Fiberglass cloth for transom
- Thread starter Joker2
- Start date
RidgeRunner
God
Where are you at? If you are near a fiberglass shop they can help. Sorry I got distracted there. I layed 24 oz of woven roven into 2 layers of 1.5 oz mat and made several applications grinding in between. One of my suppliers came up with some newer multidirectional material that had the mat stitched onto the back side. I used it on the bulkheads and the bow it was heavy like 30oz and only required one layer. One thing I noted was it did not like to make a tight radius. The liner was flipped upside down and placed on a custom made table where the rotten plywood was removed with a hammer and chisel. Wet out two layers of mat and layed the coring into that and weighted it down with old batteries, steel, blocks and whatever else was handy. To eliminate air pockets holes were drilled thru the coring which allowed air and resin to squish out from underneath the coring and up thru the holes. Grind on it after drying, prep the area again, two more layers of mat and one layer of roving to seal off the coring. Right or wrong it worked and is very very strong. The coring for the transom was marine plywood and the coring used on the floor was a hard gray foam impregnated with glass, I forget the name. I did not do the entire floor with one piece, it was cut into about 6 pieces which made it easier to do in sections. All the hatches were done the same as the liner working from the backside except I did them without the use of roving and only one layer of lightweight cloth as the final layer which got gelcoat in the end. I would definitely shop around and talk to people locally. This is just the way I was tought, I figure someone will chime in and tell me where I went wrong, this is the old school way. I have never been a fan of taking the outside skin off to replace the transom but I understand why it is done. The glass on the outside is much thicker than the inside and was layed up in the mold as one piece whereby the glass on the inside was always thin and they didn't overlap to the sides very much.
I was looking at your pictures, you have a couple of hurdles to overcome since you have no inside or outside skin. IMO The inside glass needs to be put back first. The only way I can see doing so, without removing the liner, is by digging out the rest of the plywood and using what remains of the outside as a reference for your new coring. If you use plywood and leave the contour of the transom you should make it three pieces. I don't have a problem with plywood core, just know it is going to rot eventually. The plywood if cut into three pieces could be trimmed to fit in between the inside and outside glass on the sides and set into a bonding putty similar to the putty that Wellcraft used on the transoms originally and what bonds the cap to the liner. You will probably need to use a piece of wood to hold the center section to the two side pieces until you get some glass on it and spend quite a bit of time making sure the transom is uniform in shape. Use lots of putty at the sides and let it ooze out wiping up excess before drying. You could hold the sides in place by running temporary screws thru the outer fiberglass into the coring until the putty kicks. I agree with another poster, removal of the liner would give access to the critical areas inside the hull. Glassing the inside of the transom to the liner is not as good as glassing to the sides of the hull and is not politically correct. The grinding you have done on the port side of the liner is good work and exactly what you would do if you had access to the transom inside where the coring meets the sides of the hull, allow 6" to 12" of overlap when putting new glass over old and make sure you use a wax removing agent for the best bond. If I recall the outside skin was 3/8" to 1/2" thick and the inside was barely 1/8" on my CC. The cloth you choose should be heavy to allow fast buildup. I am not sure what 10oz cloth ends up being in total thickness. I think the heavier roven must be laid into the mat to help with the wet out. The glass itself is strong but must be wet out properly to attain the strength. Too much resin and it looses strength. I think I exceeded the word count, sorry. I am famous for being long winded.
