Filler Options for Fillet PB - what can I use

VolleyGirlSC

Seaman
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Aug 9, 2012
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55
Hi - I am hoping the experts here can help me.

We are using poly resin to install our new transom and fillet it in. I have colloidal silica (1G), Milled Fiber (0.5G), West Systems 403 microfibers & West System 404 High density fibers. Are chopped strand glass or microballons a must have for fillets? From what I've read online, I don't think I have to have them, but I would like the opinions of the more experienced here to confirm.

Can i use the West Systems fillers I have on hand with poly resin?
Will a combination of colloidal silica and milled fiber work for fixing the transom to the hull and filleting it?
What ratio of colloidal silica and milled fiber should I use if I go that route?

Any advice is greatly appreciated!
 

ondarvr

Supreme Mariner
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Re: Filler Options for Fillet PB - what can I use

You can use just about anything you want in any combination to fine tune the end product to the consistency you desire. Fibers of any length make it more difficult to work with, and the more you add the less cooperative it will be, but will increase the strength a little. Silica will thicken it and reduce the sagging, microballons will make it lighter and easier to sand. The ratio depends on how you plan to use the putty and the exact resin you mix them with.
 

saginawbayboater

Senior Chief Petty Officer
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677
Re: Filler Options for Fillet PB - what can I use

IMHO yes you do need the thickener so your resin isn't a liquid, hence the word peanut butter, and the chop strand makes the fillets structural, or in other words gives it its strength.

Being new to fiberglass work I had to do some homework. I am using 435 Poly from UScomposites in my resto and I live near the West System home base of Bay City Michigan and around here I can only find West System product. I prefer cabosil and chopped strand to make PB with Poly. I ran out of cabosil so I checked out the WS fillers. What I found was WS fillers have saw dust and walnut shells and those types of materials and they can soak up water. Poly needs fillers that won't atract water like cabosil or glass bubbles. I am not sure about micro balloons!! The Pro's can correct me where I'm wrong!!!

I prefer cabosil because it is translucent to a point. It makes it easy to see bubbles and problem areas. Like I said I ran out of cabosil and I was hurrying trying to get somethng to work with for the weekend and all I found was WS fillers and I ended up taking them back to the store. I had glass bubbles but I didn't like them as much for filleting because they make the PB white and its hard to see imperfections in the work.

I mix 1.5 quarts cabosil to 1 quart resin plus about a quarter to half cup of 1/4" chopped strand.
I was always running out of cabosil while installing transom and stringers because I was getting a 5quart container. I think I used more than 5quarts in the transom alone. The chopped strand I bought 2 lbs and after the transom and stringers I still have quite a bit left. I would recommend the 4 gallon size of cabosil from UScomposites you will go through it repairing transom strings and deck.
Take Care!!!
 

VolleyGirlSC

Seaman
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Re: Filler Options for Fillet PB - what can I use

Thanks for the assistance. We went ahead and used the silica and the milled fibers to bed the transom and it worked really well. We are going to get some chop strand from TAP to do the fillets for the stringers though.
 

Georgesalmon

Lieutenant Commander
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Apr 14, 2012
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Re: Filler Options for Fillet PB - what can I use

cabosil is a brand name not a product. I don't know what colloidal silaca is but cabosil is "fumed" silica and is just a light weight filler used to make the resin thick for working with. It has no strength to speak of. Other filler are fine to. Gelcoat used to maybe still can have walnut shells in it along with fumed silaca and other stuff to make it thixotropic and you never hear about gelcoat soaking up water. Milled fibers are just fine for using in PB type material you don't need to buy chopped strands they are the same thing but maybe longer. Typically i see 1/8 or 1/4" milled fibers but there are more sizes. I believe that chopped strands also contain binder which has been blamed for blistering in the past. Milled fibers have no binder. "binder" often a chrome silane type is the glue used to hold bundles of itty bitty glass threads together. When the "white" fiberglass gets clear after putting resin on it the binder dissolves in the styrene and thats when it gets clear. The time it takes to get clear is called wetout time and is one of the criteria used by glass suppliers when evaluating fiberglass materials for manufacturers.
 

ondarvr

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Re: Filler Options for Fillet PB - what can I use

The chopped strand you buy has no binders, the stuff you cut yourself from mat does, they are used to hold the mat together. Silane and other finishes for glass fibers are designed to help the resin bond to the glass. The binders can possibly contribute to blistering, products like silane can help reduce them by forming a better bond with the fiber. Binders can be a polyester, or a water soluble glue type product, depending on the exact makeup and how much and well it was applied, they can contribute to blistering.

