Author Topic: Question about how Jimmy Lewis faired the overlap in this video...  (Read 17765 times)

magentawave

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Near the beginning of Jimmy Lewis's video (below) he shows a super trick way of using a grinder to fair where the cloth meets the masking tape. I have always used a single edged razor blade but this seems way better. Anyone done this?

1) What grit do you think I should use to do this? 60??

2) Would this method work with 5.7 oz carbon cloth?

Thanks

Pluto Platter: 7-10 x 29.25 x 4.25 x 114.5 liters

TallDude

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Re: Question about how Jimmy Lewis faired the overlap in this video...
« Reply #1 on: March 08, 2019, 02:46:18 PM »
First of all. Great video. Anyone who knows Jimmy personally, please tell him that a novice kook glasser like me really appreciates him sharing his secrets.
As for the grit, maybe 120 or 180? I've faired the lap with both. I use a Sureform pocket plane to fair the 5.7 CF by hand first (if you have CF in your lap). It's pretty tough. I'd be worried with 60 or 80 on just Glass. You could do some damage in the blink of an eye. 
It's not overhead to me!
8'8" L-41 ST and a whole pile of boards I rarely use.

Bean

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Re: Question about how Jimmy Lewis faired the overlap in this video...
« Reply #2 on: March 08, 2019, 03:04:46 PM »
It seems that he hits it with a grinder first then switches to a soft pad.  The grinder is probably in the sub 50 grit range, and the soft pad in the mid 100’s like TD said.

Sanding CF isn’t difficult but it is a carcinogen for sure, so be careful.

Yup, JL rules...

TallDude

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Re: Question about how Jimmy Lewis faired the overlap in this video...
« Reply #3 on: March 08, 2019, 04:56:59 PM »
A little off subject, but I was walking through the CNC dept. at the College I teach at part-time. I looked in a room and saw surfboard blanks and a board cutting CNC machine! I talked to the dept. manager and he said if bring in the foam and the file in 3Dx he'll get a student to cut it for me ;D I have the foam and the file already!
It's not overhead to me!
8'8" L-41 ST and a whole pile of boards I rarely use.

PonoBill

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Re: Question about how Jimmy Lewis faired the overlap in this video...
« Reply #4 on: March 08, 2019, 06:04:25 PM »
Near the beginning of Jimmy Lewis's video (below) he shows a super trick way of using a grinder to fair where the cloth meets the masking tape. I have always used a single edged razor blade but this seems way better. Anyone done this?

1) What grit do you think I should use to do this? 60??

2) Would this method work with 5.7 oz carbon cloth?

Thanks



Yeah, I always do it with a grinder. Most of my work is repairs or modifications, so I can't comment on a full lap, but I expect I'd do it that way.

Jimmy is fun to watch. He keeps up a running commentary as he works, that has nothing to do with what he's doing. He's got no filter, even less than I do. I don't know how they kept him on the straight and narrow to do this video.
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

toolate

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Re: Question about how Jimmy Lewis faired the overlap in this video...
« Reply #5 on: March 08, 2019, 11:09:03 PM »
my goodness watching a master at work is something!
What a great guy!

magentawave

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Re: Question about how Jimmy Lewis faired the overlap in this video...
« Reply #6 on: March 09, 2019, 01:10:10 PM »

Yeah, I always do it with a grinder. Most of my work is repairs or modifications, so I can't comment on a full lap, but I expect I'd do it that way.

Jimmy is fun to watch. He keeps up a running commentary as he works, that has nothing to do with what he's doing. He's got no filter, even less than I do. I don't know how they kept him on the straight and narrow to do this video.

What grit would you recommend for fairing the lap of a 5.7 oz carbon, Bill?



A little off subject, but I was walking through the CNC dept. at the College I teach at part-time. I looked in a room and saw surfboard blanks and a board cutting CNC machine! I talked to the dept. manager and he said if bring in the foam and the file in 3Dx he'll get a student to cut it for me ;D I have the foam and the file already!

Score!!!
« Last Edit: March 09, 2019, 01:12:51 PM by magentawave »
Pluto Platter: 7-10 x 29.25 x 4.25 x 114.5 liters

outcast

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Re: Question about how Jimmy Lewis faired the overlap in this video...
« Reply #7 on: March 09, 2019, 02:52:56 PM »
I just used 120 to take down a similar edge on some  6ish Carbon

The tape definitely defines a line to come down to   I got lucky and was able to bring the tape up to perpendicular when things were late tacky.... ..maybe 150 if you are just gonna finis there.....

