Resin choice

I am using US Comp Med hardner. I switched from West System and the West Slow looked like it had the same pot as US Med.......was a little worried about using the extra slow......still might not be a bad idea to use it?

Also needed so advice on the inside stringer glass. The stringers are only 8 inches apart, they have a small 1/2 in ply X 4 inches X half the stringer down the center between them that were glassed over when the stringers were set so only 2 inches of glass on the hull from the stringer. This created a higher flat spot between them with a depression at the transom for water to pool and another one at the fuel tank for the pumps. When I removed the old stringer glass this came right up as it was not glued down exposing the V in the hull. So, should i leave it out so I have more exposed hull to glass the stringers in and then add the ply and glass back to create the same design?
Just thinking two inches of glass is not a lot of bonding area
Here is a pic before they were removed

Another question, should i cut the glass in sections for each section. For example, Should I cut the glass for the fuel section and over lap on the small bulk head and then cut the bulk head glass to over lap the fuel area so I would have double the glass in the joints, then cut the glass for the engine stringer to over lap the bulk.

Will I gain anything by taping then laying the full glass. I plan to just lay 4 layers of full glass longer to shorter. Thanks

 

On your tightly spaced stringers, you got what you got, so just lay in a "U" shaped piece and work up from there. Generally, everything gets over lapped in tight quarters. As to piece sizes, well this is really up to you and how big a piece you can handle. Lots of little pieces are a pain in the butt, though more manageable. You'll figure out about how big a piece you feel comfortable with, but for the most part the area will dictate how much you need and where. Eventually you make a piece too big and you'll rip it out before it cures. You'll work smaller than this afterward.

 

OK....sounds like i will glass the stringers in with the center wood between the two still removed and then glass the wood spacer in when the stringers are complete or does it matter......more hull to bond to. With the wood installed between the two i will only have about two inches of exposed hull to bond with and the remaining glass from the stringer would only be bonded to this "spacer" so to speak.

I have the glass cut and the plan is:
Use US Comp Med hardner.....same pot as West slow
Mix and pour in cool Foil pie plates to extend pot life
Stringers 4or 5 layers 1700/epoxy.......old VE was 15mm thick 2 heavy woven and csm
Fuel stringer 3 layers ........old 8 mm 1 woven/csm
Bulk heads 3 layers ....old 6 mm 1 heavy woven.csm

Hope this is correct

 

No tape....only full glass

 

If you have all that gear on how can you work ??? People become complacent and if they think becasue the are protected from head to toe they can make a mess yet nothing will touch them .
Take away all that gear and have just a pair of surgical gloves and you will make a much better job and wont make a mess .
I had a team of 8 guys and was given another guy from another department that was forever having accidents all the time !!, so he was banded from having any protective gear what so ever for a week !!! first thing he said was how can i work ?? so we all did the same thing to show him and others and had no protective gear for the same one week . Accidents didnt happen the work rate stayed the same , the quality of the work shot up dramaticly and the guys even noticed it them selves . so after 4 days they made up there own minds about all the protection gear and that it was causing more problems than it was solving sure there is some things we all need but we dont have to look like a space man !!,Its all in the mind .
Think a little !!,traffic accidents and the way people drive ,because cars are loaded with airbags and protective this and that we have this mind set we wont or cant get hirt so our driving skills have dropped and our speeds have increased and we have become more stupid on the road and its getting worse as time goes on . We actually need protection from protection there to much of it !!

 

We don't have accidents because of our confidence in safety devices, at least no more than a motorcycle rider does his jeans and 60 MPH.

I disagree about safety gear, but do admit I don't use much personally. I'm not sensitized and I work clean with gloves. Experience breeds contempt, so don't let my or Tunnels personal habits sway you. Epoxy isn't an acid that's going to burn through your skin or any thing, so it's nothing to be afraid of, but you also don't want exposure, so use the protection you need to prevent it.

 

Great stuff

 

OK.... laying the glass today
4 layers 17 oz double on the stringers and 3 on all others......no tape
Do have one question, With epoxy and VE not far apart, how is the epoxy and 17 oz better than the 3 24 oz woven/CSM and VE Sea ray used.......the glass?
Also does it matter if I cut all the glass layers along the length of the roll so I can get soild layers? Thanks

 

Elongation and modulus are the big differences between epoxy and vinylester. Epoxy will be able to take advantage of the 'glass fiber strength, just as the 'glass is stretched to it's breaking point, but vinylester will have failed before this point. Roving will stretch and kink it's fibers as it's tensioned. Because the fibers are woven, they tend to cut each other in the perpendicular direction of the stress. Directional fabrics, like biax aren't woven, so the fibers begin to resist these strains immediately.

When using biax (assuming 45/45) try to arrange the fiber orientation so it's long axis is across the joint. This places all the fibers in a advantaged orientation across the joint. The orientation is easy to see with 17 ounce, so the sort side of the "X" runs perpendicular to the joint.

 

Cannot say thanks enough!! Have the cloth cut rough to size.....now trying to get it close so it will not be such a pain and a time waster while trying to lam.........real pain on these compounds in such a tight space.......might wish i had used some tape....lol

 

Par, still having second thoughts with the 4 layers of 1700 (around 4mm) being as strong as the 12/18 mm the boat had with VE.......should I use something else with the 17......have always heard to build back to the same thickness.........i understand epoxy is much stronger but from 12/18mm to 4mm is a large reduction

 

I'm not sure I understand the 1/2" to 3/4" thick tabbing. Is this all fabrics (CSM and/or roving) or is the bulk just resin slopped on with fabrics floating between? The previous pictures of tabbing laminate didn't show a lot of fabric, but lots of resin. This is weak and brittle, but not uncommon on production boats.

In the area between the two tightly spaced stringers, use more material and pack it in good. It'll cure into a U shape and the bonding patch against the hull is what you get. I also wouldn't use any fabric between the layers of the stringers. Just bond them together with thickened epoxy, then tab them down with fabric.

Again, if you feel insecure about the tabbing weight, add more.

 

You are correct, looks like mostly resin with thick...REALLY THICK CSM and woven ...2 of each...just wondered if only 4 layers of 17 was what i needed...the test patch of 17 looked a little thin compared to the MFG....the boat yard said to use 5 layers of 1708....from what I have read it is not needed...as always thanks for your input!!

 

68 ounces of material seems suitable, though bumping it up (5 layers) to 85 ounces couldn't hurt, if it makes you feel better.

 

What do you think about using 1708 with epoxy. Thanks!!