Author Topic: Gluing Formica onto a disk  (Read 653 times)

swittetsakee

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Gluing Formica onto a disk
« on: December 27, 2017, 12:28:35 AM »
I'm going to paste a few Formica into alt-bearing disk edges.  Because there are not any obvious start-stop areas on a disc, I'd like to have both Formica ends butt together cleanly.  The strips are cut a little longer than needed at the moment.  Is there a favorite way to get them to line up as tightly as you can?  I plan to use contact cement to adhere the Formica.
If I dry fit to a tight joint, then paste, I guess the change in circumference due to this glue-line will open the gap greater than you would expect.  If my math is right, the gap could be glue-line thickness*2pi, or about 6x the glue-line.  That's not insignificant.  The problem is I do not have a means to correctly ascertain glue line thickness beforehand.

If I paste bits with overlapping ends, then trim (an approach that I'm leaning toward), there is the risk that the cut will likely be slightly off.  And exactly what to cut it with?  A knife will require multiple moves and will have to be guided correctly.

Any words of wisdom before I put down the adhesive?



Ryan Fletcher

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Re: Gluing Formica onto a disk
« Reply #1 on: December 30, 2017, 06:24:21 AM »
Overlap now, trim to fit later.

Marvin Alexander

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Re: Gluing Formica onto a disk
« Reply #2 on: January 01, 2018, 09:16:06 AM »
Do you have a small block plane?
Leave as small an overlap as you can and glue on except for the last 2" or so. Plane the loose end until it fits then glue down. Remember if using contact glue it can be reactivated with heat and the laminate can be stretched slightly if heated and repressed to take up a small gap.
When gluing with contact, too dry is better than too wet especially on a curved surface. Too wet and the laminate will try to lift. Too dry, just apply heat and repress.
On tight curves the laminate (especially the ends) can be pre-bent with heat. Use a scrap pieceto test how much heat it can stand before blistering. It's a surprising amount. It can get a lot hotter than you can bear to hold. Heat it then bend to a tighter curve than required and let cool then glue. It'll be less likely to try to lift.

Lastly, although it will be more visible, when placing the bearing put the join in a position where it won't ride over one of the Teflon pads.

Dave

PS: I usually cut narrow strips with side cutters before using the block plane,

wordpuzzlesubc

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Re: Gluing Formica onto a disk
« Reply #3 on: January 03, 2018, 05:48:56 PM »
Tin snips (sheet metal scissors) will also cut laminate, here too its best to cut the waste off in thin strips, and test-try beforehand. Most snips leave one side basically straight, and curl the other as they cut. Be sure the curl is the scrap side.

Waka Belcher

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Re: Gluing Formica onto a disk
« Reply #4 on: January 04, 2018, 10:38:05 AM »
Hi Dave,

where did you get your laminate from? Ready to do the alt bearings for my 33" dob. Used to get it from Scopestuff, but they are out of stock. My bearings 1" wide on 23" radius semicircles.

Best regards

Stephen.(45deg.S.)

seucamthepo

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Re: Gluing Formica onto a disk
« Reply #5 on: January 09, 2018, 04:19:43 AM »
I like the suggestion Dave made to plane the edge for the last few thousandths of tweaking and to glue it down last. You're right that the adhesive gap is not insignificant and your circumference will increase by pi times twice that adhesive thickness. 0.010" glue gap can turn into 1/16" gap end to end in a hurry. A plane can be tuned to shave only 0.001" easily enough.

Dale Khan

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Re: Gluing Formica onto a disk
« Reply #6 on: January 10, 2018, 05:00:10 PM »
Steve.Private message sent.Dave

aththrilnalo

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Re: Gluing Formica onto a disk
« Reply #7 on: January 12, 2018, 01:05:00 AM »
Thanks for the tips. There are some nuggets mentioned above like heating and pre-curling the ends to match the disk curvature. I wouldn't have considered that. Great idea!

I do have a block plane, so will give that a try.

BTW, I experimented cutting some scraps of the laminate in various ways. A guillotine paper cutter separates or chips the laminate from the backing unless the business side is face up. I couldn't use it to trim the last bit from the disk anyway.

