User Tools

Site Tools


projects:crokinole_board:work_logs:work_log_4

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revisionPrevious revision
Next revision
Previous revision
projects:crokinole_board:work_logs:work_log_4 [2019/07/08 11:46] – [What I want to accomplish next time] tjhowseprojects:crokinole_board:work_logs:work_log_4 [2022/01/23 00:23] (current) tjhowse
Line 1: Line 1:
 {{indexmenu_n>4}} {{indexmenu_n>4}}
 +[<6>]
 ====== What I want to accomplish ====== ====== What I want to accomplish ======
-  * Cut out the main board.+  * Determine how to mark the lines on the board.
  
 ====== What I've done ====== ====== What I've done ======
  
-=== Aaarrgh! Scary! ===+=== Experiments === 
 +Other people have used V-shaped router bits to gouge the circles and lines into the board, then filled them with paint. I did a few experiments with that technique and found it hard to get reliable results. If it goes wrong the entire top board is a write-off, so I was very nervous. If the pivot point moves by a tiny amount the circle won't meet up at the end of the sweep, and that would be unfixable. The specification calls for the lines to be between 1/16" and 1/8". It didn't take much slop in the system for the depth and cleanliness of the cut to be significantly affected.
  
-I worried for a long time about this, and did lots of test cuts and preparation. It was the only nice piece of plywood for a reasonable price I could fit in my car. If I ruined it I'd have to spend more time and money getting a new bit. Stakes were high. My woodshopping table had a bend in it, so I belted it with a hammer for a bit until it was flattish, I then laid some particle board offcuts over it as as buffer.+{{:projects:crokinole_board:work_logs:pasted:20190710-121328.png}}
  
-=== Cut === +I attached a bolt to the side of a router dremel attachment, thinking the smaller tool would give me more control, but I didn't have good success here eitherThough I got nice clean grooves cut in scrap wood when freehanding, I couldn't get reliable results when drawing big circlesIt was too easy for the pivot to jam slightly, or the dremel to tip, and ruin the groove.
-{{:projects:crokinole_board:work_logs:pasted:20190708-113503.png}} +
-{{:projects:crokinole_board:work_logs:pasted:20190708-113656.png}} +
-{{:projects:crokinole_board:work_logs:pasted:20190708-113703.png}}+
  
-Marvellous! Nice sharp edges, no wonky bitsTwo minor burn marks where had to stop and change arm positions, but they will sand out easily. I exposed three minor voids in the edge as I was cutting. I haven't quite worked out what to do with them. I might fill them with sawdust and PVA glue, or I might rout the circle down a little smaller and put oak banding on this part too. That would look nice, but it would mean buying more wood.+Instead I decided to go with a black permanent marker. I can easily build a lightweight circle-drawing jigIf it goes bad can simply wipe off the ink with a solvent. I ran some trials and got some good data.
  
-I gave the circle a light sand with some 180 grit sandpaper and a cork sanding block. I could feel no irregularities in the surface at all. It was all very nicely smooth. I went over it again with some 240 grit to remove the marks from the 180 grit. I also sanded around the edge, being very careful not to create any flat spots. Some parts had some fuzzy burrs leftover from the routing, but they fell away with light sanding.+{{:projects:crokinole_board:work_logs:pasted:20190710-123018.png}} 
 +The marker used.
  
-came back to my workshop a few hours later to put another coat of varnish on a test piecewhen I noticed that the antlions under my workbench had cleared the sawdust out of their holesVery cool+had gone through five varnish -> light sand cycles to this piece of scrap ply before drawing on it with the marker. I drew some straight-ish linesa black patch and a big squiggle then let the ink dry for half an hour. I then drew some fresh lines as a comparison a few minutes before varnishing. I noticed that some of the ink had wicked out slightly from the lines. I suspect this would be wicking along the scratch lines from the sanding. 
-{{:projects:crokinole_board:work_logs:pasted:20190708-114430.png}}+ 
 +The ink did not streak or bleed during or after the varnishing! Great success! 
 + 
 +{{:projects:crokinole_board:work_logs:pasted:20190710-122131.png}} 
 +{{:projects:crokinole_board:work_logs:pasted:20190710-122326.png}} 
 +{{:projects:crokinole_board:work_logs:pasted:20190710-122333.png}} 
 + 
 +After that coat of varnish had dried I gave it a light sand in preparation for another coatI think I sanded a bit too hard because I broke through the previous layer of varnish and erased some of my lines, though many were unaffected. 
 + 
 +{{:projects:crokinole_board:work_logs:pasted:20190710-122939.png}} 
 +{{:projects:crokinole_board:work_logs:pasted:20190710-122958.png}} 
 +These photos show two coats of varnish atop the ink. 
 + 
 +I think my solution to this will be ensuring my varnish sandings are sufficiently gentle, and perhaps re-marking lines if they start to fade during the subsequent varnish layers. Overall I think this technique looks great and it's likely the one I'll be using on the final board.
  
  
 ====== What I want to accomplish next time ====== ====== What I want to accomplish next time ======
  
-  * Varnish a piece of scrap ply and sand itthen varnish itthen sand it... +  * Cut out the top, 
-  * Work out how to mark the lines on the board.+  * Glue the offcuts and cut out the base, 
 +  * Drill the hole in the centre of the top
 +  * Attach the bands to the base. 
 +[<6>]
projects/crokinole_board/work_logs/work_log_4.1562586393.txt.gz · Last modified: 2019/07/08 11:46 by tjhowse