G10 Fiberglass

[Alisske]

I have to admit, after some research, I came across this material a few years back when re-doing the rudder table on my boat. The rudder table sits in water a lot on my boat due to the design. Any wood table/backer plate for the steering stuffing box would get destroyed pretty quick. So I found this material and have used it now for every backing plate in the boat. (Thruhulls, prop shaft stuffing box, strut, keel bolts etc…..)

Simply put, the stuff is indestructible. (Its also a monster to cut.). I tried my table saw, and it cut well, but it was just abusive to the saw. (I apologized to my beloved table saw after such horrible actions, lol) now a-days a wet tile saw does the trick.

I just wanted to share because I am really a pessimist about material durability on boats since its such a harsh environment and this stuff has passed my expectations. . (I’m a teak, fiberglass, bronze type of guy).

 

[diver dave]

I have to admit, after some research, I came across this material a few years back when re-doing the rudder table on my boat. The rudder table sits in water a lot on my boat due to the design. Any wood table/backer plate for the steering stuffing box would get destroyed pretty quick. So I found this material and have used it now for every backing plate in the boat. (Thruhulls, prop shaft stuffing box, strut, keel bolts etc…..)



Simply put, the stuff is indestructible. (Its also a monster to cut.). I tried my table saw, and it cut well, but it was jus abusive to the saw. (I apologized to my beloved table saw after such horrible actions, lol) now a-days a wet tile saw it the trick.



I just wanted to share because I am really a pessimist about material durability on boats since its such a harsh environment and this stuff has passed my expectations. . (I’m a teak, fiberglass, bronze type of guy).

Agreed. And mcmaster car sells it in 4x8 sheets. [emoji106]. Yes, it begs for carbide.

 

[Alisske]

Agreed. And mcmaster car sells it in 4x8 sheets. [emoji106]. Yes, it begs for carbide.

My wallet just cried out loud at the thought of how much a full sheet of 1/2 inch would cost! Lmao

 

[diver dave]

Yeah, really. My sheet was just 1/4”, but shipped by truck. [emoji30]

 

[rslifkin]

G10 isn't cheap, but it's the good stuff.

 

[Comodave]

Jamestown Distributers also sells it. I have not checked prices compared to McMaster-Carr.

 

[Alisske]

Found a pic of the rudder table, Just FYI

 

[sean9c]

For small pieces or shapes a diamond grit jig saw blade works pretty well. You can get them at HD and they're not too expensive, they use them to cut ceramic tile. Carbide tipped table saw blade works well but it's tough on them so you might dedicate one blade to G10.

 

[HopCar]

G10 is the perfect material to use as a seacock backing plate.

 

[Lou_tribal]

I read an article about backing plates that was stating that it was the best material for this.
However I am wondering how it is comparing to a well made plywood/fiberglass sandwich?

L

 

[Frosty]

I have used G10 and agree it's great stuff.

For a more economical alternative (which can be fine for certain projects), McMaster Carr also sells their regular FRP board (dark green). Not up to the same spec as the G10, but you don't always need that spec.

I am wondering how it is comparing to a well made plywood/fiberglass sandwich?

L

Lou_tribal: I've used a few types of FRP board for seacock backing blocks. To me what makes them great is that they are basically inert. No plywood "filling" that could possibly rot or compress (even if coated with epoxy or even epoxy/cloth).

I can't think of why I would prefer to use plywood. Well maybe if it's what I had and I had no access to FRP board. And too, the dust from cutting it is not as obnoxious.

Edited to add: Typically a cored sandwich type construction is used to save weight and to provide stiffness. Say in a large/horizontal deck surface. To make that of solid fiberglass and have it remain stiff it would be super thick and heavy.

OTOH, you don't need "large surface horizontal" stiffness in a seacock backing block. It's so small in relative diameter that it's super stiff (and not grossly heavy) in its natural size (say 3/4" thick and 6-8" in diameter).

So I can't see why one would desire the downsides to cored construction (can compress, can get wet, can delaminate after that).

That's not to say a block like you describe might not work (I'm sure many have), but I just can't see why it would be preferred.

 

[Alisske]

I read an article about backing plates that was stating that it was the best material for this.
However I am wondering how it is comparing to a well made plywood/fiberglass sandwich?

