Official Luthiers Forum!

Thanks again to everyone who was able to join this month's roundtable meeting.

If you would like to submit anonymous feedback on topics, experience, etc... please fill out the form here - https://forms.office.com/r/HHEni87fAP

Recording:
Direct Link - https://youtu.be/swQDRewZZg0
Meeting Archive Playlist - https://www.youtube.com/playlist?list=P ... d2qUiezNGN

Episode 26 of a monthly meeting with members of the Official Luthiers Forum.

Agenda:
- Meet and Greet
- Open agenda

Attendees:
James Wud Lindley
Ken Nagy
Jay DeRocher
Brent Tobin
Don Parker
Bob Gramann
Craig Wilson
Brad Combs

See you next month!

Brad

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Thanks for setting this up Brad. I'm glad they are recorded. I missed the first part because my camera wasn't turning on. What is so hard about Zoom turning on the camera. Oh, do you really want the camera on? Come on man. Then when Bob was talking it was going in and out; then died. Our 10mbs DSL couldn't handle both the computer and a tablet at the same time! So I had to sign back in.

I know nothing about computers and electronics.

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Why be normal?

Well look what showed up under the Christmas tree this year. After this roundtable session, I may have mentioned the Assilex started kit to my wife. I may have also provided her with a link to where to find it.

Thanks to everyone who shared their experience with this product. I'm looking forward to trying it out in a few weeks on the current instrument I'm building.

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

Nice!


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Got me interested too after watching the meeting video.

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Steve Smith
"Music is what feelings sound like"

Try this. This stuff works great! https://eagleabrasives.com/sample/sampl ... or=assilex

Thanks Carl, I ordered some to try.

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Steve Smith
"Music is what feelings sound like"

I got the free sample pack awhile back. Very impressive stuff!

So, I started the final sanding/polishing on my current instrument using Assilex for the first time and I have a question for you guys. When you move to the next higher grit in the sequence, do you have a good way to tell when you've sanded enough to move on to the next higher grit? After sanding with the K-800 there were no visible scratches in the surface that I could see so I can't just sand with the K-1000 until K-800 scratches are gone. There is a definite increase in reflectivity after having sanded some with the K-1000, but I don't know if further sanding would just be removing more finish with no added benefit.

So far, I like this stuff a lot. It cuts fast, there is no gumming up, and it doesn't leave visible scratches as far as I can tell.

K-800:


K-1000:

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

What I’m thinking about at 1000 and up is just being methodical and thorough. I know that doesn’t help answer the question of when to stop. In a way it’s, when it moves from cutting to gliding, and thats a fine line. So I just try to be thorough and go up to 1500 then to the buffer.

Hope that helps. It’s great stuff for sure.


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What Brad said except I don’t think it’s that fine a line between cutting and gliding. I feel it, sometimes pretty suddenly, where the resistance to my pushing about disappears. In the finer grits, it doesn’t seem to take very long for each to get there. It seems magical.

Thanks, guys. I noticed something with the K-800 that was like a transition from cutting to gliding so I'll keep an eye out for that.

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

I noticed that feeling the other day with some really cheap 1000 grip from Harbor Freight I must have bought at least 10 years ago. I don't use much sandpaper. I was taking some grit (pigment?) bumps off the viola with oil. It could be that the paper just gave out! But it came out really smooth, but I did cut through a few small spots, so I had to put another coat on.

I never filter my varnish, it is so thick it doesn't flow through. A coffee filter worked good the first batch I made because I really thinned it with turpentine, and then filtered it when it was still hot into a large jar. Cool it would be too thick to filter. If you grind in pigment, or oil paint, the tiniest little thing will pop up. I suppose it would be best to mix up far more than I need; thin it, then let it settle. Then not put the brush all the way down, or stir.

Maybe it would filter through something after thinning it?

Edit:

Looking into paint/varnish filters, there is a dizzying array of them. Some say the microns. I wouldn't know. Will varnish flow through a medium filter; 226 microns? I'm guessing that is the Trimaco 5 3/4 filter Home Depot sells in a 4 pack. Maybe I should pick some up the next time I go into town.