Definitely helps to have some sacrificial 4oz glass on top 

And yeah appreciate JL's vid....I use the new Glad wrap for poor mans vac bag and smaller  areas...it's nice to pull it smooth
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PonoBill

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Re: Question about how Jimmy Lewis faired the overlap in this video...
« Reply #8 on: March 09, 2019, 04:16:59 PM »
I use 60, I use the same pad as Jimmy does, though I got the idea from Meister talldude. I'm addicted to them, I have four different pad firmness's on four different angle grinders. I didn't have to buy any, body grinders are one of those tools that seem to accumulate. They're too big to store in an easy to remember place, so when you need one you have to buy one. Last time I did that was after I bought the pads and couldn't find anything to spin them. I opened a big drawer to put away my new purchase and found three more.

The trick to getting a clean cut on the tape is to use the softest pad and go flat on the tape. For smaller repairs I've doubled up the tape a few times and that makes it even easier. If you don't push hard on the glass that laps past the tape, just lifting the masking tape will pop off the glass, even if it's fully set. You want the epoxy to be rock hard or it will gum up your sanding disks. Those bugguahs ain't cheap.
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

magentawave

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Re: Question about how Jimmy Lewis faired the overlap in this video...
« Reply #9 on: March 09, 2019, 06:31:39 PM »
I use 60, I use the same pad as Jimmy does, though I got the idea from Meister talldude. I'm addicted to them, I have four different pad firmness's on four different angle grinders. I didn't have to buy any, body grinders are one of those tools that seem to accumulate. They're too big to store in an easy to remember place, so when you need one you have to buy one. Last time I did that was after I bought the pads and couldn't find anything to spin them. I opened a big drawer to put away my new purchase and found three more.

The trick to getting a clean cut on the tape is to use the softest pad and go flat on the tape. For smaller repairs I've doubled up the tape a few times and that makes it even easier. If you don't push hard on the glass that laps past the tape, just lifting the masking tape will pop off the glass, even if it's fully set. You want the epoxy to be rock hard or it will gum up your sanding disks. Those bugguahs ain't cheap.

I just used 120 to take down a similar edge on some  6ish Carbon

The tape definitely defines a line to come down to   I got lucky and was able to bring the tape up to perpendicular when things were late tacky.... ..maybe 150 if you are just gonna finis there.....

Definitely helps to have some sacrificial 4oz glass on top 

And yeah appreciate JL's vid....I use the new Glad wrap for poor mans vac bag and smaller  areas...it's nice to pull it smooth

Thanks everyone for replying. Have a few more questions...

1) I'm concerned about the edge of the 5.7 oz carbon getting "fuzzy" and funky when I sand the edge down to the masking tape. Are you able to get a clean line next to the tape WITH CARBON like Jimmy did in the video even though he was using fiberglass cloth? Will the carbon kinda "crack away" from the tape line like Jimmy said it does with fiberglass cloth?

2) My backing pad is rigid rubber like this http://tinyurl.com/y2h7fy43 which is similar to what Jimmy is using in the video. (See image below) Is that what you guys use to fair the cloth edge to the masking tape?

3) In one of the videos you can see a box of Home Depot Husky Painters Plastic Sheeting (0.31 mil) just like this: http://tinyurl.com/y2jhnlgf   Are you using 0.31 mil too?

« Last Edit: March 09, 2019, 06:40:34 PM by magentawave »
Pluto Platter: 7-10 x 29.25 x 4.25 x 114.5 liters

PonoBill

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Re: Question about how Jimmy Lewis faired the overlap in this video...
« Reply #10 on: March 09, 2019, 06:55:45 PM »
If you look at the video about 2 minutes in you'll see the pad system I use. I also have a Festool angle grinder/vacuum with a selection of different pad stiffness's.

If the carbon is well saturated and you take it off right at the tape it will probably not fuzz much. I almost never use carbon without at least one layer of 2 OZ glass on it.
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

magentawave

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Re: Question about how Jimmy Lewis faired the overlap in this video...
« Reply #11 on: March 09, 2019, 07:37:10 PM »
If you look at the video about 2 minutes in you'll see the pad system I use. I also have a Festool angle grinder/vacuum with a selection of different pad stiffness's.

If the carbon is well saturated and you take it off right at the tape it will probably not fuzz much. I almost never use carbon without at least one layer of 2 OZ glass on it.

A) I want to keep the weight down for this repair but was thinking I should probably do a 2 oz veil over the carbon. What's the big advantage to putting 2 oz cloth over carbon? Less chance of sanding through later?

B) Do you put the 2 oz down at the same time as the carbon?

C) The only 2 oz locally is mat. Is mat okay or does it need to be cloth?

