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Lessons learned from my first CA finish
This past weekend I posted pictures of my first set of scales finished in CA (see here). Today I thought I’d share some lessons learned.
TYPE OF GLUE - First I recommend trying the thin CA formulation. I started my scales with the normal medium Gorilla brand super glue. I didn’t purchase any thin CA until I had already applied about 10 coats of medium. I applied a coat of thin on top of the Gorilla glue and immediately noticed that the thin applies much smoother with far fewer stroke marks that need to be sanded out. I also noticed that less glue is needed for each coating – one or two drops are all that’s really needed to completely coat the scale. In any event, I’ve made additional CA scales now and have used the thin glue for both a wash coat and as a final coat and this seemed to work well for me.
SUPPORT JIG – I made my jig using pencils drilled into a scrap piece of wood, as demonstrated in another user’s post. This works well, but the graphite/lead does leave marks on the scale if for some reason the tape falls off. I ultimately took the stand to the drill press and drilled out the pencil lead.
TYPE OF TAPE – I started the project with good ‘ol fashioned clear double sided tape. This does not work very well, especially if the tape gets coated with sanding dust. Carpet tape worked much much better. I also tried filling the pencil lead holes with 1/16 pinstock so I could “stake down” the scales for an extra secure platform. I found that the CA just bonded the scale and pins together, creating an unnecessary separation step at the end of the process. Carpet tape alone worked the best. (For the insides of the scales, I was able to get by without any support jig because the glue is not needed to wrap around the sides of the scales.)
TYPE OF GLOVES – I originally started the project using disposable plastic gloves (the kind the guys at the supermarket deli use). I later switched to a latex/rubber type glove and noticed that this glove left a slightly smoother finish. A previous poster recommended even trying bare fingers. I tried this too and, yes, it does generate a smooth finish, but the cleanup afterwards wasn’t worth it to me (although acetone does help).
INSIDE OF SCALES – Coating the inside of the scales was done first and was relative easy. However, keeping the bottoms clean when applying CA to the outside of the scales was a challenge. I seemed to spend more time than necessary sanding off the driplets that formed on the inside of the scales. I ultimately had to drop down to 200 grit sandpaper to speed up the sanding process.
SANDING PROGRESSION – I usually sanded each coat lightly with 200 grit sandpaper and escalated to the other grits only every third coat or so. For every third coat I used 400/1500/2000 (and 200 only if needed). For the final coat I replaced the 200 with 800 as follows: 400/800/1500/2000. The key, as Glen’s excellent tutorial states, is to remove all shiny spots with the 400 before moving onto the other grits. After 400, I only did very light and quick sanding. (I have since purchased some micro mesh sandpaper – will have to give them a try.)
DRILLING – The CA will fill the holes, requiring redrilling. I recommend drilling from the back of the scale. I once drilled from the front and misaligned the drill press and created an error that I attempted to fill with CA and sawdust. The fix left a noticeable blemish. Had I drilled from the back, I could have caught the error quicker and the error would have been hidden and far less a problem.
TYPE OF WOOD – I have now made several CA scales. It might be my imagination, but I’ve noticed that different woods appear easier to work with. For example, lignum vitae was much more effort to sand between coats than say Honduran rosewood. This did not make sense to me because when sanding you’re only sanding off a thin layer of CA, not the wood itself – so the type of wood should not matter after the first coat or so, right? But I nevertheless noticed a difference. The rosewood sanded clean with minimal effort.
POLISHING – I eventually purchased some Turtle Wax rubbing compound, but for my first set of CA scales I did not have any handy. What I used instead was some Dico plastic buffing compound on a sewn cotton wheel. This compound produced the same glassy finish as the Turtle Wax did for subsequent scales, but with less mess (and less expense). (As a side note: plastic scales with scratches or file marks can be restored to shiny factory new with 400/800/1500/2000 sandpaper followed by the Dico compound – you might be surprised how shiny and perfect looking old beaten up scales can become!)
ACCELERATOR – I really wish I had some accelerator spray. The process took a long time due to the wait time between coats. For future projects I’m definitely going to experiment with some accelerator spray.
Overall the process was reasonably straightforward. Was a lot of fun too! Thanks for reading.
Brian
