What Pad is best for foiling fiberglass Fins?

General Discussion
1

Just curious what most are using

Have been foiling fins with my medium 8"power pad with a variable speed grinder. The smaller fins have been challenging with the larger pad.

I see that probox Larry suggests the 6" hard powerpad with the drill attachment in his bamboo post. Others recommend soft pads.

I like the control the variable speed gives me and am not comfortable enough to use the angle grinder

Thanks

cj

2

I prefer small diameter (4-5") stiff pads. for me the small diameter makes it easier to get the trailing edge of typically shaped shortboard fin. Most of the pads I use for fins don’t have any foam on them.

3

Hey Christian…

Really hard and thin pads are best for foiling…better control. I have a festo one I nicked from somewhere, but I imagine powerpads would do one.

Josh

4

over a long period of trial-and-error, I found a 4" hard disk on a High-speed angle grinder

is best. 11,000 rpm and 36 grit. Takes few tries to get good at it, but it’s quick and

accurate. Well worth the effort. I’ve used this method for glass and wood fins

for over 30 years.

With that said I know a guy at a fin production company who uses a hard Power Pad

on a single speed grinder and 50 grit and gets the same results on glass fins. He runs

into slight accuracy problems when doing all-wood fins, and ends up blocking them out.

HTH,

George

5

Hey Christian,

Whatever you end up using, a tip:-

Do the leading edges first…this allows a better area for fixing the clamp than when the leading edge is already done…

Josh

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6

4-4.5 inch high speed angle grinder

Plastic pad, no foam.

24 grit or 80 grit for most of the work.

Move the grinder from base to tip along contour

lines of equal thickness. Or stick the grinder

in the vise and move the fin the same way.

Take a big fan and blow the dust away from you while

you grind.

7

Hey cj3,

We use the 6" Hard PowerPad on the variable speed Milwalkee set around 2,500 rpm. 60 or 80 grit to foil.

In my experience 4" grinders require many more passes to take away material.

I stick side fin pairs together with 3M Super77 and foil them at the same time. It’s easy to check symmetry that way.

~Brian

www.greenlightsurfsupply.com

8

Thanks everyone

Blakestah,George -

Could you point me in the right direction on where to get the 4" hard discs that you use. The local hardware store in Santa Cruz does not have much wrt sanding pads.

Powerpad look like they only come in 8" and 6" sizes

I have made a my first few sets of fins based on Greg Griffins templates in G10 with some sucess but the little ones in the rear are a little more challenging to for me to foil. I think the smaller pad should help

Thanks again

CJ

9

cj3-

I got the disk at the same place as the 4" grinder. It’s a hard plastic disk with

no soft foam backing on it. The grit disk is the same as for automotive grinding,

aluminum oxide 36 grit, red-resin impregnated.

HTH,

George

10

cj i got a 7 inch pad and held the grinder in the vice a got knife and held it agains the pad surface

it drew a circle on the pad as the grinder spun round

then i took it off the machine and cut it with a stanley knife

the i held a surform up against it as it was spinning and trued up the pad

the grinder was 5 inch variable speed

this is excellent machine for foiling fins

angel grinders are too fast have kick when using thicker pads and disks

i can run the grinder at about 2000

real easy

btw holding a knife/scredriver against a spinning pad is probably dangerous

but it seemed easy at the time and the grinder was slow spining

i held it firmly in two hands and the ofcourse the disk was spining away for the blade

a safer way would be to get some dividers and mark it with the dividers

then cut it then true it up with a surform

11
Quote:

Just curious what most are using

Have been foiling fins with my medium 8"power pad with a variable speed grinder. The smaller fins have been challenging with the larger pad.

I see that probox Larry suggests the 6" hard powerpad with the drill attachment in his bamboo post. Others recommend soft pads.

I like the control the variable speed gives me and am not comfortable enough to use the angle grinder

Thanks

cj

Hi cj, I only recommended a 6" hard pad on a drill for home builders foiling a Bamboo fin which is a tool most home guys have.

In our factory we foil using a 50 grit on a angle grinder then we soft pad the fin with a Medium Power Pad using 80 grit paper like PlusOne states. If you feel nervous using a angle grinder, us a finer grinding disc grit which takes less off at a time. I will post some pics in a few days showing you these steps.

Mahalo,Larry

12

Thanks Larry for the reply and I look forward to seeing your pics when you get the time.

CJ

13

I will try to get pics tomorrow. Mahalo,Larry

14

I agree with Plusoneshaper and Blakestah. I have used the small angle grinder with 24 or 36 gt. to foil glass and wood skegs for years. You get a much better “feel” of the tool with a small angle grinder than with a larger disc machine on something as small as a skeg (fin). I’m right handed so I go with left to right continuous passes along the edges just like doing rail bands. I clamp the skeg down flat with the edge I’m working on hangin out over the bench, then move the skeg around and work other sides, etc. Have tried many methods and this one is best for me. Ask 20 people and get 20 answers, but experience is the best long run teacher. Bottom line: Whatever works best for you personally is the way to go. It’s just a good idea to get advice from those who have been there and try different ways before settling in on your way. The two goals are accuracy and efficiency, so the angle grinder does both for me.

Enjoy the ride!

Richard

15
Quote:

Thanks everyone

Blakestah,George -

Could you point me in the right direction on where to get the 4" hard discs that you use. The local hardware store in Santa Cruz does not have much wrt sanding pads.

IIRC, the Home Depot just south of SF was where I got the angle grinder, the hard pad, and the sanding discs.

16
Quote:

Thanks Larry for the reply and I look forward to seeing your pics when you get the time.

CJ

Hi Cj, Here are some pics has I promised you.

Here’s a grinder we use with 50 grit disc.

The next two pics shows the grinder in use.

Mahalo,Larry



17
Quote:
Quote:

Thanks Larry for the reply and I look forward to seeing your pics when you get the time.

CJ

Hi Cj, Here are some pics has I promised you.

Here’s a grinder we use with 50 grit disc.

The next two pics shows the grinder in use.

Mahalo,Larry

Hi Cj, Here is the machine we soft pad with.

The next two pics are showing the machine in use.

Mahalo,Larry



18

choooicce

modded multigrips

thanks larry

wheres ya dust extractors

cmon guys this is the nortys

19

itchy koo park

                   im not having my lunch on that bench larry



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20

Christian,

I used a 7" sander polisher with a hard and soft pad. grit from 40 to 120. This was choice for windsurf fins and longboard fins.

For the small quad and thruster fins, I now use a 4 1/2" grinder with the plastic or rubber backer with 24 or 36 grit alu oxide, same as Blakestah. You have to get used to the speed, but with G10, shouldn’t be a problem. Small size makes it much easier to handle on small fins and in a way safer,as there is no soft foam to catch on the fin tip!