them perpendicular, but also you don't want them flat - that makes assembly much more difficult and time consuming.



[Twisting the remaining vanes through 45 degrees lets you align them later]

Step 6. Gluing The Guide Vanes

Put a drop of CA glue on a piece of scrap paper and make sure your pin is clean. Holding part 1 in one hand and part 6 in the other, bring them together so that the two guide vanes you created in step 4 lie correctly in opposing slots of the back plate (part 1). Be careful that the two parts are also centered - any error here will mean that some of the vanes will not line up with their corresponding slots. Holding the two parts together with thumb and two fingers around the edge should ensure that the two parts are correctly aligned. When you are content that the two parts are lined up and the guide vanes are snug in their slots, trickle some CA glue along the join between guide vanes and their slots. Don't use too much glue, less is more here. Just use enough to keep the parts together for the next couple of steps.



[The main thing here is to get the two parts centered using the guide vanes]

Step 7. Gluing The Front-Plate

Separate part 3, the disc front plate, from the photo-etch sheet and clean up any sprue remains. Bring the front plate up to meet the guide vanes in the same way as before, by locating two slots 180 degrees apart and pushing the guide vanes into them. When you are happy with the fit, fix it in place it by trickling some more CA glue down the seam between guide vane and the slots. Again, the fit here is crucial. In fact, this is the most critical step for getting properly aligned vanes. Align the parts by gripping around the edge of all three parts to keep them centered. Also, make sure that the guide vanes are snug in their slots before gluing.



[Part 3 is the front plate]



[Use the two guide vanes to center the front plate]

Step 8.Aligning The Remaining Vanes

If all has gone well, you will now have a front and a back plate with the vanes in between. Two of the vanes will be in the correct positions and glued, while the rest will be inclined at around 45 degrees but not yet aligned in their slots. Now take the pointed tweezers and carefully turn each remaining vane through its final 45 degrees. This is best done while holding the back and front plates between your thumb and forefinger in order to apply some pressure. As you twist each vane, you will hear a satisfying click as it locates itself in its groove. Some of the vanes may break as you twist them. If they do and you have a spare photo-etch sheet (step 1), then they can be fixed afterwards.



[The thin points of the tweezers allow you to rotate each vane into its two channels]

Step 9.Gluing The Remaining Vanes

Once all vanes are in their correct positions, glue each by trickling some CA glue between the vanes using the pin. Be careful not to dislodge any of the vanes while gluing them. If you do, quickly re-align them with the tweezers before the glue sets.

Step 10. Replace Any Broken Vanes

If any of the vanes have broken off while twisting, and you have a spare part 3, then twist off a new vane from the spare part 3 and insert into the two empty slots after running a little CA glue into them first.

Step 11. Clean-Up

Carefully clean up the edge of the disc with a needle file to remove any remaining sprues. The disc is now complete. For steel discs, you can now continue assembling the hub, while for carbon-ceramic versions, the discs are now ready for painting.



Now paint the discs if needed and continue with the remaining hub parts.

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