I was looking at your pictures, you have a couple of hurdles to overcome since you have no inside or outside skin. IMO The inside glass needs to be put back first. The only way I can see doing so, without removing the liner, is by digging out the rest of the plywood and using what remains of the outside as a reference for your new coring. If you use plywood and leave the contour of the transom you should make it three pieces. I don't have a problem with plywood core, just know it is going to rot eventually. The plywood if cut into three pieces could be trimmed to fit in between the inside and outside glass on the sides and set into a bonding putty similar to the putty that Wellcraft used on the transoms originally and what bonds the cap to the liner. You will probably need to use a piece of wood to hold the center section to the two side pieces until you get some glass on it and spend quite a bit of time making sure the transom is uniform in shape. Use lots of putty at the sides and let it ooze out wiping up excess before drying. You could hold the sides in place by running temporary screws thru the outer fiberglass into the coring until the putty kicks. I agree with another poster, removal of the liner would give access to the critical areas inside the hull. Glassing the inside of the transom to the liner is not as good as glassing to the sides of the hull and is not politically correct. The grinding you have done on the port side of the liner is good work and exactly what you would do if you had access to the transom inside where the coring meets the sides of the hull, allow 6" to 12" of overlap when putting new glass over old and make sure you use a wax removing agent for the best bond. If I recall the outside skin was 3/8" to 1/2" thick and the inside was barely 1/8" on my CC. The cloth you choose should be heavy to allow fast buildup. I am not sure what 10oz cloth ends up being in total thickness. I think the heavier roven must be laid into the mat to help with the wet out. The glass itself is strong but must be wet out properly to attain the strength. Too much resin and it looses strength. I think I exceeded the word count, sorry. I am famous for being long winded.
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Call these Guys they will answer any questions you have , My supply shop 
Crap I miss the link here it is sorry
http://www.fiberglassservices.com/catalog.htm
Crap I miss the link here it is sorry
http://www.fiberglassservices.com/catalog.htm
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bkurtz5001
Member
Cloth
You will want to use a biaxial fabric either 1208 or 1708 is up to you.
1208 is 12oz cloth with .75 oz mat intergrated into it. you want to get the cloth that is woven at 45 degrees not 0/90 degrees. the 90 is fine but if you want the strongest 45 is the best bet
1708 is exactly the same thing but 18oz instead of 12oz.
I have 3 layers of 1208 on my transom.
You will want to use a biaxial fabric either 1208 or 1708 is up to you.
1208 is 12oz cloth with .75 oz mat intergrated into it. you want to get the cloth that is woven at 45 degrees not 0/90 degrees. the 90 is fine but if you want the strongest 45 is the best bet
1708 is exactly the same thing but 18oz instead of 12oz.
I have 3 layers of 1208 on my transom.
RidgeRunner
God
Do these numbers represent what West Marine sells or is this a standard in the industry? Vinylester resin or epoxy? Three layers wet out equals what thickness?
bkurtz5001
Member
Its a standard in the industry. I used epoxy resin by West system. Its expensive but by far the best to use. I am not sure how thick my three layers are due to the way i layed my transom in. I thickend some west with 403 and spread it all over the existing skin, then i layed in my first layer of wood which was coated with 3 coats of west. I threw bolted it in 30 places with threaded rod to make sure there were no places it didnt get pulled tight. once it hardened i removed the bolts, scuffed it up and layed one layer of 1208 cloth. when it started to kick off i put another coat of epoxy on the cloth and then through bolted the next layer of wood and let it dry. Then removed the bolts filled the holes with dowel rods soaked in west. then put two layers of the 1208 cloth on top. If i had to guess the 1208 is about 1/8th thick for 2 layers. The reason i used the lighter cloth is it is a lot easier and a more efficient way of encapsulating the wood as air pockets and areas that wont wet out are easily rolled out with a fiberglass roller. It is imperitive you get a fiberglass roller by the way
RidgeRunner
God
Thanks for the input
Thanks, It has been a while since my glass project. I couldn't agree more,
bubble buster rollers are a must. I also liked to use the 7" x 3/8" pile rollers to put the resin on out of the reuseable plastic pales. You can cover a lot of ground quick with minor cleanup to the roller frame and the resin can be popped out of the pale after it kicks.
I have been told, Epoxy resin is great to use over vinylester or polyester resin but you can't use poly or vinyl resins over the top of epoxy as it won't bond. Is this true and what limitations does epoxy have with respect to your topcoat?
(ie can you put gelcoat over epoxy or must you use a urethane?)