I'm not aware of walnut shells being used in gel coat, but I'm sure at one time someone has used them. I can possibly see them being used as a filler to make putty though.
Adding fibers to putty can help, but the glass to resin ratio is low, so the strength isn’t great, just better than without it. For most of this type of work it’s not going to make much of a difference whether fibers are added or not. The typical small boat didn’t have any putty used to bed the stringers or transom when new, so using anything is an upgrade from the original build.
 

Yacht Dr.

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Re: Filler Options for Fillet PB - what can I use

For most of this type of work it’s not going to make much of a difference whether fibers are added or not. The typical small boat didn’t have any putty used to bed the stringers or transom when new, so using anything is an upgrade from the original build.

This is spot on. For just using a putty for filleting your only need .. well ... Filler. Nothing special.. no need for glass

Your fillet is basically helping the glass transition from hull to stringer/bulkies.

I make mine about 1/2 - 3/4" radi. Not too big and not much material to do it with. I like to use cabosil and resin only.

*trick* after you apply your fillet .. mix a little resin and lightly brush over it to 'smooth' it out. That way you dont have to deburr it after it gels and/or cures.

YD.
 

krakatoa

Senior Chief Petty Officer
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Re: Filler Options for Fillet PB - what can I use

This thread will be more than interesting.... Cant wait to see big gurus coming by... IMHO totally agreed with Georgesalmon and Ondarvr, now back to the bleachers...
 

F14CRAZY

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Re: Filler Options for Fillet PB - what can I use

Get some cabosil from US Composites (.com). It's so much cheaper than West System at West Marine. When I was restoring my Bayliner I didn't feel like waiting for it to ship so I went to my local WM for colloidal silica, though a couple of those little cans cost what a 2-2.5 gallon bucket from US Composites was. I came very, very close to filling the cans back up, putting a new staple on the cap, and getting refunded for them
 

Yacht Dr.

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Re: Filler Options for Fillet PB - what can I use

This thread will be more than interesting.... Cant wait to see big gurus coming by... IMHO totally agreed with Georgesalmon and Ondarvr, now back to the bleachers...

You just Did :)

And its not just gonna be more than interesting because its been hashed over with multiple threads on how to ' set your stringers/bulkies .. stringers to bulkies ' etc.

Thanks any ways from the bleachers.

YD.
 

krakatoa

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Re: Filler Options for Fillet PB - what can I use

You just Did :)

And its not just gonna be more than interesting because its been hashed over with multiple threads on how to ' set your stringers/bulkies .. stringers to bulkies ' etc.

Thanks any ways from the bleachers.

YD.

My point is that there is other products BETTER than chopped strand for help PB. I like saw dust, to make PB, its light weight and when cure its stronger than CS and easy to work with DA sanders. Soak water? I dont think so..... its already soaked in resin and the main idea when working with poly resin in boats is to maintain water out from "filling" your job on decks, stringers or transoms...... Im not an expert in this "materia" but there is a lot of things that isnt learned on school.....My cents. ;)
 

wellcraft-classic210

Master Chief Petty Officer
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Re: Filler Options for Fillet PB - what can I use

My mother in laws Oatmeal should have all the characterstics you need. Sticks to anything and harder than a rock.


Pretty sure Epoxy taste's better though.:rolleyes:
 

krakatoa

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Re: Filler Options for Fillet PB - what can I use

My mother in laws Oatmeal should have all the characterstics you need. Sticks to anything and harder than a rock.


Pretty sure Epoxy taste's better though.:rolleyes:
:D jajajaja thats a good one! LOL!!!
 