L

Hey, plywood/fiberglassed back plates can easily last years, if not decades. Been used for a long time and has worked good enough.

That being said, get yourself a chunk of this stuff in your hand, and you’ll make the call yourself.

The stuff is some of the toughest material Ive seen. Its not your typical fiberglass that you grandad had. Lol.

Plus, scuff it up, thicken some epoxy, and slap it on a prepped fiberglass hull (I tab it in also, but I think the tabbing is unnecessary - I just had some cloth laying around) and it becomes part of the hull. So easy to use that way. When I redid my backing plates, I would fiberglass it in and drill the hole the next day. Just makes for a super clean install

I also paint it with interlux 2000e as soon as the thickened epoxy starts to set.

 

[DDW]

If you don't have a wet tile saw, the best way to cut it (in straight lines) is a diamond grit blade made for tile or concrete. Can be in a table saw or a skill saw. It makes a lot of fine dust and the dust isn't good for your lungs so keep your Covid mask on when you do it.

Another thing about G10: it is a bit stronger than aluminum alloy or hot rolled mild steel, but can be cleaved between the layers fairly easily, kind of like plywood. So screws sunk into the edge for example aren't that strong. Into the face, you can tap for machine screws and they will hold very well. If you need a thinner piece cleave it with a chisel starting at a corner.

 

[Alisske]

Ive tapped it befor, but never thought about cleaving it. Very cool. Like the stuff even more now, lol

 

[FF]

Toothed blade cutting GRP is slow and dusty , using a blade with abrasives , is less dusty and far easier to be accurate.

 

[DCDC]

G10 is very useful for instrument and electrical panels. 1/16”- 1/8” is sufficient for support. Stiff but bendable for some curvature. Able to make clean cuts for good fit to boat and components. Small panels are available online at reasonable cost.

 

[Frosty]

I've had great luck cutting any FRP board with what I call a "grit blade" in a jigsaw. I believe this is the same type of blade DDW mentioned that is meant for cutting tile. I looks like a toothless jigsaw blade "blank" with the cutting edge dipped in grit/granules. Goes through like butter, and lasts a long time (many, many cuts).

I definitely wear a good respirator and usually a Tyvek to prevent itchies. I tend to try to make all the cuts I'll need for awhile at once so I can just suit up/clean up one time (at least until the next time).

Tapping has worked well for me also.

 

[DDW]

A jigsaw grit blade works in G10, although slowly. There are now available diamond grit blades that are a little faster and last much longer (fiberglass dulls carbide fairly quickly).

The circular saw blade I was talking about doesn't look like a grit jigsaw blade, it has diamond dust imbedded in a wearing metal, looks like a wet saw blade but intended to be used dry on brick, stone, tile. You will find them in Home Depot or Lowes, a bit pricey but they do last awhile.

 

[diver dave]

I suppose if the hull inside/outside skins are not exactly parallel, plywood might have an advantage. But i use peanut butter like thickened epoxy.
Epoxy has no issue in thick sections.

 

[DDW]

You can grind G10 to any shape or taper. If doing a big area, I've scored it to depths along the taper using the diamond blade, then cleaved off the waste which gets you closer to shape before you begin grinding. Grinding G10 or any fiberglass isn't my favorite thing, but better than carbon fiber any day.

For a backing plate, G10 is around 30 times the compressive strength of plywood and does not suffer from being wet or even submersed.

 

[Frosty]

A jigsaw grit blade works in G10, although slowly. There are now available diamond grit blades that are a little faster and last much longer (fiberglass dulls carbide fairly quickly).

The circular saw blade I was talking about ...

DDW: I read your previous post too quickly and completely missed what you were saying in my previous response. I'm sorry about that. I will have to look for the diamond grit blades! (I'm a scaredy-cat with the circular saw so will probably stick with jigsaw for the FRP.)

 

[FF]

"I've decided to rebuild the existing engines. I have one of them almost ready to run. I will get started on the other soon. I'm doing most of the work myself."


The oscillating saws also work and can easily be had with grit blades for removing tile grout.

 

[Hippocampus]

Love the stuff. Unfortunately haven’t seen it in white around here. Have had some success with outdoor furniture paint sprays. What do you folks use?