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Why be normal?

Here's an update on my use of Eagle abrasives. After sanding with the K-1500, the surface it left was very nice. No visible scratches, but the reflectivity was not very high. For the last several instruments, I used Abrilon pads to sand the finish up to their 4000 grit which left a very reflective surface. For the heck of it, I sanded the K-1500 surface on the back of the mandocello with Abrilon 4000 and got a very reflective surface BUT with visible micro-scratches. I think I now know where the micro scratches in the final finish that have been driving me crazy have been coming from. So, I re-sanded the back with K-1500 and got back to no visible scratches but low reflectivity.

Assilex K-1500:


So, I ordered the Bufflex starter kit. After sanding with the K-2000 and K-2500, I got a very reflective surface AND with no visible scratches. Yes!

Bufflex K-2500:


Here's a closeup of the reflection in the K-2500-sanded surface of the ceiling light above the bench which has LED arrays:


Now, here's the really weird part. I then sanded with the highest grit Bufflex K-3000 and it cut much more aggressively than the K-2000 or K-2500 and completely removed the reflectivity. It says 3000 on the back of the sheet and it's black which is the correct color. I re-sanded with the K-2500 and recovered the high reflectivity. What the heck? So, for now I'm good with K-2500 and I'm really looking forward to seeing how it looks after the buffer.

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

Thanks for keeping the updates coming , Jay. I think you’ll find the buffing will go much faster.

I only go to K-1500 but I probably go more course buffing compound than you are using too.



Brad


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Yea, I've been using P204 and P175.

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

Looking good…

Sorry I missed this round table. I've been using the Tolecut refinishing kit from Eagle Abrasives for spot finish repair - the product exceeded my expectations. Part of the magic is the small size and rigid pads, and the self stick action of the sheets to the blocks.
I have reused the pads multiple times and they clean off easy on cotton bath towel: https://a.co/d/g3fhLbE

I've read many forum comments across the finishing space about starting with a standard abrasive paper for the first finish sanding. I'm switching to the assilex on my next guitar which should be up in a month or so, I'm glad to see this Round Table thread.

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Measure Twice,

Karl Borum

Here's the final result and it's the best finish I've produced to date. Happy camper and I'll be using Assilex and Buflex from now on.

Endurovar over SilverTip epoxy, sanded with Assilex 800, 1000, 1200, & 1500 and Buflex 2000 & 2500, buffed with Menzerna P204 & P175, and polished with Meguiar's Mirror Glaze #10.

I sanded the top and back to 2500 and the sides to 1500 and then went to the buffer. I got much better results on the top and back (2500) than on the sides (1500) maybe because I went to the medium cut P204 Menzerna. Brad goes to the buffer from 1500 but he buffs starting with the coarser GW18 Menzerna.

I messaged Eagle Abrasives and asked why the high reflectivity I saw after sanding with the K-2500 was removed when I then sanded with the K-3000. They had a couple possible explanations. First that maybe I had used too much pressure with the K-3000. I'm sure it wasn't that because I follow the rule of letting the sandpaper do the work. They also said it's important to use the Super Buflex Extra Soft Interface Pad (971-0068) for sheet grits 2000-3000. I had used a hard interface pad. However, the Buflex starter kit strangely comes with a soft interface pad that's specific for Buflex, but doesn't come with the Extra Soft Interface Pad. I tried sanding the K-2500-sanded surface with the K-3000 on the soft pad and it removed the reflectivity again. They also said that reflectivity may not be a good indicator of how fast the finish will buff out.

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

Man, that is lovely!!


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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

Jay, is that Original EnduroVar or the "new" one?

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

Stunning, Jay!

It's the original. I just opened my last can of it. I'm thinking I'll need to try the Endurovar II by the end of this year. Have you tried it?

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

Yes, not very successfully. Seems very different to the original, which I really liked

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.