Thanks, It has been a while since my glass project. I couldn't agree more,
bubble buster rollers are a must. I also liked to use the 7" x 3/8" pile rollers to put the resin on out of the reuseable plastic pales. You can cover a lot of ground quick with minor cleanup to the roller frame and the resin can be popped out of the pale after it kicks.
I have been told, Epoxy resin is great to use over vinylester or polyester resin but you can't use poly or vinyl resins over the top of epoxy as it won't bond. Is this true and what limitations does epoxy have with respect to your topcoat?
(ie can you put gelcoat over epoxy or must you use a urethane?)
bkurtz5001
Member
That is true. epoxy is fine over vinylester and poly. but not the other way around. You cannot use gelcoat over epoxy either. that is why you see your high end yachts using epoxy paint/two part urethanes as their topcoat. i personally think it is a lot better. and theres a reason why hatteras yachts/and paul mann yachts uses epoxy. They aint cheap either.
Skools Out
God
There's a nice 2008 Paul Mann sitting in 200 ft of water off Beaufort Inlet due to an epoxy issue, epoxy tends to crack when under a lot stess and you never see the high end race boats built with it due to stress cracking and weight.
RidgeRunner
God
Epoxy would then limit the rebuilt transom to painting with epoxy paint or urethane. It would seem that epoxy would be more expensive and require more paint work than using regular vinylester resin and gelcoat, I mean you can match and blend gelcoat back to the edge of your repair, sand, buff done.
When using epoxy would you recommend stopping at the edge of repair and attempt to feather it in or paint the entire hull?
School, I never heard of epoxy being prone to crack under stress. All I ever hear is good. Is it an issue with it being so ridgid that it won't give? Or maybe a glass issue? I thought high performance boat guys built epoxy boats. I think some jet skis are also epoxy.
One more question and I will unhijack this post- What is used to wet out kevlar?
When using epoxy would you recommend stopping at the edge of repair and attempt to feather it in or paint the entire hull?
School, I never heard of epoxy being prone to crack under stress. All I ever hear is good. Is it an issue with it being so ridgid that it won't give? Or maybe a glass issue? I thought high performance boat guys built epoxy boats. I think some jet skis are also epoxy.
One more question and I will unhijack this post- What is used to wet out kevlar?
Skools Out
God
you can wet it out the same as fiberglass cloth, you have so many issues with epoxy, set up and sanding is a pain too. just get resin from a local boat builder.
RidgeRunner
God
You guys need a ref
Damn, i will re-subsribe after all.
Ben Fishin may know epoxy, I think epoxy has a much longer pot life, it is quite strong and cost more money. The fact that it cost more money is a huge drawback so the "superior anyway you look at it" approach is BS. It may be far superior to the vinylester or poly resin in your eyes as an engineer or on paper. However, I don't have a boat constructed with epoxy. My Wellcraft was all vinylester resin from the factory and it remains so after a major rebuild without any structural issues. You are an engineer, as such I am sure you are aware that engineers designed and built the Titanic. Having such a wealth of knowledge that most of us do not have, you may have come off being a bit condescending. Perhaps you should have said that you strongly believe it to be the best resin. I don't put words in anyones mouth. Resin is a wetting agent not the impact strength of a boat. Without fiberglass the epoxy is useless, same holds true with any resin. The cup of resin test defies logic. The reason the vinylester cracks is due to the thermal reaction from mixing it hot, anyone that has used vinylester resin knows that if you mix it hot it will be brittle. The correct mixture of tiny amounts of catalyst to vinyl and poly resin and the correct ratio of resin to glass is an art that has proven its durability and stood the test of time. You suggest we mix the vinylester resin and allow it to heat up in a cup beyond the working parameters of the product. You don't apply resin when it is on fire, you mix the product and get it to the glass ASAP. Because the resin is spread thin over the glass in a much larger area, the heat during kick simply dissipates.
Epoxy is in its infancy when compared with polyester and vinylester resin. I have nothing against it at all. As a layman I would think if it were stronger than the surrounding vinylester product that you were repairing it would not bend, flex, expand, contract or vibrate at the same frequency and eventually you would have a failure in the form of delamination. It may bond so well it will never come apart, can't say.