 

[DDW]

G10 is a light brown or greenish color. It is only white if it has been painted. Anything works, but in the sun a PU paint like Perfection or Awlgrip works best.

Before painting (or gluing) sand it well as there is often some mold release left on the surface.

 

[Hippocampus]

Thanks. Found adhesion to be a problem. Found hit it 50-80 grit but it needs 2-3 coats of paint. Binz doesn’t help but outdoor furniture paint seems to work and last. Just wondering if anything works better.

 

[Alisske]

Love the stuff. Unfortunately haven’t seen it in white around here. Have had some success with outdoor furniture paint sprays. What do you folks use?

I found sanding with 80 grit and epoxy barrier coat is a bullet proof primer. But then again, i have just used for backing plates etc….

 

[Frosty]

Thanks. Found adhesion to be a problem.

I wipe any pre-made sheet stock of FRP (I buy from McMaster-Carr) with Interlux 202 Solvent Wash, and then a clean towel, before I do any sanding or other prep. To me the surface looks like it was laid into some kind of mold, so I want to be totally sure any mold-release wax is removed before I start sanding or etc. and potentially grind it in.

So far that has prevented any adhesion problems. I've used gelcoat, a 1-part fancy alkyd paint (such as Brightsides), and generic spray paint on various pieces and all adhered well.

 

[Dan Newland]

Dealing with G10

Hi folks

I've been building boats, rockets, submarines, AC campaigns, taught classes in advanced composites, etc. and use G10 a fair amount. G10 is very hard and strong but it is also difficult to get really good structural bonds to. West System and System 3 type epoxies don't bond all that well and have poor peel strength. A two phase toughened epoxy has a lot better bonding, in fact pretty much all of the aerospace high performance epoxy adhesives are two phase (the second phase is a separate reaction that forms an elastomer into the backbone of the epoxy molecule). There are a couple of really good adhesives you can use that come in caulking tubes and aren't hard to get.

1. Lord Chemical makes a two part putty, "Fusor T10" used in aerospace and also approved by Ford, GM, Volvo for repair of their cars by body shops and is used for original assembly. It is available on line or even through Walmart. Fusor is a viscous dark gray adhesive that I use for a lot of difficult to bond materials. It also has excellent bonds to stainless steel when the stainless is cleaned and prepared well. You will develop a serious set of biceps if you are squeezing a lot out!

2. Proset ADV 175/ADV276 or ADV 176/ADV 276, NOTE: Proset is the professional division of Gougeon Brothers epoxy. Also toughened and easy to use. It is a lot softer than Fusor and squeeze's out beautifully but it doesn't sand worth a damn.

Unfortunately they both need a special two part caulking gun although the T10 can be purchased in cans you measure.

3. Cutting is best done with abrasive saw blades. Diamond works although I normally used a carborundum abrasive blade. These are used in jig saws for cutting tile. If I'm doing a lot, I will switch to my band saw with a "gulleted" blade, i.e. a blade with notches in the bands.

4. When cutting ALWAYS use a vacuum to control dust. You paid a good chunk on money for the G10 and the itch from the dust is clearly superior to almost all other dust! Your lungs will be grateful!

5. When prepping for bonding, you need to sand the surface to get a clean, rough surface. If using a grinder with an old sanding disk, it can burn the epoxy. Use a new disk and use light pressure.

6. Clean the surface with CLEAN acetone, MEK or lacquer thinner. NEVER hold the rag against the spout!!! Pour clean solvent into the rag, (this should harken back to your ChemLab 101 in college).

Happy cutting!

Dan

 

[diver dave]

Good writeup- Dan[emoji106]

 

[Frosty]

If my post looked weird it's because I thought Hippo was referring to adhesion problems with paint onto it (not with adhering the FRP board to fiberglass structure).

**************

That said, I haven't had any issues bonding the FRP board to clean existing fiberglass (202 wash, sand, clean, plain epoxy, thickened epoxy); but then too, I don't tend to use it where I'm 100% reliant on the bond. For example I'll use it for seacock backing blocks, or under-deck backing blocks for cleats.

I haven't noticed any bond failures in the last 15 years but I also don't tend to use it in places where there are peel forces. I'd probably glass it in place if I were going to.