Woodonglass

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Re: Filler Options for Fillet PB - what can I use

Poly resin thickened with Talc, Wood Flour or any other water absorbing material, will render the mix NON Water proof. Especially if you use it below the water line or in areas where standing water could be. That's why most not all bondo products are not recommended for Marine use. They use Non waterproof filler agents. If you research this and talk to the pro's they will tell you "From Life Experiences" that this is a fact. Not sure about the oatmeal. I'll have to give it a test.;):p:D
 

Decker83

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Re: Filler Options for Fillet PB - what can I use

If you want to learn about PB then you need to listen to ondarvr, yacth dr and woodonglass.
Ondarvr and Yacth Dr do this work for a living and or 100% at what they do. Woodonglass is like the encyclopedia of i-boats. He has tons of research for just about anything you want.
Just my two cents worth from the bleachers.:rolleyes:
 

Yacht Dr.

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Re: Filler Options for Fillet PB - what can I use

Woodonglass is like the encyclopedia of i-boats. He has tons of research for just about anything you want.
Just my two cents worth from the bleachers.:rolleyes:

Woody Has done Tons of research .. and will continue to research Any problem/part/location/contact etc. for the members here. He is a valued member of Iboats and I personally respect him very much for the time and effort that has been given and will continue to give in the future.

We spar at times.. but in Most cases he brings the the proper information to the thread.

Cheers to Woody :) ...

Now back on topic.

You just want something to help roll the glass. You dont want something thats a sponge material in there :) .

You dont need a LOT of filler in the corners .. just enough to wrap glass up comfortably.

Peace.

YD.
 

Woodonglass

Supreme Mariner
Joined
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25,924
Re: Filler Options for Fillet PB - what can I use

If you want to learn about PB then you need to listen to ondarvr, yacth dr and woodonglass.
Ondarvr and Yacth Dr do this work for a living and or 100% at what they do. Woodonglass is like the encyclopedia of i-boats. He has tons of research for just about anything you want.
Just my two cents worth from the bleachers.:rolleyes:

Woody Has done Tons of research .. and will continue to research Any problem/part/location/contact etc. for the members here. He is a valued member of Iboats and I personally respect him very much for the time and effort that has been given and will continue to give in the future.

We spar at times.. but in Most cases he brings the the proper information to the thread.

Cheers to Woody :) ...

Blushing_smiley_face.png

Thanks guys. YD and ondarvr ARE the PRO's, and I'm just an Old Dumb Okie, that enjoys helping out when and where I can
 

sphelps

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Nov 16, 2011
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Re: Filler Options for Fillet PB - what can I use

Hmmm oatmeal .. Down here we all eat grits aka " Georgia Ice cream " ... When fully cured its as strong as any filler !:D
 

krakatoa

Senior Chief Petty Officer
Joined
Aug 8, 2008
Messages
705
Re: Filler Options for Fillet PB - what can I use

If you want to learn about PB then you need to listen to ondarvr, yacth dr and woodonglass.
Ondarvr and Yacth Dr do this work for a living and or 100% at what they do. Woodonglass is like the encyclopedia of i-boats. He has tons of research for just about anything you want.
Just my two cents worth from the bleachers.:rolleyes:


WOW~!:facepalm:
 

VolleyGirlSC

Seaman
Joined
Aug 9, 2012
Messages
55
Re: Filler Options for Fillet PB - what can I use

Thank you for all the great responses. We got the transom in with PB using fumed silica, milled fibers and at the end a little wheat flour when we ran low on thickener.

We ended up putting about 2 pints of silica in with 2 pints of resin and 1 pint of milled fibers. It probably could have been thickened up even more, but it was spreadable and stuck to the vertical surfaces. I want to play around with the ratios more. Am I in the right ballpark?

I've now loaded up my garage with several fillers that I am going to test out before doing the stringers and deck. I've gotten more fumed silica and milled fibers and I've added 1/4" chop strand and MAS epoxies Cell-o-Fill to the supply sitting on my work bench. I'm going to play a bit this weekend and see what mixture I like best.

Has anyone use the MAS Cell-o-Fill? They represent it as favorable to the silica, but I am not sure what to make of the claims - they are trying to sell it after all. ;)
 
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