Pluto Platter: 7-10 x 29.25 x 4.25 x 114.5 liters

TallDude

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Re: Question about how Jimmy Lewis faired the overlap in this video...
« Reply #12 on: March 09, 2019, 09:12:01 PM »
If you look at the video about 2 minutes in you'll see the pad system I use. I also have a Festool angle grinder/vacuum with a selection of different pad stiffness's.

If the carbon is well saturated and you take it off right at the tape it will probably not fuzz much. I almost never use carbon without at least one layer of 2 OZ glass on it.

A) I want to keep the weight down for this repair but was thinking I should probably do a 2 oz veil over the carbon. What's the big advantage to putting 2 oz cloth over carbon? Less chance of sanding through later?

B) Do you put the 2 oz down at the same time as the carbon?

C) The only 2 oz locally is mat. Is mat okay or does it need to be cloth?
Definitely 2oz cloth, at least.  https://www.fibreglast.com/category/Surfacing_Veils    I think the 4oz is fine too. You're going to sand half way through it anyway. You need something over the CF.
If I was doing a long 14' to 18' race board with a hand layup, I would do the CF, let cure, then Veil 2oz. For a surfboard, I'd do it just like Jimmy. If you notice, his CF is held way back from the lap. He doesn't have to deal with the CF edge.
The stiff grinder pad will cut a narrow line along the tape line. The softer pads will flex and sand a wider, less accurate line. You can do it with the yellow pad, you just have to float it so just the outer edge of the sanding disk is making contact.
It's not overhead to me!
8'8" L-41 ST and a whole pile of boards I rarely use.

outcast

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Re: Question about how Jimmy Lewis faired the overlap in this video...
« Reply #13 on: March 10, 2019, 09:48:22 AM »
definitely  some glass cloth over... 4oz for me cause i have a roll with a  fine weave.

Mat 2oz i think would just pull apart and be uneven

That CF is thick and rough....the glass lets you work in the poxy without pulling the cf apart, and it gives you an edge taper  for a nice edge. i overlay just a 1/2 "  past  the cf.....Hard to cut the CF cloth that thick and have a nice fine edge....the glass kind of holds it down and smooths it    Again, alot of it comes off

Kick it all off at once=stronger, two distinct layers probably gives a  finer finish

I am not 60 grit certified....i would create much bigger problems....but again i love lifting the tape when late tacky-stiff from outside edge towards the cloth and at that point you can cut the glass right at the tape line with a razor   Timing is everything
« Last Edit: March 10, 2019, 09:56:54 AM by outcast »
Too many for the rack
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magentawave

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Re: Question about how Jimmy Lewis faired the overlap in this video...
« Reply #14 on: March 10, 2019, 11:50:54 AM »
definitely  some glass cloth over... 4oz for me cause i have a roll with a  fine weave.

Mat 2oz i think would just pull apart and be uneven

That CF is thick and rough....the glass lets you work in the poxy without pulling the cf apart, and it gives you an edge taper  for a nice edge. i overlay just a 1/2 "  past  the cf.....Hard to cut the CF cloth that thick and have a nice fine edge....the glass kind of holds it down and smooths it    Again, alot of it comes off

Kick it all off at once=stronger, two distinct layers probably gives a  finer finish

I am not 60 grit certified....i would create much bigger problems....but again i love lifting the tape when late tacky-stiff from outside edge towards the cloth and at that point you can cut the glass right at the tape line with a razor   Timing is everything

outcast, laying down the carbon and the veil at the same time and overlapping the veil 1/2" past the carbon won't work for this application because I need a clean cut where the carbon meets the tape. (I should have mentioned before that I won't be applying paint later.)



Definitely 2oz cloth, at least.  https://www.fibreglast.com/category/Surfacing_Veils    I think the 4oz is fine too. You're going to sand half way through it anyway. You need something over the CF.
If I was doing a long 14' to 18' race board with a hand layup, I would do the CF, let cure, then Veil 2oz. For a surfboard, I'd do it just like Jimmy. If you notice, his CF is held way back from the lap. He doesn't have to deal with the CF edge.
The stiff grinder pad will cut a narrow line along the tape line. The softer pads will flex and sand a wider, less accurate line. You can do it with the yellow pad, you just have to float it so just the outer edge of the sanding disk is making contact.

I'm confused about the part above (in red) where you said Jimmy used carbon fiber cuz I didn't see that?? Again, I'll be doing a clear finish (no pigment or paint afterwards) so I definitely will be dealing with the edge of the carbon. Having said that, should this be the procedure I should follow...

1) Lay down the carbon, let cure, fair to the tape, fair the rough stuff. (If needed, I can "clean up" the cut line with black acrylic paint.)

2) Do the same with the veil but let it overlap the carbon a little.
Pluto Platter: 7-10 x 29.25 x 4.25 x 114.5 liters

 


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