A nicely sharpened veneer saw (which is really a serrated knife) didn't work well. I even tried my ancient Exacto razor saw from the 1960s meant for cutting balsa, but my blade is dull. Hand scissors cut it, but leave cracks in the plastic surface at the cut edge. These cracks run almost perpendicular to the cut line.

I'm looking forward to seeing how well the block plane works to shave the edge.

exjeraca

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Re: Gluing Formica onto a disk
« Reply #8 on: January 20, 2018, 04:08:51 PM »
Quote
I'm looking forward to seeing how well the block plane works to shave the edge.
Just make sure the blade is sharp and set it to take a small amount off. The tricky part is holding the laminate while planing. An appropriate sized block or wedge held under the loose end can help and make sure you hold the laminate from moving in the direction of the plane stroke. This is where cutting too deep will tend to grab the laminate. Again, try a test piece first if you can to see what it feels like.Dave

Seth Mamidi

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Re: Gluing Formica onto a disk
« Reply #9 on: January 23, 2018, 07:10:03 AM »
Thanks, Dave. I'll sharpen the plane iron first thing tomorrow, and then experiment on some scrap.

Great tips, so thanks!

Quas Padilla

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Re: Gluing Formica onto a disk
« Reply #10 on: January 30, 2018, 12:33:31 PM »
A properly sharpened plane makes all the difference. Be sure you don't bevel the back side in the slightest, and make sure you finish by removing any tiny burr on the tip with a pull stroke on a strop or really fine stone with that back side pressed nice and flat on that surface.

grateganir

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Re: Gluing Formica onto a disk
« Reply #11 on: January 31, 2018, 02:47:00 AM »
For that last bit of trimming, the best "plane" is not a block plane but asharp (new) single-cut mill bast*rd file. (CN text sensor does not know about tool names  )
No danger of catching or cutting too deep, self leveling cut, no 'chatter' and more control over material removal with every stroke. All that and they produce a very smooth cut surface on all materials, even hardwood end-grain. I use them all the time in woodworking for final fitting of joints, etc.

I have a drawer of these kept strictly for wood and soft metals. They never see steel ! All my steel-cutting files started life as wood-only tools, eventually moving to steel use as they lost that sharp factory edge. They do stay sharp a very long time when reserved for wood-only use.

Joseph Garrison

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Re: Gluing Formica onto a disk
« Reply #12 on: January 31, 2018, 08:05:37 AM »
Thanks for the additional information. It sounds like I have some options with which to experiment.

J.T. - The waterstones are soaking now. I complete plane iron sharpening on a piece of MDF "buttered" with a very fine polishing abrasive. The iron gets the arm hair shaving test before it's reinstalled.

Bob4BVM - I don't have fresh, unused files handy, but a trip to Lowe's should take care of that. Don't know about the quality of their files, but I'll find out.

(Side story - right out of engineering school in the 70s, I interviewed for a job at a Simonds file factory in Newcomerstown, Ohio. While I didn't take that job, it was very interesting seeing how files were made. Hot blanks were struck by a sharp knife in a reciprocating machine - each strike making one tooth in the file as the blank was fed forward. The factory is gone now and I wonder if any files are made domestically today?)

bauradoubpay

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Re: Gluing Formica onto a disk
« Reply #13 on: January 31, 2018, 08:55:59 AM »
Indeed, I've wondered if any files are made domestically at all nowadays. I've noticed that the Nicholson files in the stores are made in Mexico. I was fortunate enough last month to buy several triangular saw sharpening files on eBay that appear new and unused, but are stamped "NICHOLSON Made in USA". I'm curious as to how old they must be.
I like the suggestion to keep a few files strictly for wood so they don't get worn too much to cut wood fibers crisply.
A file might do a good job indeed. Just be careful to keep it flat against the material to avoid rounding the ends. I noticed the instructions for a piece of edge Formica for my kitchen counters recommended either a laminate trimming bit on a router or a file for the final fitting after glue. I did a tidy job with a block plane to within a few thousandths though, and finished with very fine sandpaper on a hardwood block. You might want to experiment a bit with these various tools on a scrap piece of your material to see what works best for you.

nuitropheneg

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Re: Gluing Formica onto a disk
« Reply #14 on: January 31, 2018, 11:30:40 AM »
Make the seam angled instead of 90 degrees and fit it dry. When gluing it down any glue thickness will be taken up by sliding the angled joint..

Ed