Author Topic: Fiberglass (Read 18100 times)

Hyperacme · « **on:** October 14, 2012, 11:37:09 AM »

I know the choices for plywood and resin, but don't know anything about mat, cloth, glass stuff.
Before I talk to Express C I need a quick course in fiberglass mat, cloth, stuff.
Would be for transom & small floor section/drain bowl.
Gonna call Joe tonight, but the more opinions & info I get the better !

Thanks guys ...

Jerry · « **Reply #1 on:** October 14, 2012, 03:52:28 PM »

If you want to finish and paint it Bi-Axle with mat, for the most strength like the floor where you will cover it, Roving with mat.. All ya need to know.

Hyperacme · « **Reply #2 on:** October 14, 2012, 05:12:15 PM »

This ?

Rich_V174SS · « **Reply #3 on:** October 14, 2012, 05:43:33 PM »

I think he means 1708 Biaxial fiberglass which is a combination of roving and chop-strand married together.

Hyperacme · « **Reply #4 on:** October 14, 2012, 06:03:27 PM »

This ?

Did a quick scan of your rebuild thread Rich, you said you used Poly and marine ply but nothing about fiberglass ...
Unless I missed it ?

Rich_V174SS · « **Reply #5 on:** October 14, 2012, 06:14:44 PM »

My rebuild was done with mostly chop-strand mat. I wish I had biaxial at the time.

Hyperacme · « **Reply #6 on:** October 14, 2012, 06:19:53 PM »

A full roll of this stuff is less then $7 ?
I must be missing something ....

thedeuceman · « **Reply #7 on:** October 14, 2012, 06:28:13 PM »

Im no expert, but from all the info i got here and elseware...
Tim basicly confirmed this info (correct me please if this is wrong)
I used biax for most everything, tab stringers, tying in braces to transom and floor, and for the splas well.
Used 1.5 oz CSM for sandwiching ply and between transom and hull
Used 7 and 9 ply cab grad plywood
Coated all wood with 50-50 resin / aceatone
Bedded and or filled all edges with cabosil resin mixed to the consistancy of penut butter.
Covered floor with CSM (1.5 oz may have been too heavy as i used lots of resin)
I got 50" biax and cut it cuz it was cheaper and i needed varying widths.

Hyperacme · « **Reply #8 on:** October 14, 2012, 07:05:46 PM »

My plan ...

Remove deck, cut/dig/rip transom out, try to save side foam floatation boxes, glass everything back together.

Boards that make up drain bowl are 6x8 inches.
Floor cut out under splash well is 1' 6" x 2'
Transom is about 4' x 2'
Floatation boxes are about 1' tall

Would the 1708 Biaxel stuff work for all repairs ?
Is the full roll enough ?

If I coat all wood with a mix of resin/acetone plus all glassing, would one gal. of resin be enough ?
My plans could change if floatation boxes get screwed up when ripping out transom & other unforeseeable problems.

Rich_V174SS · « **Reply #9 on:** October 14, 2012, 07:10:09 PM »

Quote from: Hyperacme on October 14, 2012, 06:19:53 PM

A full roll of this stuff is less then $7 ?
I must be missing something ....

I think they're saying it's $6.75 per yard provided you buy a full roll of 50 inches wide by however long a full roll is. You need to find out how long a full roll is.

Hyperacme · « **Reply #10 on:** October 14, 2012, 07:27:01 PM »

That make sence ...

Jerry · « **Reply #11 on:** October 14, 2012, 08:47:02 PM »

HANG ON!

you still need regular glass for tabbing and stringers, The stuff with mat on the back doesn't bend around corners real well, and I use thinned bondo for bedding (cheap and easy to work with). Also the use of Marine plywood is a total waste of money, it's no stronger or more waterproof than regular exterior plywood. when laminating just coat both pieces with resin and screw them together (no glass) when you put the transom in you can use mat between the plywood and the old exterior fiberglass. I don't think you will get by with a gallon. start with a couple, you can get that anyplace. Get extra MEKP at Express, and MEASURE!! this is chemistry no guessing! When coating (50/50) add enough MEKP for the acetone too.

Jerry · « **Reply #12 on:** October 14, 2012, 08:57:15 PM »

Forgot, bi-ax/mat does inside corners fine, just outside corners it doesn't work real well on.

tip
put the glass on with your electric staple gun, then wet it down, Otherwise you'll be chasing it around.

WetRaider · « **Reply #13 on:** October 14, 2012, 10:34:16 PM »

The 1708 was really easy to work with ... chopped side down. I cut my strips for stringers at 24 inches long, laid them out dry with chopped side up, rolled resin on the chopped side & on the floor and stringer, grabbed the wet strip (it's thick enough that you don't get very much soak through when wetting the chopped side) and married the wet chopped side to the wet stringer and floor ... wetrolled the biaxial side and worked the roller almost like a squeegee, pushing all air out.

As far as plywood - the marine supposedly has fewer voids - I would look for the highest number of plys ... my 3/4" was 11 ply core plus the two oak veneer layers. The oak was a good open and absorbent grain to adhere the resined glass to.

Jerry · « **Reply #14 on:** October 15, 2012, 12:23:12 AM »

Quote from: WetRaider on October 14, 2012, 10:34:16 PM

As far as plywood - the marine supposedly has fewer voids - I would look for the highest number of plys ... my 3/4" was 11 ply core plus the two oak veneer layers. The oak was a good open and absorbent grain to adhere the resined glass to.

You have never seen a transom come apart that wasn't rotted, Voids don't matter. Marine grade is for wood boats and is just a waste of money on fiberglass.

74 Carlson the II · « **Reply #15 on:** October 15, 2012, 09:14:00 AM »

Marine plywood is NOT a wast of money, if you want the Best you can get!!!

Jerry · « **Reply #16 on:** October 15, 2012, 10:39:52 AM »

All it does is make you feel good. If you want to feel good give the extra money to your local food shelf.

74 Carlson the II · « **Reply #17 on:** October 15, 2012, 11:35:21 AM »

There ARE differances between the 2, did a research between them both. And it's just not the price that is different. Voids in the wood make a differance, any pocket of air such as a void can build up condensation and that alone will start rotting from the inside. There are more ply's in the marine grade which makes it stronger. Yeah sure the exterior grade is great for the side of your shed cause its not subjected to a marine enviroment or have constant force against it everytime you hit the throttle.

Rich_V174SS · « **Reply #18 on:** October 15, 2012, 12:07:46 PM »

When I rebuilt the transom in my boat I made two of them, one out of exterior ply and the other with marine ply, both using 3/4ths inch thick pieces laminated together. The exterior plywood had 5 plies and the marine grade had 7. The exterior ply chipped and splintered very easily when cut with a skill saw, the marine ply was rock hard and cut cleanly. Even after laminating the pieces together there was some flexing in the exterior ply, none in the marine. Guess which one I ended up using in my rebuild.

Jason · « **Reply #19 on:** October 15, 2012, 12:13:04 PM »

Interesting: They conclude that they were about equally the same in strength even after coating in epoxy and soaking in water for a couple months.

part 1:
Marine Plywood and Construction Adhesive Testing - Part 1of 2

Part 2:
Marine Plywood and Construction Adhesive Testing - Part 2 of 2