Rubberized Contacts: 7. Final Thoughts (maybe)

When I wrote my last post on this topic, Rubberized Contacts: 6. Revised Calculations and Wrap-Up, I thought I was done with this blog series. But no, it turns out I have more to say. Here are some random things I’ve come up with recently, which may evolve into a more formal “Part 8: FAQ”.

How can I avoid the one-time expense for things like the postal scale and the trowel?

I’m glad you asked. With the blessing of The Bay Team Board, I have assembled a “Rubberizing Loaner Kit”, complete with a reference binder full of instructions and tips. As soon as we have finished up the SMART and Bay Team equipment, this will be made available on a limited basis to members. I will be the Program Administrator, and the kit will stay around until it is no longer (a) in demand or (b) usable, whichever comes first. We have not discussed any budget for sustaining this program if the equipment becomes unusable or is lost.

How much contact cement do I really need?

A lot. And as I have previously mentioned, only the Original (red label) stuff will do – stay far far away from the non-flammable (green label) crap. As an aside, Home Depot only carries small cans of the good stuff, not gallons – you have to go to True Value or OSH or Lowes to get gallons.

OK, I admit that “a lot” isn’t really a very helpful answer. So I did some rough calculations based on even rougher estimates and came up with some numbers. Your mileage may vary, but least this will give you a starting point.

  • Table (top only): 21 oz (2/3 qt)
  • A-frame: 128 oz (1 gal)
  • Dogwalk: 85 oz (2/3 gal)
  • Teeter: 28 oz (almost a quart)
  • Chute pad (small): 11 oz (1/3 qt)
  • Chute pad (large: 13 oz (not quite 1/2 qt)

If you read Part 6 (referenced above), you already know that contact cement costs over $35/gal. Based on these calculations, if you’re doing a full set of equipment, you’re looking at well over 2 gallons of cement. Now I’ll admit that I was doing my gluing in the sun, so I probably used more than I might have in cooler conditions. On the other hand, my a-frame is aluminum, which means it didn’t absorb the cement the way plywood would have. So there is probably quite a lot of variability, but at this will give you an idea so you can be prepared.

Brushes vs Rollers?

I previously posted that though the book recommends 2″ brushes, I thought they were a waste of time and suggested at least 3″ and preferably 4″ brushes. I now must confess that I didn’t fully read the supplemental material that Darlene included with the kits. Had I done that, I would have noticed that she updated her recommendation to a 6″ foam roller. Sure wish I had seen that earlier.

How many people does it take to glue the skins on the contacts?

The table can easily be done by one person if you use the technique in the book – clamping in the middle, folding half back, applying cement, roll into position. Then just do the other half the same way. There is one thing I didn’t see mentioned in the book – be sure to put a piece of plastic or paper between the two layers when it is folded back – you don’t want to accidentally get contact cement on the finished contact surface.

I used a similar technique for the blue end of the a-frame and it worked fine. However, I tried to do the yellow side / match-up by myself and that was a mistake. I think that takes two people.

I haven’t done a teeter or dogwalk yet, so I can’t yet speak to the requirements for the longer pieces.

Have any of the formulas or measurements changed since the book was published?

Yes. Darlene has changed her formula for the table mats (and I assume the chute mats). In addition, she is providing a kit for a larger chute mat than what is published in the book. Here are the corrections to the book based on these changes.

Table and Chute, page 29

This chart replaces the last two sections of the original chart and reflects two key changes:

  • New formula for the table tops
  • Additional measurements for a larger chute mat, not included in the book
Obstacle Sq Ft Rubber Granules Binder ** Acetone
Table (if you include the sides, all pieces are made from a 45” square)
Top with sides (4”x36”) 14 sq ft 18 lbs (approx 1.28 lbs/sq ft) 3 lbs 10 oz None
Top only (36”x36”) 9.5 sq ft 12.2 lbs 2 lbs 7 oz None
Chute (30” long barrel)
Barrel mat: 24” x 27” 4.5 sq ft 5 lbs 13 oz (approx 1.28 lbs/sq ft) 1 lb 3 oz None
Barrel mat: 36” x 27” 6.75 sq ft 8 lbs 12 oz 1 lb 12 oz None
Chute rim: 6” x 78” 3.3 sq ft 3 lbs 11 oz 12 oz None

Table and Chute, pages 22-23

This chart reflects two key additions to the diagrams on these pages:

  • New sizing for table top alone (no sides)
  • Additional measurements for a larger chute mat, not included in the book\

Note: I haven’t even begun to try rebuilding the nested taping job with these options – you’re on your own for that.

Item Tape Plastic
Table Top without sides (36” x 36”) 37” x 37” 40” x 40”
Chute Barrel Mat (36” x 27”) 36” x 27” 39” x 30”

Conclusion

If you have any other questions about this process, please let me know and I’ll develop this list into a more serious FAQ.

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