Epoxy and fiberglass input

[JJB]

I am finally got up the nerve to get into my rotted transom on my 20' bayliner trophy after lots of advice from this site and a $5000 + estimate from a pro. I have found a epoxy called progressive epoxy out of NH . it's about 1/2 the price of west system and has claim's that a lot of boat builders are using it . Has anyone here heard of it ? I have found a good video on fiberglass transom repair . He tells you to use 2 layers fat mat or stiched mat to bond to outside of the transom fiberglass and the new wood. He used one layer of 1 1/2 oz between the layers of 3/4 plywood and one 1 1/2 oz on the inside of transom when building the transom . there was no metion of the weight that the fat mat should be . could someone please advise me on proper weight of fat mat and best type of fiberglass to use with epoxy . I will try to post pictures as I go to help anyone that is thinking about taking on a transom like this . Thanks for all your help ! JJB

 

[Boomyal]

Re: Epoxy and fiberglass input

Never heard of 'fat mat', jjb. Maybe someone else has but it would be a lot more effective if you broke your multiple questions down into different paragraphs.

Your post has had a lot of views, but no responses. Could be that viewers find your post too difficult to digest.

If viewers can get through it, one may have an answer to one part and another a different part. They're not going to bother when it is all jumbled together.

 

[sbklf]

Re: Epoxy and fiberglass input

Did you price Raka Epoxy? I researched many epoxies before buying and found it the best for my project but don't think I looked at Progressive. Larry over there will answere questions.

 

[JJB]

Re: Epoxy and fiberglass input

Thank for the input boomyal, will do !

 

[sdunt]

Re: Epoxy and fiberglass input

1st there are two kinds of fiberglass mat. The Original type is for use with Polyester resins and the binder in the mat is dissolved by the polyester resin. There is a second, actually special, type of mat for use with epoxy, because Epoxy WILL NOT dissolve the binders in regular fiberglass mat (the mat will remain stiff if used with Epoxy resins).

Of the various kinds of reinforcements available for composite construction, mat has the LEAST amount of strength and is used primarily to build the thickness of the composite. Fiberglass clothe and roven woving are stronger, but neither will absorb as much resin as matting.

Matting is generally used in transom repairs, between the hull and transom and in the lamination, because it will create a larger layer of resin to compensate for the irregularities in the hull and the wood you're installing. It is better structurally to use cloth or roven moving on the inside of the transom to attach it to the floor and sides of the boat.

Regular fiberglass mat comes in a variety of weights, from what is called veil mat, to 2 oz per Sq FT mat. http://www.uscomposites.com/mat.html

Notice at the bottom of that listing is "1-1/2oz Epoxy Mat - Chopped Strand Mat compatible for use with epoxies. Material is stitched together, as opposed to the adhesive binders used in common fiberglass mats."

US composites also sells Epoxies and I have had good luck with them.

I am in the Polyester - 'Fiberglass resin camp myself. If the stuff held up for 30 years in my boat before, then I'll be in a rest home by the time it fails again. Also, the more modern chemistry of today's Polyester resins is the better than the resin of the 1960's.

Check out my share a project, about 1/2 way down we get into the transom repair.

You might also read Jim Anderson's "Runabout Renovation" book : http://www.amazon.com/Runabout-Reno...0255336?ie=UTF8&s=books&qid=1176401117&sr=8-1

 

[JJB]

Re: Epoxy and fiberglass input

Hey Sdunt , Thanks for the great input . What do you think about 2 layers of1708 biaxial with mat for between outside of transom and 4 layers 1700 biaxial 45/45 for inside ? Thanks JJB

 

[Yacht Dr.]

Re: Epoxy and fiberglass input

Ive used your "fat mat" with epoxy..and lemme tell ya its no fun. Its Very thick and hard to wet and roll. the mat isnt chopped up like poly bound mat..its long and stringy. if you get one string on your roller you will have to cut with scissors. now I understand what hes saying..you get your thick mat for bonding of 2 plates of 3/4 ply for transom. eh..Id use 2 layers of 1.5 oz poly mat for that..

your 1708 should be fine for your job ( though Im a roving roving kinda guy with mat between layers )

DO NOT use what is normally called "cloth" also named "finish cloth" for anything at all structurally ! This stuff is normally found in little fiberglass kits and is worthless. It looks like a very small roving type glass and is weak. Trust me m8.

YD.