"I know so and so and You don't know crap" sounds kinda godlike, but the pissing contest is useless to the poster that wanted to know what weight of cloth he needs. I'm not even looking for glass, mine is done. Frank Sinatra
School, I don't know about the Mann boat that went down, you might be right. IMO epoxy is not the best for all applications. Most mass production boats don't use it because it is cost prohibitive and it is incompatable with gelcoat in the molds. Because epoxy hulls must be painted after, it probably lends itself to larger boats where the molds are not as tooled and the manufacturer will spend hours making the hull smooth enough for primer and paint. You may have gone off a bit early on the new guy. Sounds like he can hold his own, well educated too. But I don't suspect my opinion matters much, I am a newbie too and fully expect to fall on deaf ears.
You both got passion for the thread, I will give you that.
I always appreciated your input.
MJ - Take my name off the list for that Album would you.
Damn, i will re-subsribe after all.
Ben Fishin may know epoxy, I think epoxy has a much longer pot life, it is quite strong and cost more money. The fact that it cost more money is a huge drawback so the "superior anyway you look at it" approach is BS. It may be far superior to the vinylester or poly resin in your eyes as an engineer or on paper. However, I don't have a boat constructed with epoxy. My Wellcraft was all vinylester resin from the factory and it remains so after a major rebuild without any structural issues. You are an engineer, as such I am sure you are aware that engineers designed and built the Titanic. Having such a wealth of knowledge that most of us do not have, you may have come off being a bit condescending. Perhaps you should have said that you strongly believe it to be the best resin. I don't put words in anyones mouth. Resin is a wetting agent not the impact strength of a boat. Without fiberglass the epoxy is useless, same holds true with any resin. The cup of resin test defies logic. The reason the vinylester cracks is due to the thermal reaction from mixing it hot, anyone that has used vinylester resin knows that if you mix it hot it will be brittle. The correct mixture of tiny amounts of catalyst to vinyl and poly resin and the correct ratio of resin to glass is an art that has proven its durability and stood the test of time. You suggest we mix the vinylester resin and allow it to heat up in a cup beyond the working parameters of the product. You don't apply resin when it is on fire, you mix the product and get it to the glass ASAP. Because the resin is spread thin over the glass in a much larger area, the heat during kick simply dissipates.
Epoxy is in its infancy when compared with polyester and vinylester resin. I have nothing against it at all. As a layman I would think if it were stronger than the surrounding vinylester product that you were repairing it would not bend, flex, expand, contract or vibrate at the same frequency and eventually you would have a failure in the form of delamination. It may bond so well it will never come apart, can't say.
"I know so and so and You don't know crap" sounds kinda godlike, but the pissing contest is useless to the poster that wanted to know what weight of cloth he needs. I'm not even looking for glass, mine is done. Frank Sinatra
School, I don't know about the Mann boat that went down, you might be right. IMO epoxy is not the best for all applications. Most mass production boats don't use it because it is cost prohibitive and it is incompatable with gelcoat in the molds. Because epoxy hulls must be painted after, it probably lends itself to larger boats where the molds are not as tooled and the manufacturer will spend hours making the hull smooth enough for primer and paint. You may have gone off a bit early on the new guy. Sounds like he can hold his own, well educated too. But I don't suspect my opinion matters much, I am a newbie too and fully expect to fall on deaf ears.
You both got passion for the thread, I will give you that.
I always appreciated your input.
MJ - Take my name off the list for that Album would you.
BenFishin you are new and Skools no's better, But as owner op here I do not allow personal attacks here!!!!
We all get along here and I like it that way, and I do my best to head off stuff as soon as I can, So this thread has been edited and we will go back to what Joker was asking, If we can't do it with out a fight i will band the fighters!
This will be thye only warning!!
We all get along here and I like it that way, and I do my best to head off stuff as soon as I can, So this thread has been edited and we will go back to what Joker was asking, If we can't do it with out a fight i will band the fighters!
This will be thye only warning!!
bkurtz5001
Member
understood completely.